1// SPDX-License-Identifier: AGPL-3.0-or-later
2
3// Package web is the HTML front of ermite: the pages of the read-only
4// showcase, rendered with templ from the data of the use cases.
5//
6// Like every other inbound adapter, the package reads and writes through the
7// use case interfaces of package ports (ADR 0024), never through the API. The
8// caller of every use case call is passed explicitly: the principal of the
9// request, which is anonymous unless the request carries a valid owner session
10// (ServeHTTP sets it in the context, principal reads it). The use cases then
11// show public repositories only to an anonymous caller; a private repository
12// is indistinguishable from a missing one (domain.ErrNotFound), here as
13// everywhere.
14//
15// Adding a page: a handler on Server, a route in routes, a templ page in
16// pages.templ and its view model in view.go.
17package web
18
19import (
20 "bytes"
21 "context"
22 "crypto/rand"
23 "encoding/hex"
24 "errors"
25 "fmt"
26 "net/http"
27 "net/netip"
28 "net/url"
29 "strings"
30 "time"
31
32 "github.com/a-h/templ"
33 "github.com/bnema/zerowrap"
34
35 "bnema.dev/ermite/internal/domain"
36 "bnema.dev/ermite/internal/ports"
37)
38
39// Patterns are the ServeMux patterns the handler serves: everything. The
40// router of the package answers the paths it does not know with its 404
41// page, and the more specific patterns of the server (health, API, Git) win
42// over this one.
43var Patterns = []string{"/"}
44
45// requestTimeout bounds the use case calls that build one page.
46const requestTimeout = 30 * time.Second
47
48// Config configures a Server.
49type Config struct {
50 // Mirrors answers the push mirror badge shown to repository admins. Without it there is
51 // no badge. Leave it unset rather than assigning a typed nil pointer.
52 Mirrors ports.MirrorWarner
53 // Repos and Browse are the use cases the pages are built from.
54 Repos ports.RepoService
55 Browse ports.BrowseService
56 // MergeRequests serves the merge request pages (ADR 0017). Without it
57 // there are no such pages, nor section for them. Leave it unset rather
58 // than assigning a typed nil pointer.
59 MergeRequests ports.MergeRequestService
60 // Issues serves the issue pages (ADR 0031). Without it there are no such
61 // pages, nor tab for them. Leave it unset rather than assigning a typed
62 // nil pointer.
63 Issues ports.IssueService
64 // IssueNumbers tells whether a number names an issue or a merge request,
65 // so that the page of the wrong kind redirects to the right one. Without
66 // it there is no such redirect. Leave it unset rather than assigning a
67 // typed nil pointer.
68 IssueNumbers ports.IssueNumberResolver
69 // IssueForm serves the public issue form of repositories whose issues
70 // mode is public (GET and POST /<repo>/issues/new for a visitor). Without
71 // it there is no such form. Leave it unset rather than assigning a typed
72 // nil pointer.
73 IssueForm ports.IssueSubmissionService
74 // Moderation serves the Approve, Reject and Reject-and-ban buttons of the
75 // pending issues in the inbox. It needs Inbox. Without it there are no
76 // such routes. Leave it unset rather than assigning a typed nil pointer.
77 Moderation ports.IssueModerationService
78 // Inbox serves the owner's inbox page (/-/inbox) and the button that
79 // leads to it. Without it there is neither. Leave it unset rather than
80 // assigning a typed nil pointer.
81 Inbox ports.InboxService
82 // SigningKey tells the key that signs the squash and merge commits, shown
83 // in the merge box. Without it the box does not name the key. Leave it
84 // unset rather than assigning a typed nil pointer.
85 SigningKey ports.SigningKeyService
86 // Runs serves the CI pages (/<repo>/actions) and the checks shown next to
87 // commits and merge requests. Without it there are no such pages. Leave it
88 // unset rather than assigning a typed nil pointer.
89 Runs ports.RunService
90 // Artifacts serves the artifacts of the runs: a section of the run page,
91 // their download and their deletion. It needs Runs. Without it there is
92 // neither. Leave it unset rather than assigning a typed nil pointer.
93 Artifacts ports.ArtifactService
94 // Releases serves the release pages and streamed assets. Nil disables them.
95 Releases ports.ReleaseService
96 // Events is the source of the event stream behind /-/events. Without
97 // it the pages are not live and the route answers 404. Leave it unset
98 // rather than assigning a typed nil pointer.
