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         remoteAddr := r.RemoteAddr
 189         if xff := r.Header.Get("X-Forwarded-For"); xff != "" {
 190                 remoteAddr = xff + "," + remoteAddr
 191         }
 192         if xfp := r.Header.Get("X-Forwarded-Proto"); xfp != "" && xfp != "http" {
 193                 r.URL.Scheme = xfp
 194         }
 195
 196         w := httpserver.WrapResponseWriter(wOrig)
 197
 198         if strings.HasPrefix(r.URL.Path, "/_health/") && r.Method == "GET" {
 199                 h.healthHandler.ServeHTTP(w, r)
 200                 return
 201         }
 202
 203         if method := r.Header.Get("Access-Control-Request-Method"); method != "" && r.Method == "OPTIONS" {
 204                 if !browserMethod[method] && !webdavMethod[method] {
 205                         w.WriteHeader(http.StatusMethodNotAllowed)
 206                         return
 207                 }
 208                 w.Header().Set("Access-Control-Allow-Headers", corsAllowHeadersHeader)
 209                 w.Header().Set("Access-Control-Allow-Methods", "COPY, DELETE, GET, LOCK, MKCOL, MOVE, OPTIONS, POST, PROPFIND, PROPPATCH, PUT, RMCOL, UNLOCK")
 210                 w.Header().Set("Access-Control-Allow-Origin", "*")
 211                 w.Header().Set("Access-Control-Max-Age", "86400")
 212                 return
 213         }
 214
 215         if !browserMethod[r.Method] && !webdavMethod[r.Method] {
 216                 w.WriteHeader(http.StatusMethodNotAllowed)
 217                 return
 218         }
 219
 220         if r.Header.Get("Origin") != "" {
 221                 // Allow simple cross-origin requests without user
 222                 // credentials ("user credentials" as defined by CORS,
 223                 // i.e., cookies, HTTP authentication, and client-side
 224                 // SSL certificates. See
 225                 // http://www.w3.org/TR/cors/#user-credentials).
 226                 w.Header().Set("Access-Control-Allow-Origin", "*")
 227                 w.Header().Set("Access-Control-Expose-Headers", "Content-Range")
 228         }
 229
 230         if h.serveS3(w, r) {
 231                 return
 232         }
 233
 234         pathParts := strings.Split(r.URL.Path[1:], "/")
 235
 236         var stripParts int
 237         var collectionID string
 238         var tokens []string
 239         var reqTokens []string
 240         var pathToken bool
 241         var attachment bool
 242         var useSiteFS bool
 243         credentialsOK := h.Config.cluster.Collections.TrustAllContent
 244
 245         if r.Host != "" && r.Host == h.Config.cluster.Services.WebDAVDownload.ExternalURL.Host {
 246                 credentialsOK = true
 247                 attachment = true
 248         } else if r.FormValue("disposition") == "attachment" {
 249                 attachment = true
 250         }
 251
 252         if collectionID = parseCollectionIDFromDNSName(r.Host); collectionID != "" {
 253                 // http://ID.collections.example/PATH...
 254                 credentialsOK = true
 255         } else if r.URL.Path == "/status.json" {
 256                 h.serveStatus(w, r)
 257                 return
 258         } else if strings.HasPrefix(r.URL.Path, "/metrics") {
 259                 h.MetricsAPI.ServeHTTP(w, r)
 260                 return
 261         } else if siteFSDir[pathParts[0]] {
 262                 useSiteFS = true
 263         } else if len(pathParts) >= 1 && strings.HasPrefix(pathParts[0], "c=") {
 264                 // /c=ID[/PATH...]
 265                 collectionID = parseCollectionIDFromURL(pathParts[0][2:])
 266                 stripParts = 1
 267         } else if len(pathParts) >= 2 && pathParts[0] == "collections" {
 268                 if len(pathParts) >= 4 && pathParts[1] == "download" {
 269                         // /collections/download/ID/TOKEN/PATH...
 270                         collectionID = parseCollectionIDFromURL(pathParts[2])
 271                         tokens = []string{pathParts[3]}
 272                         stripParts = 4
 273                         pathToken = true
 274                 } else {
 275                         // /collections/ID/PATH...
