services/keep-web/handler.go

   1 // Copyright (C) The Arvados Authors. All rights reserved.
   2 //
   3 // SPDX-License-Identifier: AGPL-3.0
   4
   5 package main
   6
   7 import (
   8         "encoding/json"
   9         "html"
  10         "html/template"
  11         "io"
  12         "net/http"
  13         "net/url"
  14         "os"
  15         "path/filepath"
  16         "sort"
  17         "strconv"
  18         "strings"
  19         "sync"
  20
  21         "git.arvados.org/arvados.git/sdk/go/arvados"
  22         "git.arvados.org/arvados.git/sdk/go/arvadosclient"
  23         "git.arvados.org/arvados.git/sdk/go/auth"
  24         "git.arvados.org/arvados.git/sdk/go/ctxlog"
  25         "git.arvados.org/arvados.git/sdk/go/health"
  26         "git.arvados.org/arvados.git/sdk/go/httpserver"
  27         "git.arvados.org/arvados.git/sdk/go/keepclient"
  28         "github.com/sirupsen/logrus"
  29         "golang.org/x/net/webdav"
  30 )
  31
  32 type handler struct {
  33         Config        *Config
  34         MetricsAPI    http.Handler
  35         clientPool    *arvadosclient.ClientPool
  36         setupOnce     sync.Once
  37         healthHandler http.Handler
  38         webdavLS      webdav.LockSystem
  39 }
  40
  41 // parseCollectionIDFromDNSName returns a UUID or PDH if s begins with
  42 // a UUID or URL-encoded PDH; otherwise "".
  43 func parseCollectionIDFromDNSName(s string) string {
  44         // Strip domain.
  45         if i := strings.IndexRune(s, '.'); i >= 0 {
  46                 s = s[:i]
  47         }
  48         // Names like {uuid}--collections.example.com serve the same
  49         // purpose as {uuid}.collections.example.com but can reduce
  50         // cost/effort of using [additional] wildcard certificates.
  51         if i := strings.Index(s, "--"); i >= 0 {
  52                 s = s[:i]
  53         }
  54         if arvadosclient.UUIDMatch(s) {
  55                 return s
  56         }
  57         if pdh := strings.Replace(s, "-", "+", 1); arvadosclient.PDHMatch(pdh) {
  58                 return pdh
  59         }
  60         return ""
  61 }
  62
  63 var urlPDHDecoder = strings.NewReplacer(" ", "+", "-", "+")
  64
  65 var notFoundMessage = "404 Not found\r\n\r\nThe requested path was not found, or you do not have permission to access it.\r"
  66 var unauthorizedMessage = "401 Unauthorized\r\n\r\nA valid Arvados token must be provided to access this resource.\r"
  67
  68 // parseCollectionIDFromURL returns a UUID or PDH if s is a UUID or a
  69 // PDH (even if it is a PDH with "+" replaced by " " or "-");
  70 // otherwise "".
  71 func parseCollectionIDFromURL(s string) string {
  72         if arvadosclient.UUIDMatch(s) {
  73                 return s
  74         }
  75         if pdh := urlPDHDecoder.Replace(s); arvadosclient.PDHMatch(pdh) {
  76                 return pdh
  77         }
  78         return ""
  79 }
  80
  81 func (h *handler) setup() {
  82         // Errors will be handled at the client pool.
  83         arv, _ := arvados.NewClientFromConfig(h.Config.cluster)
  84         h.clientPool = arvadosclient.MakeClientPoolWith(arv)
  85
  86         keepclient.RefreshServiceDiscoveryOnSIGHUP()
  87         keepclient.DefaultBlockCache.MaxBlocks = h.Config.cluster.Collections.WebDAVCache.MaxBlockEntries
  88
  89         h.healthHandler = &health.Handler{
  90                 Token:  h.Config.cluster.ManagementToken,
  91                 Prefix: "/_health/",
  92         }
  93
  94         // Even though we don't accept LOCK requests, every webdav
  95         // handler must have a non-nil LockSystem.