99 Events ports.EventService
100 // Heartbeat is how often an idle event stream gets a comment line;
101 // DefaultHeartbeat when zero.
102 Heartbeat time.Duration
103 // Owner is the owner login the GitHub-shaped URLs of CI show
104 // (<server>/<owner>/<repo>/...). A GET or HEAD of /<owner>/<rest> is
105 // redirected to /<rest> unless a repository named like the owner is
106 // visible to the caller. Empty: no redirect.
107 Owner string
108 // PublicURL is the base URL of the instance, without a trailing slash:
109 // the clone URLs are built on it, and its host is the instance name.
110 PublicURL string
111 // SourceURL is the link to the source of the running version (AGPL §13).
112 SourceURL string
113 // Version is the version of the running server.
114 Version string
115 // Now is the clock of relative dates; time.Now when nil.
116 Now func() time.Time
117 // Sessions signs the owner in (ADR 0018). Without it there are no login
118 // routes and every visitor is anonymous.
119 Sessions ports.WebSessionService
120 // Passkeys signs the owner in with a passkey and manages the passkeys
121 // (ADR 0026). Without it, or without Sessions, there are no passkey
122 // routes and no link to them. Leave it unset rather than assigning a typed
123 // nil pointer.
124 Passkeys ports.WebPasskeyService
125 // Limiter counts the failed logins; required with Sessions. Share it with
126 // the API and Git, so that a client has one budget of failures.
127 Limiter ports.FailureLimiter
128 // TrustedProxies are the networks allowed to set X-Forwarded-For, to find
129 // the address of the client that fails a login.
130 TrustedProxies []netip.Prefix
131}
132
133// Server serves the pages. It is an http.Handler.
134type Server struct {
135 cfg Config
136 instance string
137 origin string // scheme://host of the public URL, what a POST must come from
138 assets *assetSet
139 md *markdown
140 // pathCache holds the path lists the file finder fetches.
141 pathCache *pathCache
142 // hl holds the colours of highlighted diffs.
143 hl *hlCache
144 mux *http.ServeMux
145 // ownerRepo is the owner login as a repository name, zero when it is not
146 // a valid one (then no repository can be named like the owner).
147 ownerRepo domain.RepoName
148 // refsFan shares the fragments of the refs page between the watchers of
149 // a push; entries are few and short-lived.
150 refsFan fanout
151 // pulses holds the activity curves of the home rows.
152 pulses pulseCache
153}
154
155// New builds the web handler.
156func New(cfg Config) (*Server, error) {
157 if cfg.Repos == nil || cfg.Browse == nil {
158 return nil, errors.New("web: the repository and browse use cases are required")
159 }
160 u, err := url.Parse(cfg.PublicURL)
161 if err != nil || u.Host == "" {
162 return nil, fmt.Errorf("web: public URL %q is not a valid base URL", cfg.PublicURL)
163 }
164 if cfg.Now == nil {
165 cfg.Now = time.Now
166 }
167 assets, err := loadAssets()
168 if err != nil {
169 return nil, fmt.Errorf("web: load assets: %w", err)
170 }
171 if cfg.Sessions != nil && cfg.Limiter == nil {
172 return nil, errors.New("web: sessions need a failure limiter")
173 }
174 s := &Server{
175 cfg: cfg, instance: u.Host, assets: assets, md: newMarkdown(),
176 pathCache: newPathCache(pathCacheBytes, pathBuilds),
177 hl: newHLCache(hlCacheBytes),
178 origin: originOf(u),
179 }
180 s.ownerRepo, _ = domain.ParseRepoName(cfg.Owner)
181 s.mux = s.routes()
182 return s, nil
183}
184
185// routes is the router of the web. Any path that is not a page is the 404
186// page.
