Initial implementation.

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) <year> <owner> . All rights reserved.
+Copyright (c) 2019 <solderpunk@sdf.org> . All rights reserved.
 
 Redistribution and use in source and binary forms, with or without modification,
 are permitted provided that the following conditions are met:

README.md

@@ -1,3 +1,46 @@
-# gemini-demo-2
+# gemini-demo-1
 
-Minimal but usable interactive Gemini client in < 100 LOC of Lua
+Minimal but usable interactive Gemini client in < 100 LOC of Lua.
+
+Depends upon:
+
+* [LuaSocket](http://w3.impa.br/~diego/software/luasocket/)
+* [LuaSec](https://github.com/brunoos/luasec)
+* [Microlight](https://stevedonovan.github.io/microlight/)
+
+## Rationale
+
+One of the original design criteria for the Gemini protocol was that
+"a basic but usable (not ultra-spartan) client should fit comfortably
+within 50 or so lines of code in a modern high-level language.
+Certainly not more than 100".  This client was written to gauge how
+close to (or far from!) that goal the initial rough specification is.
+
+## Capabilities
+
+This crude but functional client:
+
+* Has a minimal interactive interface for "Gemini maps"
+* Will print plain text in any encoding if it is properly declared in
+  the server's response header
+* Will follow redirects
+* Will report errors
+* Does NOT DO ANY validation of TLS certificates
+
+Non-text files are not yet handled.
+
+It's a *snug* fit in 100 lines, but it's possible.  A 50 LOC client
+would need to be much simpler.
+
+## Usage
+
+Run the script and you'll get a prompt.  Type a Gemini URL (the scheme
+is implied, so simply entering e.g. `gemini.conman.org` will work) to
+visit a Gemini location.
+
+If a Gemini menu is visited, you'll see numeric indices for links, ala
+VF-1 or AV-98.  Type a number to visit that link.
+
+There is very crude history: you can type `b` to go "back".
+
+Type `q` to quit.

gemini-demo.lua

@@ -0,0 +1,103 @@
+socket = require("socket")
+socket.url = require("socket.url")
+ssl = require("ssl")
+ml = require('ml')
+
+ssl_params = {
+    mode = "client",
+    protocol = "tlsv1_2"
+}
+
+links = {}
+history = {}
+
+while true do
+    ::main_loop::
+    io.write("> ")
+    cmd = io.read()
+    if string.lower(cmd) == "q" then
+        io.write("Bye!\n")
+        break
+    elseif tonumber(cmd) ~= nil then
+        url = links[tonumber(cmd)]
+    elseif string.lower(cmd) == "b" then
+        -- Yes, twice
+        url = table.remove(history)
+        url = table.remove(history)
+    else
+        url = cmd
+    end
+    
+    -- Add scheme if missing
+    if string.find(url, "://") == nil then
+        url = "gemini://" .. url
+    end
+    -- Add empty path if needed
+    if string.find(string.sub(url, 10, -1), "/") == nil then
+        url = url .. "/"
+    end
+    ::parse_url::
+    parsed_url = socket.url.parse(url)
+    -- Open connection
+    conn = socket.tcp()
+    ret, str = conn:connect(parsed_url.host, 1965)
+    if ret == nil then
+        io.write(str) goto main_loop
+    end
+    conn, err = ssl.wrap(conn, ssl_params)
+    if conn == nil then
+        io.write(err) goto main_loop
+    end
+    conn:dohandshake()
+    -- Send request
+    conn:send(url .. "\r\n")
+    -- Parse response header
+    header = conn:receive("*l")
+    status, meta = table.unpack(ml.split(header, "%s+", 2))
+    -- Handle sucessful response
+    if string.sub(status, 1, 1) == "2" then
+	if meta == "text/gemini" then
+	    --  Handle Geminimap
+            links = {}
+            while true do
+                line, err = conn:receive("*l")
+                if line ~= nil then
+                    if string.sub(line,1,2) == "=>" then
+			line = string.sub(line,3,-1) -- Trim off =>
+			line = string.gsub(line,"^%s+","") -- Trim spaces
+                        link_url, text = table.unpack(ml.split(line, "%s+", 2))
+                        if text == nil then text = link_url end
+                        table.insert(links, socket.url.absolute(url, link_url))
+                        io.write("[" .. #links .. "] " .. text .. "\n")
+                    else
+                        io.write(line .. "\n")
+                    end
+                else
+                    break
+                end
+	    end
+	elseif string.sub(meta, 1, 5) == "text/" then
+	    -- Print text
+            while true do
+                line, err = conn:receive("*l")
+                if line ~= nil then
+                        io.write(line .. "\n")
+                else
+                    break
+                end
+	    end
+        end
+    -- Handle redirects
+    elseif string.sub(status, 1, 1) == "3" then
+        url = socket.url.absolute(url, meta)
+        goto parse_url
+    -- Handle errors
+    elseif string.sub(status, 1, 1) == "4" or string.sub(status, 1, 1) == "5" then
+        io.write("Error: " .. meta)
+    elseif string.sub(status, 1, 1) == "6" then
+        io.write("Client certificates not supported.")
+    else
+        io.write("Invalid response from server.")
+    end
+    table.insert(history, url)
+end