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| 1 | +// Copyright 2013 The Go Authors. All rights reserved. |
| 2 | +// |
| 3 | +// Use of this source code is governed by a BSD-style |
| 4 | +// license that can be found in the LICENSE file or at |
| 5 | +// https://developers.google.com/open-source/licenses/bsd. |
| 6 | + |
| 7 | +// Package talksapp implements the go-talks.appspot.com server. |
| 8 | +package talksapp |
| 9 | + |
| 10 | +import ( |
| 11 | + "bytes" |
| 12 | + "errors" |
| 13 | + "fmt" |
| 14 | + "html/template" |
| 15 | + "io" |
| 16 | + "net/http" |
| 17 | + "os" |
| 18 | + "path" |
| 19 | + "time" |
| 20 | + |
| 21 | + "appengine" |
| 22 | + "appengine/memcache" |
| 23 | + "appengine/urlfetch" |
| 24 | + |
| 25 | + "code.google.com/p/go.tools/present" |
| 26 | + "github.com/golang/gddo/gosrc" |
| 27 | +) |
| 28 | + |
| 29 | +var ( |
| 30 | + presentTemplates = map[string]*template.Template{ |
| 31 | + ".article": parsePresentTemplate("article.tmpl"), |
| 32 | + ".slide": parsePresentTemplate("slides.tmpl"), |
| 33 | + } |
| 34 | + homeArticle = loadHomeArticle() |
| 35 | + contactEmail = "[email protected]" |
| 36 | + gitHubCredentials = "" |
| 37 | +) |
| 38 | + |
| 39 | +func init() { |
| 40 | + http.Handle("/", handlerFunc(serveRoot)) |
| 41 | + http.Handle("/compile", handlerFunc(serveCompile)) |
| 42 | + http.Handle("/bot.html", handlerFunc(serveBot)) |
| 43 | + present.PlayEnabled = true |
| 44 | +} |
| 45 | + |
| 46 | +func playable(c present.Code) bool { |
| 47 | + return present.PlayEnabled && c.Play && c.Ext == ".go" |
| 48 | +} |
| 49 | + |
| 50 | +func parsePresentTemplate(name string) *template.Template { |
| 51 | + t := present.Template() |
| 52 | + t = t.Funcs(template.FuncMap{"playable": playable}) |
| 53 | + if _, err := t.ParseFiles("present/templates/"+name, "present/templates/action.tmpl"); err != nil { |
| 54 | + panic(err) |
| 55 | + } |
| 56 | + t = t.Lookup("root") |
| 57 | + if t == nil { |
| 58 | + panic("root template not found for " + name) |
| 59 | + } |
| 60 | + return t |
| 61 | +} |
| 62 | + |
| 63 | +func loadHomeArticle() []byte { |
| 64 | + const fname = "assets/home.article" |
| 65 | + f, err := os.Open(fname) |
| 66 | + if err != nil { |
| 67 | + panic(err) |
| 68 | + } |
| 69 | + defer f.Close() |
| 70 | + doc, err := present.Parse(f, fname, 0) |
| 71 | + if err != nil { |
| 72 | + panic(err) |
| 73 | + } |
| 74 | + var buf bytes.Buffer |
| 75 | + if err := renderPresentation(&buf, fname, doc); err != nil { |
| 76 | + panic(err) |
| 77 | + } |
| 78 | + return buf.Bytes() |
| 79 | +} |
| 80 | + |
| 81 | +func renderPresentation(w io.Writer, fname string, doc *present.Doc) error { |
| 82 | + t := presentTemplates[path.Ext(fname)] |
| 83 | + if t == nil { |
| 84 | + return errors.New("unknown template extension") |
| 85 | + } |
| 86 | + data := struct { |
| 87 | + *present.Doc |
| 88 | + Template *template.Template |
| 89 | + PlayEnabled bool |
| 90 | + }{ |
| 91 | + doc, |
| 92 | + t, |
| 93 | + true, |
| 94 | + } |
| 95 | + return t.Execute(w, &data) |
| 96 | +} |
| 97 | + |
| 98 | +type presFileNotFoundError string |
| 99 | + |
| 100 | +func (s presFileNotFoundError) Error() string { return fmt.Sprintf("File %s not found.", string(s)) } |
| 101 | + |
| 102 | +func writeHTMLHeader(w http.ResponseWriter, status int) { |
| 103 | + w.Header().Set("Content-Type", "text/html; charset=utf-8") |
| 104 | + w.WriteHeader(status) |
| 105 | +} |
| 106 | + |
| 107 | +func writeTextHeader(w http.ResponseWriter, status int) { |
| 108 | + w.Header().Set("Content-Type", "text/plain; charset=utf-8") |
| 109 | + w.WriteHeader(status) |
| 110 | +} |
| 111 | + |
| 112 | +type transport struct { |
| 113 | + rt http.RoundTripper |
| 114 | + ua string |
| 115 | +} |
| 116 | + |
| 117 | +func (t transport) RoundTrip(r *http.Request) (*http.Response, error) { |
| 118 | + r.Header.Set("User-Agent", t.ua) |
| 119 | + if r.URL.Host == "api.github.com" && gitHubCredentials != "" { |
| 120 | + if r.URL.RawQuery == "" { |
| 121 | + r.URL.RawQuery = gitHubCredentials |
| 122 | + } else { |
| 123 | + r.URL.RawQuery += "&" + gitHubCredentials |
| 124 | + } |
| 125 | + } |
| 126 | + return t.rt.RoundTrip(r) |
| 127 | +} |
| 128 | + |
| 129 | +func httpClient(r *http.Request) *http.Client { |
| 130 | + c := appengine.NewContext(r) |