187func (s *Server) routes() *http.ServeMux {
188 mux := http.NewServeMux()
189 mux.HandleFunc("GET "+StaticPrefix, s.assets.serve)
190 mux.HandleFunc("GET /-/events", s.events)
191 mux.HandleFunc("GET "+ServiceWorkerPath, s.assets.sw.serve)
192 if s.cfg.Sessions != nil {
193 mux.HandleFunc("GET "+loginPrefix+"{nonce}", s.loginConfirm)
194 mux.HandleFunc("POST "+loginPrefix+"{nonce}", s.loginPost)
195 mux.HandleFunc("POST /-/logout", s.logout)
196 }
197 if s.passkeysOn() {
198 s.passkeyRoutes(mux)
199 }
200 if s.cfg.Inbox != nil {
201 mux.HandleFunc("GET "+inboxPath, s.page(s.inbox))
202 if s.cfg.Moderation != nil {
203 mux.HandleFunc("POST "+inboxPath+"/pending/{repo}/{id}/approve", s.mrAction(s.pendingApprove))
204 mux.HandleFunc("POST "+inboxPath+"/pending/{repo}/{id}/reject", s.mrAction(s.pendingReject(false)))
205 mux.HandleFunc("POST "+inboxPath+"/pending/{repo}/{id}/ban", s.mrAction(s.pendingReject(true)))
206 }
207 }
208 mux.HandleFunc("GET /{$}", s.page(s.home))
209 mux.HandleFunc("GET /{repo}", s.page(s.summary))
210 mux.HandleFunc("GET /{repo}/{$}", s.page(s.summary))
211 mux.HandleFunc("GET /{repo}/refs", s.page(s.refs))
212 mux.HandleFunc("GET /{repo}/commits", s.page(s.commits))
213 mux.HandleFunc("GET /{repo}/commits/{rest...}", s.page(s.commits))
214 mux.HandleFunc("GET /{repo}/commit/{sha}", s.page(s.commit))
215 mux.HandleFunc("GET /{repo}/commit/{sha}/files", s.page(s.commitFiles))
216 mux.HandleFunc("GET /{repo}/tree", s.page(s.tree))
217 mux.HandleFunc("GET /{repo}/tree/{rest...}", s.page(s.tree))
218 mux.HandleFunc("GET /{repo}/blob/{rest...}", s.page(s.blob))
219 mux.HandleFunc("GET /{repo}/raw/{rest...}", s.raw)
220 mux.HandleFunc("GET /{repo}/paths/{sha}", s.paths)
221 mux.HandleFunc("GET /{repo}/context/{sha}", s.page(s.diffContext))
222 if s.cfg.MergeRequests != nil {
223 mux.HandleFunc("GET /{repo}/merge-requests", s.page(s.mrList))
224 mux.HandleFunc("GET /{repo}/merge-requests/{$}", s.page(s.mrList))
225 mux.HandleFunc("GET /{repo}/merge-requests/{n}", s.pageOrRedirect(s.mrShow, s.mrToIssue))
226 mux.HandleFunc("GET /{repo}/merge-requests/{n}/since", s.page(s.mrSince))
227 mux.HandleFunc("GET /{repo}/merge-requests/{n}/files", s.page(s.mrFiles))
228 mux.HandleFunc("GET /{repo}/compare/{rest...}", s.page(s.compare))
229 // The writes: POST only, behind the gate (ServeHTTP).
230 mux.HandleFunc("POST /{repo}/merge-requests", s.mrAction(s.mrCreate))
231 mux.HandleFunc("POST /{repo}/merge-requests/{n}/comments", s.mrAction(s.mrComment))
232 mux.HandleFunc("POST /{repo}/merge-requests/{n}/comments/{id}/resolve", s.mrAction(s.mrResolve))
233 mux.HandleFunc("POST /{repo}/merge-requests/{n}/comments/{id}/edit", s.mrAction(s.mrEditComment))
234 mux.HandleFunc("POST /{repo}/merge-requests/{n}/comments/{id}/delete", s.mrAction(s.mrDeleteComment))
235 mux.HandleFunc("POST /{repo}/merge-requests/{n}/merge", s.mrAction(s.mrMerge))
236 mux.HandleFunc("POST /{repo}/merge-requests/{n}/auto-merge", s.mrAction(s.mrAutoMerge))
237 mux.HandleFunc("POST /{repo}/merge-requests/{n}/auto-merge/cancel", s.mrAction(s.mrCancelAutoMerge))
238 mux.HandleFunc("POST /{repo}/merge-requests/{n}/close", s.mrAction(s.mrClose))
239 mux.HandleFunc("POST /{repo}/merge-requests/{n}/ready", s.mrAction(s.mrReady))
240 mux.HandleFunc("POST /{repo}/merge-requests/{n}/read", s.mrAction(s.mrRead))
241 }
242 if s.cfg.Issues != nil {
243 mux.HandleFunc("GET /{repo}/issues", s.page(s.issueList))
244 mux.HandleFunc("GET /{repo}/issues/{$}", s.page(s.issueList))
245 mux.HandleFunc("GET /{repo}/issues/new", s.issueNewRoute)
246 mux.HandleFunc("GET /{repo}/issues/{n}", s.pageOrRedirect(s.issueShow, s.issueToMR))
247 // The writes: POST only, behind the gate (ServeHTTP).