  96         h.webdavLS = &noLockSystem{}
  97 }
  98
  99 func (h *handler) serveStatus(w http.ResponseWriter, r *http.Request) {
 100         json.NewEncoder(w).Encode(struct{ Version string }{version})
 101 }
 102
 103 // updateOnSuccess wraps httpserver.ResponseWriter. If the handler
 104 // sends an HTTP header indicating success, updateOnSuccess first
 105 // calls the provided update func. If the update func fails, a 500
 106 // response is sent, and the status code and body sent by the handler
 107 // are ignored (all response writes return the update error).
 108 type updateOnSuccess struct {
 109         httpserver.ResponseWriter
 110         logger     logrus.FieldLogger
 111         update     func() error
 112         sentHeader bool
 113         err        error
 114 }
 115
 116 func (uos *updateOnSuccess) Write(p []byte) (int, error) {
 117         if !uos.sentHeader {
 118                 uos.WriteHeader(http.StatusOK)
 119         }
 120         if uos.err != nil {
 121                 return 0, uos.err
 122         }
 123         return uos.ResponseWriter.Write(p)
 124 }
 125
 126 func (uos *updateOnSuccess) WriteHeader(code int) {
 127         if !uos.sentHeader {
 128                 uos.sentHeader = true
 129                 if code >= 200 && code < 400 {
 130                         if uos.err = uos.update(); uos.err != nil {
 131                                 code := http.StatusInternalServerError
 132                                 if err, ok := uos.err.(*arvados.TransactionError); ok {
 133                                         code = err.StatusCode
 134                                 }
 135                                 uos.logger.WithError(uos.err).Errorf("update() returned error type %T, changing response to HTTP %d", uos.err, code)
 136                                 http.Error(uos.ResponseWriter, uos.err.Error(), code)
 137                                 return
 138                         }
 139                 }
 140         }
 141         uos.ResponseWriter.WriteHeader(code)
 142 }
 143
 144 var (
 145         corsAllowHeadersHeader = strings.Join([]string{
 146                 "Authorization", "Content-Type", "Range",
 147                 // WebDAV request headers:
 148                 "Depth", "Destination", "If", "Lock-Token", "Overwrite", "Timeout",
 149         }, ", ")
 150         writeMethod = map[string]bool{
 151                 "COPY":      true,
 152                 "DELETE":    true,
 153                 "LOCK":      true,
 154                 "MKCOL":     true,
 155                 "MOVE":      true,
 156                 "PROPPATCH": true,
 157                 "PUT":       true,
 158                 "RMCOL":     true,
 159                 "UNLOCK":    true,
 160         }
 161         webdavMethod = map[string]bool{
 162                 "COPY":      true,
 163                 "DELETE":    true,
 164                 "LOCK":      true,
 165                 "MKCOL":     true,
 166                 "MOVE":      true,
 167                 "OPTIONS":   true,
 168                 "PROPFIND":  true,
 169                 "PROPPATCH": true,
 170                 "PUT":       true,
 171                 "RMCOL":     true,
 172                 "UNLOCK":    true,
 173         }
 174         browserMethod = map[string]bool{
 175                 "GET":  true,
 176                 "HEAD": true,
 177                 "POST": true,
 178         }
 179         // top-level dirs to serve with siteFS
 180         siteFSDir = map[string]bool{
 181                 "":      true, // root directory
 182                 "by_id": true,
 183                 "users": true,
 184         }
 185 )
 186
 187 // ServeHTTP implements http.Handler.
