Merge remote-tracking branch 'pc3/master'

Protocoale-Comunicatie-3/.gitignore

@@ -0,0 +1,7 @@
+# gdb stuff
+.gdb_history
+.gdbinit
+
+# object files and executable
+*.o
+client

Protocoale-Comunicatie-3/Makefile

@@ -0,0 +1,32 @@
+CLIENT=client
+SOURCES=$(wildcard *.c)
+LIBRARY=none
+INCPATHS=include
+LIBPATHS=
+LDFLAGS=
+CCFLAGS=-c -Wall -g3
+CC=gcc
+
+# Automatic generation of some important lists
+
+# tell the makefile to generate object files for each source file
+OBJECTS=$(SOURCES:.c=.o) 
+INCFLAGS=$(foreach TMP,$(INCPATHS),-I$(TMP))
+LIBFLAGS=$(foreach TMP,$(LIBPATHS),-L$(TMP))
+
+# Set up the output file names for the different output types
+
+all: $(SOURCES) $(CLIENT) 
+
+$(CLIENT): $(OBJECTS)
+	$(CC) $(LIBFLAGS) $(OBJECTS) $(LDFLAGS) -o $@
+
+.c.o:
+	$(CC) $(INCFLAGS) $(CCFLAGS) -fPIC $< -o $@
+
+distclean: clean
+	rm -f $(CLIENT)
+
+clean:
+	rm -f $(OBJECTS)
+

Protocoale-Comunicatie-3/README

@@ -0,0 +1,110 @@
+POPESCU LUCIAN IOAN 321CD
+-------------------------
+
+    TEMA 3 PROTOCOALE DE COMUNICATIE
+    --------------------------------
+
+
+I. File structure
+-----------------
+
+include/
+authentication.h Contains a auth_info_t object
+book.h           Contains a book_info_t object and a book_id_t object
+buffer.h         Functions used in connection.c
+cJSON.h          JSON parsing library
+commands.h       Prototypes of the implemented commands
+connection.h     Functions that deal with connection with the server
+dns.h            Functions that send DNS requests
+error.h          Macros used to print and deal with errors
+http.h           Functions that extract info from HTTP headers, etc
+memory.h         Macros used for safe memory management(CALLOC, MALLOC, FREE)
+prompt.h         Extract data from prompts (for example: username, password)
+requests.h       Functions that build GET, POST and DELETE requests
+server.h         Information about the server (URLS, NAME, etc)
+./
+authentication.c Implements specific functionality
+book.c           Implements specific functionality 
+buffer.c         Implements specific functionality 
+cJSON.c          JSON library implementation
+client.c         Main driver for client
+commands.c       Implements specific functionality 
+connection.c     Implements specific functionality 
+dns.c            Implements specific functionality 
+http.c           Implements specific functionality 
+prompt.c         Implements specific functionality 
+requests.c       Implements specific functionality 
+Makefile         Makefile to build the client
+README           This file
+
+II. Design
+----------
+
+A. Client and operations(commands)
+----------------------------------
+
+The implementation of the client is pretty straight forward. The client reads
+input from stdin and using a huge block of if..else statements, it decides which
+operation to make.
+
+Each operation has three return status codes: OPERATION_SUCCESSFUL,
+OPERATION_CONNECTION_CLOSED and OPERATION_FAILED. The client checks after each
+operation the return code to make sure that the connection with the server is
+still ok, if not it retries to re-establish it. It also checks that the
+operations were successful in order to manage the correct creation and deletion
+of cookies and JWT tokens.
+
+The operations are implemented using the same rules:
+    - fetch data from user if needed
+    - build the HTTP request
+    - send the request and receive the response
+    - work with the response if needed
+
+Moreover each operation takes care of the errors which may occur during the
+above mentioned steps. For this each variable is declared at the beginning
+of each opearion and if an error occurs the memory will be free'd for this
+variables using a goto statement and a label at the end of the current
+operation.
+
+B. JSON
+-------
+
+For parsing, converting and working with JSON objects I used the cJSON library.
+It is a simple library containing only a header file and a source file, that
+can easily be inserted in the project.
+
+I chose this library because it has a basic interface containing functions and
+objects that require a small amount of time to understand, as the authors say:
+"cJSON aims to be the dumbest possible parser that you can get your job done 
+with".
+
+More info and tutorials can be found on their github page:
+"https://github.com/DaveGamble/cJSON".
+
+C. Reading data from user
+-------------------------
+
+prompt.c is the file where this functionality is implemented. It pops up a
+prompt for the required data and using a basic read function like fgets it
+gets the job done. I also added password safety by turning off the echoing
+when the password is inserted.
+
+D. Other objects and functionality
+----------------------------------
+
+For keeping all as simple as possible, I encapsulated the information coming
+from the user (username, password, book info) in objects that have their own
+metods for parsing to JSON or deletion. Their location can be found in
+I. File structure.
+
+The functionality for connecting with the server and creating requests is
+mainly borrowed from lab10 HTTP with some minor changes.
+
+
+III. Conclusions
+----------------
+
+Overall, the application works very smoothly and does not have problems with
+memory leaks or any kind of buffer overflows coming from user. It covers the
+basic functionality of working with a REST API and has a clean and readable
+codebase.

Protocoale-Comunicatie-3/authentication.c

@@ -0,0 +1,63 @@
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <termios.h>
+
+#include "authentication.h"
+#include "cJSON.h"
+#include "error.h"
+#include "memory.h"
+#include "prompt.h"
+
+auth_info_t *get_auth_info() {
+    char *username = read_item(USERNAME, MAX_USER_SZ, ECHO_ON);
+    char *password = read_item(PASSWORD, MAX_PASS_SZ, ECHO_OFF);
+
+    if (username == NULL || password == NULL) {
+        FREE(username);
+        FREE(password);
+
+        return NULL;
+    }
+
+    /*
+     * Declare the return variable.
+     *
+     */
+    auth_info_t *auth_info;
+    CALLOC(auth_info, sizeof(auth_info_t));
+
+    auth_info->username = username;
+    auth_info->password = password;
+
+    return auth_info;
+
+}
+
+cJSON *auth_to_json(auth_info_t *auth_info) {
+
+    cJSON *json_object = cJSON_CreateObject();
+
+    cJSON *username_item = cJSON_CreateString(auth_info->username);
+    cJSON_AddItemToObject(json_object, USERNAME, username_item);
+
+    cJSON *password_item = cJSON_CreateString(auth_info->password);
+    cJSON_AddItemToObject(json_object, PASSWORD, password_item);
+
+    return json_object;
+
+}
+
+void delete_auth_info(auth_info_t *auth_info) {
+
+    if (auth_info == NULL) {
+        return;
+    }
+
+    FREE(auth_info->username);
+    FREE(auth_info->password);
+
+    FREE(auth_info);
+
+}

Protocoale-Comunicatie-3/book.c

@@ -0,0 +1,220 @@
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include "book.h"
+#include "error.h"
+#include "memory.h"
+#include "prompt.h"
+#include "cJSON.h"
+
+book_info_t *get_book_info() {
+    /*
+     * Read the elements from a book.
+     *
+     */
+    char *title      = read_item(TITLE, MAX_BOOK_ELEM_SIZE, ECHO_ON);
+    char *author     = read_item(AUTHOR, MAX_BOOK_ELEM_SIZE, ECHO_ON);
+    char *genre      = read_item(GENRE, MAX_BOOK_ELEM_SIZE, ECHO_ON);
+    char *page_count = read_item(PAGE_COUNT, MAX_BOOK_ELEM_SIZE, ECHO_ON);
+    char *publisher  = read_item(PUBLISHER, MAX_BOOK_ELEM_SIZE, ECHO_ON);
+
+    if (title == NULL || author == NULL || genre == NULL || page_count == NULL
+            || publisher == NULL) {
+
+        FREE(title);
+        FREE(author);
+        FREE(genre);
+        FREE(page_count);
+        FREE(publisher);
+
+        return NULL;
+
+    }
+
+    /*
+     * Convert page_count to int and delete page_count.
+     *
+     */
+    int *page_count_integer;
+    CALLOC(page_count_integer, sizeof(int));
+
+    sscanf(page_count, "%d", page_count_integer);
+    FREE(page_count);
+
+    /*
+     * Build the book_info_t data type.
+     *
+     */
+    book_info_t *book_info;
+    CALLOC(book_info, sizeof(book_info));
+
+    book_info->title      = title;
+    book_info->author     = author;
+    book_info->genre      = genre;
+    book_info->page_count = page_count_integer;
+    book_info->publisher  = publisher;
+
+    return book_info;
+}
+
+book_id_t *get_book_id() {
+
+    char *id = read_item(ID, MAX_BOOK_ID_ELEM_SIZE, ECHO_ON);
+
+    if (id == NULL) {
+        FREE(id);
+
+        return NULL;
+    }
+
+    /*
+     * Build the book_id_t data type.
+     *
+     */
+    book_id_t *book_id;
+    CALLOC(book_id, sizeof(book_id));
+
+    book_id->id = id;
+    return book_id;
+
+}
+
+cJSON *book_to_json(book_info_t *book_info) {
+
+    cJSON *json_object = cJSON_CreateObject();
+
+    cJSON *title_item = cJSON_CreateString(book_info->title);
+    cJSON_AddItemToObject(json_object, TITLE, title_item);
+
+    cJSON *author_item = cJSON_CreateString(book_info->author);
+    cJSON_AddItemToObject(json_object, AUTHOR, author_item);
+
+    cJSON *genre_item = cJSON_CreateString(book_info->genre);
+    cJSON_AddItemToObject(json_object, GENRE, genre_item);
+
+    cJSON *page_count_item = cJSON_CreateNumber(*(book_info->page_count));
+    cJSON_AddItemToObject(json_object, PAGE_COUNT, page_count_item);
+
+    cJSON *publisher_item = cJSON_CreateString(book_info->publisher);
+    cJSON_AddItemToObject(json_object, PUBLISHER, publisher_item);
+
+    return json_object;
+
+}
+
+
+
+void delete_book_info(book_info_t *book_info) {
+
+    if (book_info == NULL) {
+        return;
+    }
+
+    FREE(book_info->title);
+    FREE(book_info->author);
+    FREE(book_info->genre);
+    FREE(book_info->page_count);
+    FREE(book_info->publisher);
+
+    FREE(book_info);
+
+}
+
+void delete_book_id(book_id_t *book_id) {
+
+    if (book_id == NULL) {
+        return;
+    }
+
+    FREE(book_id->id);
+    FREE(book_id);
+
+}
+
+void print_json_book_list(char *book_list_string) {
+
+    int books_counter = 0;
+
+    cJSON *book_list = cJSON_Parse(book_list_string);
+    cJSON *book      = NULL;
+
+    cJSON_ArrayForEach(book, book_list) {
+
+        cJSON *title  = cJSON_GetObjectItemCaseSensitive(book, TITLE);
+        cJSON *id     = cJSON_GetObjectItemCaseSensitive(book, ID);
+
+        char *title_string = cJSON_Print(title);
+        char *id_string = cJSON_Print(id);
+
+        printf("\n%s: %s\n"
+               "%s: %s\n\n",
+               TITLE, title_string,
+               ID,    id_string);
+
+        FREE(title_string);
+        FREE(id_string);
+
+        books_counter++;
+    }
+
+    cJSON_Delete(book_list);
+
+    if (books_counter == 0) {
+        puts(NO_BOOKS_ERROR);
+    }
+
+}
+
+void print_json_book(char *book_string) {
+
+    int books_counter = 0;
+
+    cJSON *books = cJSON_Parse(book_string);
+    cJSON *book  = NULL;
+
+    cJSON_ArrayForEach(book, books) {
+
+        cJSON *title       = cJSON_GetObjectItemCaseSensitive(book, TITLE);
+        cJSON *author      = cJSON_GetObjectItemCaseSensitive(book, AUTHOR);
+        cJSON *genre       = cJSON_GetObjectItemCaseSensitive(book, GENRE);
+        cJSON *page_count  = cJSON_GetObjectItemCaseSensitive(book, PAGE_COUNT);
+        cJSON *publisher   = cJSON_GetObjectItemCaseSensitive(book, PUBLISHER);
+
+        char *title_string      = cJSON_Print(title);
+        char *author_string     = cJSON_Print(author);
+        char *genre_string      = cJSON_Print(genre);
+        char *page_count_string = cJSON_Print(page_count);
+        char *publisher_string  = cJSON_Print(publisher);
+
+        printf("\n%s: %s\n"
+               "%s: %s\n"
+               "%s: %s\n"
+               "%s: %s\n"
+               "%s: %s\n",
+               TITLE,      title_string,
+               AUTHOR,     author_string,
+               GENRE,      genre_string,
+               PAGE_COUNT, page_count_string,
+               PUBLISHER,  publisher_string);
+
+        FREE(title_string);
+        FREE(author_string);
+        FREE(genre_string);
+        FREE(page_count_string);
+        FREE(publisher_string);
+
+        books_counter++;
+
+    }
+
+    cJSON_Delete(books);
+
+    if (books_counter == 0) {
+        puts(NO_BOOKS_ERROR);
+    }
+
+}
+
+