 276                         collectionID = parseCollectionIDFromURL(pathParts[1])
 277                         stripParts = 2
 278                         // This path is only meant to work for public
 279                         // data. Tokens provided with the request are
 280                         // ignored.
 281                         credentialsOK = false
 282                 }
 283         }
 284
 285         if collectionID == "" && !useSiteFS {
 286                 w.WriteHeader(http.StatusNotFound)
 287                 return
 288         }
 289
 290         forceReload := false
 291         if cc := r.Header.Get("Cache-Control"); strings.Contains(cc, "no-cache") || strings.Contains(cc, "must-revalidate") {
 292                 forceReload = true
 293         }
 294
 295         if credentialsOK {
 296                 reqTokens = auth.CredentialsFromRequest(r).Tokens
 297         }
 298
 299         formToken := r.FormValue("api_token")
 300         if formToken != "" && r.Header.Get("Origin") != "" && attachment && r.URL.Query().Get("api_token") == "" {
 301                 // The client provided an explicit token in the POST
 302                 // body. The Origin header indicates this *might* be
 303                 // an AJAX request, in which case redirect-with-cookie
 304                 // won't work: we should just serve the content in the
 305                 // POST response. This is safe because:
 306                 //
 307                 // * We're supplying an attachment, not inline
 308                 //   content, so we don't need to convert the POST to
 309                 //   a GET and avoid the "really resubmit form?"
 310                 //   problem.
 311                 //
 312                 // * The token isn't embedded in the URL, so we don't
 313                 //   need to worry about bookmarks and copy/paste.
 314                 reqTokens = append(reqTokens, formToken)
 315         } else if formToken != "" && browserMethod[r.Method] {
 316                 // The client provided an explicit token in the query
 317                 // string, or a form in POST body. We must put the
 318                 // token in an HttpOnly cookie, and redirect to the
 319                 // same URL with the query param redacted and method =
 320                 // GET.
 321                 h.seeOtherWithCookie(w, r, "", credentialsOK)
 322                 return
 323         }
 324
 325         if useSiteFS {
 326                 h.serveSiteFS(w, r, reqTokens, credentialsOK, attachment)
 327                 return
 328         }
 329
 330         targetPath := pathParts[stripParts:]
 331         if tokens == nil && len(targetPath) > 0 && strings.HasPrefix(targetPath[0], "t=") {
 332                 // http://ID.example/t=TOKEN/PATH...
 333                 // /c=ID/t=TOKEN/PATH...
 334                 //
 335                 // This form must only be used to pass scoped tokens
 336                 // that give permission for a single collection. See
 337                 // FormValue case above.
 338                 tokens = []string{targetPath[0][2:]}
 339                 pathToken = true
 340                 targetPath = targetPath[1:]
 341                 stripParts++
 342         }
 343
 344         if tokens == nil {
 345                 tokens = append(reqTokens, h.Config.cluster.Users.AnonymousUserToken)
 346         }
 347
 348         if len(targetPath) > 0 && targetPath[0] == "_" {
 349                 // If a collection has a directory called "t=foo" or
 350                 // "_", it can be served at
 351                 // //collections.example/_/t=foo/ or
 352                 // //collections.example/_/_/ respectively:
 353                 // //collections.example/t=foo/ won't work because
 354                 // t=foo will be interpreted as a token "foo".
 355                 targetPath = targetPath[1:]
 356                 stripParts++
 357         }
 358
 359         arv := h.clientPool.Get()
 360         if arv == nil {
 361                 http.Error(w, "client pool error: "+h.clientPool.Err().Error(), http.StatusInternalServerError)
 362                 return
 363         }
 364         defer h.clientPool.Put(arv)
 365
 366         var collection *arvados.Collection
 367         tokenResult := make(map[string]int)
 368         for _, arv.ApiToken = range tokens {
 369                 var err error
 370                 collection, err = h.Config.Cache.Get(arv, collectionID, forceReload)
 371                 if err == nil {
 372                         // Success
 373                         break
 374                 }
 375                 if srvErr, ok := err.(arvadosclient.APIServerError); ok {
 376                         switch srvErr.HttpStatusCode {
 377                         case 404, 401:
 378                                 // Token broken or insufficient to
 379                                 // retrieve collection
 380                                 tokenResult[arv.ApiToken] = srvErr.HttpStatusCode
 381                                 continue
 382                         }
 383                 }
 384                 // Something more serious is wrong
 385                 http.Error(w, "cache error: "+err.Error(), http.StatusInternalServerError)
 386                 return
 387         }
 388         if collection == nil {
 389                 if pathToken || !credentialsOK {
 390                         // Either the URL is a "secret sharing link"
 391                         // that didn't work out (and asking the client
 392                         // for additional credentials would just be
 393                         // confusing), or we don't even accept
 394                         // credentials at this path.