 188 func (h *handler) ServeHTTP(wOrig http.ResponseWriter, r *http.Request) {
 189         h.setupOnce.Do(h.setup)
 190
 191         if xfp := r.Header.Get("X-Forwarded-Proto"); xfp != "" && xfp != "http" {
 192                 r.URL.Scheme = xfp
 193         }
 194
 195         w := httpserver.WrapResponseWriter(wOrig)
 196
 197         if strings.HasPrefix(r.URL.Path, "/_health/") && r.Method == "GET" {
 198                 h.healthHandler.ServeHTTP(w, r)
 199                 return
 200         }
 201
 202         if method := r.Header.Get("Access-Control-Request-Method"); method != "" && r.Method == "OPTIONS" {
 203                 if !browserMethod[method] && !webdavMethod[method] {
 204                         w.WriteHeader(http.StatusMethodNotAllowed)
 205                         return
 206                 }
 207                 w.Header().Set("Access-Control-Allow-Headers", corsAllowHeadersHeader)
 208                 w.Header().Set("Access-Control-Allow-Methods", "COPY, DELETE, GET, LOCK, MKCOL, MOVE, OPTIONS, POST, PROPFIND, PROPPATCH, PUT, RMCOL, UNLOCK")
 209                 w.Header().Set("Access-Control-Allow-Origin", "*")
 210                 w.Header().Set("Access-Control-Max-Age", "86400")
 211                 return
 212         }
 213
 214         if !browserMethod[r.Method] && !webdavMethod[r.Method] {
 215                 w.WriteHeader(http.StatusMethodNotAllowed)
 216                 return
 217         }
 218
 219         if r.Header.Get("Origin") != "" {
 220                 // Allow simple cross-origin requests without user
 221                 // credentials ("user credentials" as defined by CORS,
 222                 // i.e., cookies, HTTP authentication, and client-side
 223                 // SSL certificates. See
 224                 // http://www.w3.org/TR/cors/#user-credentials).
 225                 w.Header().Set("Access-Control-Allow-Origin", "*")
 226                 w.Header().Set("Access-Control-Expose-Headers", "Content-Range")
 227         }
 228
 229         if h.serveS3(w, r) {
 230                 return
 231         }
 232
 233         pathParts := strings.Split(r.URL.Path[1:], "/")
 234
 235         var stripParts int
 236         var collectionID string
 237         var tokens []string
 238         var reqTokens []string
 239         var pathToken bool
 240         var attachment bool
 241         var useSiteFS bool
 242         credentialsOK := h.Config.cluster.Collections.TrustAllContent
 243
 244         if r.Host != "" && r.Host == h.Config.cluster.Services.WebDAVDownload.ExternalURL.Host {
 245                 credentialsOK = true
 246                 attachment = true
 247         } else if r.FormValue("disposition") == "attachment" {
 248                 attachment = true
 249         }
 250
 251         if collectionID = parseCollectionIDFromDNSName(r.Host); collectionID != "" {
 252                 // http://ID.collections.example/PATH...
 253                 credentialsOK = true
 254         } else if r.URL.Path == "/status.json" {
 255                 h.serveStatus(w, r)
 256                 return
 257         } else if strings.HasPrefix(r.URL.Path, "/metrics") {
 258                 h.MetricsAPI.ServeHTTP(w, r)
 259                 return
 260         } else if siteFSDir[pathParts[0]] {
 261                 useSiteFS = true
 262         } else if len(pathParts) >= 1 && strings.HasPrefix(pathParts[0], "c=") {
 263                 // /c=ID[/PATH...]
 264                 collectionID = parseCollectionIDFromURL(pathParts[0][2:])
 265                 stripParts = 1
 266         } else if len(pathParts) >= 2 && pathParts[0] == "collections" {
 267                 if len(pathParts) >= 4 && pathParts[1] == "download" {
 268                         // /collections/download/ID/TOKEN/PATH...
 269                         collectionID = parseCollectionIDFromURL(pathParts[2])
 270                         tokens = []string{pathParts[3]}
 271                         stripParts = 4
 272                         pathToken = true
 273                 } else {
 274                         // /collections/ID/PATH...
 275                         collectionID = parseCollectionIDFromURL(pathParts[1])
 276                         stripParts = 2
 277                         // This path is only meant to work for public
 278                         // data. Tokens provided with the request are
 279                         // ignored.
 280                         credentialsOK = false
 281                 }
 282         }
 283
 284         if collectionID == "" && !useSiteFS {
 285                 http.Error(w, notFoundMessage, http.StatusNotFound)
 286                 return
 287         }
 288
 289         forceReload := false
 290         if cc := r.Header.Get("Cache-Control"); strings.Contains(cc, "no-cache") || strings.Contains(cc, "must-revalidate") {
 291                 forceReload = true
 292         }
 293
 294         if credentialsOK {
 295                 reqTokens = auth.CredentialsFromRequest(r).Tokens
 296         }
 297
 298         formToken := r.FormValue("api_token")
 299         if formToken != "" && r.Header.Get("Origin") != "" && attachment && r.URL.Query().Get("api_token") == "" {
 300                 // The client provided an explicit token in the POST
 301                 // body. The Origin header indicates this *might* be
 302                 // an AJAX request, in which case redirect-with-cookie
 303                 // won't work: we should just serve the content in the
 304                 // POST response. This is safe because:
 305                 //
 306                 // * We're supplying an attachment, not inline
 307                 //   content, so we don't need to convert the POST to
 308                 //   a GET and avoid the "really resubmit form?"