Protocoale-Comunicatie-3/buffer.c

@@ -0,0 +1,86 @@
+#include "buffer.h"
+#include "memory.h"
+
+buffer buffer_init(void)
+{
+    buffer buffer;
+
+    buffer.data = NULL;
+    buffer.size = 0;
+
+    return buffer;
+}
+
+void buffer_destroy(buffer *buffer)
+{
+    if (buffer->data != NULL) {
+        FREE(buffer->data);
+        buffer->data = NULL;
+    }
+
+    buffer->size = 0;
+}
+
+int buffer_is_empty(buffer *buffer)
+{
+    return buffer->data == NULL;
+}
+
+void buffer_add(buffer *buffer, const char *data, size_t data_size)
+{
+    if (buffer->data != NULL) {
+        buffer->data = realloc(buffer->data, (buffer->size + data_size) * sizeof(char));
+    } else {
+        CALLOC(buffer->data, data_size);
+    }
+
+    memcpy(buffer->data + buffer->size, data, data_size);
+
+    buffer->size += data_size;
+}
+
+int buffer_find(buffer *buffer, const char *data, size_t data_size)
+{
+    if (data_size > buffer->size)
+        return -1;
+
+    size_t last_pos = buffer->size - data_size + 1;
+
+    for (size_t i = 0; i < last_pos; ++i) {
+        size_t j;
+
+        for (j = 0; j < data_size; ++j) {
+            if (buffer->data[i + j] != data[j]) {
+                break;
+            }
+        }
+
+        if (j == data_size)
+            return i;
+    }
+
+    return -1;
+}
+
+int buffer_find_insensitive(buffer *buffer, const char *data, size_t data_size)
+{
+    if (data_size > buffer->size)
+        return -1;
+
+    size_t last_pos = buffer->size - data_size + 1;
+
+    for (size_t i = 0; i < last_pos; ++i) {
+        size_t j;
+
+        for (j = 0; j < data_size; ++j) {
+            if (tolower(buffer->data[i + j]) != tolower(data[j])) {
+                break;
+            }
+        }
+
+        if (j == data_size)
+            return i;
+    }
+
+    return -1;
+}

Protocoale-Comunicatie-3/client.c

@@ -0,0 +1,185 @@
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include "error.h"
+#include "connection.h"
+#include "server.h"
+#include "dns.h"
+#include "memory.h"
+#include "commands.h"
+
+int main() {
+
+    /*
+     * Get the IP of the server.
+     *
+     */
+    char *server_ip = get_ip(SERVER);
+
+    /*
+     * If the DNS request did not succeed then there is no internet connection.
+     *
+     */
+    if (server_ip == NULL) {
+        ERROR(NO_INTERNET_CONNECTION);
+        exit(EXIT_FAILURE);
+    }
+
+    /*
+     * Open a connection with the server.
+     *
+     */
+    int sockfd = open_connection(server_ip, PORT, AF_INET, SOCK_STREAM, 0);
+
+    /*
+     * Buffer for reading the input from the user.
+     *
+     */
+    char input_buffer[MAX_COMMAND_SZ] = {0};
+
+    /*
+     * Login @cookie is computed in #login and @jwt_token is computed
+     * in #enter_libary.
+     *
+     */
+    char *cookie    = NULL;
+    char *jwt_token = NULL;
+
+    while (1) {
+        /*
+         * Display promt.
+         *
+         */
+        printf("$ ");
+        fflush(stdout);
+
+        /*
+         * Fill the buffer with 0's and read the input.
+         *
+         */
+        memset(input_buffer, 0x00, MAX_COMMAND_SZ);
+        fgets(input_buffer, MAX_COMMAND_SZ - 1, stdin);
+
+        /*
+         * Possible values:
+         *
+         * OPERATION_SUCCESSFUL
+         * OPERATION_FAILED
+         * OPERATION_CONNECTION_CLOSED
+         *
+         */
+        int operation_status;
+
+        if (strncmp(input_buffer, REGISTER, sizeof(REGISTER) - 1) == 0) {
+
+            operation_status = op_register(&sockfd);
+
+            if (operation_status == OPERATION_CONNECTION_CLOSED) {
+                restore_connection(&sockfd, server_ip);
+            }
+
+        } else if (strncmp(input_buffer, LOGIN, sizeof(LOGIN) - 1) == 0) {
+            
+            operation_status = login(&sockfd, &cookie);
+
+            if (operation_status == OPERATION_CONNECTION_CLOSED) {
+                restore_connection(&sockfd, server_ip);
+            }
+
+            /*
+             * If the login was successful then the client must delete the previous
+             * @jwt_token.
+             *
+             */
+            if (operation_status == OPERATION_SUCCESSFUL) {
+                FREE(jwt_token);
+            }
+
+        } else if (strncmp(input_buffer, ENTER_LIBRARY, sizeof(ENTER_LIBRARY) - 1) == 0) {
+
+            /*
+             * If a jwt_token was already stored in the @jwt_token then
+             * delete it because a new enter_library will generate a new jwt_token.
+             *
+             */
+            operation_status = enter_library(&sockfd, cookie, &jwt_token);
+
+            if (operation_status == OPERATION_CONNECTION_CLOSED) {
+                restore_connection(&sockfd, server_ip);
+            }
+
+        } else if (strncmp(input_buffer, GET_BOOKS, sizeof(GET_BOOKS) - 1) == 0) {
+
+            operation_status = get_books(&sockfd, jwt_token);
+
+            if (operation_status == OPERATION_CONNECTION_CLOSED) {
+                restore_connection(&sockfd, server_ip);
+            }
+
+        } else if (strncmp(input_buffer, GET_BOOK, sizeof(GET_BOOK) - 1) == 0) {
+
+            operation_status = get_book(&sockfd, jwt_token);
+
+            if (operation_status == OPERATION_CONNECTION_CLOSED) {
+                restore_connection(&sockfd, server_ip);
+            }
+
+        } else if (strncmp(input_buffer, ADD_BOOK, sizeof(ADD_BOOK) - 1) == 0) {
+
+            operation_status = add_book(&sockfd, jwt_token);
+
+            if (operation_status == OPERATION_CONNECTION_CLOSED) {
+                restore_connection(&sockfd, server_ip);
+            }
+
+        } else if (strncmp(input_buffer, DELETE_BOOK, sizeof(DELETE_BOOK) - 1) == 0) {
+
+            operation_status = delete_book(&sockfd, jwt_token);
+
+            if (operation_status == OPERATION_CONNECTION_CLOSED) {
+                restore_connection(&sockfd, server_ip);
+            }
+        
+        } else if (strncmp(input_buffer, LOGOUT, sizeof(LOGOUT) - 1) == 0) {
+
+            operation_status = logout(&sockfd, cookie);
+
+            if (operation_status == OPERATION_CONNECTION_CLOSED) {
+                restore_connection(&sockfd, server_ip);
+            }
+
+            /*
+             * Delete the cookie and the jwt_token if the operation was successful.
+             *
+             */
+            if (operation_status == OPERATION_SUCCESSFUL) {
+                FREE(cookie);
+                FREE(jwt_token);
+            }
+
+        } else if (strncmp(input_buffer, EXIT, sizeof(EXIT) - 1) == 0) {
+
+            puts(GOODBYE);
+            close(sockfd);
+
+            FREE(cookie);
+            FREE(jwt_token);
+
+            break;
+
+        } else {
+            
+            /*
+             * The command does not exist.
+             *
+             */
+            ERROR(INVALID_COMMAND_ERROR);
+
+        }
+
+    }
+
+    return EXIT_SUCCESS;
+}

