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         MetricsAPI    http.Handler
  35         clientPool    *arvadosclient.ClientPool
  36         setupOnce     sync.Once
  37         healthHandler http.Handler
  38         webdavLS      webdav.LockSystem
  39 }
  40
  41 // parseCollectionIDFromDNSName returns a UUID or PDH if s begins with
  42 // a UUID or URL-encoded PDH; otherwise "".
  43 func parseCollectionIDFromDNSName(s string) string {
  44         // Strip domain.
  45         if i := strings.IndexRune(s, '.'); i >= 0 {
  46                 s = s[:i]
  47         }
  48         // Names like {uuid}--collections.example.com serve the same
  49         // purpose as {uuid}.collections.example.com but can reduce
  50         // cost/effort of using [additional] wildcard certificates.
  51         if i := strings.Index(s, "--"); i >= 0 {
  52                 s = s[:i]
  53         }
  54         if arvadosclient.UUIDMatch(s) {
  55                 return s
  56         }
  57         if pdh := strings.Replace(s, "-", "+", 1); arvadosclient.PDHMatch(pdh) {
  58                 return pdh
  59         }
  60         return ""
  61 }
  62
  63 var urlPDHDecoder = strings.NewReplacer(" ", "+", "-", "+")
  64
  65 // parseCollectionIDFromURL returns a UUID or PDH if s is a UUID or a
  66 // PDH (even if it is a PDH with "+" replaced by " " or "-");
  67 // otherwise "".
  68 func parseCollectionIDFromURL(s string) string {
  69         if arvadosclient.UUIDMatch(s) {
  70                 return s
  71         }
  72         if pdh := urlPDHDecoder.Replace(s); arvadosclient.PDHMatch(pdh) {
  73                 return pdh
  74         }
  75         return ""
  76 }
  77
  78 func (h *handler) setup() {
  79         h.clientPool = arvadosclient.MakeClientPool()
  80
  81         keepclient.RefreshServiceDiscoveryOnSIGHUP()
  82
  83         h.healthHandler = &health.Handler{
  84                 Token:  h.Config.ManagementToken,
  85                 Prefix: "/_health/",
  86         }
  87
  88         // Even though we don't accept LOCK requests, every webdav
  89         // handler must have a non-nil LockSystem.
  90         h.webdavLS = &noLockSystem{}
  91 }
  92
  93 func (h *handler) serveStatus(w http.ResponseWriter, r *http.Request) {
  94         json.NewEncoder(w).Encode(struct{ Version string }{version})
  95 }
  96
  97 // updateOnSuccess wraps httpserver.ResponseWriter. If the handler
  98 // sends an HTTP header indicating success, updateOnSuccess first
  99 // calls the provided update func. If the update func fails, a 500
 100 // response is sent, and the status code and body sent by the handler
 101 // are ignored (all response writes return the update error).
 102 type updateOnSuccess struct {
 103         httpserver.ResponseWriter
 104         update     func() error
 105         sentHeader bool
 106         err        error
 107 }
 108
 109 func (uos *updateOnSuccess) Write(p []byte) (int, error) {
 110         if !uos.sentHeader {
 111                 uos.WriteHeader(http.StatusOK)
 112         }
 113         if uos.err != nil {
 114                 return 0, uos.err
 115         }
 116         return uos.ResponseWriter.Write(p)
 117 }
 118
 119 func (uos *updateOnSuccess) WriteHeader(code int) {
 120         if !uos.sentHeader {
 121                 uos.sentHeader = true
 122                 if code >= 200 && code < 400 {
 123                         if uos.err = uos.update(); uos.err != nil {
 124                                 code := http.StatusInternalServerError
 125                                 if err, ok := uos.err.(*arvados.TransactionError); ok {
 126                                         code = err.StatusCode
 127                                 }
 128                                 log.Printf("update() changes response to HTTP %d: %T %q", code, uos.err, uos.err)
 129                                 http.Error(uos.ResponseWriter, uos.err.Error(), code)
 130                                 return
 131                         }
 132                 }
 133         }
 134         uos.ResponseWriter.WriteHeader(code)
 135 }
 136
 137 var (
 138         corsAllowHeadersHeader = strings.Join([]string{
 139                 "Authorization", "Content-Type", "Range",
 140                 // WebDAV request headers:
 141                 "Depth", "Destination", "If", "Lock-Token", "Overwrite", "Timeout",
 142         }, ", ")
 143         writeMethod = map[string]bool{
 144                 "COPY":   true,
 145                 "DELETE": true,
 146                 "LOCK":   true,
 147                 "MKCOL":  true,
 148                 "MOVE":   true,
 149                 "PUT":    true,
 150                 "RMCOL":  true,
 151                 "UNLOCK": true,
 152         }
 153         webdavMethod = map[string]bool{
 154                 "COPY":     true,
 155                 "DELETE":   true,
 156                 "LOCK":     true,
 157                 "MKCOL":    true,
 158                 "MOVE":     true,
 159                 "OPTIONS":  true,
 160                 "PROPFIND": true,
 161                 "PUT":      true,
 162                 "RMCOL":    true,
 163                 "UNLOCK":   true,
 164         }
 165         browserMethod = map[string]bool{
 166                 "GET":  true,
 167                 "HEAD": true,
 168                 "POST": true,
 169         }
 170         // top-level dirs to serve with siteFS
 171         siteFSDir = map[string]bool{
 172                 "":      true, // root directory
 173                 "by_id": true,
 174                 "users": true,
 175         }
 176 )
 177
 178 // ServeHTTP implements http.Handler.