 309                 //   problem.
 310                 //
 311                 // * The token isn't embedded in the URL, so we don't
 312                 //   need to worry about bookmarks and copy/paste.
 313                 reqTokens = append(reqTokens, formToken)
 314         } else if formToken != "" && browserMethod[r.Method] {
 315                 // The client provided an explicit token in the query
 316                 // string, or a form in POST body. We must put the
 317                 // token in an HttpOnly cookie, and redirect to the
 318                 // same URL with the query param redacted and method =
 319                 // GET.
 320                 h.seeOtherWithCookie(w, r, "", credentialsOK)
 321                 return
 322         }
 323
 324         if useSiteFS {
 325                 h.serveSiteFS(w, r, reqTokens, credentialsOK, attachment)
 326                 return
 327         }
 328
 329         targetPath := pathParts[stripParts:]
 330         if tokens == nil && len(targetPath) > 0 && strings.HasPrefix(targetPath[0], "t=") {
 331                 // http://ID.example/t=TOKEN/PATH...
 332                 // /c=ID/t=TOKEN/PATH...
 333                 //
 334                 // This form must only be used to pass scoped tokens
 335                 // that give permission for a single collection. See
 336                 // FormValue case above.
 337                 tokens = []string{targetPath[0][2:]}
 338                 pathToken = true
 339                 targetPath = targetPath[1:]
 340                 stripParts++
 341         }
 342
 343         if tokens == nil {
 344                 tokens = append(reqTokens, h.Config.cluster.Users.AnonymousUserToken)
 345         }
 346
 347         if len(targetPath) > 0 && targetPath[0] == "_" {
 348                 // If a collection has a directory called "t=foo" or
 349                 // "_", it can be served at
 350                 // //collections.example/_/t=foo/ or
 351                 // //collections.example/_/_/ respectively:
 352                 // //collections.example/t=foo/ won't work because
 353                 // t=foo will be interpreted as a token "foo".
 354                 targetPath = targetPath[1:]
 355                 stripParts++
 356         }
 357
 358         arv := h.clientPool.Get()
 359         if arv == nil {
 360                 http.Error(w, "client pool error: "+h.clientPool.Err().Error(), http.StatusInternalServerError)
 361                 return
 362         }
 363         defer h.clientPool.Put(arv)
 364
 365         var collection *arvados.Collection
 366         tokenResult := make(map[string]int)
 367         for _, arv.ApiToken = range tokens {
 368                 var err error
 369                 collection, err = h.Config.Cache.Get(arv, collectionID, forceReload)
 370                 if err == nil {
 371                         // Success
 372                         break
 373                 }
 374                 if srvErr, ok := err.(arvadosclient.APIServerError); ok {
 375                         switch srvErr.HttpStatusCode {
 376                         case 404, 401:
 377                                 // Token broken or insufficient to
 378                                 // retrieve collection
 379                                 tokenResult[arv.ApiToken] = srvErr.HttpStatusCode
 380                                 continue
 381                         }
 382                 }
 383                 // Something more serious is wrong
 384                 http.Error(w, "cache error: "+err.Error(), http.StatusInternalServerError)
 385                 return
 386         }
 387         if collection == nil {
 388                 if pathToken || !credentialsOK {
 389                         // Either the URL is a "secret sharing link"
 390                         // that didn't work out (and asking the client
 391                         // for additional credentials would just be
 392                         // confusing), or we don't even accept
 393                         // credentials at this path.
 394                         http.Error(w, notFoundMessage, http.StatusNotFound)
 395                         return
 396                 }
 397                 for _, t := range reqTokens {
 398                         if tokenResult[t] == 404 {
 399                                 // The client provided valid token(s), but the
 400                                 // collection was not found.