 395                         w.WriteHeader(http.StatusNotFound)
 396                         return
 397                 }
 398                 for _, t := range reqTokens {
 399                         if tokenResult[t] == 404 {
 400                                 // The client provided valid token(s), but the
 401                                 // collection was not found.
 402                                 w.WriteHeader(http.StatusNotFound)
 403                                 return
 404                         }
 405                 }
 406                 // The client's token was invalid (e.g., expired), or
 407                 // the client didn't even provide one.  Propagate the
 408                 // 401 to encourage the client to use a [different]
 409                 // token.
 410                 //
 411                 // TODO(TC): This response would be confusing to
 412                 // someone trying (anonymously) to download public
 413                 // data that has been deleted.  Allow a referrer to
 414                 // provide this context somehow?
 415                 w.Header().Add("WWW-Authenticate", "Basic realm=\"collections\"")
 416                 w.WriteHeader(http.StatusUnauthorized)
 417                 return
 418         }
 419
 420         kc, err := keepclient.MakeKeepClient(arv)
 421         if err != nil {
 422                 http.Error(w, "error setting up keep client: "+err.Error(), http.StatusInternalServerError)
 423                 return
 424         }
 425         kc.RequestID = r.Header.Get("X-Request-Id")
 426
 427         var basename string
 428         if len(targetPath) > 0 {
 429                 basename = targetPath[len(targetPath)-1]
 430         }
 431         applyContentDispositionHdr(w, r, basename, attachment)
 432
 433         client := (&arvados.Client{
 434                 APIHost:   arv.ApiServer,
 435                 AuthToken: arv.ApiToken,
 436                 Insecure:  arv.ApiInsecure,
 437         }).WithRequestID(r.Header.Get("X-Request-Id"))
 438
 439         fs, err := collection.FileSystem(client, kc)
 440         if err != nil {
 441                 http.Error(w, "error creating collection filesystem: "+err.Error(), http.StatusInternalServerError)
 442                 return
 443         }
 444
 445         writefs, writeOK := fs.(arvados.CollectionFileSystem)
 446         targetIsPDH := arvadosclient.PDHMatch(collectionID)
 447         if (targetIsPDH || !writeOK) && writeMethod[r.Method] {
 448                 http.Error(w, errReadOnly.Error(), http.StatusMethodNotAllowed)
 449                 return
 450         }
 451
 452         if webdavMethod[r.Method] {
 453                 if writeMethod[r.Method] {
 454                         // Save the collection only if/when all
 455                         // webdav->filesystem operations succeed --
 456                         // and send a 500 error if the modified
 457                         // collection can't be saved.
 458                         w = &updateOnSuccess{
 459                                 ResponseWriter: w,
 460                                 logger:         ctxlog.FromContext(r.Context()),
 461                                 update: func() error {
 462                                         return h.Config.Cache.Update(client, *collection, writefs)
 463                                 }}
 464                 }
 465                 h := webdav.Handler{
 466                         Prefix: "/" + strings.Join(pathParts[:stripParts], "/"),
 467                         FileSystem: &webdavFS{
 468                                 collfs:        fs,
 469                                 writing:       writeMethod[r.Method],
 470                                 alwaysReadEOF: r.Method == "PROPFIND",
 471                         },
 472                         LockSystem: h.webdavLS,
 473                         Logger: func(_ *http.Request, err error) {
 474                                 if err != nil {
 475                                         ctxlog.FromContext(r.Context()).WithError(err).Error("error reported by webdav handler")
 476                                 }
 477                         },
 478                 }
 479                 h.ServeHTTP(w, r)
 480                 return
 481         }
 482
 483         openPath := "/" + strings.Join(targetPath, "/")
 484         if f, err := fs.Open(openPath); os.IsNotExist(err) {
 485                 // Requested non-existent path
 486                 w.WriteHeader(http.StatusNotFound)
 487         } else if err != nil {
 488                 // Some other (unexpected) error
 489                 http.Error(w, "open: "+err.Error(), http.StatusInternalServerError)
 490         } else if stat, err := f.Stat(); err != nil {
 491                 // Can't get Size/IsDir (shouldn't happen with a collectionFS!)
