Convert images to images instead of links

Image links will result in a `img` tag instead of a `a` tag. This
behaviour is disabled by default and can be enabled by adding the
following line to to config file:

convertimages: true

To get access to the config in the convert file, I had to move the
config file inside the gmitohtml namespace. This is specially handy
later on if the config file contains other settings which are useful for
the rest of the codebase.

config.go

@@ -1,4 +1,4 @@
-package main
+package gmitohtml
 
 import (
 	"crypto/tls"
@@ -22,12 +22,17 @@ type certConfig struct {
 type appConfig struct {
 	Bookmarks map[string]string
 
+	// Convert image links to images instead of normal links
+	ConvertImages bool
+
 	Certs map[string]*certConfig
 }
 
 var config = &appConfig{
 	Bookmarks: make(map[string]string),
 
+	ConvertImages: false,
+
 	Certs: make(map[string]*certConfig),
 }
 

main.go

@@ -46,7 +46,7 @@ func main() {
 	// TODO option to include response header in page
 	flag.Parse()
 
-	defaultConfig := defaultConfigPath()
+	defaultConfig := gmitohtml.DefaultConfigPath()
 	if configFile == "" {
 		configFile = defaultConfig
 	}
@@ -58,18 +58,18 @@ func main() {
 		}
 
 		if configExists || configFile != defaultConfig {
-			err := readconfig(configFile)
+			err := gmitohtml.ReadConfig(configFile)
 			if err != nil {
 				log.Fatalf("failed to read configuration file at %s: %v\nSee CONFIGURATION.md for information on configuring gmitohtml", configFile, err)
 			}
 
-			for u, label := range config.Bookmarks {
+			for u, label := range gmitohtml.Config.Bookmarks {
 				gmitohtml.AddBookmark(u, label)
 			}
 		}
 	}
 
-	for domain, cc := range config.Certs {
+	for domain, cc := range gmitohtml.Config.Certs {
 		certData, err := ioutil.ReadFile(cc.Cert)
 		if err != nil {
 			log.Fatalf("failed to load client certificate for domain %s: %s", domain, err)
@@ -88,9 +88,9 @@ func main() {
 
 	if daemon != "" {
 		gmitohtml.SetOnBookmarksChanged(func() {
-			config.Bookmarks = gmitohtml.GetBookmarks()
+			gmitohtml.Config.Bookmarks = gmitohtml.GetBookmarks()
 
-			err := saveConfig(configFile)
+			err := gmitohtml.SaveConfig(configFile)
 			if err != nil {
 				log.Fatal(err)
 			}

pkg/gmitohtml/convert.go

@@ -19,6 +19,8 @@ var daemonAddress string
 
 var assetLock sync.Mutex
 
+var imageExtensions = []string{"png", "jpg", "jpeg", "gif", "svg", "webp"}
+
 func rewriteURL(u string, loc *url.URL) string {
 	if daemonAddress != "" {
 		scheme := "gemini"
@@ -126,12 +128,31 @@ func Convert(page []byte, u string) []byte {
 				linkLabel = line[splitStart:]
 			}
 
-			link := append([]byte(`<a href="`), html.EscapeString(rewriteURL(string(linkURL), parsedURL))...)
+			// If link ends with gif/png/jpg, add a image instead of a link
-			link = append(link, []byte(`">`)...)
+			parts := strings.Split(string(linkURL), ".")
-			link = append(link, html.EscapeString(string(linkLabel))...)
+			extension := parts[len(parts)-1]
-			link = append(link, []byte(`</a>`)...)
+			isImage := false
-			result = append(result, link...)
+			for _, ext := range imageExtensions {
-			result = append(result, []byte("<br>")...)
+				if extension == ext {
+					isImage = true
+				}
+			}
+
+			if isImage && Config.ConvertImages {
+				img := append([]byte(`<img src="`), html.EscapeString(rewriteURL(string(linkURL), parsedURL))...)
+				img = append(img, []byte(`" alt="`)...)
+				img = append(img, html.EscapeString(string(linkLabel))...)
+				img = append(img, []byte(`"/>`)...)
+				result = append(result, img...)
+			} else {
+				link := append([]byte(`<a href="`), html.EscapeString(rewriteURL(string(linkURL), parsedURL))...)
+				link = append(link, []byte(`">`)...)
+				link = append(link, html.EscapeString(string(linkLabel))...)
+				link = append(link, []byte(`</a>`)...)
+				result = append(result, link...)
+			    result = append(result, []byte("<br>")...)
+			}
+
 			continue
 		}