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