 492                 http.Error(w, "stat: "+err.Error(), http.StatusInternalServerError)
 493         } else if stat.IsDir() && !strings.HasSuffix(r.URL.Path, "/") {
 494                 // If client requests ".../dirname", redirect to
 495                 // ".../dirname/". This way, relative links in the
 496                 // listing for "dirname" can always be "fnm", never
 497                 // "dirname/fnm".
 498                 h.seeOtherWithCookie(w, r, r.URL.Path+"/", credentialsOK)
 499         } else if stat.IsDir() {
 500                 h.serveDirectory(w, r, collection.Name, fs, openPath, true)
 501         } else {
 502                 http.ServeContent(w, r, basename, stat.ModTime(), f)
 503                 if wrote := int64(w.WroteBodyBytes()); wrote != stat.Size() && r.Header.Get("Range") == "" {
 504                         // If we wrote fewer bytes than expected, it's
 505                         // too late to change the real response code
 506                         // or send an error message to the client, but
 507                         // at least we can try to put some useful
 508                         // debugging info in the logs.
 509                         n, err := f.Read(make([]byte, 1024))
 510                         ctxlog.FromContext(r.Context()).Errorf("stat.Size()==%d but only wrote %d bytes; read(1024) returns %d, %s", stat.Size(), wrote, n, err)
 511
 512                 }
 513         }
 514 }
 515
 516 func (h *handler) getClients(reqID, token string) (arv *arvadosclient.ArvadosClient, kc *keepclient.KeepClient, client *arvados.Client, release func(), err error) {
 517         arv = h.clientPool.Get()
 518         if arv == nil {
 519                 return nil, nil, nil, nil, err
 520         }
 521         release = func() { h.clientPool.Put(arv) }
 522         arv.ApiToken = token
 523         kc, err = keepclient.MakeKeepClient(arv)
 524         if err != nil {
 525                 release()
 526                 return
 527         }
 528         kc.RequestID = reqID
 529         client = (&arvados.Client{
 530                 APIHost:   arv.ApiServer,
 531                 AuthToken: arv.ApiToken,
 532                 Insecure:  arv.ApiInsecure,
 533         }).WithRequestID(reqID)
 534         return
 535 }
 536
 537 func (h *handler) serveSiteFS(w http.ResponseWriter, r *http.Request, tokens []string, credentialsOK, attachment bool) {
 538         if len(tokens) == 0 {
 539                 w.Header().Add("WWW-Authenticate", "Basic realm=\"collections\"")
 540                 http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
 541                 return
 542         }
 543         if writeMethod[r.Method] {
 544                 http.Error(w, errReadOnly.Error(), http.StatusMethodNotAllowed)
 545                 return
 546         }
 547         _, kc, client, release, err := h.getClients(r.Header.Get("X-Request-Id"), tokens[0])
 548         if err != nil {
 549                 http.Error(w, "Pool failed: "+h.clientPool.Err().Error(), http.StatusInternalServerError)
 550                 return
 551         }
 552         defer release()
 553
 554         fs := client.SiteFileSystem(kc)
 555         fs.ForwardSlashNameSubstitution(h.Config.cluster.Collections.ForwardSlashNameSubstitution)
 556         f, err := fs.Open(r.URL.Path)
 557         if os.IsNotExist(err) {
 558                 http.Error(w, err.Error(), http.StatusNotFound)
 559                 return
 560         } else if err != nil {
 561                 http.Error(w, err.Error(), http.StatusInternalServerError)
 562                 return
 563         }
 564         defer f.Close()
 565         if fi, err := f.Stat(); err == nil && fi.IsDir() && r.Method == "GET" {
 566                 if !strings.HasSuffix(r.URL.Path, "/") {
 567                         h.seeOtherWithCookie(w, r, r.URL.Path+"/", credentialsOK)
 568                 } else {
 569                         h.serveDirectory(w, r, fi.Name(), fs, r.URL.Path, false)
 570                 }
 571                 return
 572         }
 573         if r.Method == "GET" {
 574                 _, basename := filepath.Split(r.URL.Path)
 575                 applyContentDispositionHdr(w, r, basename, attachment)
 576         }
 577         wh := webdav.Handler{
 578                 Prefix: "/",
 579                 FileSystem: &webdavFS{
 580                         collfs:        fs,
