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