 179 func (h *handler) ServeHTTP(wOrig http.ResponseWriter, r *http.Request) {
 180         h.setupOnce.Do(h.setup)
 181
 182         var statusCode = 0
 183         var statusText string
 184
 185         remoteAddr := r.RemoteAddr
 186         if xff := r.Header.Get("X-Forwarded-For"); xff != "" {
 187                 remoteAddr = xff + "," + remoteAddr
 188         }
 189         if xfp := r.Header.Get("X-Forwarded-Proto"); xfp != "" && xfp != "http" {
 190                 r.URL.Scheme = xfp
 191         }
 192
 193         w := httpserver.WrapResponseWriter(wOrig)
 194         defer func() {
 195                 if statusCode == 0 {
 196                         statusCode = w.WroteStatus()
 197                 } else if w.WroteStatus() == 0 {
 198                         w.WriteHeader(statusCode)
 199                 } else if w.WroteStatus() != statusCode {
 200                         log.WithField("RequestID", r.Header.Get("X-Request-Id")).Warn(
 201                                 fmt.Sprintf("Our status changed from %d to %d after we sent headers", w.WroteStatus(), statusCode))
 202                 }
 203                 if statusText == "" {
 204                         statusText = http.StatusText(statusCode)
 205                 }
 206         }()
 207
 208         if strings.HasPrefix(r.URL.Path, "/_health/") && r.Method == "GET" {
 209                 h.healthHandler.ServeHTTP(w, r)
 210                 return
 211         }
 212
 213         if method := r.Header.Get("Access-Control-Request-Method"); method != "" && r.Method == "OPTIONS" {
 214                 if !browserMethod[method] && !webdavMethod[method] {
 215                         statusCode = http.StatusMethodNotAllowed
 216                         return
 217                 }
 218                 w.Header().Set("Access-Control-Allow-Headers", corsAllowHeadersHeader)
 219                 w.Header().Set("Access-Control-Allow-Methods", "COPY, DELETE, GET, MKCOL, MOVE, OPTIONS, POST, PROPFIND, PUT, RMCOL")
 220                 w.Header().Set("Access-Control-Allow-Origin", "*")
 221                 w.Header().Set("Access-Control-Max-Age", "86400")
 222                 statusCode = http.StatusOK
 223                 return
 224         }
 225
 226         if !browserMethod[r.Method] && !webdavMethod[r.Method] {
 227                 statusCode, statusText = http.StatusMethodNotAllowed, r.Method
 228                 return
 229         }
 230
 231         if r.Header.Get("Origin") != "" {
 232                 // Allow simple cross-origin requests without user
 233                 // credentials ("user credentials" as defined by CORS,
 234                 // i.e., cookies, HTTP authentication, and client-side
 235                 // SSL certificates. See
 236                 // http://www.w3.org/TR/cors/#user-credentials).
 237                 w.Header().Set("Access-Control-Allow-Origin", "*")
 238                 w.Header().Set("Access-Control-Expose-Headers", "Content-Range")
 239         }
 240
 241         pathParts := strings.Split(r.URL.Path[1:], "/")
 242
 243         var stripParts int
 244         var collectionID string
 245         var tokens []string
 246         var reqTokens []string
 247         var pathToken bool
 248         var attachment bool
 249         var useSiteFS bool
 250         credentialsOK := h.Config.TrustAllContent
 251
 252         if r.Host != "" && r.Host == h.Config.AttachmentOnlyHost {
 253                 credentialsOK = true
 254                 attachment = true
 255         } else if r.FormValue("disposition") == "attachment" {
 256                 attachment = true
 257         }
 258
 259         if collectionID = parseCollectionIDFromDNSName(r.Host); collectionID != "" {
 260                 // http://ID.collections.example/PATH...