Protocoale-Comunicatie-3/commands.c

@@ -0,0 +1,663 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include "commands.h"
+#include "cJSON.h"
+#include "requests.h"
+#include "error.h"
+#include "connection.h"
+#include "authentication.h"
+#include "book.h"
+#include "memory.h"
+#include "http.h"
+
+#include "server.h"
+
+int op_register(int *sockfd) {
+    auth_info_t *auth_info     = NULL;
+    cJSON *register_json       = NULL;
+    char *register_json_string = NULL;
+    char *request              = NULL;
+    char *response             = NULL;
+
+    int return_status = OPERATION_SUCCESSFUL;
+
+    /*
+     * Get the authentication info.
+     *
+     */
+    auth_info = get_auth_info();
+    if (auth_info == NULL) {
+        ERROR(AUTH_INFO_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto op_register_end;
+    }
+
+    /*
+     * Generate the json payload for the POST request. And convert
+     * the JSON object to a string.
+     *
+     */
+    register_json        = auth_to_json(auth_info);
+    register_json_string = cJSON_Print(register_json);
+
+    /*
+     * Generate the POST request.
+     *
+     */
+    request = compute_post_request(SERVER, REGISTER_URL, 
+            JSON_CONTENT_TYPE, &register_json_string, 1, NULL, 0, NULL);
+
+    if (request == NULL) {
+        ERROR(POST_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto op_register_end;
+    }
+
+    /*
+     * Send the request and receive the response.
+     *
+     */
+    int send_and_receive_ret = send_and_receive(sockfd, request, &response);
+
+    if (send_and_receive_ret == SEND_RECV_FAIL) {
+        return_status = OPERATION_CONNECTION_CLOSED;
+        goto op_register_end;
+    }
+
+    if (!contains_status_code(response, CREATED)) {
+        print_http_error(basic_extract_json_response(response));
+
+        return_status = OPERATION_FAILED;
+        goto op_register_end;
+
+    }
+
+    puts(REGISTER_SUCCESS);
+
+op_register_end:
+
+    delete_auth_info(auth_info);
+    cJSON_Delete(register_json);
+
+    FREE(register_json_string);
+    FREE(request);
+    FREE(response);
+
+    return return_status;
+}
+
+int login(int *sockfd, char **cookie) {
+
+    auth_info_t *auth_info         = NULL;
+    cJSON       *login_json        = NULL;
+    char        *login_json_string = NULL;
+    char        *request           = NULL;
+    char        *response          = NULL;
+
+    int return_status = OPERATION_SUCCESSFUL;
+
+    /*
+     * Guard for input.
+     *
+     */
+    if (cookie == NULL) {
+        ERROR(COOKIE_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto login_end;
+    }
+
+    /*
+     * If there is already an active session then the user must
+     * firstly logout before it wants to login.
+     *
+     */
+    if (*cookie != NULL) {
+        ERROR(ACTIVE_COOKIE_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto login_end;
+    }
+
+    /*
+     * Get auth info.
+     *
+     */
+    auth_info = get_auth_info();
+    if (auth_info == NULL) {
+        ERROR(AUTH_INFO_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto login_end;
+    }
+
+
+    /*
+     * Generate the json payload for the POST request. And convert
+     * the JSON object to a string.
+     *
+     */
+    login_json        = auth_to_json(auth_info);
+    login_json_string = cJSON_Print(login_json);
+
+    /*
+     * Generate the POST request.
+     *
+     */
+    request = compute_post_request(SERVER, LOGIN_URL, 
+            JSON_CONTENT_TYPE, &login_json_string, 1, NULL, 0, NULL);
+
+    if (request == NULL) {
+        ERROR(POST_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto login_end;
+    }
+
+    /*
+     * Send the request and receive the response.
+     *
+     */
+    int send_and_receive_ret = send_and_receive(sockfd, request, &response);
+
+    if (send_and_receive_ret == SEND_RECV_FAIL) {
+        return_status = OPERATION_CONNECTION_CLOSED;
+        goto login_end;
+    }
+
+    if (!contains_status_code(response, SUCCESS)) {
+        print_http_error(basic_extract_json_response(response));
+
+        return_status = OPERATION_FAILED;
+        goto login_end;
+
+    }
+
+    /*
+     * Extract the cookie from the response and put its value in the @cookie argument.
+     *
+     */
+    char *cookie_line     = basic_extract_cookie_response(response);
+    char *cookie_line_end = basic_extract_crlf_response(cookie_line);
+
+    cookie_line[cookie_line_end - cookie_line] = 0x00;
+
+    CALLOC(*cookie, strlen(cookie_line) + 1);
+    strcpy(*cookie, cookie_line);
+
+    puts(LOGIN_SUCCESS);
+
+login_end:
+
+    delete_auth_info(auth_info);
+    cJSON_Delete(login_json);
+
+    FREE(login_json_string);
+    FREE(request);
+    FREE(response);
+
+    return return_status;
+}
+
+int enter_library(int *sockfd, char *cookie, char **jwt_token) {
+
+    char *request  = NULL;
+    char *response = NULL;
+
+    cJSON *json_received_object = NULL;
+
+    int return_status = OPERATION_SUCCESSFUL;
+
+    /*
+     * Guard for input.
+     *
+     */
+    if (cookie == NULL) {
+        ERROR(COOKIE_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto enter_library_end;
+    }
+
+    if (jwt_token == NULL) {
+        ERROR(JWT_TOKEN_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto enter_library_end;
+    }
+
+    /*
+     * If the user is already logged in in library then skip this operation.
+     *
+     */
+    if (*jwt_token != NULL && cookie != NULL) {
+        puts(ENTER_LIBARY_ERROR);
+        
+        return_status = OPERATION_FAILED;
+        goto enter_library_end;
+    }
+
+    /*
+     * Generate the GET request using the @cookie.
+     *
+     */
+    request = compute_get_request(SERVER, ENTER_LIBRARY_URL, NULL, &cookie, 1, NULL);
+    if (request == NULL) {
+        ERROR(GET_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto enter_library_end;
+    }
+
+    /*
+     * Send the request and receive the response.
+     *
+     */
+    int send_and_receive_ret = send_and_receive(sockfd, request, &response);
+
+    if (send_and_receive_ret == SEND_RECV_FAIL) {
+        return_status = OPERATION_CONNECTION_CLOSED;
+        goto enter_library_end;
+    }
+
+    if (!contains_status_code(response, SUCCESS)) {
+        print_http_error(basic_extract_json_response(response));
+
+        return_status = OPERATION_FAILED;
+        goto enter_library_end;
+
+    }
+
+    /*
+     * Parse the JWT token received in the HTTP response.
+     *
+     */
+    char *json_body = basic_extract_json_response(response);
+
+    json_received_object = cJSON_Parse(json_body);
+
+    cJSON *cJSON_token = cJSON_GetObjectItemCaseSensitive(json_received_object,
+            JWT_TOKEN);
+
+    /*
+     * Put the token in @jwt_token.
+     *
+     */
+    CALLOC(*jwt_token, strlen(cJSON_token->valuestring) + 1);
+    strcpy(*jwt_token, cJSON_token->valuestring);
+
+    puts(ENTER_LIBRARY_SUCCESS);
+
+enter_library_end:
+
+    cJSON_Delete(json_received_object);
+
+    FREE(request);
+    FREE(response);
+
+    return return_status;
+}
+
+int get_books(int *sockfd, char *jwt_token) {
+    char *request  = NULL;
+    char *response = NULL;
+
+    int return_status = OPERATION_SUCCESSFUL;
+
+    /*
+     * Guard for input.
+     *
+     */
+    if (jwt_token == NULL) {
+        ERROR(JWT_TOKEN_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto get_books_end;
+    }
+
+    /*
+     * Add the jwt token to the GET request.
+     *
+     */
+    request = compute_get_request(SERVER, GET_BOOKS_URL, NULL, NULL, 0, jwt_token);
+    if (request == NULL) {
+        ERROR(GET_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto get_books_end;
+    }
+
+    /*
+     * Send the request and receive the response.
+     *
+     */
+    int send_and_receive_ret = send_and_receive(sockfd, request, &response);
+
+    if (send_and_receive_ret == SEND_RECV_FAIL) {
+        return_status = OPERATION_CONNECTION_CLOSED;
+        goto get_books_end;
+    }
+
+
+    if (!contains_status_code(response, SUCCESS)) {
+        print_http_error(basic_extract_json_response(response));
+
+        return_status = OPERATION_FAILED;
+        goto get_books_end;
+
+    }
+
+    print_json_book_list(basic_extract_json_list_response(response));
+
+get_books_end:
+
+    FREE(request);
+    FREE(response);
+
+    return return_status;
+}
+
+int get_book(int *sockfd, char *jwt_token) {
+
+    book_id_t *book_id = NULL;
+    char *book_url     = NULL;
+
+    char *request  = NULL;
+    char *response = NULL;
+
+    int return_status = OPERATION_SUCCESSFUL;
+
+    /*
+     * Guard for input.
+     *
+     */
+    if (jwt_token == NULL) {
+        ERROR(JWT_TOKEN_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto get_book_end;
+    }
+    
+    /*
+     * Get the ID from user.
+     *
+     */
+    book_id = get_book_id();
+
+    /*
+     * Add the jwt token to the GET request. Add the book id to URL.
+     *
+     */
+    CALLOC(book_url, sizeof(GET_BOOKS_URL) - 1 + strlen("/") + strlen(book_id->id) + 1);
+    sprintf(book_url, "%s/%s", GET_BOOKS_URL, book_id->id);
+
+    request = compute_get_request(SERVER, book_url, NULL, NULL, 0, jwt_token);
+    if (request == NULL) {
+        ERROR(GET_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto get_book_end;
+    }
+
+    /*
+     * Send the request and receive the response.
+     *
+     */
+    int send_and_receive_ret = send_and_receive(sockfd, request, &response);
+
+    if (send_and_receive_ret == SEND_RECV_FAIL) {
+        return_status = OPERATION_CONNECTION_CLOSED;
+        goto get_book_end;
+    }
+
+
+    if (!contains_status_code(response, SUCCESS)) {
+        print_http_error(basic_extract_json_response(response));
+
+        return_status = OPERATION_FAILED;
+        goto get_book_end;
+
+    }
+
+    print_json_book(basic_extract_json_list_response(response));
+
+get_book_end:
+
+    delete_book_id(book_id);
+    FREE(book_url);
+
+    FREE(request);
+    FREE(response);
+
+    return return_status;
+
+}
+
+
+int add_book(int *sockfd, char *jwt_token) {
+
+    book_info_t *book_info        = NULL;
+    cJSON       *book_json        = NULL;
+    char        *book_json_string = NULL;
+    char        *request          = NULL;
+    char        *response         = NULL;
+
+    int return_status = OPERATION_SUCCESSFUL;
+
+    /*
+     * Guard for input.
+     *
+     */
+    if (jwt_token == NULL) {
+        ERROR(JWT_TOKEN_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto add_book_end;
+    }
+
+    /*
+     * Get book info.
+     *
+     */
+    book_info = get_book_info();
+    if (book_info == NULL) {
+        ERROR("Could not get book info");
+
+        return_status = OPERATION_FAILED;
+        goto add_book_end;
+    }
+
+    /*
+     * Generate the payload for the POST request.
+     *
+     */
+    book_json = book_to_json(book_info);
+    book_json_string = cJSON_Print(book_json);
+
+    /*
+     * Generate the POST request.
+     *
+     */
+    request = compute_post_request(SERVER, ADD_BOOK_URL,
+        JSON_CONTENT_TYPE, &book_json_string, 1, NULL, 0, jwt_token);
+
+    if (request == NULL) {
+        ERROR(POST_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto add_book_end;
+    }
+
+    /*
+     * Send the request and receive the response.
+     *
+     */
+    int send_and_receive_ret = send_and_receive(sockfd, request, &response);
+
+    if (send_and_receive_ret == SEND_RECV_FAIL) {
+        return_status = OPERATION_CONNECTION_CLOSED;
+        goto add_book_end;
+    }
+
+    if (!contains_status_code(response, SUCCESS)) {
+        print_http_error(basic_extract_json_response(response));
+
+        return_status = OPERATION_FAILED;
+        goto add_book_end;
+    }
+
+    puts(ADD_BOOK_SUCCESS);
+
+add_book_end:
+
+    delete_book_info(book_info);
+    cJSON_Delete(book_json);
+
+    FREE(book_json_string);
+    FREE(request);
+    FREE(response);
+
+    return return_status;
+
+}
+
+int delete_book(int *sockfd, char *jwt_token) {
+
+    book_id_t *book_id = NULL;
+    char     *book_url = NULL;
+
+    char *request  = NULL;
+    char *response = NULL;
+
+    int return_status = OPERATION_SUCCESSFUL;
+
+    /*
+     * Guard for input.
+     *
+     */
+    if (jwt_token == NULL) {
+        ERROR(JWT_TOKEN_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto delete_book_end;
+    }
+    
+    /*
+     * Get the ID from user.
+     *
+     */
+    book_id = get_book_id();
+
+    /*
+     * Add the jwt token to the DELETE request. Add the book id to URL.
+     *
+     */
+    CALLOC(book_url, sizeof(DELETE_BOOK_URL) - 1 + strlen("/") + strlen(book_id->id) + 1);
+    sprintf(book_url, "%s/%s", DELETE_BOOK_URL, book_id->id);
+
+    request = compute_delete_request(SERVER, book_url, NULL, NULL, 0, jwt_token);
+    if (request == NULL) {
+        ERROR(DELETE_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto delete_book_end;
+    }
+
+    /*
+     * Send the request and receive the response.
+     *
+     */
+    int send_and_receive_ret = send_and_receive(sockfd, request, &response);
+
+    if (send_and_receive_ret == SEND_RECV_FAIL) {
+        return_status = OPERATION_CONNECTION_CLOSED;
+        goto delete_book_end;
+    }
+
+    if (!contains_status_code(response, SUCCESS)) {
+        print_http_error(basic_extract_json_response(response));
+
+        return_status = OPERATION_FAILED;
+        goto delete_book_end;
+
+    }
+
+    puts(DELETE_BOOK_SUCCESS);
+
+delete_book_end:
+
+    delete_book_id(book_id);
+    FREE(book_url);
+
+    FREE(request);
+    FREE(response);
+
+    return return_status;
+
+}
+
+
+int logout(int *sockfd, char *cookie) {
+
+    char *request  = NULL;
+    char *response = NULL;
+
+    int return_status = OPERATION_SUCCESSFUL;
+
+    /*
+     * Guard for input.
+     *
+     */
+    if (cookie == NULL) {
+        ERROR(COOKIE_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto logout_end;
+    }
+
+    /*
+     * Generate the GET request using the @cookie.
+     *
+     */
+    request = compute_get_request(SERVER, LOGOUT_URL, NULL, &cookie, 1, NULL);
+    if (request == NULL) {
+        ERROR(GET_ERROR);
+
+        return_status = OPERATION_FAILED;
+        goto logout_end;
+    }
+
+    /*
+     * Send the request and receive the response.
+     *
+     */
+    int send_and_receive_ret = send_and_receive(sockfd, request, &response);
+
+    if (send_and_receive_ret == SEND_RECV_FAIL) {
+        return_status = OPERATION_CONNECTION_CLOSED;
+        goto logout_end;
+    }
+
+    if (!contains_status_code(response, SUCCESS)) {
+        print_http_error(basic_extract_json_response(response));
+
+        return_status = OPERATION_FAILED;
+        goto logout_end;
+
+    }
+
+    puts(LOGOUT_SUCCESS);
+
+logout_end:
+
+    FREE(response);
+    FREE(request);
+
+    return return_status;
+
+}