248 mux.HandleFunc("POST /{repo}/issues", s.issueAction(s.issueCreate))
249 mux.HandleFunc("POST /{repo}/issues/{n}/comments", s.issueAction(s.issueComment))
250 mux.HandleFunc("POST /{repo}/issues/{n}/close", s.issueAction(s.issueClose))
251 mux.HandleFunc("POST /{repo}/issues/{n}/reopen", s.issueAction(s.issueReopen))
252 }
253 if s.cfg.IssueForm != nil {
254 mux.HandleFunc("GET /{repo}/issues/submitted", s.issueSubmittedPage)
255 mux.HandleFunc("POST /{repo}/issues/new", s.issueFormPost)
256 }
257 if s.cfg.Releases != nil {
258 mux.HandleFunc("GET /{repo}/releases", s.page(s.releaseList))
259 mux.HandleFunc("GET /{repo}/releases/{$}", s.page(s.releaseList))
260 mux.HandleFunc("GET /{repo}/releases/tag/{tag...}", s.page(s.releaseShow))
261 mux.HandleFunc("GET /{repo}/releases/latest", s.releaseLatest)
262 mux.HandleFunc("GET /{repo}/releases/download/{tag}/{asset}", s.releaseDownload)
263 mux.HandleFunc("GET /{repo}/releases/latest/download/{asset}", s.releaseDownload)
264 mux.HandleFunc("GET /{repo}/releases/assets/{id}", s.releaseDownload)
265 }
266 if s.cfg.Runs != nil {
267 mux.HandleFunc("GET /{repo}/actions", s.page(s.actions))
268 mux.HandleFunc("GET /{repo}/actions/{$}", s.page(s.actions))
269 mux.HandleFunc("GET /{repo}/actions/runs/{id}", s.page(s.run))
270 mux.HandleFunc("GET /{repo}/actions/runs/{id}/job/{job}", s.page(s.job))
271 mux.HandleFunc("GET /{repo}/actions/runs/{id}/job/{job}/raw", s.rawLog)
272 mux.HandleFunc("GET /{repo}/actions/runs/{id}/job/{job}/stream", s.logStream)
273 mux.HandleFunc("POST /{repo}/actions/runs/{id}/cancel", s.ciAction(s.runCancel))
274 mux.HandleFunc("POST /{repo}/actions/runs/{id}/rerun", s.ciAction(s.runRerun(false)))
275 mux.HandleFunc("POST /{repo}/actions/runs/{id}/rerun-failed", s.ciAction(s.runRerun(true)))
276 if s.cfg.Artifacts != nil {
277 mux.HandleFunc("GET /{repo}/actions/runs/{id}/artifacts/{artifact}", s.artifactDownload)
278 mux.HandleFunc("POST /{repo}/actions/runs/{id}/artifacts/{artifact}/delete", s.ciAction(s.artifactDelete))
279 }
280 }
281 mux.HandleFunc(catchAll, s.page(s.notFound))
282 return mux
283}
284
285// ServeHTTP implements http.Handler.
286func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
287 // Whatever the context carried, the caller is anonymous until a valid
288 // session says otherwise (withSession).
289 r = r.WithContext(domain.ContextWithPrincipal(r.Context(), domain.Anonymous()))
290 r = s.withSession(w, r)
291 if !s.gate(w, r) {
292 return
293 }
294 if to, ok := s.ownerRedirect(r); ok {
295 http.Redirect(w, r, to, http.StatusPermanentRedirect)
296 return
297 }
298 s.mux.ServeHTTP(w, r)
299}
300
301// catchAll is the pattern of the paths that are no page.
302const catchAll = "GET /{repo}/{rest...}"
303
304// ownerRedirect maps /<owner>/<repo>[.git][/rest] to /<repo>[.git][/rest]: the
305// URLs that the github context of CI shows (html_url, commit and compare
306// URLs, clone_url) have the owner of the instance in front, like GitHub's.
307//
308// The rule is by repository, not by route: when no repository named like the
309// owner is visible to the caller, every GET or HEAD of /<owner>/<rest> is
310// redirected, so /<owner>/actions reaches the repository named "actions". A
311// repository named like the owner keeps its own pages. A private one is seen
312// as missing by an anonymous caller (the use case answers ErrNotFound), so the
313// redirect is the same as for a name nobody has and tells nothing.
