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