 401                                 http.Error(w, notFoundMessage, http.StatusNotFound)
 402                                 return
 403                         }
 404                 }
 405                 // The client's token was invalid (e.g., expired), or
 406                 // the client didn't even provide one.  Propagate the
 407                 // 401 to encourage the client to use a [different]
 408                 // token.
 409                 //
 410                 // TODO(TC): This response would be confusing to
 411                 // someone trying (anonymously) to download public
 412                 // data that has been deleted.  Allow a referrer to
 413                 // provide this context somehow?
 414                 w.Header().Add("WWW-Authenticate", "Basic realm=\"collections\"")
 415                 http.Error(w, unauthorizedMessage, http.StatusUnauthorized)
 416                 return
 417         }
 418
 419         kc, err := keepclient.MakeKeepClient(arv)
 420         if err != nil {
 421                 http.Error(w, "error setting up keep client: "+err.Error(), http.StatusInternalServerError)
 422                 return
 423         }
 424         kc.RequestID = r.Header.Get("X-Request-Id")
 425
 426         var basename string
 427         if len(targetPath) > 0 {
 428                 basename = targetPath[len(targetPath)-1]
 429         }
 430         applyContentDispositionHdr(w, r, basename, attachment)
 431
 432         client := (&arvados.Client{
 433                 APIHost:   arv.ApiServer,
 434                 AuthToken: arv.ApiToken,
 435                 Insecure:  arv.ApiInsecure,
 436         }).WithRequestID(r.Header.Get("X-Request-Id"))
 437
 438         fs, err := collection.FileSystem(client, kc)
 439         if err != nil {
 440                 http.Error(w, "error creating collection filesystem: "+err.Error(), http.StatusInternalServerError)
 441                 return
 442         }
 443
 444         writefs, writeOK := fs.(arvados.CollectionFileSystem)
 445         targetIsPDH := arvadosclient.PDHMatch(collectionID)
 446         if (targetIsPDH || !writeOK) && writeMethod[r.Method] {
 447                 http.Error(w, errReadOnly.Error(), http.StatusMethodNotAllowed)
 448                 return
 449         }
 450
 451         if webdavMethod[r.Method] {
 452                 if writeMethod[r.Method] {
 453                         // Save the collection only if/when all
 454                         // webdav->filesystem operations succeed --
 455                         // and send a 500 error if the modified
 456                         // collection can't be saved.
 457                         w = &updateOnSuccess{
 458                                 ResponseWriter: w,
 459                                 logger:         ctxlog.FromContext(r.Context()),
 460                                 update: func() error {
 461                                         return h.Config.Cache.Update(client, *collection, writefs)
 462                                 }}
 463                 }
 464                 h := webdav.Handler{
 465                         Prefix: "/" + strings.Join(pathParts[:stripParts], "/"),
 466                         FileSystem: &webdavFS{
 467                                 collfs:        fs,
 468                                 writing:       writeMethod[r.Method],
 469                                 alwaysReadEOF: r.Method == "PROPFIND",
 470                         },
 471                         LockSystem: h.webdavLS,
 472                         Logger: func(_ *http.Request, err error) {
 473                                 if err != nil {
 474                                         ctxlog.FromContext(r.Context()).WithError(err).Error("error reported by webdav handler")
 475                                 }
 476                         },
 477                 }
 478                 h.ServeHTTP(w, r)
 479                 return
 480         }
 481
 482         openPath := "/" + strings.Join(targetPath, "/")
 483         if f, err := fs.Open(openPath); os.IsNotExist(err) {
 484                 // Requested non-existent path
 485                 http.Error(w, notFoundMessage, http.StatusNotFound)
 486         } else if err != nil {
 487                 // Some other (unexpected) error
 488                 http.Error(w, "open: "+err.Error(), http.StatusInternalServerError)
 489         } else if stat, err := f.Stat(); err != nil {
 490                 // Can't get Size/IsDir (shouldn't happen with a collectionFS!)