 261                 credentialsOK = true
 262         } else if r.URL.Path == "/status.json" {
 263                 h.serveStatus(w, r)
 264                 return
 265         } else if strings.HasPrefix(r.URL.Path, "/metrics") {
 266                 h.MetricsAPI.ServeHTTP(w, r)
 267                 return
 268         } else if siteFSDir[pathParts[0]] {
 269                 useSiteFS = true
 270         } else if len(pathParts) >= 1 && strings.HasPrefix(pathParts[0], "c=") {
 271                 // /c=ID[/PATH...]
 272                 collectionID = parseCollectionIDFromURL(pathParts[0][2:])
 273                 stripParts = 1
 274         } else if len(pathParts) >= 2 && pathParts[0] == "collections" {
 275                 if len(pathParts) >= 4 && pathParts[1] == "download" {
 276                         // /collections/download/ID/TOKEN/PATH...
 277                         collectionID = parseCollectionIDFromURL(pathParts[2])
 278                         tokens = []string{pathParts[3]}
 279                         stripParts = 4
 280                         pathToken = true
 281                 } else {
 282                         // /collections/ID/PATH...
 283                         collectionID = parseCollectionIDFromURL(pathParts[1])
 284                         tokens = h.Config.AnonymousTokens
 285                         stripParts = 2
 286                 }
 287         }
 288
 289         if collectionID == "" && !useSiteFS {
 290                 statusCode = http.StatusNotFound
 291                 return
 292         }
 293
 294         forceReload := false
 295         if cc := r.Header.Get("Cache-Control"); strings.Contains(cc, "no-cache") || strings.Contains(cc, "must-revalidate") {
 296                 forceReload = true
 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                 tokens = append(tokens, 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                 if tokens == nil {
 327                         tokens = auth.CredentialsFromRequest(r).Tokens
 328                 }
 329                 h.serveSiteFS(w, r, tokens, credentialsOK, attachment)
 330                 return
 331         }
 332
 333         targetPath := pathParts[stripParts:]
 334         if tokens == nil && len(targetPath) > 0 && strings.HasPrefix(targetPath[0], "t=") {
 335                 // http://ID.example/t=TOKEN/PATH...
 336                 // /c=ID/t=TOKEN/PATH...
 337                 //
 338                 // This form must only be used to pass scoped tokens
 339                 // that give permission for a single collection. See
 340                 // FormValue case above.
 341                 tokens = []string{targetPath[0][2:]}
 342                 pathToken = true
 343                 targetPath = targetPath[1:]
 344                 stripParts++
 345         }
 346
 347         if tokens == nil {
 348                 if credentialsOK {
 349                         reqTokens = auth.CredentialsFromRequest(r).Tokens
 350                 }
 351                 tokens = append(reqTokens, h.Config.AnonymousTokens...)
 352         }
 353
 354         if len(targetPath) > 0 && targetPath[0] == "_" {
 355                 // If a collection has a directory called "t=foo" or
 356                 // "_", it can be served at
 357                 // //collections.example/_/t=foo/ or
 358                 // //collections.example/_/_/ respectively:
 359                 // //collections.example/t=foo/ won't work because
 360                 // t=foo will be interpreted as a token "foo".
 361                 targetPath = targetPath[1:]
 362                 stripParts++
 363         }
 364
 365         arv := h.clientPool.Get()
 366         if arv == nil {
 367                 statusCode, statusText = http.StatusInternalServerError, "Pool failed: "+h.clientPool.Err().Error()
 368                 return
 369         }
 370         defer h.clientPool.Put(arv)
 371
 372         var collection *arvados.Collection
 373         tokenResult := make(map[string]int)
 374         for _, arv.ApiToken = range tokens {
 375                 var err error
 376                 collection, err = h.Config.Cache.Get(arv, collectionID, forceReload)
 377                 if err == nil {
 378                         // Success
 379                         break
 380                 }
 381                 if srvErr, ok := err.(arvadosclient.APIServerError); ok {
 382                         switch srvErr.HttpStatusCode {
 383                         case 404, 401:
 384                                 // Token broken or insufficient to
 385                                 // retrieve collection
 386                                 tokenResult[arv.ApiToken] = srvErr.HttpStatusCode
 387                                 continue
 388                         }
 389                 }
 390                 // Something more serious is wrong
 391                 statusCode, statusText = http.StatusInternalServerError, err.Error()
 392                 return
 393         }
 394         if collection == nil {
 395                 if pathToken || !credentialsOK {
 396                         // Either the URL is a "secret sharing link"
 397                         // that didn't work out (and asking the client
 398                         // for additional credentials would just be
 399                         // confusing), or we don't even accept
 400                         // credentials at this path.
 401                         statusCode = http.StatusNotFound
 402                         return
 403                 }
 404                 for _, t := range reqTokens {
 405                         if tokenResult[t] == 404 {
 406                                 // The client provided valid token(s), but the
 407                                 // collection was not found.