Protocoale-Comunicatie-3/connection.c

@@ -0,0 +1,242 @@
+#include <stdlib.h>     
+#include <stdio.h>
+#include <unistd.h>     
+#include <string.h>     
+#include <sys/socket.h> 
+#include <netinet/in.h> 
+#include <netdb.h>      
+#include <arpa/inet.h>
+#include <stdbool.h>
+#include <time.h>
+
+#include "connection.h"
+#include "error.h"
+#include "buffer.h"
+#include "server.h"
+#include "dns.h"
+
+void compute_message(char *message, const char *line) {
+
+    strcat(message, line);
+    strcat(message, "\r\n");
+
+}
+
+int open_connection(char *host_ip, int portno, int ip_type, int socket_type, int flag) {
+    /*
+     * Open the socket.
+     *
+     */
+    int sockfd = socket(ip_type, socket_type, flag);
+    ERROR_HANDLER(sockfd < 0, OPEN_CONNECTION_FAILED);
+
+    /*
+     * Fill the information about the server in a struct sockaddr_in.
+     *
+     */
+    struct sockaddr_in serv_addr;
+    memset(&serv_addr, 0x00, sizeof(serv_addr));
+
+    serv_addr.sin_family = ip_type;
+    serv_addr.sin_port = htons(portno);
+    inet_aton(host_ip, &serv_addr.sin_addr);
+
+    /*
+     * Set timeout.
+     *
+     */
+    struct timeval tv;
+    tv.tv_sec  = CONNECTION_TIMEOUT;
+    tv.tv_usec = 0;
+
+    setsockopt(sockfd, IPPROTO_TCP, SO_RCVTIMEO, (const char *) &tv, sizeof(tv));
+
+    /*
+     * Connect to server.
+     *
+     */
+    int connect_ret = connect(sockfd, (struct sockaddr*) &serv_addr, sizeof(serv_addr));
+    ERROR_HANDLER(connect_ret < 0, OPEN_CONNECTION_FAILED);
+
+    return sockfd;
+}
+
+void close_connection(int sockfd) {
+
+    close(sockfd);
+
+}
+
+int send_to_server(int sockfd, char *message) {
+    int bytes, sent = 0;
+    int total = strlen(message);
+
+    do {
+        bytes = write(sockfd, message + sent, total - sent);
+        ERROR_HANDLER(bytes < 0, SEND_TO_SERVER_FAILED);
+
+        if (bytes == 0) {
+            puts("[DEBUG] Message sent successfully!");
+            break;
+        }
+
+        sent += bytes;
+    } while (sent < total);
+
+    return SEND_TO_SERVER_SUCCESSFUL;
+}
+
+char *receive_from_server(int sockfd) {
+
+    char response[BUFLEN];
+    buffer buffer = buffer_init();
+    int header_end = 0;
+    int content_length = 0;
+
+    /*
+     * Read the header.
+     *
+     */
+    do {
+        int bytes = read(sockfd, response, BUFLEN);
+
+        if (bytes < 0){
+            buffer_destroy(&buffer);
+            ERROR_HANDLER(true, NULL);
+        }
+
+        if (bytes == 0) {
+            buffer_destroy(&buffer);
+            ERROR_HANDLER(true, NULL);
+        }
+
+        buffer_add(&buffer, response, (size_t) bytes);
+        
+        header_end = buffer_find(&buffer, HEADER_TERMINATOR, HEADER_TERMINATOR_SIZE);
+
+        if (header_end >= 0) {
+            header_end += HEADER_TERMINATOR_SIZE;
+            
+            int content_length_start = buffer_find_insensitive(&buffer, CONTENT_LENGTH, CONTENT_LENGTH_SIZE);
+            
+            if (content_length_start < 0) {
+                continue;           
+            }
+
+            content_length_start += CONTENT_LENGTH_SIZE;
+            content_length = strtol(buffer.data + content_length_start, NULL, 10);
+            break;
+        }
+    } while (1);
+
+    /*
+     * Read the content.
+     *
+     */
+    size_t total = content_length + (size_t) header_end;
+    
+    while (buffer.size < total) {
+        int bytes = read(sockfd, response, BUFLEN);
+
+        if (bytes < 0){
+            buffer_destroy(&buffer);
+            ERROR_HANDLER(true, NULL);
+        }
+
+        if (bytes == 0) {
+            buffer_destroy(&buffer);
+            ERROR_HANDLER(true, NULL);
+        }
+
+        buffer_add(&buffer, response, (size_t) bytes);
+    }
+
+    buffer_add(&buffer, "", 1);
+    return buffer.data;
+}
+
+
+int send_and_receive(int *sockfd, char *request, char **response) {
+
+    char *server_ip = get_ip(SERVER);
+
+    /*
+     * If the internet connection dies while the client runs, get_ip will
+     * detect this because it makes a DNS request that will use the connection.
+     *
+     * So the client will die to.
+     *
+     */
+    if (server_ip == NULL) {
+        ERROR(NO_INTERNET_CONNECTION);
+        exit(EXIT_FAILURE);
+    }
+
+    bool connection_failed = false;
+
+    int return_status = SEND_RECV_FAIL;
+
+    for (size_t i = 0; i < SEND_RECV_TIMEOUT; i++) {
+
+        /*
+         * Repoen the connection if it closed.
+         *
+         */
+        if (connection_failed == true) {
+            *sockfd = open_connection(server_ip, PORT, AF_INET, SOCK_STREAM, 0);
+            connection_failed = false;
+        }
+
+        /*
+         * Maybe the connection failed and sockfd is now -1.
+         *
+         */
+        if (*sockfd == -1) {
+            continue;
+        }
+
+        /*
+         * Try to send to server and to receive.
+         *
+         */
+        int send_to_server_ret = send_to_server(*sockfd, request);
+
+        if (send_to_server_ret == SEND_TO_SERVER_FAILED) {
+            connection_failed = true;
+            continue;
+        }
+
+        *response = receive_from_server(*sockfd);
+
+        if (*response == NULL) {
+            connection_failed = true;
+            continue;
+        }
+
+        /*
+         * If the above operations did not fail then break from loop.
+         *
+         */
+        return_status = SEND_RECV_SUCC;
+        break;
+    }
+
+    return return_status;
+
+}
+
+void restore_connection(int *sockfd, char *server_ip) {
+
+    for (size_t i = 0; i < SEND_RECV_TIMEOUT; i++) {
+        *sockfd = open_connection(server_ip, PORT, AF_INET, SOCK_STREAM, 0);
+
+        if (*sockfd > 0) {
+            return;
+        }
+
+    }
+
+    ERROR(UNSTABLE_INTERNET_CONNECTION);
+    exit(EXIT_FAILURE);
+
+}

Protocoale-Comunicatie-3/dns.c

@@ -0,0 +1,46 @@
+#include <stdio.h>
+
+#include "dns.h"
+#include "error.h"
+
+char *get_ip(char *name) {
+
+    /*
+     * Set the hints for getaddrinfo(3).
+     *
+     */
+    struct addrinfo hints = {
+        .ai_flags     = 0,
+        .ai_family    = AF_INET,
+        .ai_socktype  = SOCK_DGRAM,
+        .ai_protocol  = 0,
+
+        .ai_addrlen   = 0,
+        .ai_addr      = NULL,
+        .ai_canonname = NULL,
+        .ai_next      = NULL,
+    };
+
+    /*
+     * Call getaddrinfo(3) and store the info in @result.
+     *
+     */
+    struct addrinfo *result;
+    int getaddrinfo_ret = getaddrinfo(name, NULL, &hints, &result);
+    ERROR_HANDLER(getaddrinfo_ret < 0, NULL);
+
+    /*
+     * Get the IPv4 address from @result.
+     *
+     */
+    struct sockaddr_in *ipv4_addr = (struct sockaddr_in *) result->ai_addr;
+    uint32_t ip_addr = ipv4_addr->sin_addr.s_addr;
+
+    freeaddrinfo(result);
+
+    /*
+     * Return the IPv4 address converted to char array.
+     *
+     */
+    return inet_ntoa((struct in_addr) { .s_addr = ip_addr});
+}

Protocoale-Comunicatie-3/http.c

@@ -0,0 +1,56 @@
+#include <stddef.h>
+#include <string.h>
+
+#include <stdio.h>
+
+#include <http.h>
+#include <cJSON.h>
+#include "error.h"
+
+#define ERROR_JSON_OBJECT "error"
+
+bool contains_status_code(char *response, char *status_code) {
+
+    if (strstr(response, status_code) != NULL) {
+        return true;
+    } else {
+        return false;
+    }
+
+}
+
+char *basic_extract_json_response(char *response) {
+    return strstr(response, "{\"");
+}
+
+char *basic_extract_json_list_response(char *response) {
+    return strstr(response, "[");
+}
+
+char *basic_extract_cookie_response(char *response) {
+    return strstr(response, SET_COOKIE) + SET_COOKIE_SIZE;
+}
+
+char *basic_extract_crlf_response(char *response) {
+    return strstr(response, CRLF);
+}
+
+void print_http_error(char *json_response) {
+
+    if (json_response == NULL) {
+        return;
+    }
+
+    cJSON *cjson_response = cJSON_Parse(json_response);
+
+    if (cjson_response == NULL) {
+        return;
+    }
+
+    cJSON *cjson_error = cJSON_GetObjectItemCaseSensitive(cjson_response, ERROR_JSON_OBJECT);
+
+    ERROR(cjson_error->valuestring);
+    cJSON_Delete(cjson_response);
+
+}
+

