2 tofuproxy -- flexible HTTP proxy, TLS terminator, X.509 certificates
3 manager, WARC/Gemini browser
4 Copyright (C) 2021 Sergey Matveev <stargrave@stargrave.org>
6 This program is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, version 3 of the License.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
33 "go.stargrave.org/tofuproxy/fifos"
34 ttls "go.stargrave.org/tofuproxy/tls"
38 ContentTypeGemini = "text/gemini"
39 SchemeGemini = "gemini://"
40 GeminiEntrypoint = "https://gemini"
44 var GemCodeName = map[int]string{
46 11: "SENSITIVE INPUT",
48 30: "REDIRECT - TEMPORARY",
49 31: "REDIRECT - PERMANENT",
50 40: "TEMPORARY FAILURE",
51 41: "SERVER UNAVAILABLE",
55 50: "PERMANENT FAILURE",
58 53: "PROXY REQUEST REFUSED",
60 60: "CLIENT CERTIFICATE REQUIRED",
61 61: "CERTIFICATE NOT AUTHORISED",
62 62: "CERTIFICATE NOT VALID",
65 func absolutizeURL(host, u string, paths ...string) string {
66 host = strings.TrimSuffix(host, GeminiPort)
67 if strings.Contains(u, "://") {
70 if strings.HasPrefix(u, "/") {
71 return GeminiEntrypoint + "/" + host + u
73 paths = append([]string{GeminiEntrypoint, host}, paths...)
74 paths = append(paths, u)
75 return strings.Join(paths, "/")
78 func geminifyURL(host, u string, paths ...string) string {
79 u = absolutizeURL(host, u, paths...)
80 if !strings.HasPrefix(u, SchemeGemini) {
83 return GeminiEntrypoint + "/" + strings.TrimPrefix(u, SchemeGemini)
89 w http.ResponseWriter,
95 paths := strings.Split(strings.TrimPrefix(req.URL.Path, "/"), "/")
96 host, paths = paths[0], paths[1:]
98 if !strings.Contains(hostWithPort, ":") {
99 hostWithPort += GeminiPort
101 conn, err := ttls.DialTLS(context.TODO(), "tcp", hostWithPort)
103 log.Printf("%s: can not dial: %+v\n", req.URL, err)
106 _, err = fmt.Fprintf(
108 SchemeGemini, host, strings.Join(paths, "/"),
111 log.Printf("%s: can not send request: %+v\n", req.URL, err)
114 if len(paths) > 0 && paths[len(paths)-1] == "" {
115 paths = paths[:len(paths)-1]
117 br := bufio.NewReader(conn)
118 rawResp, err := br.ReadString('\n')
120 log.Printf("%s: can not read response: %+v\n", req.URL, err)
123 cols := strings.SplitN(rawResp, " ", 2)
125 err = fmt.Errorf("invalid response format: %s", rawResp)
126 log.Printf("%s: %s\n", req.URL, err)
129 code, err := strconv.Atoi(cols[0])
131 log.Printf("%s: can not parse response code: %+v\n", req.URL, err)
134 codeName := GemCodeName[code]
138 if 10 <= code && code <= 19 {
139 w.Header().Add("Content-Type", "text/plain")
140 w.WriteHeader(http.StatusBadRequest)
141 fmt.Fprintf(w, "%s\n%d (%s): INPUT is not supported\n", cols[1], code, codeName)
144 if 30 <= code && code <= 39 {
145 w.Header().Add("Content-Type", "text/html")
146 w.WriteHeader(http.StatusOK)
147 u := geminifyURL(host, cols[1], paths...)
151 <html><head><title>%d (%s) redirection</title></head>
152 <body>Redirection to <a href="%s">%s</a></body></html>`,
153 code, codeName, u, u,
155 fifos.LogRedir <- fmt.Sprintf(
156 "%s %s\t%d\t%s", req.Method, req.URL, code, cols[1],
160 if 40 <= code && code <= 49 {
161 w.Header().Add("Content-Type", "text/plain")
162 w.WriteHeader(http.StatusBadGateway)
163 fmt.Fprintf(w, "%s\n%d (%s)\n", cols[1], code, codeName)
166 if 50 <= code && code <= 59 {
167 w.Header().Add("Content-Type", "text/plain")
168 w.WriteHeader(http.StatusBadGateway)
169 fmt.Fprintf(w, "%s\n%d (%s)\n", cols[1], code, codeName)
172 if 60 <= code && code <= 69 {
173 w.Header().Add("Content-Type", "text/plain")
174 w.WriteHeader(http.StatusUnauthorized)
175 fmt.Fprintf(w, "%s\n%d (%s)\n", cols[1], code, codeName)
178 if !(20 <= code && code <= 29) {
179 err = fmt.Errorf("unknown response code: %d", code)
180 log.Printf("%s: %s\n", req.URL, err)
183 contentType := strings.Split(strings.TrimRight(cols[1], "\r\n"), ";")[0]
184 if contentType == ContentTypeGemini &&
185 !strings.Contains(req.Header.Get("Accept"), ContentTypeGemini) {
186 w.Header().Add("Content-Type", "text/html")
187 w.WriteHeader(http.StatusOK)
188 raw, err := io.ReadAll(br)
190 log.Printf("%s: can not read response body: %+v\n", req.URL, err)
194 fmt.Fprintf(&buf, `<!DOCTYPE html>
195 <html><head><title>%d (%s)</title></head><body>
198 for _, line := range strings.Split(string(raw), "\n") {
199 if strings.HasPrefix(line, "```") {
201 buf.WriteString("</pre>\n")
203 buf.WriteString("<pre>" + line[3:] + "\n")
209 fmt.Fprintf(&buf, "%s\n", line)
212 if strings.HasPrefix(line, "=> ") {
213 cols = strings.Fields(line)
214 u := geminifyURL(host, cols[1], paths...)
218 &buf, "<a href=\"%s\">%s</a><br/>\n",
219 u, html.EscapeString(cols[1]),
223 &buf, "<a href=\"%s\">%s</a> (<tt>%s</tt>)<br/>\n",
224 u, html.EscapeString(strings.Join(cols[2:], " ")), cols[1],
229 if strings.HasPrefix(line, "# ") {
230 fmt.Fprintf(&buf, "<h1>%s</h1>\n", html.EscapeString(line[2:]))
233 if strings.HasPrefix(line, "## ") {
234 fmt.Fprintf(&buf, "<h2>%s</h2>\n", html.EscapeString(line[3:]))
237 if strings.HasPrefix(line, "### ") {
238 fmt.Fprintf(&buf, "<h3>%s</h3>\n", html.EscapeString(line[4:]))
241 if strings.HasPrefix(line, "* ") {
242 fmt.Fprintf(&buf, "• %s\n", html.EscapeString(line[2:]))
245 if strings.HasPrefix(line, "> ") {
247 &buf, "<blockquote><tt>%s</tt></blockquote>\n",
248 html.EscapeString(line[2:]),
252 fmt.Fprintf(&buf, "%s<br/>\n", html.EscapeString(line))
254 buf.WriteString("</body></html>\n")
255 _, err = w.Write(buf.Bytes())
258 w.Header().Add("Content-Type", contentType)
259 w.WriteHeader(http.StatusOK)
260 _, err = io.Copy(w, br)
262 log.Printf("%s: can not read response body: %+v\n", req.URL, err)