314//
315// The target is built from a segment that parses as a repository name, which
316// has no slash, backslash, percent sign or dot-dot: it can only be a path on
317// this origin, never a "//host" one.
318func (s *Server) ownerRedirect(r *http.Request) (string, bool) {
319 if s.cfg.Owner == "" || (r.Method != http.MethodGet && r.Method != http.MethodHead) {
320 return "", false
321 }
322 first, rest, ok := strings.Cut(strings.TrimPrefix(r.URL.EscapedPath(), "/"), "/")
323 if !ok || !domain.OwnerMatches(s.cfg.Owner, first) || rest == "" {
324 return "", false
325 }
326 repo, _, _ := strings.Cut(rest, "/")
327 if _, err := domain.ParseRepoPath(repo); err != nil {
328 return "", false
329 }
330 if s.ownerNamesARepo(r) {
331 return "", false
332 }
333 to := "/" + rest
334 if r.URL.RawQuery != "" {
335 to += "?" + r.URL.RawQuery
336 }
337 return to, true
338}
339
340// ownerNamesARepo tells whether the caller can see a repository named like
341// the owner. A lookup that fails otherwise counts as yes: the request is then
342// served as it was before, without a redirect.
343func (s *Server) ownerNamesARepo(r *http.Request) bool {
344 if s.ownerRepo.IsZero() {
345 return false // the owner login is not a repository name
346 }
347 ctx := r.Context()
348 _, err := s.cfg.Repos.Get(ctx, principal(ctx), s.ownerRepo)
349 switch {
350 case err == nil:
351 return true
352 case errors.Is(err, domain.ErrNotFound):
353 return false
354 }
355 log := zerowrap.FromCtx(ctx)
356 log.Debug().Err(err).Msg("owner redirect: the lookup of the repository named like the owner failed")
357 return true
358}
359
360// handler builds a page. It returns the component and its status, or an
361// error, which becomes the 404 or 500 page.
362type handler func(ctx context.Context, r *http.Request) (templ.Component, int, error)
363
364// page adapts a handler: it bounds the use case calls, renders the component into
365// a buffer (so that a failure never leaves half a page), and maps errors to
366// the state pages.
367func (s *Server) page(h handler) http.HandlerFunc {
368 return func(w http.ResponseWriter, r *http.Request) {
369 ctx, cancel := context.WithTimeout(r.Context(), requestTimeout)
370 defer cancel()
371 c, status, err := h(ctx, r)
372 if err != nil {
373 s.fail(ctx, w, r, err)
374 return
375 }
376 s.write(ctx, w, r, status, c)
377 }
378}
379
380// write renders c with the given status.
381func (s *Server) write(ctx context.Context, w http.ResponseWriter, r *http.Request, status int, c templ.Component) {
382 var buf bytes.Buffer
383 if err := c.Render(ctx, &buf); err != nil {
384 // The error page itself failed: a bare answer is all that is left.
385 log := zerowrap.FromCtx(ctx)
386 log.Error().Err(err).Str("path", logPath(r.URL.Path)).Msg("render page")
387 http.Error(w, "internal error", http.StatusInternalServerError)
388 return
389 }
390 h := w.Header()
391 h.Set("Content-Type", "text/html; charset=utf-8")
392 // Links on this origin are prefetched on hover, so a click shows the page
393 // at once. Every GET page is safe to load (nothing is marked read on GET).
394 h.Set("Speculation-Rules", `"`+s.assets.urls.Rules+`"`)
395 // Public pages: the browser and any proxy revalidate each time. A page
396 // rendered for the owner is private and never stored; a handler that set
397 // its own Cache-Control keeps it.
398 if h.Get("Cache-Control") == "" {
399 cacheHeaders(ctx, h, "no-cache", sessionCache)
400 }
401 body := buf.Bytes()
402 // Whether the body is sent gzipped follows from its size and the request
403 // alone, so that the tag is known before the compression is spent.
404 gz := len(body) >= minCompress && acceptsGzip(r.Header) &&
405 !noTransform(h) && h.Get("Content-Encoding") == ""
406 addVary(h, "Accept-Encoding")
407 readOnly := r.Method == http.MethodGet || r.Method == http.MethodHead
408 // A page that may be stored gets a validator: the browser then
409 // revalidates with If-None-Match and a page that did not change costs a
410 // 304. A no-store page (the owner's) is never revalidated.
