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         "log"
  14         "net/http"
  15         "net/url"
  16         "os"
  17         "path/filepath"
  18         "sort"
  19         "strconv"
  20         "strings"
  21         "sync"
  22
  23         "git.curoverse.com/arvados.git/sdk/go/arvados"
  24         "git.curoverse.com/arvados.git/sdk/go/arvadosclient"
  25         "git.curoverse.com/arvados.git/sdk/go/auth"
  26         "git.curoverse.com/arvados.git/sdk/go/health"
  27         "git.curoverse.com/arvados.git/sdk/go/httpserver"
  28         "git.curoverse.com/arvados.git/sdk/go/keepclient"
  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                         httpserver.Log(r.RemoteAddr, "WARNING",
 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                 httpserver.Log(remoteAddr, statusCode, statusText, w.WroteBodyBytes(), r.Method, r.Host, r.URL.Path, r.URL.RawQuery)
 201         }()
 202
 203         if strings.HasPrefix(r.URL.Path, "/_health/") && r.Method == "GET" {
 204                 h.healthHandler.ServeHTTP(w, r)
 205                 return
 206         }
 207
 208         if method := r.Header.Get("Access-Control-Request-Method"); method != "" && r.Method == "OPTIONS" {
 209                 if !browserMethod[method] && !webdavMethod[method] {
 210                         statusCode = http.StatusMethodNotAllowed
 211                         return
 212                 }
 213                 w.Header().Set("Access-Control-Allow-Headers", "Authorization, Content-Type, Range")
 214                 w.Header().Set("Access-Control-Allow-Methods", "COPY, DELETE, GET, MKCOL, MOVE, OPTIONS, POST, PROPFIND, PUT, RMCOL")
 215                 w.Header().Set("Access-Control-Allow-Origin", "*")
 216                 w.Header().Set("Access-Control-Max-Age", "86400")
 217                 statusCode = http.StatusOK
 218                 return
 219         }
 220
 221         if !browserMethod[r.Method] && !webdavMethod[r.Method] {
 222                 statusCode, statusText = http.StatusMethodNotAllowed, r.Method
 223                 return
 224         }
 225
 226         if r.Header.Get("Origin") != "" {
 227                 // Allow simple cross-origin requests without user
 228                 // credentials ("user credentials" as defined by CORS,
 229                 // i.e., cookies, HTTP authentication, and client-side
 230                 // SSL certificates. See
 231                 // http://www.w3.org/TR/cors/#user-credentials).
 232                 w.Header().Set("Access-Control-Allow-Origin", "*")
 233                 w.Header().Set("Access-Control-Expose-Headers", "Content-Range")
 234         }
 235
 236         pathParts := strings.Split(r.URL.Path[1:], "/")
 237
 238         var stripParts int
 239         var collectionID string
 240         var tokens []string
 241         var reqTokens []string
 242         var pathToken bool
 243         var attachment bool
 244         var useSiteFS bool
 245         credentialsOK := h.Config.TrustAllContent
 246
 247         if r.Host != "" && r.Host == h.Config.AttachmentOnlyHost {
 248                 credentialsOK = true
 249                 attachment = true
 250         } else if r.FormValue("disposition") == "attachment" {
 251                 attachment = true
 252         }
 253
 254         if collectionID = parseCollectionIDFromDNSName(r.Host); collectionID != "" {
 255                 // http://ID.collections.example/PATH...
 256                 credentialsOK = true
 257         } else if r.URL.Path == "/status.json" {
 258                 h.serveStatus(w, r)
 259                 return
 260         } else if siteFSDir[pathParts[0]] {
 261                 useSiteFS = true
 262         } else if len(pathParts) >= 1 && strings.HasPrefix(pathParts[0], "c=") {
 263                 // /c=ID[/PATH...]