 581                         writing:       writeMethod[r.Method],
 582                         alwaysReadEOF: r.Method == "PROPFIND",
 583                 },
 584                 LockSystem: h.webdavLS,
 585                 Logger: func(_ *http.Request, err error) {
 586                         if err != nil {
 587                                 ctxlog.FromContext(r.Context()).WithError(err).Error("error reported by webdav handler")
 588                         }
 589                 },
 590         }
 591         wh.ServeHTTP(w, r)
 592 }
 593
 594 var dirListingTemplate = `<!DOCTYPE HTML>
 595 <HTML><HEAD>
 596   <META name="robots" content="NOINDEX">
 597   <TITLE>{{ .CollectionName }}</TITLE>
 598   <STYLE type="text/css">
 599     body {
 600       margin: 1.5em;
 601     }
 602     pre {
 603       background-color: #D9EDF7;
 604       border-radius: .25em;
 605       padding: .75em;
 606       overflow: auto;
 607     }
 608     .footer p {
 609       font-size: 82%;
 610     }
 611     ul {
 612       padding: 0;
 613     }
 614     ul li {
 615       font-family: monospace;
 616       list-style: none;
 617     }
 618   </STYLE>
 619 </HEAD>
 620 <BODY>
 621
 622 <H1>{{ .CollectionName }}</H1>
 623
 624 <P>This collection of data files is being shared with you through
 625 Arvados.  You can download individual files listed below.  To download
 626 the entire directory tree with wget, try:</P>
 627
 628 <PRE>$ wget --mirror --no-parent --no-host --cut-dirs={{ .StripParts }} https://{{ .Request.Host }}{{ .Request.URL.Path }}</PRE>
 629
 630 <H2>File Listing</H2>
 631
 632 {{if .Files}}
 633 <UL>
 634 {{range .Files}}
 635 {{if .IsDir }}
 636   <LI>{{" " | printf "%15s  " | nbsp}}<A href="{{print "./" .Name}}/">{{.Name}}/</A></LI>
 637 {{else}}
 638   <LI>{{.Size | printf "%15d  " | nbsp}}<A href="{{print "./" .Name}}">{{.Name}}</A></LI>
 639 {{end}}
 640 {{end}}
 641 </UL>
 642 {{else}}
 643 <P>(No files; this collection is empty.)</P>
 644 {{end}}
 645
 646 <HR noshade>
 647 <DIV class="footer">
 648   <P>
 649     About Arvados:
 650     Arvados is a free and open source software bioinformatics platform.
 651     To learn more, visit arvados.org.
 652     Arvados is not responsible for the files listed on this page.
 653   </P>
 654 </DIV>
 655
 656 </BODY>
 657 `
 658
 659 type fileListEnt struct {
 660         Name  string
 661         Size  int64
 662         IsDir bool
 663 }
 664
 665 func (h *handler) serveDirectory(w http.ResponseWriter, r *http.Request, collectionName string, fs http.FileSystem, base string, recurse bool) {
 666         var files []fileListEnt
 667         var walk func(string) error
 668         if !strings.HasSuffix(base, "/") {
 669                 base = base + "/"
 670         }
 671         walk = func(path string) error {
 672                 dirname := base + path
 673                 if dirname != "/" {
 674                         dirname = strings.TrimSuffix(dirname, "/")
 675                 }
 676                 d, err := fs.Open(dirname)
 677                 if err != nil {
 678                         return err
 679                 }
 680                 ents, err := d.Readdir(-1)
 681                 if err != nil {
 682                         return err
 683                 }
 684                 for _, ent := range ents {
 685                         if recurse && ent.IsDir() {
 686                                 err = walk(path + ent.Name() + "/")
 687                                 if err != nil {
 688                                         return err
 689                                 }
 690                         } else {
 691                                 files = append(files, fileListEnt{
 692                                         Name:  path + ent.Name(),
 693                                         Size:  ent.Size(),
 694                                         IsDir: ent.IsDir(),
 695                                 })
 696                         }
 697                 }
 698                 return nil
 699         }
 700         if err := walk(""); err != nil {
 701                 http.Error(w, "error getting directory listing: "+err.Error(), http.StatusInternalServerError)
 702                 return
 703         }
 704
 705         funcs := template.FuncMap{
 706                 "nbsp": func(s string) template.HTML {