 491                 http.Error(w, "stat: "+err.Error(), http.StatusInternalServerError)
 492         } else if stat.IsDir() && !strings.HasSuffix(r.URL.Path, "/") {
 493                 // If client requests ".../dirname", redirect to
 494                 // ".../dirname/". This way, relative links in the
 495                 // listing for "dirname" can always be "fnm", never
 496                 // "dirname/fnm".
 497                 h.seeOtherWithCookie(w, r, r.URL.Path+"/", credentialsOK)
 498         } else if stat.IsDir() {
 499                 h.serveDirectory(w, r, collection.Name, fs, openPath, true)
 500         } else {
 501                 http.ServeContent(w, r, basename, stat.ModTime(), f)
 502                 if wrote := int64(w.WroteBodyBytes()); wrote != stat.Size() && r.Header.Get("Range") == "" {
 503                         // If we wrote fewer bytes than expected, it's
 504                         // too late to change the real response code
 505                         // or send an error message to the client, but
 506                         // at least we can try to put some useful
 507                         // debugging info in the logs.
 508                         n, err := f.Read(make([]byte, 1024))
 509                         ctxlog.FromContext(r.Context()).Errorf("stat.Size()==%d but only wrote %d bytes; read(1024) returns %d, %s", stat.Size(), wrote, n, err)
 510
 511                 }
 512         }
 513 }
 514
 515 func (h *handler) getClients(reqID, token string) (arv *arvadosclient.ArvadosClient, kc *keepclient.KeepClient, client *arvados.Client, release func(), err error) {
 516         arv = h.clientPool.Get()
 517         if arv == nil {
 518                 return nil, nil, nil, nil, err
 519         }
 520         release = func() { h.clientPool.Put(arv) }
 521         arv.ApiToken = token
 522         kc, err = keepclient.MakeKeepClient(arv)
 523         if err != nil {
 524                 release()
 525                 return
 526         }
 527         kc.RequestID = reqID
 528         client = (&arvados.Client{
 529                 APIHost:   arv.ApiServer,
 530                 AuthToken: arv.ApiToken,
 531                 Insecure:  arv.ApiInsecure,
 532         }).WithRequestID(reqID)
 533         return
 534 }
 535
 536 func (h *handler) serveSiteFS(w http.ResponseWriter, r *http.Request, tokens []string, credentialsOK, attachment bool) {
 537         if len(tokens) == 0 {
 538                 w.Header().Add("WWW-Authenticate", "Basic realm=\"collections\"")
 539                 http.Error(w, unauthorizedMessage, http.StatusUnauthorized)
 540                 return
 541         }
 542         if writeMethod[r.Method] {
 543                 http.Error(w, errReadOnly.Error(), http.StatusMethodNotAllowed)
 544                 return
 545         }
 546         _, kc, client, release, err := h.getClients(r.Header.Get("X-Request-Id"), tokens[0])
 547         if err != nil {
 548                 http.Error(w, "Pool failed: "+h.clientPool.Err().Error(), http.StatusInternalServerError)
 549                 return
 550         }
 551         defer release()
 552
 553         fs := client.SiteFileSystem(kc)
 554         fs.ForwardSlashNameSubstitution(h.Config.cluster.Collections.ForwardSlashNameSubstitution)
 555         f, err := fs.Open(r.URL.Path)
 556         if os.IsNotExist(err) {
 557                 http.Error(w, err.Error(), http.StatusNotFound)
 558                 return
 559         } else if err != nil {
 560                 http.Error(w, err.Error(), http.StatusInternalServerError)
 561                 return
 562         }
 563         defer f.Close()
 564         if fi, err := f.Stat(); err == nil && fi.IsDir() && r.Method == "GET" {
 565                 if !strings.HasSuffix(r.URL.Path, "/") {
 566                         h.seeOtherWithCookie(w, r, r.URL.Path+"/", credentialsOK)
 567                 } else {
 568                         h.serveDirectory(w, r, fi.Name(), fs, r.URL.Path, false)
 569                 }
 570                 return
 571         }
 572         if r.Method == "GET" {
 573                 _, basename := filepath.Split(r.URL.Path)
 574                 applyContentDispositionHdr(w, r, basename, attachment)
 575         }
 576         wh := webdav.Handler{
 577                 Prefix: "/",
 578                 FileSystem: &webdavFS{
 579                         collfs:        fs,