 264                 collectionID = parseCollectionIDFromURL(pathParts[0][2:])
 265                 stripParts = 1
 266         } else if len(pathParts) >= 2 && pathParts[0] == "collections" {
 267                 if len(pathParts) >= 4 && pathParts[1] == "download" {
 268                         // /collections/download/ID/TOKEN/PATH...
 269                         collectionID = parseCollectionIDFromURL(pathParts[2])
 270                         tokens = []string{pathParts[3]}
 271                         stripParts = 4
 272                         pathToken = true
 273                 } else {
 274                         // /collections/ID/PATH...
 275                         collectionID = parseCollectionIDFromURL(pathParts[1])
 276                         tokens = h.Config.AnonymousTokens
 277                         stripParts = 2
 278                 }
 279         }
 280
 281         if collectionID == "" && !useSiteFS {
 282                 statusCode = 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         formToken := r.FormValue("api_token")
 292         if formToken != "" && r.Header.Get("Origin") != "" && attachment && r.URL.Query().Get("api_token") == "" {
 293                 // The client provided an explicit token in the POST
 294                 // body. The Origin header indicates this *might* be
 295                 // an AJAX request, in which case redirect-with-cookie
 296                 // won't work: we should just serve the content in the
 297                 // POST response. This is safe because:
 298                 //
 299                 // * We're supplying an attachment, not inline
 300                 //   content, so we don't need to convert the POST to
 301                 //   a GET and avoid the "really resubmit form?"
 302                 //   problem.
 303                 //
 304                 // * The token isn't embedded in the URL, so we don't
 305                 //   need to worry about bookmarks and copy/paste.
 306                 tokens = append(tokens, formToken)
 307         } else if formToken != "" && browserMethod[r.Method] {
 308                 // The client provided an explicit token in the query
 309                 // string, or a form in POST body. We must put the
 310                 // token in an HttpOnly cookie, and redirect to the
 311                 // same URL with the query param redacted and method =
 312                 // GET.
 313                 h.seeOtherWithCookie(w, r, "", credentialsOK)
 314                 return
 315         }
 316
 317         if useSiteFS {
 318                 if tokens == nil {
 319                         tokens = auth.NewCredentialsFromHTTPRequest(r).Tokens
 320                 }
 321                 h.serveSiteFS(w, r, tokens, credentialsOK, attachment)
 322                 return
 323         }
 324
 325         targetPath := pathParts[stripParts:]
 326         if tokens == nil && len(targetPath) > 0 && strings.HasPrefix(targetPath[0], "t=") {
 327                 // http://ID.example/t=TOKEN/PATH...
 328                 // /c=ID/t=TOKEN/PATH...
 329                 //
 330                 // This form must only be used to pass scoped tokens
 331                 // that give permission for a single collection. See
 332                 // FormValue case above.
 333                 tokens = []string{targetPath[0][2:]}
 334                 pathToken = true
 335                 targetPath = targetPath[1:]
 336                 stripParts++
 337         }
 338
 339         if tokens == nil {
 340                 if credentialsOK {
 341                         reqTokens = auth.NewCredentialsFromHTTPRequest(r).Tokens
 342                 }
 343                 tokens = append(reqTokens, h.Config.AnonymousTokens...)
 344         }
 345
 346         if len(targetPath) > 0 && targetPath[0] == "_" {
 347                 // If a collection has a directory called "t=foo" or
 348                 // "_", it can be served at
 349                 // //collections.example/_/t=foo/ or
 350                 // //collections.example/_/_/ respectively:
 351                 // //collections.example/t=foo/ won't work because
 352                 // t=foo will be interpreted as a token "foo".
