mimetype handling

upon general navigation:
1. check for any configured handlers for the mimetype
2. normal printing for gophermap, gemtext, and text/plain
3. save the file to downloads folder

README.gmi

@@ -119,10 +119,11 @@ On any other nagivation, this context is cleared and next/previous actions won't
 
 The config file is located at XDG_DATA_HOME/x-1/config.toml. This is usually under .local/share in your home directory.
 
-It contains the following configuration options:
-
+It has a "[main]" section with the following configuration options:
 * quiet (bool): disables automatic printing of pages upon navigation. default "false"
 * vim_keys (bool): whether to activate vim keybindings for the readline prompt. default "true"
 * default_scheme (string): the URL scheme to use in the "go" command when none is provided. default "gemini"
 * soft_wrap (int): the number of columns to wrap, or -1 to not add soft wrapping. default 72
 * download_folder (string): path at which to store files saved by the "save" command. default $HOME
+
+Then a "[handlers]" section contains mappings of mimetypes to shell commands which should be used to handle them.

actions.go

@@ -8,6 +8,7 @@ import (
 	"net/url"
 	"os"
 	"os/exec"
+	"path"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -176,7 +177,7 @@ func Reload(state *BrowserState, conf *Config) error {
 		return err
 	}
 
-	return print(state)
+	return HandleResource(state, conf)
 }
 
 func externalMessage() ([]byte, error) {
@@ -470,6 +471,23 @@ func Print(state *BrowserState) error {
 	return print(state)
 }
 
+func HandleResource(state *BrowserState, conf *Config) error {
+	if state.Modal != nil {
+		return Print(state)
+	}
+
+	if handler, ok := conf.Handlers[state.DocType]; ok {
+		return Pipe(state, handler)
+	}
+
+	switch state.DocType {
+	case "text/gemini", "text/x-gophermap", "text/plain":
+		return print(state)
+	}
+
+	return Save(state, path.Base(state.Url.Path), conf)
+}
+
 func Outline(state *BrowserState, conf *Config) error {
 	if state.Body == nil {
 		return ErrMustBeOnAPage

files.go

@@ -26,6 +26,8 @@ type ConfigMain struct {
 
 type Config struct {
 	ConfigMain `toml:"main"`
+
+	Handlers map[string]string `toml:"handlers"`
 }
 
 func getConfig() (*Config, error) {
@@ -41,7 +43,7 @@ func getConfig() (*Config, error) {
 	}
 
 	c := Config{
-		ConfigMain{
+		ConfigMain: ConfigMain{
 			VimKeys:        true,
 			DefaultScheme:  "gemini",
 			SoftWrap:       100,
@@ -49,6 +51,7 @@ func getConfig() (*Config, error) {
 			Quiet:          false,
 			Pager:          "auto",
 		},
+		Handlers: map[string]string{},
 	}
 	if _, err := toml.DecodeFile(path, &c); err != nil {
 		return nil, err

handlers.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"fmt"
 	"mime"
+	"net/http"
 	"net/url"
 	"strings"
 
@@ -57,6 +58,14 @@ func docType(u *url.URL, response *sliderule.Response) string {
 		}
 	}
 
+	if u.Scheme == "http" || u.Scheme == "https" {
+		resp := response.Meta.(*http.Response)
+		mtype, _, err := mime.ParseMediaType(resp.Header.Get("Content-Type"))
+		if err == nil {
+			return mtype
+		}
+	}
+
 	return "text/plain"
 }