 707                         return template.HTML(strings.Replace(s, " ", "&nbsp;", -1))
 708                 },
 709         }
 710         tmpl, err := template.New("dir").Funcs(funcs).Parse(dirListingTemplate)
 711         if err != nil {
 712                 http.Error(w, "error parsing template: "+err.Error(), http.StatusInternalServerError)
 713                 return
 714         }
 715         sort.Slice(files, func(i, j int) bool {
 716                 return files[i].Name < files[j].Name
 717         })
 718         w.WriteHeader(http.StatusOK)
 719         tmpl.Execute(w, map[string]interface{}{
 720                 "CollectionName": collectionName,
 721                 "Files":          files,
 722                 "Request":        r,
 723                 "StripParts":     strings.Count(strings.TrimRight(r.URL.Path, "/"), "/"),
 724         })
 725 }
 726
 727 func applyContentDispositionHdr(w http.ResponseWriter, r *http.Request, filename string, isAttachment bool) {
 728         disposition := "inline"
 729         if isAttachment {
 730                 disposition = "attachment"
 731         }
 732         if strings.ContainsRune(r.RequestURI, '?') {
 733                 // Help the UA realize that the filename is just
 734                 // "filename.txt", not
 735                 // "filename.txt?disposition=attachment".
 736                 //
 737                 // TODO(TC): Follow advice at RFC 6266 appendix D
 738                 disposition += "; filename=" + strconv.QuoteToASCII(filename)
 739         }
 740         if disposition != "inline" {
 741                 w.Header().Set("Content-Disposition", disposition)
 742         }
 743 }
 744
 745 func (h *handler) seeOtherWithCookie(w http.ResponseWriter, r *http.Request, location string, credentialsOK bool) {
 746         if formToken := r.FormValue("api_token"); formToken != "" {
 747                 if !credentialsOK {
 748                         // It is not safe to copy the provided token
 749                         // into a cookie unless the current vhost
 750                         // (origin) serves only a single collection or
 751                         // we are in TrustAllContent mode.
 752                         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)
 753                         return
 754                 }
 755
 756                 // The HttpOnly flag is necessary to prevent
 757                 // JavaScript code (included in, or loaded by, a page
 758                 // in the collection being served) from employing the
 759                 // user's token beyond reading other files in the same
 760                 // domain, i.e., same collection.
 761                 //
 762                 // The 303 redirect is necessary in the case of a GET
 763                 // request to avoid exposing the token in the Location
 764                 // bar, and in the case of a POST request to avoid
 765                 // raising warnings when the user refreshes the
 766                 // resulting page.
 767                 http.SetCookie(w, &http.Cookie{
 768                         Name:     "arvados_api_token",
 769                         Value:    auth.EncodeTokenCookie([]byte(formToken)),
 770                         Path:     "/",
 771                         HttpOnly: true,
 772                 })
 773         }
 774
 775         // Propagate query parameters (except api_token) from
 776         // the original request.
 777         redirQuery := r.URL.Query()
 778         redirQuery.Del("api_token")
 779
 780         u := r.URL
 781         if location != "" {
 782                 newu, err := u.Parse(location)
 783                 if err != nil {
 784                         http.Error(w, "error resolving redirect target: "+err.Error(), http.StatusInternalServerError)
 785                         return
 786                 }
 787                 u = newu
 788         }
 789         redir := (&url.URL{
 790                 Scheme:   r.URL.Scheme,
 791                 Host:     r.Host,
 792                 Path:     u.Path,
 793                 RawQuery: redirQuery.Encode(),
 794         }).String()
 795
 796         w.Header().Add("Location", redir)
 797         w.WriteHeader(http.StatusSeeOther)
 798         io.WriteString(w, `<A href="`)
 799         io.WriteString(w, html.EscapeString(redir))
 800         io.WriteString(w, `">Continue</A>`)
 801 }