 353                 targetPath = targetPath[1:]
 354                 stripParts++
 355         }
 356
 357         arv := h.clientPool.Get()
 358         if arv == nil {
 359                 statusCode, statusText = http.StatusInternalServerError, "Pool failed: "+h.clientPool.Err().Error()
 360                 return
 361         }
 362         defer h.clientPool.Put(arv)
 363
 364         var collection *arvados.Collection
 365         tokenResult := make(map[string]int)
 366         for _, arv.ApiToken = range tokens {
 367                 var err error
 368                 collection, err = h.Config.Cache.Get(arv, collectionID, forceReload)
 369                 if err == nil {
 370                         // Success
 371                         break
 372                 }
 373                 if srvErr, ok := err.(arvadosclient.APIServerError); ok {
 374                         switch srvErr.HttpStatusCode {
 375                         case 404, 401:
 376                                 // Token broken or insufficient to
 377                                 // retrieve collection
 378                                 tokenResult[arv.ApiToken] = srvErr.HttpStatusCode
 379                                 continue
 380                         }
 381                 }
 382                 // Something more serious is wrong
 383                 statusCode, statusText = http.StatusInternalServerError, err.Error()
 384                 return
 385         }
 386         if collection == nil {
 387                 if pathToken || !credentialsOK {
 388                         // Either the URL is a "secret sharing link"
 389                         // that didn't work out (and asking the client
 390                         // for additional credentials would just be
 391                         // confusing), or we don't even accept
 392                         // credentials at this path.
 393                         statusCode = http.StatusNotFound
 394                         return
 395                 }
 396                 for _, t := range reqTokens {
 397                         if tokenResult[t] == 404 {
 398                                 // The client provided valid token(s), but the
 399                                 // collection was not found.
 400                                 statusCode = http.StatusNotFound
 401                                 return
 402                         }
 403                 }
 404                 // The client's token was invalid (e.g., expired), or
 405                 // the client didn't even provide one.  Propagate the
 406                 // 401 to encourage the client to use a [different]
 407                 // token.
 408                 //
 409                 // TODO(TC): This response would be confusing to
 410                 // someone trying (anonymously) to download public
 411                 // data that has been deleted.  Allow a referrer to
 412                 // provide this context somehow?
 413                 w.Header().Add("WWW-Authenticate", "Basic realm=\"collections\"")
 414                 statusCode = http.StatusUnauthorized
 415                 return
 416         }
 417
 418         kc, err := keepclient.MakeKeepClient(arv)
 419         if err != nil {
 420                 statusCode, statusText = http.StatusInternalServerError, err.Error()
 421                 return
 422         }
 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         }
 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         client := &arvados.Client{
 536                 APIHost:   arv.ApiServer,
 537                 AuthToken: arv.ApiToken,
 538                 Insecure:  arv.ApiInsecure,
 539         }
 540         fs := client.SiteFileSystem(kc)
 541         f, err := fs.Open(r.URL.Path)
 542         if os.IsNotExist(err) {
 543                 http.Error(w, err.Error(), http.StatusNotFound)
 544                 return
 545         } else if err != nil {
 546                 http.Error(w, err.Error(), http.StatusInternalServerError)
 547                 return
 548         }
 549         defer f.Close()
 550         if fi, err := f.Stat(); err == nil && fi.IsDir() && r.Method == "GET" {
 551                 if !strings.HasSuffix(r.URL.Path, "/") {
 552                         h.seeOtherWithCookie(w, r, r.URL.Path+"/", credentialsOK)
 553                 } else {
 554                         h.serveDirectory(w, r, fi.Name(), fs, r.URL.Path, false)
 555                 }