| 131 | + return &http.Client{ |
| 132 | + Transport: &transport{ |
| 133 | + rt: &urlfetch.Transport{Context: c, Deadline: 10 * time.Second}, |
| 134 | + ua: fmt.Sprintf("%s (+http://%s/bot.html)", appengine.AppID(c), r.Host), |
| 135 | + }, |
| 136 | + } |
| 137 | +} |
| 138 | + |
| 139 | +type handlerFunc func(http.ResponseWriter, *http.Request) error |
| 140 | + |
| 141 | +func (f handlerFunc) ServeHTTP(w http.ResponseWriter, r *http.Request) { |
| 142 | + c := appengine.NewContext(r) |
| 143 | + err := f(w, r) |
| 144 | + if err == nil { |
| 145 | + return |
| 146 | + } else if gosrc.IsNotFound(err) { |
| 147 | + writeTextHeader(w, 400) |
| 148 | + io.WriteString(w, "Not Found.") |
| 149 | + } else if e, ok := err.(*gosrc.RemoteError); ok { |
| 150 | + writeTextHeader(w, 500) |
| 151 | + fmt.Fprintf(w, "Error accessing %s.\n%v", e.Host, e) |
| 152 | + c.Infof("Remote error %s: %v", e.Host, e) |
| 153 | + } else if e, ok := err.(presFileNotFoundError); ok { |
| 154 | + writeTextHeader(w, 200) |
| 155 | + io.WriteString(w, e.Error()) |
| 156 | + } else if err != nil { |
| 157 | + writeTextHeader(w, 500) |
| 158 | + io.WriteString(w, "Internal server error.") |
| 159 | + c.Errorf("Internal error %v", err) |
| 160 | + } |
| 161 | +} |
| 162 | + |
| 163 | +func serveRoot(w http.ResponseWriter, r *http.Request) error { |
| 164 | + switch { |
| 165 | + case r.Method != "GET" && r.Method != "HEAD": |
| 166 | + writeTextHeader(w, 405) |
| 167 | + _, err := io.WriteString(w, "Method not supported.") |
| 168 | + return err |
| 169 | + case r.URL.Path == "/": |
| 170 | + writeHTMLHeader(w, 200) |
| 171 | + _, err := w.Write(homeArticle) |
| 172 | + return err |
| 173 | + default: |
| 174 | + return servePresentation(w, r) |
| 175 | + } |
| 176 | +} |
| 177 | + |
| 178 | +func servePresentation(w http.ResponseWriter, r *http.Request) error { |
| 179 | + c := appengine.NewContext(r) |
| 180 | + importPath := r.URL.Path[1:] |
| 181 | + |
| 182 | + item, err := memcache.Get(c, importPath) |
| 183 | + if err == nil { |
| 184 | + writeHTMLHeader(w, 200) |
| 185 | + w.Write(item.Value) |
| 186 | + return nil |
| 187 | + } else if err != memcache.ErrCacheMiss { |
| 188 | + return err |
| 189 | + } |
| 190 | + |
| 191 | + c.Infof("Fetching presentation %s.", importPath) |
| 192 | + pres, err := gosrc.GetPresentation(httpClient(r), importPath) |
| 193 | + if err != nil { |
| 194 | + return err |
| 195 | + } |
| 196 | + |
| 197 | + ctx := &present.Context{ |
| 198 | + ReadFile: func(name string) ([]byte, error) { |
| 199 | + if p, ok := pres.Files[name]; ok { |
| 200 | + return p, nil |
| 201 | + } |
| 202 | + return nil, presFileNotFoundError(name) |
| 203 | + }, |
| 204 | + } |
| 205 | + |
| 206 | + doc, err := ctx.Parse(bytes.NewReader(pres.Files[pres.Filename]), pres.Filename, 0) |
| 207 | + if err != nil { |
| 208 | + return err |
| 209 | + } |
| 210 | + |
| 211 | + var buf bytes.Buffer |
| 212 | + if err := renderPresentation(&buf, importPath, doc); err != nil { |
| 213 | + return err |
| 214 | + } |
| 215 | + |
| 216 | + if err := memcache.Add(c, &memcache.Item{ |
| 217 | + Key: importPath, |
| 218 | + Value: buf.Bytes(), |
| 219 | + Expiration: time.Hour, |
| 220 | + }); err != nil { |
| 221 | + return err |
| 222 | + } |
| 223 | + |
| 224 | + writeHTMLHeader(w, 200) |
| 225 | + _, err = w.Write(buf.Bytes()) |
| 226 | + return err |
| 227 | +} |
| 228 | + |
| 229 | +func serveCompile(w http.ResponseWriter, r *http.Request) error { |
| 230 | + client := urlfetch.Client(appengine.NewContext(r)) |
| 231 | + if err := r.ParseForm(); err != nil { |
| 232 | + return err |
| 233 | + } |
| 234 | + resp, err := client.PostForm("http://play.golang.org/compile", r.Form) |
| 235 | + if err != nil { |
| 236 | + return err |
| 237 | + } |
| 238 | + defer resp.Body.Close() |
| 239 | + w.Header().Set("Content-Type", resp.Header.Get("Content-Type")) |
| 240 | + _, err = io.Copy(w, resp.Body) |
| 241 | + return err |
| 242 | +} |
| 243 | + |
| 244 | +func serveBot(w http.ResponseWriter, r *http.Request) error { |
| 245 | + c := appengine.NewContext(r) |
| 246 | + writeTextHeader(w, 200) |
| 247 | + _, err := fmt.Fprintf(w, "Contact %s for help with the %s bot.", contactEmail, appengine.AppID(c)) |
| 248 | + return err |
| 249 | +} |
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