 580                         writing:       writeMethod[r.Method],
 581                         alwaysReadEOF: r.Method == "PROPFIND",
 582                 },
 583                 LockSystem: h.webdavLS,
 584                 Logger: func(_ *http.Request, err error) {
 585                         if err != nil {
 586                                 ctxlog.FromContext(r.Context()).WithError(err).Error("error reported by webdav handler")
 587                         }
 588                 },
 589         }
 590         wh.ServeHTTP(w, r)
 591 }
 592
 593 var dirListingTemplate = `<!DOCTYPE HTML>
 594 <HTML><HEAD>
 595   <META name="robots" content="NOINDEX">
 596   <TITLE>{{ .CollectionName }}</TITLE>
 597   <STYLE type="text/css">
 598     body {
 599       margin: 1.5em;
 600     }
 601     pre {
 602       background-color: #D9EDF7;
 603       border-radius: .25em;
 604       padding: .75em;
 605       overflow: auto;
 606     }
 607     .footer p {
 608       font-size: 82%;
 609     }
 610     ul {
 611       padding: 0;
 612     }
 613     ul li {
 614       font-family: monospace;
 615       list-style: none;
 616     }
 617   </STYLE>
 618 </HEAD>
 619 <BODY>
 620
 621 <H1>{{ .CollectionName }}</H1>
 622
 623 <P>This collection of data files is being shared with you through
 624 Arvados.  You can download individual files listed below.  To download
 625 the entire directory tree with wget, try:</P>
 626
 627 <PRE>$ wget --mirror --no-parent --no-host --cut-dirs={{ .StripParts }} https://{{ .Request.Host }}{{ .Request.URL.Path }}</PRE>
 628
 629 <H2>File Listing</H2>
 630
 631 {{if .Files}}
 632 <UL>
 633 {{range .Files}}
 634 {{if .IsDir }}
 635   <LI>{{" " | printf "%15s  " | nbsp}}<A href="{{print "./" .Name}}/">{{.Name}}/</A></LI>
 636 {{else}}
 637   <LI>{{.Size | printf "%15d  " | nbsp}}<A href="{{print "./" .Name}}">{{.Name}}</A></LI>
 638 {{end}}
 639 {{end}}
 640 </UL>
 641 {{else}}
 642 <P>(No files; this collection is empty.)</P>
 643 {{end}}
 644
 645 <HR noshade>
 646 <DIV class="footer">
 647   <P>
 648     About Arvados:
 649     Arvados is a free and open source software bioinformatics platform.
 650     To learn more, visit arvados.org.
 651     Arvados is not responsible for the files listed on this page.
 652   </P>
 653 </DIV>
 654
 655 </BODY>
 656 `
 657
 658 type fileListEnt struct {
 659         Name  string
 660         Size  int64
 661         IsDir bool
 662 }
 663
 664 func (h *handler) serveDirectory(w http.ResponseWriter, r *http.Request, collectionName string, fs http.FileSystem, base string, recurse bool) {
 665         var files []fileListEnt
 666         var walk func(string) error
 667         if !strings.HasSuffix(base, "/") {
 668                 base = base + "/"
 669         }
 670         walk = func(path string) error {
 671                 dirname := base + path
 672                 if dirname != "/" {
 673                         dirname = strings.TrimSuffix(dirname, "/")
 674                 }
 675                 d, err := fs.Open(dirname)
 676                 if err != nil {
 677                         return err
 678                 }
 679                 ents, err := d.Readdir(-1)
 680                 if err != nil {
 681                         return err
 682                 }
 683                 for _, ent := range ents {
 684                         if recurse && ent.IsDir() {
 685                                 err = walk(path + ent.Name() + "/")
 686                                 if err != nil {
 687                                         return err
 688                                 }
 689                         } else {
 690                                 files = append(files, fileListEnt{
 691                                         Name:  path + ent.Name(),
 692                                         Size:  ent.Size(),
 693                                         IsDir: ent.IsDir(),
 694                                 })
 695                         }
 696                 }
 697                 return nil
 698         }
 699         if err := walk(""); err != nil {
 700                 http.Error(w, "error getting directory listing: "+err.Error(), http.StatusInternalServerError)
 701                 return
 702         }
 703
 704         funcs := template.FuncMap{
 705                 "nbsp": func(s string) template.HTML {
 706                         return template.HTML(strings.Replace(s, " ", "&nbsp;", -1))
 707                 },