 556                 return
 557         }
 558         if r.Method == "GET" {
 559                 _, basename := filepath.Split(r.URL.Path)
 560                 applyContentDispositionHdr(w, r, basename, attachment)
 561         }
 562         wh := webdav.Handler{
 563                 Prefix: "/",
 564                 FileSystem: &webdavFS{
 565                         collfs:        fs,
 566                         writing:       writeMethod[r.Method],
 567                         alwaysReadEOF: r.Method == "PROPFIND",
 568                 },
 569                 LockSystem: h.webdavLS,
 570                 Logger: func(_ *http.Request, err error) {
 571                         if err != nil {
 572                                 log.Printf("error from webdav handler: %q", err)
 573                         }
 574                 },
 575         }
 576         wh.ServeHTTP(w, r)
 577 }
 578
 579 var dirListingTemplate = `<!DOCTYPE HTML>
 580 <HTML><HEAD>
 581   <META name="robots" content="NOINDEX">
 582   <TITLE>{{ .CollectionName }}</TITLE>
 583   <STYLE type="text/css">
 584     body {
 585       margin: 1.5em;
 586     }
 587     pre {
 588       background-color: #D9EDF7;
 589       border-radius: .25em;
 590       padding: .75em;
 591       overflow: auto;
 592     }
 593     .footer p {
 594       font-size: 82%;
 595     }
 596     ul {
 597       padding: 0;
 598     }
 599     ul li {
 600       font-family: monospace;
 601       list-style: none;
 602     }
 603   </STYLE>
 604 </HEAD>
 605 <BODY>
 606
 607 <H1>{{ .CollectionName }}</H1>
 608
 609 <P>This collection of data files is being shared with you through
 610 Arvados.  You can download individual files listed below.  To download
 611 the entire directory tree with wget, try:</P>
 612
 613 <PRE>$ wget --mirror --no-parent --no-host --cut-dirs={{ .StripParts }} https://{{ .Request.Host }}{{ .Request.URL.Path }}</PRE>
 614
 615 <H2>File Listing</H2>
 616
 617 {{if .Files}}
 618 <UL>
 619 {{range .Files}}
 620 {{if .IsDir }}
 621   <LI>{{" " | printf "%15s  " | nbsp}}<A href="{{print "./" .Name}}/">{{.Name}}/</A></LI>
 622 {{else}}
 623   <LI>{{.Size | printf "%15d  " | nbsp}}<A href="{{print "./" .Name}}">{{.Name}}</A></LI>
 624 {{end}}
 625 {{end}}
 626 </UL>
 627 {{else}}
 628 <P>(No files; this collection is empty.)</P>
 629 {{end}}
 630
 631 <HR noshade>
 632 <DIV class="footer">
 633   <P>
 634     About Arvados:
 635     Arvados is a free and open source software bioinformatics platform.
 636     To learn more, visit arvados.org.
 637     Arvados is not responsible for the files listed on this page.
 638   </P>
 639 </DIV>
 640
 641 </BODY>
 642 `
 643
 644 type fileListEnt struct {
 645         Name  string
 646         Size  int64
 647         IsDir bool
 648 }
 649
 650 func (h *handler) serveDirectory(w http.ResponseWriter, r *http.Request, collectionName string, fs http.FileSystem, base string, recurse bool) {
 651         var files []fileListEnt
 652         var walk func(string) error
 653         if !strings.HasSuffix(base, "/") {
 654                 base = base + "/"
 655         }
 656         walk = func(path string) error {
 657                 dirname := base + path
 658                 if dirname != "/" {
 659                         dirname = strings.TrimSuffix(dirname, "/")
 660                 }
 661                 d, err := fs.Open(dirname)
 662                 if err != nil {
 663                         return err
 664                 }
 665                 ents, err := d.Readdir(-1)
 666                 if err != nil {
 667                         return err
 668                 }
 669                 for _, ent := range ents {
 670                         if recurse && ent.IsDir() {
 671                                 err = walk(path + ent.Name() + "/")
 672                                 if err != nil {
 673                                         return err
 674                                 }
 675                         } else {
 676                                 files = append(files, fileListEnt{
 677                                         Name:  path + ent.Name(),
 678                                         Size:  ent.Size(),
 679                                         IsDir: ent.IsDir(),
 680                                 })
 681                         }
 682                 }
 683                 return nil
 684         }
 685         if err := walk(""); err != nil {