Protocoale-Comunicatie-3/include/authentication.h

@@ -0,0 +1,48 @@
+#ifndef AUTHENTICATION_H_
+#define AUTHENTICATION_H_
+
+#include "cJSON.h"
+
+#define MAX_USER_SZ    100
+#define MAX_PASS_SZ    100
+
+/*
+ * Number of components used in a register/login operation:
+ *  username
+ *  psasword
+ *
+ */
+#define AUTH_INFO_ELEMS 2
+
+/*
+ * Names of the fields in auth_info_t.
+ *
+ */
+#define USERNAME "username"
+#define PASSWORD "password"
+
+typedef struct auth_info {
+    char *username;
+    char *password;
+} auth_info_t;
+
+/*
+ * Display a prompt with username and password, let the user enter the
+ * info and return it in a auth_info_t data type.
+ *
+ */
+auth_info_t *get_auth_info();
+
+/*
+ * Convert a auth_info_t object to JSON format.
+ *
+ */
+cJSON *auth_to_json(auth_info_t *auth_info);
+
+/*
+ * Frees the memory for a auth_info_t object.
+ *
+ */
+void delete_auth_info(auth_info_t *auth_info);
+
+#endif

Protocoale-Comunicatie-3/include/book.h

@@ -0,0 +1,89 @@
+#ifndef BOOK_H_
+#define BOOK_H_
+
+#include "cJSON.h"
+
+/*
+ * Number of elements in a book_info structure.
+ *
+ */
+#define BOOK_INFO_ELEMS 5
+
+/*
+ * Max number of characters in the strings defined in book_info_t.
+ *
+ */
+#define MAX_BOOK_ELEM_SIZE    100
+#define MAX_BOOK_ID_ELEM_SIZE 100
+
+/*
+ * Names of prompts in ADD_BOOK operation.
+ *
+ */
+#define ID         "id"
+
+#define TITLE      "title"
+#define AUTHOR     "author"
+#define GENRE      "genre"
+#define PUBLISHER  "publisher"
+#define PAGE_COUNT "page_count"
+
+typedef struct book_id {
+    char *id;
+} book_id_t;
+
+
+typedef struct book_info {
+    char *title;
+    char *author;
+    char *genre;
+    int  *page_count;
+    char *publisher;
+} book_info_t;
+
+/*
+ * Display a prompt for each element in book_info_t, let the user enter the
+ * info and return it in a book_info_t data type.
+ *
+ */
+book_info_t *get_book_info();
+
+/*
+ * Display a prompt for each element in book_id_t, let the user enter the
+ * info and return it in a book_id_t data type.
+ *
+ */
+book_id_t *get_book_id();
+
+/*
+ * Convert the book_info_t object to JSON format.
+ *
+ */
+cJSON *book_to_json(book_info_t *book_info);
+
+/*
+ * Frees the memory for a book_info_t object.
+ *
+ */
+void delete_book_info(book_info_t *book_info);
+
+/*
+ * Frees the memory for a book_id_t object.
+ *
+ */
+void delete_book_id(book_id_t *book_id);
+
+/*
+ * Print the ID and the TITLE of each book received in @book_list_string
+ *
+ */
+void print_json_book_list(char *book_list_string);
+
+/*
+ * Print a JSON book accordingly to book_info_t and book_id_t format.
+ *
+ */
+void print_json_book(char *book_string);
+
+
+#endif

Protocoale-Comunicatie-3/include/buffer.h

@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+
+typedef struct {
+    char *data;
+    size_t size;
+} buffer;
+
+// initializes a buffer
+buffer buffer_init(void);
+
+// destroys a buffer
+void buffer_destroy(buffer *buffer);
+
+// adds data of size data_size to a buffer
+void buffer_add(buffer *buffer, const char *data, size_t data_size);
+
+// checks if a buffer is empty
+int buffer_is_empty(buffer *buffer);
+
+// finds data of size data_size in a buffer and returns its position
+int buffer_find(buffer *buffer, const char *data, size_t data_size);
+
+// finds data of size data_size in a buffer in a
+// case-insensitive fashion and returns its position
+int buffer_find_insensitive(buffer *buffer, const char *data, size_t data_size);