411 if readOnly && status == http.StatusOK && h.Get("ETag") == "" && !hasCacheDirective(h, noStore) {
412 tag := pageETag(body, SignedIn(ctx), gz)
413 h.Set("ETag", tag)
414 if etagMatches(strings.Join(r.Header.Values("If-None-Match"), ","), tag) {
415 h.Del("Content-Type")
416 w.WriteHeader(http.StatusNotModified)
417 return
418 }
419 }
420 if gz {
421 if z, err := gzipPage(body); err == nil && len(z) < len(body) {
422 body = z
423 h.Set("Content-Encoding", "gzip")
424 }
425 }
426 h.Set("Content-Length", itoa(len(body)))
427 w.WriteHeader(status)
428 if r.Method != http.MethodHead {
429 _, _ = w.Write(body)
430 }
431}
432
433// fail answers an error of a use case: not found (and a name or revision the
434// use case refuses, which no page can show either) gives the 404 page, a
435// visitor that left gives nothing, anything else gives the 500 page with an id
436// to find the cause in the log.
437func (s *Server) fail(ctx context.Context, w http.ResponseWriter, r *http.Request, err error) {
438 switch {
439 case errors.Is(err, domain.ErrNotFound), domain.IsInvalid(err):
440 s.write(ctx, w, r, http.StatusNotFound, s.notFoundPage())
441 case errors.Is(err, context.Canceled):
442 // The client is gone; there is nobody to answer.
443 default:
444 id := requestID()
445 log := zerowrap.FromCtx(ctx)
446 log.Error().Err(err).Str("request_id", id).Str("path", logPath(r.URL.Path)).Msg("web request failed")
447 s.write(ctx, w, r, http.StatusInternalServerError, s.errorPage(id))
448 }
449}
450
451// errNotFound is returned by handlers for a resource that does not exist
452// although the use case did not say so (a ref or a path that is not there).
453var errNotFound = domain.ErrNotFound
454
455// requestID is a short random id, shown on the 500 page and logged.
456func requestID() string {
457 var b [4]byte
458 _, _ = rand.Read(b[:])
459 return hex.EncodeToString(b[:])
460}
461
462// notFound is the handler of the paths without a page.
463func (s *Server) notFound(context.Context, *http.Request) (templ.Component, int, error) {
464 return nil, 0, errNotFound
465}
466
467// base is the Layout every page starts from.
468func (s *Server) base() Layout {
469 return Layout{
470 Owner: s.cfg.Owner,
471 Version: s.cfg.Version,
472 SourceURL: s.cfg.SourceURL,
473 Assets: s.assets.urls,
474 Passkeys: s.passkeysOn(),
475 }
476}
477
478// stateLayout is the layout of a state page: only the way home.
479func (s *Server) stateLayout(title string, crumbs []Crumb) Layout {
480 l := s.base()
481 l.Title = title + " · " + s.instance
482 l.Crumbs = crumbs
483 l.Cmd = []CmdItem{{Kind: "go", Label: "home", Href: "/"}}
484 return l
485}
486
487func (s *Server) notFoundPage() templ.Component {
488 l := s.stateLayout("404", []Crumb{{Label: "not found", Current: true}})
489 return State(l, StatePage{
490 Code: "404", Title: "not found",
491 Lines: []string{"no such page, ref or path.", "check the URL, or start from the repo list."},
492 Back: []Link{{Label: "home", Href: "/"}},
493 })
494}
495
496func (s *Server) errorPage(id string) templ.Component {
497 l := s.stateLayout("error", []Crumb{{Label: "error", Current: true}})
498 return State(l, StatePage{
499 Code: "500", Title: "internal error",
500 Lines: []string{
501 "the server failed to answer this request.",
502 "request id: " + id,
503 "retry in a moment; if it persists, the owner has the log.",
504 },
505 Back: []Link{{Label: "home", Href: "/"}},
506 })
507}
508
509// originOf is the origin of a URL as a browser writes it in the Origin
510// header: scheme and host in lower case, the port only when it is not the
511// default of the scheme.
512func originOf(u *url.URL) string {
513 scheme, host, port := strings.ToLower(u.Scheme), strings.ToLower(u.Hostname()), u.Port()
514 if strings.Contains(host, ":") {
515 host = "[" + host + "]"
516 }
517 defaultPort := (scheme == "http" && port == "80") || (scheme == "https" && port == "443")
518 if port != "" && !defaultPort {
519 host += ":" + port
520 }
521 return scheme + "://" + host
522}