 686                 http.Error(w, err.Error(), http.StatusInternalServerError)
 687                 return
 688         }
 689
 690         funcs := template.FuncMap{
 691                 "nbsp": func(s string) template.HTML {
 692                         return template.HTML(strings.Replace(s, " ", "&nbsp;", -1))
 693                 },
 694         }
 695         tmpl, err := template.New("dir").Funcs(funcs).Parse(dirListingTemplate)
 696         if err != nil {
 697                 http.Error(w, err.Error(), http.StatusInternalServerError)
 698                 return
 699         }
 700         sort.Slice(files, func(i, j int) bool {
 701                 return files[i].Name < files[j].Name
 702         })
 703         w.WriteHeader(http.StatusOK)
 704         tmpl.Execute(w, map[string]interface{}{
 705                 "CollectionName": collectionName,
 706                 "Files":          files,
 707                 "Request":        r,
 708                 "StripParts":     strings.Count(strings.TrimRight(r.URL.Path, "/"), "/"),
 709         })
 710 }
 711
 712 func applyContentDispositionHdr(w http.ResponseWriter, r *http.Request, filename string, isAttachment bool) {
 713         disposition := "inline"
 714         if isAttachment {
 715                 disposition = "attachment"
 716         }
 717         if strings.ContainsRune(r.RequestURI, '?') {
 718                 // Help the UA realize that the filename is just
 719                 // "filename.txt", not
 720                 // "filename.txt?disposition=attachment".
 721                 //
 722                 // TODO(TC): Follow advice at RFC 6266 appendix D
 723                 disposition += "; filename=" + strconv.QuoteToASCII(filename)
 724         }
 725         if disposition != "inline" {
 726                 w.Header().Set("Content-Disposition", disposition)
 727         }
 728 }
 729
 730 func (h *handler) seeOtherWithCookie(w http.ResponseWriter, r *http.Request, location string, credentialsOK bool) {
 731         if formToken := r.FormValue("api_token"); formToken != "" {
 732                 if !credentialsOK {
 733                         // It is not safe to copy the provided token
 734                         // into a cookie unless the current vhost
 735                         // (origin) serves only a single collection or
 736                         // we are in TrustAllContent mode.
 737                         w.WriteHeader(http.StatusBadRequest)
 738                         return
 739                 }
 740
 741                 // The HttpOnly flag is necessary to prevent
 742                 // JavaScript code (included in, or loaded by, a page
 743                 // in the collection being served) from employing the
 744                 // user's token beyond reading other files in the same
 745                 // domain, i.e., same collection.
 746                 //
 747                 // The 303 redirect is necessary in the case of a GET
 748                 // request to avoid exposing the token in the Location
 749                 // bar, and in the case of a POST request to avoid
 750                 // raising warnings when the user refreshes the
 751                 // resulting page.
 752                 http.SetCookie(w, &http.Cookie{
 753                         Name:     "arvados_api_token",
 754                         Value:    auth.EncodeTokenCookie([]byte(formToken)),
 755                         Path:     "/",
 756                         HttpOnly: true,
 757                 })
 758         }
 759
 760         // Propagate query parameters (except api_token) from
 761         // the original request.
 762         redirQuery := r.URL.Query()
 763         redirQuery.Del("api_token")
 764
 765         u := r.URL
 766         if location != "" {
 767                 newu, err := u.Parse(location)
 768                 if err != nil {
 769                         w.WriteHeader(http.StatusInternalServerError)
 770                         return
 771                 }
 772                 u = newu
 773         }
 774         redir := (&url.URL{
 775                 Host:     r.Host,
 776                 Path:     u.Path,
 777                 RawQuery: redirQuery.Encode(),
 778         }).String()
 779
 780         w.Header().Add("Location", redir)
 781         w.WriteHeader(http.StatusSeeOther)
 782         io.WriteString(w, `<A href="`)
 783         io.WriteString(w, html.EscapeString(redir))
 784         io.WriteString(w, `">Continue</A>`)
 785 }