Protocoale-Comunicatie-3/include/cJSON.h

@@ -0,0 +1,293 @@
+/*
+  Copyright (c) 2009-2017 Dave Gamble and cJSON contributors
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+  THE SOFTWARE.
+*/
+
+#ifndef cJSON__h
+#define cJSON__h
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+#if !defined(__WINDOWS__) && (defined(WIN32) || defined(WIN64) || defined(_MSC_VER) || defined(_WIN32))
+#define __WINDOWS__
+#endif
+
+#ifdef __WINDOWS__
+
+/* When compiling for windows, we specify a specific calling convention to avoid issues where we are being called from a project with a different default calling convention.  For windows you have 3 define options:
+
+CJSON_HIDE_SYMBOLS - Define this in the case where you don't want to ever dllexport symbols
+CJSON_EXPORT_SYMBOLS - Define this on library build when you want to dllexport symbols (default)
+CJSON_IMPORT_SYMBOLS - Define this if you want to dllimport symbol
+
+For *nix builds that support visibility attribute, you can define similar behavior by
+
+setting default visibility to hidden by adding
+-fvisibility=hidden (for gcc)
+or
+-xldscope=hidden (for sun cc)
+to CFLAGS
+
+then using the CJSON_API_VISIBILITY flag to "export" the same symbols the way CJSON_EXPORT_SYMBOLS does
+
+*/
+
+#define CJSON_CDECL __cdecl
+#define CJSON_STDCALL __stdcall
+
+/* export symbols by default, this is necessary for copy pasting the C and header file */
+#if !defined(CJSON_HIDE_SYMBOLS) && !defined(CJSON_IMPORT_SYMBOLS) && !defined(CJSON_EXPORT_SYMBOLS)
+#define CJSON_EXPORT_SYMBOLS
+#endif
+
+#if defined(CJSON_HIDE_SYMBOLS)
+#define CJSON_PUBLIC(type)   type CJSON_STDCALL
+#elif defined(CJSON_EXPORT_SYMBOLS)
+#define CJSON_PUBLIC(type)   __declspec(dllexport) type CJSON_STDCALL
+#elif defined(CJSON_IMPORT_SYMBOLS)
+#define CJSON_PUBLIC(type)   __declspec(dllimport) type CJSON_STDCALL
+#endif
+#else /* !__WINDOWS__ */
+#define CJSON_CDECL
+#define CJSON_STDCALL
+
+#if (defined(__GNUC__) || defined(__SUNPRO_CC) || defined (__SUNPRO_C)) && defined(CJSON_API_VISIBILITY)
+#define CJSON_PUBLIC(type)   __attribute__((visibility("default"))) type
+#else
+#define CJSON_PUBLIC(type) type
+#endif
+#endif
+
+/* project version */
+#define CJSON_VERSION_MAJOR 1
+#define CJSON_VERSION_MINOR 7
+#define CJSON_VERSION_PATCH 13
+
+#include <stddef.h>
+
+/* cJSON Types: */
+#define cJSON_Invalid (0)
+#define cJSON_False  (1 << 0)
+#define cJSON_True   (1 << 1)
+#define cJSON_NULL   (1 << 2)
+#define cJSON_Number (1 << 3)
+#define cJSON_String (1 << 4)
+#define cJSON_Array  (1 << 5)
+#define cJSON_Object (1 << 6)
+#define cJSON_Raw    (1 << 7) /* raw json */
+
+#define cJSON_IsReference 256
+#define cJSON_StringIsConst 512
+
+/* The cJSON structure: */
+typedef struct cJSON
+{
+    /* next/prev allow you to walk array/object chains. Alternatively, use GetArraySize/GetArrayItem/GetObjectItem */
+    struct cJSON *next;
+    struct cJSON *prev;
+    /* An array or object item will have a child pointer pointing to a chain of the items in the array/object. */
+    struct cJSON *child;
+
+    /* The type of the item, as above. */
+    int type;
+
+    /* The item's string, if type==cJSON_String  and type == cJSON_Raw */
+    char *valuestring;
+    /* writing to valueint is DEPRECATED, use cJSON_SetNumberValue instead */
+    int valueint;
+    /* The item's number, if type==cJSON_Number */
+    double valuedouble;
+
+    /* The item's name string, if this item is the child of, or is in the list of subitems of an object. */
+    char *string;
+} cJSON;
+
+typedef struct cJSON_Hooks
+{
+      /* malloc/free are CDECL on Windows regardless of the default calling convention of the compiler, so ensure the hooks allow passing those functions directly. */
+      void *(CJSON_CDECL *malloc_fn)(size_t sz);
+      void (CJSON_CDECL *free_fn)(void *ptr);
+} cJSON_Hooks;
+
+typedef int cJSON_bool;
+
+/* Limits how deeply nested arrays/objects can be before cJSON rejects to parse them.
+ * This is to prevent stack overflows. */
+#ifndef CJSON_NESTING_LIMIT
+#define CJSON_NESTING_LIMIT 1000
+#endif
+
+/* returns the version of cJSON as a string */
+CJSON_PUBLIC(const char*) cJSON_Version(void);
+
+/* Supply malloc, realloc and free functions to cJSON */
+CJSON_PUBLIC(void) cJSON_InitHooks(cJSON_Hooks* hooks);
+
+/* Memory Management: the caller is always responsible to free the results from all variants of cJSON_Parse (with cJSON_Delete) and cJSON_Print (with stdlib free, cJSON_Hooks.free_fn, or cJSON_free as appropriate). The exception is cJSON_PrintPreallocated, where the caller has full responsibility of the buffer. */
+/* Supply a block of JSON, and this returns a cJSON object you can interrogate. */
+CJSON_PUBLIC(cJSON *) cJSON_Parse(const char *value);
+CJSON_PUBLIC(cJSON *) cJSON_ParseWithLength(const char *value, size_t buffer_length);
+/* ParseWithOpts allows you to require (and check) that the JSON is null terminated, and to retrieve the pointer to the final byte parsed. */
+/* If you supply a ptr in return_parse_end and parsing fails, then return_parse_end will contain a pointer to the error so will match cJSON_GetErrorPtr(). */
+CJSON_PUBLIC(cJSON *) cJSON_ParseWithOpts(const char *value, const char **return_parse_end, cJSON_bool require_null_terminated);
+CJSON_PUBLIC(cJSON *) cJSON_ParseWithLengthOpts(const char *value, size_t buffer_length, const char **return_parse_end, cJSON_bool require_null_terminated);
+
+/* Render a cJSON entity to text for transfer/storage. */
+CJSON_PUBLIC(char *) cJSON_Print(const cJSON *item);
+/* Render a cJSON entity to text for transfer/storage without any formatting. */
+CJSON_PUBLIC(char *) cJSON_PrintUnformatted(const cJSON *item);
+/* Render a cJSON entity to text using a buffered strategy. prebuffer is a guess at the final size. guessing well reduces reallocation. fmt=0 gives unformatted, =1 gives formatted */
+CJSON_PUBLIC(char *) cJSON_PrintBuffered(const cJSON *item, int prebuffer, cJSON_bool fmt);
+/* Render a cJSON entity to text using a buffer already allocated in memory with given length. Returns 1 on success and 0 on failure. */
+/* NOTE: cJSON is not always 100% accurate in estimating how much memory it will use, so to be safe allocate 5 bytes more than you actually need */
+CJSON_PUBLIC(cJSON_bool) cJSON_PrintPreallocated(cJSON *item, char *buffer, const int length, const cJSON_bool format);
+/* Delete a cJSON entity and all subentities. */
+CJSON_PUBLIC(void) cJSON_Delete(cJSON *item);
+
+/* Returns the number of items in an array (or object). */
+CJSON_PUBLIC(int) cJSON_GetArraySize(const cJSON *array);
+/* Retrieve item number "index" from array "array". Returns NULL if unsuccessful. */
+CJSON_PUBLIC(cJSON *) cJSON_GetArrayItem(const cJSON *array, int index);
+/* Get item "string" from object. Case insensitive. */
+CJSON_PUBLIC(cJSON *) cJSON_GetObjectItem(const cJSON * const object, const char * const string);
+CJSON_PUBLIC(cJSON *) cJSON_GetObjectItemCaseSensitive(const cJSON * const object, const char * const string);
+CJSON_PUBLIC(cJSON_bool) cJSON_HasObjectItem(const cJSON *object, const char *string);
+/* For analysing failed parses. This returns a pointer to the parse error. You'll probably need to look a few chars back to make sense of it. Defined when cJSON_Parse() returns 0. 0 when cJSON_Parse() succeeds. */
+CJSON_PUBLIC(const char *) cJSON_GetErrorPtr(void);
+
+/* Check item type and return its value */
+CJSON_PUBLIC(char *) cJSON_GetStringValue(cJSON *item);
+CJSON_PUBLIC(double) cJSON_GetNumberValue(cJSON *item);
+
+/* These functions check the type of an item */
+CJSON_PUBLIC(cJSON_bool) cJSON_IsInvalid(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsFalse(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsTrue(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsBool(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsNull(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsNumber(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsString(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsArray(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsObject(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsRaw(const cJSON * const item);
+
+/* These calls create a cJSON item of the appropriate type. */
+CJSON_PUBLIC(cJSON *) cJSON_CreateNull(void);
+CJSON_PUBLIC(cJSON *) cJSON_CreateTrue(void);
+CJSON_PUBLIC(cJSON *) cJSON_CreateFalse(void);
+CJSON_PUBLIC(cJSON *) cJSON_CreateBool(cJSON_bool boolean);
+CJSON_PUBLIC(cJSON *) cJSON_CreateNumber(double num);
+CJSON_PUBLIC(cJSON *) cJSON_CreateString(const char *string);
+/* raw json */
+CJSON_PUBLIC(cJSON *) cJSON_CreateRaw(const char *raw);
+CJSON_PUBLIC(cJSON *) cJSON_CreateArray(void);
+CJSON_PUBLIC(cJSON *) cJSON_CreateObject(void);
+
+/* Create a string where valuestring references a string so
+ * it will not be freed by cJSON_Delete */
+CJSON_PUBLIC(cJSON *) cJSON_CreateStringReference(const char *string);
+/* Create an object/array that only references it's elements so
+ * they will not be freed by cJSON_Delete */
+CJSON_PUBLIC(cJSON *) cJSON_CreateObjectReference(const cJSON *child);
+CJSON_PUBLIC(cJSON *) cJSON_CreateArrayReference(const cJSON *child);
+
+/* These utilities create an Array of count items.
+ * The parameter count cannot be greater than the number of elements in the number array, otherwise array access will be out of bounds.*/
+CJSON_PUBLIC(cJSON *) cJSON_CreateIntArray(const int *numbers, int count);
+CJSON_PUBLIC(cJSON *) cJSON_CreateFloatArray(const float *numbers, int count);
+CJSON_PUBLIC(cJSON *) cJSON_CreateDoubleArray(const double *numbers, int count);
+CJSON_PUBLIC(cJSON *) cJSON_CreateStringArray(const char *const *strings, int count);
+
+/* Append item to the specified array/object. */
+CJSON_PUBLIC(cJSON_bool) cJSON_AddItemToArray(cJSON *array, cJSON *item);
+CJSON_PUBLIC(cJSON_bool) cJSON_AddItemToObject(cJSON *object, const char *string, cJSON *item);
+/* Use this when string is definitely const (i.e. a literal, or as good as), and will definitely survive the cJSON object.
+ * WARNING: When this function was used, make sure to always check that (item->type & cJSON_StringIsConst) is zero before
+ * writing to `item->string` */
+CJSON_PUBLIC(cJSON_bool) cJSON_AddItemToObjectCS(cJSON *object, const char *string, cJSON *item);
+/* Append reference to item to the specified array/object. Use this when you want to add an existing cJSON to a new cJSON, but don't want to corrupt your existing cJSON. */
+CJSON_PUBLIC(cJSON_bool) cJSON_AddItemReferenceToArray(cJSON *array, cJSON *item);
+CJSON_PUBLIC(cJSON_bool) cJSON_AddItemReferenceToObject(cJSON *object, const char *string, cJSON *item);
+
+/* Remove/Detach items from Arrays/Objects. */
+CJSON_PUBLIC(cJSON *) cJSON_DetachItemViaPointer(cJSON *parent, cJSON * const item);
+CJSON_PUBLIC(cJSON *) cJSON_DetachItemFromArray(cJSON *array, int which);
+CJSON_PUBLIC(void) cJSON_DeleteItemFromArray(cJSON *array, int which);
+CJSON_PUBLIC(cJSON *) cJSON_DetachItemFromObject(cJSON *object, const char *string);
+CJSON_PUBLIC(cJSON *) cJSON_DetachItemFromObjectCaseSensitive(cJSON *object, const char *string);
+CJSON_PUBLIC(void) cJSON_DeleteItemFromObject(cJSON *object, const char *string);
+CJSON_PUBLIC(void) cJSON_DeleteItemFromObjectCaseSensitive(cJSON *object, const char *string);
+
+/* Update array items. */
+CJSON_PUBLIC(cJSON_bool) cJSON_InsertItemInArray(cJSON *array, int which, cJSON *newitem); /* Shifts pre-existing items to the right. */
+CJSON_PUBLIC(cJSON_bool) cJSON_ReplaceItemViaPointer(cJSON * const parent, cJSON * const item, cJSON * replacement);
+CJSON_PUBLIC(cJSON_bool) cJSON_ReplaceItemInArray(cJSON *array, int which, cJSON *newitem);
+CJSON_PUBLIC(cJSON_bool) cJSON_ReplaceItemInObject(cJSON *object,const char *string,cJSON *newitem);
+CJSON_PUBLIC(cJSON_bool) cJSON_ReplaceItemInObjectCaseSensitive(cJSON *object,const char *string,cJSON *newitem);
+
+/* Duplicate a cJSON item */
+CJSON_PUBLIC(cJSON *) cJSON_Duplicate(const cJSON *item, cJSON_bool recurse);
+/* Duplicate will create a new, identical cJSON item to the one you pass, in new memory that will
+ * need to be released. With recurse!=0, it will duplicate any children connected to the item.
+ * The item->next and ->prev pointers are always zero on return from Duplicate. */
+/* Recursively compare two cJSON items for equality. If either a or b is NULL or invalid, they will be considered unequal.
+ * case_sensitive determines if object keys are treated case sensitive (1) or case insensitive (0) */
+CJSON_PUBLIC(cJSON_bool) cJSON_Compare(const cJSON * const a, const cJSON * const b, const cJSON_bool case_sensitive);
+
+/* Minify a strings, remove blank characters(such as ' ', '\t', '\r', '\n') from strings.
+ * The input pointer json cannot point to a read-only address area, such as a string constant, 
+ * but should point to a readable and writable adress area. */
+CJSON_PUBLIC(void) cJSON_Minify(char *json);
+
+/* Helper functions for creating and adding items to an object at the same time.
+ * They return the added item or NULL on failure. */
+CJSON_PUBLIC(cJSON*) cJSON_AddNullToObject(cJSON * const object, const char * const name);
+CJSON_PUBLIC(cJSON*) cJSON_AddTrueToObject(cJSON * const object, const char * const name);
+CJSON_PUBLIC(cJSON*) cJSON_AddFalseToObject(cJSON * const object, const char * const name);
+CJSON_PUBLIC(cJSON*) cJSON_AddBoolToObject(cJSON * const object, const char * const name, const cJSON_bool boolean);
+CJSON_PUBLIC(cJSON*) cJSON_AddNumberToObject(cJSON * const object, const char * const name, const double number);
+CJSON_PUBLIC(cJSON*) cJSON_AddStringToObject(cJSON * const object, const char * const name, const char * const string);
+CJSON_PUBLIC(cJSON*) cJSON_AddRawToObject(cJSON * const object, const char * const name, const char * const raw);
+CJSON_PUBLIC(cJSON*) cJSON_AddObjectToObject(cJSON * const object, const char * const name);
+CJSON_PUBLIC(cJSON*) cJSON_AddArrayToObject(cJSON * const object, const char * const name);
+
+/* When assigning an integer value, it needs to be propagated to valuedouble too. */
+#define cJSON_SetIntValue(object, number) ((object) ? (object)->valueint = (object)->valuedouble = (number) : (number))
+/* helper for the cJSON_SetNumberValue macro */
+CJSON_PUBLIC(double) cJSON_SetNumberHelper(cJSON *object, double number);
+#define cJSON_SetNumberValue(object, number) ((object != NULL) ? cJSON_SetNumberHelper(object, (double)number) : (number))
+/* Change the valuestring of a cJSON_String object, only takes effect when type of object is cJSON_String */
+CJSON_PUBLIC(char*) cJSON_SetValuestring(cJSON *object, const char *valuestring);
+
+/* Macro for iterating over an array or object */
+#define cJSON_ArrayForEach(element, array) for(element = (array != NULL) ? (array)->child : NULL; element != NULL; element = element->next)
+
+/* malloc/free objects using the malloc/free functions that have been set with cJSON_InitHooks */
+CJSON_PUBLIC(void *) cJSON_malloc(size_t size);
+CJSON_PUBLIC(void) cJSON_free(void *object);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

