🐛 Handle empty META - fixes #176

CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fix downloading of pages that are too large or timed out
 - `about:` URLs can be typed into the bottom bar (#167)
 - Bookmarks modal closes on ESC like the others (#173)
+- Handle empty META string (#176)
 
 
 ## [1.7.2] - 2020-12-21

display/handlers.go

@@ -136,7 +136,8 @@ func handleFavicon(t *tab, host, old string) {
 		cache.AddFavicon(host, cache.KnownNoFavicon)
 		return
 	}
-	if !strings.HasPrefix(res.Meta, "text/") {
+	if !strings.HasPrefix(res.Meta, "text/") && res.Meta != "" {
+		// Not a textual page
 		cache.AddFavicon(host, cache.KnownNoFavicon)
 		return
 	}

renderer/page.go

@@ -24,14 +24,25 @@ var ErrBadMediatype = errors.New("displayable mediatype is not handled in the co
 // isUTF8 returns true for charsets that are compatible with UTF-8 and don't need to be decoded.
 func isUTF8(charset string) bool {
 	utfCharsets := []string{"", "utf-8", "us-ascii"}
-	for i := range utfCharsets {
-		if strings.ToLower(charset) == utfCharsets[i] {
+	for _, s := range utfCharsets {
+		if charset == s || strings.ToLower(charset) == s {
 			return true
 		}
 	}
 	return false
 }
 
+// getMetaInfo returns the output of mime.ParseMediaType, but handles the empty
+// META which is equal to "text/gemini; charset=utf-8" according to the spec.
+func decodeMeta(meta string) (string, map[string]string, error) {
+	if meta == "" {
+		params := make(map[string]string)
+		params["charset"] = "utf-8"
+		return "text/gemini", params, nil
+	}
+	return mime.ParseMediaType(meta)
+}
+
 // CanDisplay returns true if the response is supported by Amfora
 // for displaying on the screen.
 // It also doubles as a function to detect whether something can be stored in a Page struct.
@@ -40,7 +51,7 @@ func CanDisplay(res *gemini.Response) bool {
 		// No content
 		return false
 	}
-	mediatype, params, err := mime.ParseMediaType(res.Meta)
+	mediatype, params, err := decodeMeta(res.Meta)
 	if err != nil {
 		return false
 	}
@@ -82,7 +93,7 @@ func MakePage(url string, res *gemini.Response, width, leftMargin int, proxied b
 	}
 	// Otherwise, the error is EOF, which is what we want.
 
-	mediatype, params, _ := mime.ParseMediaType(res.Meta)
+	mediatype, params, _ := decodeMeta(res.Meta)
 
 	// Convert content first
 	var utfText string