 708         }
 709         tmpl, err := template.New("dir").Funcs(funcs).Parse(dirListingTemplate)
 710         if err != nil {
 711                 http.Error(w, "error parsing template: "+err.Error(), http.StatusInternalServerError)
 712                 return
 713         }
 714         sort.Slice(files, func(i, j int) bool {
 715                 return files[i].Name < files[j].Name
 716         })
 717         w.WriteHeader(http.StatusOK)
 718         tmpl.Execute(w, map[string]interface{}{
 719                 "CollectionName": collectionName,
 720                 "Files":          files,
 721                 "Request":        r,
 722                 "StripParts":     strings.Count(strings.TrimRight(r.URL.Path, "/"), "/"),
 723         })
 724 }
 725
 726 func applyContentDispositionHdr(w http.ResponseWriter, r *http.Request, filename string, isAttachment bool) {
 727         disposition := "inline"
 728         if isAttachment {
 729                 disposition = "attachment"
 730         }
 731         if strings.ContainsRune(r.RequestURI, '?') {
 732                 // Help the UA realize that the filename is just
 733                 // "filename.txt", not
 734                 // "filename.txt?disposition=attachment".
 735                 //
 736                 // TODO(TC): Follow advice at RFC 6266 appendix D
 737                 disposition += "; filename=" + strconv.QuoteToASCII(filename)
 738         }
 739         if disposition != "inline" {
 740                 w.Header().Set("Content-Disposition", disposition)
 741         }
 742 }
 743
 744 func (h *handler) seeOtherWithCookie(w http.ResponseWriter, r *http.Request, location string, credentialsOK bool) {
 745         if formToken := r.FormValue("api_token"); formToken != "" {
 746                 if !credentialsOK {
 747                         // It is not safe to copy the provided token
 748                         // into a cookie unless the current vhost
 749                         // (origin) serves only a single collection or
 750                         // we are in TrustAllContent mode.
 751                         http.Error(w, "cannot serve inline content at this URL (possible configuration error; see https://doc.arvados.org/install/install-keep-web.html#dns)", http.StatusBadRequest)
 752                         return
 753                 }
 754
 755                 // The HttpOnly flag is necessary to prevent
 756                 // JavaScript code (included in, or loaded by, a page
 757                 // in the collection being served) from employing the
 758                 // user's token beyond reading other files in the same
 759                 // domain, i.e., same collection.
 760                 //
 761                 // The 303 redirect is necessary in the case of a GET
 762                 // request to avoid exposing the token in the Location
 763                 // bar, and in the case of a POST request to avoid
 764                 // raising warnings when the user refreshes the
 765                 // resulting page.
 766                 http.SetCookie(w, &http.Cookie{
 767                         Name:     "arvados_api_token",
 768                         Value:    auth.EncodeTokenCookie([]byte(formToken)),
 769                         Path:     "/",
 770                         HttpOnly: true,
 771                 })
 772         }
 773
 774         // Propagate query parameters (except api_token) from
 775         // the original request.
 776         redirQuery := r.URL.Query()
 777         redirQuery.Del("api_token")
 778
 779         u := r.URL
 780         if location != "" {
 781                 newu, err := u.Parse(location)
 782                 if err != nil {
 783                         http.Error(w, "error resolving redirect target: "+err.Error(), http.StatusInternalServerError)
 784                         return
 785                 }
 786                 u = newu
 787         }
 788         redir := (&url.URL{
 789                 Scheme:   r.URL.Scheme,
 790                 Host:     r.Host,
 791                 Path:     u.Path,
 792                 RawQuery: redirQuery.Encode(),
 793         }).String()
 794
 795         w.Header().Add("Location", redir)
 796         w.WriteHeader(http.StatusSeeOther)
 797         io.WriteString(w, `<A href="`)
 798         io.WriteString(w, html.EscapeString(redir))
 799         io.WriteString(w, `">Continue</A>`)
 800 }