Protocoale-Comunicatie-3/include/commands.h

@@ -0,0 +1,107 @@
+#ifndef COMMANDS_H_
+#define COMMANDS_H_
+
+/*
+ * Maximum sizes of different inputs.
+ *
+ */
+
+#define MAX_COMMAND_SZ 20
+
+/*
+ * Format of commands given by the user.
+ *
+ */
+
+#define REGISTER      "register"
+#define LOGIN         "login"
+#define ENTER_LIBRARY "enter_library"
+#define GET_BOOKS     "get_books"
+#define GET_BOOK      "get_book"
+#define ADD_BOOK      "add_book"
+#define DELETE_BOOK   "delete_book"
+#define LOGOUT        "logout"
+#define EXIT          "exit"
+
+
+/*
+ * Status codes for all commands listed below.
+ *
+ */
+
+#define OPERATION_SUCCESSFUL          0
+#define OPERATION_FAILED              1
+#define OPERATION_CONNECTION_CLOSED   2
+
+/*
+ * Registers an account to the server. The connection
+ * with the server must be established on @*sockfd.
+ *
+ * If the server closed the connection with the client then
+ * OPERATION_CONNECTION_CLOSED error code will be returned. If any other
+ * error occured then OPERATION_FAILED will be returned.
+ *
+ * On success, OPERATION_SUCCESSFUL is returned.
+ *
+ * The function is called 'op_register', not 'register' because the
+ * latter one is a keyword in C and cannot be used as a function
+ * name.
+ */
+
+int op_register(int *sockfd);
+
+/*
+ * Logins to the server and returns a session cookie.
+ *
+ * If this function fails then it will return NULL.
+ *
+ */
+
+int login(int *sockfd, char **cookie);
+
+/*
+ * Using a @cookie, send a GET request to the library access URL and return
+ * a JWT Token in @jwt_token.
+ *
+ */
+int enter_library(int *sockfd, char *cookie, char **jwt_token);
+
+/*
+ * Using a @jwt_token, send a GET request to the library URL and print the
+ * received list of JSON object.
+ *
+ */
+int get_books(int *sockfd, char *jwt_token);
+
+/*
+ * Using a @jwt_token, send a GET request to the library URL and print the
+ * info about the book.
+ *
+ */
+
+int get_book(int *sockfd, char *jwt_token);
+
+/*
+ * Using a @jwt_token, send a POST request to the add book URL. The info
+ * about the book will be fed from a prompt.
+ *
+ */
+int add_book(int *sockfd, char *jwt_token);
+
+/*
+ * Using a @jwt_token, send a DELETE request to the add book URL. The info
+ * about the book will be fed from a prompt.
+ *
+ */
+int delete_book(int *sockfd, char *jwt_token);
+
+/*
+ * Logs out using the @cookie.
+ *
+ */
+int logout(int *sockfd, char *cookie);
+
+#endif
+
+
+

Protocoale-Comunicatie-3/include/connection.h

@@ -0,0 +1,80 @@
+#ifndef CONNECTION_H_
+#define CONNECTION_H_
+
+#define BUFLEN 4096
+#define LINELEN 1000
+
+#define HEADER_TERMINATOR "\r\n\r\n"
+#define HEADER_TERMINATOR_SIZE (sizeof(HEADER_TERMINATOR) - 1)
+
+#define CONTENT_LENGTH "Content-Length: "
+#define CONTENT_LENGTH_SIZE (sizeof(CONTENT_LENGTH) - 1)
+
+/*
+ * Waits 5 second to connect to server.
+ *
+ */
+#define CONNECTION_TIMEOUT 5
+
+/*
+ * Adds a line to a string message.
+ *
+ */
+void compute_message(char *message, const char *line);
+
+/*
+ * Opens a connection with the server at @host_ip on port @portno.
+ *
+ * If the connection is successful then it returns a new socket file descriptor,
+ * else it returns OPEN_CONNECTION_FAILED.
+ *
+ */
+#define OPEN_CONNECTION_FAILED -1
+
+int open_connection(char *host_ip, int portno, int ip_type, int socket_type, int flag);
+
+/*
+ * Closes the connection with the server on socket sockfd.
+ *
+ */
+void close_connection(int sockfd);
+
+/*
+ * Sends a message to a server on socket sockfd.
+ *
+ * Returns SEND_TO_SERVER_SUCCESSFUL on success and
+ * SEND_TO_SERVER_FAILED on failure.
+ *
+ */
+#define SEND_TO_SERVER_SUCCESSFUL 0
+#define SEND_TO_SERVER_FAILED     1
+
+int send_to_server(int sockfd, char *message);
+
+/*
+ * Receives and returns a message from server.
+ *
+ */
+char *receive_from_server(int sockfd);
+
+/*
+ * Sends request and tries SEND_RECV_TIMEOUT times to receive a response.
+ *
+ * Returns SEND_RECV_FAIL on failure and SEND_RECV_SUCC on success.
+ *
+ */
+#define SEND_RECV_FAIL -1
+#define SEND_RECV_SUCC 0
+
+#define SEND_RECV_TIMEOUT 10
+
+int send_and_receive(int *sockfd, char *request, char **response);
+
+/*
+ * Make a stabile connection with the server.
+ *
+ */
+void restore_connection(int *sockfd, char *server_ip);
+
+
+#endif

Protocoale-Comunicatie-3/include/dns.h

@@ -0,0 +1,18 @@
+#ifndef DNS_H_
+#define DNS_H_
+
+#include <stdint.h>
+
+#include <sys/socket.h>
+#include <netdb.h>
+#include <arpa/inet.h>
+
+/*
+ * Get the IPv4 address in integer format.
+ * Returns NULL on error.
+ *
+ */
+
+char *get_ip(char *name);
+
+#endif

Protocoale-Comunicatie-3/include/error.h

@@ -0,0 +1,97 @@
+#ifndef ERROR_H_
+#define ERROR_H_
+
+/*
+ * Success messages for the operations defined in commands.h
+ *
+ */
+#define REGISTER_SUCCESS      "User registered successfully!"
+#define LOGIN_SUCCESS         "User logged in successfully!"
+#define ENTER_LIBRARY_SUCCESS "Entered library successfully!"
+#define ADD_BOOK_SUCCESS      "Book added successfully!"
+#define DELETE_BOOK_SUCCESS   "Book deleted successfully!"
+#define LOGOUT_SUCCESS        "User logged out successfully!"
+
+/*
+ * Error messages for the operations defined in commands.h
+ *
+ */
+#define REGISTER_FAIL      "Username already exists!"
+#define LOGIN_FAIL         "User does not exist!"
+#define ENTER_LIBRARY_FAIL "Entered library failed!"
+#define ADD_BOOK_FAIL      "Book cannot be added at the moment!"
+#define GET_BOOKS_FAIL     "Books cannot be received at the moment!"
+#define GET_BOOK_FAIL      "Book cannot be received at the moment!"
+#define DELETE_BOOK_FAIL   "Book cannot be deleted at the moment!"
+#define LOGOUT_FAIL        "User cannot be logged out at the moment"
+
+/*
+ * Error message for inexistent operations.
+ *
+ */
+#define INVALID_COMMAND_ERROR "This command is not supported!"
+
+/*
+ * Error messages for sending and receiving a packet.
+ *
+ */
+#define SEND_ERROR "Could not send request to server"
+#define RECV_ERROR "Could not receive a response from server"
+
+/*
+ * Error messages for generating requests.
+ *
+ */
+#define POST_ERROR "Could not generate POST request"
+#define GET_ERROR  "Could not generate GET request"
+#define DELETE_ERROR  "Could not generate DELETE request"
+
+/*
+ * Error messages for prompters.
+ *
+ */
+#define AUTH_INFO_ERROR "Could not get authentication info"
+#define BOOK_INFO_ERROR "Could not get book info"
+
+/*
+ * Error messages for the books received as JSON objects.
+ *
+ */
+#define NO_BOOKS_ERROR "There are no books in the library!"
+
+/*
+ * Error messages for connection with the server.
+ *
+ */
+#define SERVER_CONNECTION_CLOSED      "Server closed the connection. Please retry the operation!"
+#define NO_INTERNET_CONNECTION        "There is no internet connection!"
+#define UNSTABLE_INTERNET_CONNECTION "Unstable internet connection! Please retry."
+
+/*
+ * Error messages for invalid cookies or tokens.
+ *
+ */
+#define ACTIVE_COOKIE_ERROR "You must logout before making this operation!"
+#define COOKIE_ERROR        "You must login before making this operation!"
+#define JWT_TOKEN_ERROR     "You must enter library before making this operation!"
+#define ENTER_LIBARY_ERROR  "You are already in library!"
+
+/*
+ * Status message for closing the client.
+ *
+ */
+#define GOODBYE "Closing the connection with the server, goodbye."
+
+#define ERROR_HANDLER(assertion, return_value) \
+	do {								\
+		if (assertion) {					\
+            return return_value; \
+		}							\
+	} while(0)
+
+#define ERROR(error)    \
+    do {    \
+        fprintf(stderr, "[ERROR] %s\n", error);     \
+    } while (0)
+
+#endif

Protocoale-Comunicatie-3/include/http.h

@@ -0,0 +1,47 @@
+#ifndef HTTP_H_
+#define HTTP_H_
+
+#include <stdbool.h>
+
+/*
+ * Name of a JWT Token in then JSON object received in #enter_library.
+ *
+ */
+#define JWT_TOKEN "token"
+
+/*
+ * Status codes received in HTTP responses.
+ *
+ */
+#define SUCCESS "200 OK"
+#define CREATED "201 Created"
+
+/*
+ * Function that checks if HTTP @response contains @status_code.
+ *
+ */
+bool contains_status_code(char *response, char *status_code);
+
+/*
+ * Functions that extract data from a HTTP response.
+ *
+ */
+
+#define CRLF "\r\n"
+#define CRLF_SIZE (sizeof(CRLF) - 1)
+
+#define SET_COOKIE "Set-Cookie: "
+#define SET_COOKIE_SIZE (sizeof(SET_COOKIE) - 1)
+
+char *basic_extract_json_response(char *response);
+
+char *basic_extract_json_list_response(char *response);
+
+char *basic_extract_cookie_response(char *respose);
+
+char *basic_extract_crlf_response(char *response);
+
+void print_http_error(char *json_response);
+
+
+#endif

Protocoale-Comunicatie-3/include/memory.h

@@ -0,0 +1,50 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+/*
+ * This header file deals with memory allocation.
+ *
+ */
+
+#define ERROR_ALLOC_MESSAGE "Insufficient memory"
+
+#define MALLOC(p, n) \
+do \
+{ \
+  if ( !( (p) = malloc(sizeof(*(p)) * (n)) ) ) \
+  { \
+    fprintf(stderr, ERROR_ALLOC_MESSAGE); \
+    exit(EXIT_FAILURE); \
+  } \
+} \
+while(0)
+
+#define CALLOC(p, n) \
+do \
+{ \
+  if ( !( (p) = calloc((n), sizeof(*(p))) ) ) \
+  { \
+    fprintf(stderr, ERROR_ALLOC_MESSAGE); \
+    exit(EXIT_FAILURE); \
+  } \
+} \
+while(0)
+
+#define REALLOC(p, n) \
+do \
+{ \
+  if ( !( (p) = realloc((p), sizeof(*(p)) * (n)) ) ) \
+  { \
+    fprintf(stderr, ERROR_ALLOC_MESSAGE); \
+    exit(EXIT_FAILURE); \
+  } \
+} \
+while(0)
+
+#define FREE(p) \
+do \
+{ \
+  free(p); \
+  p = NULL; \
+} \
+while(0)

Protocoale-Comunicatie-3/include/prompt.h

@@ -0,0 +1,16 @@
+#ifndef PROMPT_H_
+#define PROMPT_H_
+
+/*
+ * Prompts the user the message @item_name and waits for an input
+ * of at most @item_max_len bytes.
+ *
+ * Returns a heap memory array that will contain the user data.
+ *
+ */
+#define ECHO_ON  1
+#define ECHO_OFF 0
+
+char *read_item(char *item_name, int item_max_len, int echo);
+
+#endif

