From ddf2aefa09e81f0efd1dfcd3c10615ab55c6920d Mon Sep 17 00:00:00 2001
From: Feuerfuchs <git@feuerfuchs.dev>
Date: Sat, 16 Nov 2019 01:39:33 +0100
Subject: Fixed some issues with Gemini

---
 gopherproxy.go | 114 ++++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 72 insertions(+), 42 deletions(-)

(limited to 'gopherproxy.go')

diff --git a/gopherproxy.go b/gopherproxy.go
index 9a60507..ab8e906 100644
--- a/gopherproxy.go
+++ b/gopherproxy.go
@@ -46,6 +46,31 @@ type AssetList struct {
 	PropFontW2 string
 }
 
+func resolveURI(uri string, baseUrl *url.URL) (resolvedUri string) {
+	if strings.HasPrefix(uri, "//") {
+		resolvedUri = "/gemini/" + strings.TrimPrefix(uri, "//")
+	} else if strings.HasPrefix(uri, "gemini://") {
+		resolvedUri = "/gemini/" + strings.TrimPrefix(uri, "gemini://")
+	} else if strings.HasPrefix(uri, "gopher://") {
+		resolvedUri = "/gopher/" + strings.TrimPrefix(uri, "gopher://")
+	} else {
+		url, err := url.Parse(uri)
+		if err != nil {
+			return ""
+		}
+		adjustedUrl := baseUrl.ResolveReference(url)
+		if adjustedUrl.Scheme == "gemini" {
+			resolvedUri = "/gemini/" + adjustedUrl.Host + adjustedUrl.Path
+		} else if adjustedUrl.Scheme == "gopher" {
+			resolvedUri = "/gopher/" + adjustedUrl.Host + adjustedUrl.Path
+		} else {
+			resolvedUri = adjustedUrl.String()
+		}
+	}
+
+	return
+}
+
 func renderGopherDirectory(w http.ResponseWriter, tpl *template.Template, assetList AssetList, uri string, hostport string, d gopher.Directory) error {
 	var title string
 
@@ -109,9 +134,6 @@ func renderGopherDirectory(w http.ResponseWriter, tpl *template.Template, assetL
 }
 
 func parseGeminiDocument(response *GeminiResponse, uri string, hostport string) (items []Item) {
-	scanner := bufio.NewScanner(response.Body)
-	scanner.Split(bufio.ScanLines)
-
 	baseUrl, err := url.Parse(fmt.Sprintf(
 		"gemini://%s/%s",
 		hostport,
@@ -121,6 +143,9 @@ func parseGeminiDocument(response *GeminiResponse, uri string, hostport string)
 		return []Item{}
 	}
 
+	scanner := bufio.NewScanner(response.Body)
+	scanner.Split(bufio.ScanLines)
+
 	for scanner.Scan() {
 		line := strings.Trim(scanner.Text(), "\r\n")
 
@@ -131,34 +156,10 @@ func parseGeminiDocument(response *GeminiResponse, uri string, hostport string)
 
 		linkMatch := GeminiLinkPattern.FindStringSubmatch(line)
 		if len(linkMatch) != 0 && linkMatch[0] != "" {
-			link := linkMatch[1]
-
-			if strings.HasPrefix(link, "//") {
-				link = "/gemini/" + strings.TrimPrefix(link, "//")
-			} else if strings.HasPrefix(link, "gemini://") {
-				link = "/gemini/" + strings.TrimPrefix(link, "gemini://")
-			} else if strings.HasPrefix(link, "gopher://") {
-				link = "/gopher/" + strings.TrimPrefix(link, "gopher://")
-			} else {
-				linkUrl, err := url.Parse(link)
-				if err != nil {
-					continue
-				}
-				adjustedUrl := baseUrl.ResolveReference(linkUrl)
-				if adjustedUrl.Scheme == "gemini" {
-					link = "/gemini/" + adjustedUrl.Host + adjustedUrl.Path
-				} else if adjustedUrl.Scheme == "gopher" {
-					link = "/gopher/" + adjustedUrl.Host + adjustedUrl.Path
-				} else {
-					link = adjustedUrl.String()
-				}
-			}
-
 			item.Type = ITEM_TYPE_GEMINI_LINK
-			item.Link = template.URL(link)
-			if linkMatch[2] != "" {
-				item.Text = linkMatch[2]
-			} else {
+			item.Link = template.URL(resolveURI(linkMatch[1], baseUrl))
+			item.Text = linkMatch[2]
+			if item.Text == "" {
 				item.Text = linkMatch[1]
 			}
 		}
@@ -342,6 +343,29 @@ func GeminiHandler(tpl *template.Template, robotsdata *robotstxt.RobotsData, ass
 			return
 		}
 
+		if int(res.Header.Status/10) == 3 {
+			baseUrl, err := url.Parse(fmt.Sprintf(
+				"gemini://%s/%s",
+				hostport,
+				uri,
+			))
+			if err != nil {
+				tpl.Execute(w, struct {
+					Title    string
+					URI      string
+					Assets   AssetList
+					RawText  string
+					Lines    []Item
+					Error    bool
+					Protocol string
+				}{uri, fmt.Sprintf("%s/%s", hostport, uri), assetList, fmt.Sprintf("Error: %s", err), nil, true, "gemini"})
+				return
+			}
+
+			http.Redirect(w, req, resolveURI(res.Header.Meta, baseUrl), http.StatusFound)
+			return
+		}
+
 		if int(res.Header.Status/10) != 2 {
 			tpl.Execute(w, struct {
 				Title    string
@@ -355,18 +379,24 @@ func GeminiHandler(tpl *template.Template, robotsdata *robotstxt.RobotsData, ass
 			return
 		}
 
-		if strings.HasPrefix(res.Header.Meta, MIME_GEMINI) {
-			items := parseGeminiDocument(res, uri, hostport)
-			tpl.Execute(w, struct {
-				Title    string
-				URI      string
-				Assets   AssetList
-				RawText  string
-				Lines    []Item
-				Error    bool
-				Protocol string
-			}{uri, fmt.Sprintf("%s/%s", hostport, uri), assetList, "", items, false, "gemini"})
-		} else if strings.HasPrefix(res.Header.Meta, "text/") {
+		if strings.HasPrefix(res.Header.Meta, "text/") {
+			// TODO: Handle encoding
+			// https://stackoverflow.com/questions/32518432/how-to-convert-from-an-encoding-to-utf-8-in-go
+
+			if strings.HasPrefix(res.Header.Meta, MIME_GEMINI) {
+				items := parseGeminiDocument(res, uri, hostport)
+				tpl.Execute(w, struct {
+					Title    string
+					URI      string
+					Assets   AssetList
+					RawText  string
+					Lines    []Item
+					Error    bool
+					Protocol string
+				}{uri, fmt.Sprintf("%s/%s", hostport, uri), assetList, "", items, false, "gemini"})
+				return
+			}
+
 			buf := new(bytes.Buffer)
 			buf.ReadFrom(res.Body)
 			tpl.Execute(w, struct {
-- 
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