Protocoale-Comunicatie-3/include/requests.h

@@ -0,0 +1,46 @@
+#ifndef REQUESTS_H_
+#define REQUESTS_H_
+
+/*
+ * Computes a GET request addressed to the @url hosted by @host.
+ *
+ * @query_params and @cookies can be set to NULL if not needed.
+ *
+ * @return: a char array containing the GET request.
+ *          NULL if the operation faield (input was invalid)
+ *
+ */
+char *compute_get_request(char *host, char *url, char *query_params,
+							char **cookies, int cookies_count, char *auth_token);
+
+/*
+ * Computes a DELETE request addressed to the @url hosted by @host.
+ *
+ * @query_params and @cookies can be set to NULL if not needed.
+ *
+ * @return: a char array containing the DELETE request.
+ *          NULL if the operation faield (input was invalid)
+ *
+ */
+char *compute_delete_request(char *host, char *url, char *query_params,
+							char **cookies, int cookies_count, char *auth_token);
+
+/*
+ * Computes a POST request addressed to the @url hosted by @host.
+ *
+ * @cookies can be set to NULL if not needed.
+ * @body_data is the data contained in the POST request.
+ *
+ * @return: a char array containing the POST request.
+ *
+ */
+char *compute_post_request(char *host, char *url, char* content_type, char **body_data,
+		int body_data_fields_count, char** cookies, int cookies_count, char *auth_token);
+
+/*
+ * Adds a x-access-token field in the header of the GET request.
+ *
+ */
+char *add_access_token(char *request, char *jwt_token);
+
+#endif

Protocoale-Comunicatie-3/include/server.h

@@ -0,0 +1,29 @@
+#ifndef SERVER_H_
+#define SERVER_H_
+
+/*
+ * Info about the server.
+ *
+ */
+#define SERVER "ec2-3-8-116-10.eu-west-2.compute.amazonaws.com"
+#define PORT   8080
+
+/*
+ * Content types.
+ *
+ */
+#define JSON_CONTENT_TYPE "application/json"
+
+/*
+ * URLs.
+ *
+ */
+#define REGISTER_URL      "/api/v1/tema/auth/register"
+#define LOGIN_URL         "/api/v1/tema/auth/login"
+#define ENTER_LIBRARY_URL "/api/v1/tema/library/access"
+#define GET_BOOKS_URL     "/api/v1/tema/library/books"
+#define ADD_BOOK_URL      "/api/v1/tema/library/books"
+#define DELETE_BOOK_URL   "/api/v1/tema/library/books"
+#define LOGOUT_URL        "/api/v1/tema/auth/logout"
+
+#endif

Protocoale-Comunicatie-3/prompt.c

@@ -0,0 +1,79 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <termios.h>
+
+#include "prompt.h"
+#include "memory.h"
+#include "error.h"
+
+char *read_item(char *item_name, int item_max_len, int echo) {
+    /*
+     * Print the prompt.
+     *
+     */
+    printf("%s: ", item_name);
+    fflush(stdout);
+
+    struct termios current, modified;
+
+    if (echo == ECHO_OFF) {
+        /*
+         * If echoing is off then disable it usint tcgetattr, tcsetattr.
+         *
+         */
+
+        // get current attributes
+        int tcgetattr_ret = tcgetattr(STDIN_FILENO, &current);
+        ERROR_HANDLER(tcgetattr_ret == -1, NULL);
+
+        modified = current;
+        modified.c_lflag &= ~ECHO;
+
+        int tcsetattr_ret = tcsetattr(STDIN_FILENO, TCSAFLUSH, &modified);
+        ERROR_HANDLER(tcsetattr_ret == -1, NULL);
+    }
+
+    /*
+     * Read at most @item_max_len chars in a buffer allocated
+     * on stack.
+     *
+     */
+    char stack_item[item_max_len];
+    memset(stack_item, 0x00, item_max_len);
+
+    fgets(stack_item, item_max_len - 1, stdin);
+    stack_item[strlen(stack_item) - 1] = 0x00;
+
+    if (echo == ECHO_OFF) {
+        /*
+         * Restore original settings for echoing.
+         *
+         */
+        int tcsetattr_ret = tcsetattr(STDIN_FILENO, TCSANOW, &current);
+        ERROR_HANDLER(tcsetattr_ret == -1, NULL);
+    }
+
+    /*
+     * If echoing is off then put a newline after the read is done. It makes it look
+     * prettier.
+     *
+     */
+    if (echo == ECHO_OFF) {
+        puts("");
+    }
+
+    /*
+     * Return a pointer on heap that will contain excactly
+     * strlen + 1 bytes from @stack_item.
+     *
+     */
+    char *heap_item;
+    CALLOC(heap_item, strlen(stack_item) + 1);
+
+    strcpy(heap_item, stack_item);
+    return heap_item;
+
+}
+

Protocoale-Comunicatie-3/requests.c

@@ -0,0 +1,292 @@
+#include <stdlib.h>     
+#include <stdio.h>
+#include <unistd.h>     
+#include <string.h>     
+#include <stdbool.h>
+
+#include <sys/socket.h> 
+#include <netinet/in.h> 
+#include <netdb.h>      
+#include <arpa/inet.h>
+
+#include "connection.h"
+#include "requests.h"
+#include "error.h"
+#include "memory.h"
+
+char *compute_get_request(char *host, char *url, char *query_params,
+                            char **cookies, int cookies_count, char *auth_token) {
+    char *message;
+    CALLOC(message, BUFLEN);
+
+    char *line;
+    CALLOC(line, LINELEN);
+
+    /*
+     * Append queries to the first line of the request.
+     *
+     */
+    if (query_params != NULL) {
+        sprintf(line, "GET %s?%s HTTP/1.1", url, query_params);
+    } else {
+        sprintf(line, "GET %s HTTP/1.1", url);
+    }
+
+    compute_message(message, line);
+
+    if (host == NULL) {
+           
+        FREE(message);
+        FREE(line);
+
+        ERROR_HANDLER(true, NULL);
+    }
+
+    memset(line, 0x00, LINELEN);
+    sprintf(line, "Host: %s", host);
+
+    compute_message(message, line);
+
+    /*
+     * Add headers and/or cookies, according to the protocol format
+     *
+     */
+    if (cookies != NULL) {
+
+        memset(line, 0x00, LINELEN);
+        sprintf(line, "Cookie: %s", cookies[0]);
+
+        for (size_t i = 1; i < cookies_count; i++) {
+            sprintf(line, "%s; %s", line, cookies[i]);
+        }
+
+        compute_message(message, line);
+       
+    }
+
+    /*
+     * Add the authorization token.
+     *
+     */
+    if (auth_token != NULL) {
+        memset(line, 0x00, LINELEN);
+        sprintf(line, "Authorization: Bearer %s", auth_token);
+
+        compute_message(message, line);
+    }
+
+    /*
+     * Add a final newline.
+     *
+     */
+    compute_message(message, "");
+
+    /*
+     * FREE the memory and return.
+     *
+     */
+    FREE(line);
+    return message;
+}
+
+char *compute_delete_request(char *host, char *url, char *query_params,
+                            char **cookies, int cookies_count, char *auth_token) {
+    char *message;
+    CALLOC(message, BUFLEN);
+
+    char *line;
+    CALLOC(line, LINELEN);
+
+    /*
+     * Append queries to the first line of the request.
+     *
+     */
+    if (query_params != NULL) {
+        sprintf(line, "DELETE %s?%s HTTP/1.1", url, query_params);
+    } else {
+        sprintf(line, "DELETE %s HTTP/1.1", url);
+    }
+
+    compute_message(message, line);
+
+    if (host == NULL) {
+           
+        FREE(message);
+        FREE(line);
+
+        ERROR_HANDLER(true, NULL);
+    }
+
+    memset(line, 0x00, LINELEN);
+    sprintf(line, "Host: %s", host);
+
+    compute_message(message, line);
+
+    /*
+     * Add headers and/or cookies, according to the protocol format
+     *
+     */
+    if (cookies != NULL) {
+
+        memset(line, 0x00, LINELEN);
+        sprintf(line, "Cookie: %s", cookies[0]);
+
+        for (size_t i = 1; i < cookies_count; i++) {
+            sprintf(line, "%s; %s", line, cookies[i]);
+        }
+
+        compute_message(message, line);
+       
+    }
+
+    /*
+     * Add the authorization token.
+     *
+     */
+    if (auth_token != NULL) {
+        memset(line, 0x00, LINELEN);
+        sprintf(line, "Authorization: Bearer %s", auth_token);
+
+        compute_message(message, line);
+    }
+
+    /*
+     * Add a final newline.
+     *
+     */
+    compute_message(message, "");
+
+    /*
+     * FREE the memory and return.
+     *
+     */
+    FREE(line);
+    return message;
+}
+
+char *compute_post_request(char *host, char *url, char* content_type, char **body_data,
+        int body_data_fields_count, char **cookies, int cookies_count, char *auth_token) {
+
+    char *message;
+    CALLOC(message, BUFLEN);
+
+    char *line;
+    CALLOC(line, LINELEN);
+
+    char *body_data_buffer;
+    CALLOC(body_data_buffer, LINELEN);
+
+    /*
+     * Write the method name, URL and protocol type.
+     *
+     */
+    sprintf(line, "POST %s HTTP/1.1", url);
+    compute_message(message, line);
+    
+    /*
+     * Add the host.
+     *
+     */
+    if (host == NULL) {
+
+        FREE(message);
+        FREE(line);
+        FREE(body_data_buffer);
+
+        ERROR_HANDLER(true, NULL);
+    }
+
+    memset(line, 0x00, LINELEN);
+    sprintf(line, "Host: %s", host);
+
+    compute_message(message, line);
+
+    /*
+     * Add Content-Type to the request.
+     *
+     */
+    memset(line, 0x00, LINELEN);
+    sprintf(line, "Content-Type: %s", content_type);
+
+    compute_message(message, line);
+
+
+    if (body_data_fields_count == 0) {
+        FREE(message);
+        FREE(line);
+        FREE(body_data_buffer);
+
+        ERROR_HANDLER(true, NULL);
+    }
+
+    /*
+     * Compute Content-Length.
+     *
+     */
+    size_t content_length = 0;
+    for (size_t i = 0; i < body_data_fields_count; i++) {
+        content_length += strlen(body_data[i]);
+    }
+
+    // add the number of &'s from body_Data to length
+    content_length += (body_data_fields_count - 1);
+
+    memset(line, 0x00, LINELEN);
+    sprintf(line, "Content-Length: %ld", content_length);
+
+    compute_message(message, line);
+
+    /*
+     * Add the cookies.
+     *
+     */
+    if (cookies != NULL) {
+       
+        memset(line, 0x00, LINELEN);
+        sprintf(line, "Cookie: %s", cookies[0]);
+
+        for (size_t i = 1; i < cookies_count; i++) {
+            sprintf(line, "%s; %s", line, cookies[i]);
+        }
+
+        compute_message(message, line);
+
+    }
+    /*
+     * Add the authorization token.
+     *
+     */
+    if (auth_token != NULL) {
+        memset(line, 0x00, LINELEN);
+        sprintf(line, "Authorization: Bearer %s", auth_token);
+
+        compute_message(message, line);
+    }
+
+    /*
+     * Add a newline at the final of the header.
+     */
+    compute_message(message, "");
+
+    /*
+     * Add the payload of the POST request.
+     *
+     */
+    memset(body_data_buffer, 0x00, LINELEN);
+    sprintf(body_data_buffer, "%s", body_data[0]);
+
+    for (size_t i = 1; i < body_data_fields_count; i++) {
+        sprintf(body_data_buffer, "%s&%s", body_data_buffer, body_data[i]);
+    }
+
+    compute_message(message, body_data_buffer);
+
+    /*
+     * FREE the memory and return.
+     *
+     */
+    FREE(line);
+    FREE(body_data_buffer);
+
+    return message;
+}