 408                                 statusCode = http.StatusNotFound
 409                                 return
 410                         }
 411                 }
 412                 // The client's token was invalid (e.g., expired), or
 413                 // the client didn't even provide one.  Propagate the
 414                 // 401 to encourage the client to use a [different]
 415                 // token.
 416                 //
 417                 // TODO(TC): This response would be confusing to
 418                 // someone trying (anonymously) to download public
 419                 // data that has been deleted.  Allow a referrer to
 420                 // provide this context somehow?
 421                 w.Header().Add("WWW-Authenticate", "Basic realm=\"collections\"")
 422                 statusCode = http.StatusUnauthorized
 423                 return
 424         }
 425
 426         kc, err := keepclient.MakeKeepClient(arv)
 427         if err != nil {
 428                 statusCode, statusText = http.StatusInternalServerError, err.Error()
 429                 return
 430         }
 431         kc.RequestID = r.Header.Get("X-Request-Id")
 432
 433         var basename string
 434         if len(targetPath) > 0 {
 435                 basename = targetPath[len(targetPath)-1]
 436         }
 437         applyContentDispositionHdr(w, r, basename, attachment)
 438
 439         client := (&arvados.Client{
 440                 APIHost:   arv.ApiServer,
 441                 AuthToken: arv.ApiToken,
 442                 Insecure:  arv.ApiInsecure,
 443         }).WithRequestID(r.Header.Get("X-Request-Id"))
 444
 445         fs, err := collection.FileSystem(client, kc)
 446         if err != nil {
 447                 statusCode, statusText = http.StatusInternalServerError, err.Error()
 448                 return
 449         }
 450
 451         writefs, writeOK := fs.(arvados.CollectionFileSystem)
 452         targetIsPDH := arvadosclient.PDHMatch(collectionID)
 453         if (targetIsPDH || !writeOK) && writeMethod[r.Method] {
 454                 statusCode, statusText = http.StatusMethodNotAllowed, errReadOnly.Error()
 455                 return
 456         }
 457
 458         if webdavMethod[r.Method] {
 459                 if writeMethod[r.Method] {
 460                         // Save the collection only if/when all
 461                         // webdav->filesystem operations succeed --
 462                         // and send a 500 error if the modified
 463                         // collection can't be saved.
 464                         w = &updateOnSuccess{
 465                                 ResponseWriter: w,
 466                                 update: func() error {
 467                                         return h.Config.Cache.Update(client, *collection, writefs)
 468                                 }}
 469                 }
 470                 h := webdav.Handler{
 471                         Prefix: "/" + strings.Join(pathParts[:stripParts], "/"),
 472                         FileSystem: &webdavFS{
 473                                 collfs:        fs,
 474                                 writing:       writeMethod[r.Method],
 475                                 alwaysReadEOF: r.Method == "PROPFIND",
 476                         },
 477                         LockSystem: h.webdavLS,
 478                         Logger: func(_ *http.Request, err error) {
 479                                 if err != nil {
 480                                         log.Printf("error from webdav handler: %q", err)
 481                                 }
 482                         },
 483                 }
 484                 h.ServeHTTP(w, r)
 485                 return
 486         }
 487
 488         openPath := "/" + strings.Join(targetPath, "/")
 489         if f, err := fs.Open(openPath); os.IsNotExist(err) {
 490                 // Requested non-existent path
 491                 statusCode = http.StatusNotFound
 492         } else if err != nil {
 493                 // Some other (unexpected) error
 494                 statusCode, statusText = http.StatusInternalServerError, err.Error()
 495         } else if stat, err := f.Stat(); err != nil {
 496                 // Can't get Size/IsDir (shouldn't happen with a collectionFS!)
 497                 statusCode, statusText = http.StatusInternalServerError, err.Error()
 498         } else if stat.IsDir() && !strings.HasSuffix(r.URL.Path, "/") {
 499                 // If client requests ".../dirname", redirect to
 500                 // ".../dirname/". This way, relative links in the
 501                 // listing for "dirname" can always be "fnm", never
 502                 // "dirname/fnm".
 503                 h.seeOtherWithCookie(w, r, r.URL.Path+"/", credentialsOK)
 504         } else if stat.IsDir() {
 505                 h.serveDirectory(w, r, collection.Name, fs, openPath, true)
 506         } else {
 507                 http.ServeContent(w, r, basename, stat.ModTime(), f)
 508                 if r.Header.Get("Range") == "" && int64(w.WroteBodyBytes()) != stat.Size() {
 509                         // If we wrote fewer bytes than expected, it's
 510                         // too late to change the real response code
 511                         // or send an error message to the client, but
 512                         // at least we can try to put some useful
 513                         // debugging info in the logs.
 514                         n, err := f.Read(make([]byte, 1024))
 515                         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)
 516
 517                 }
 518         }
 519 }
 520
 521 func (h *handler) serveSiteFS(w http.ResponseWriter, r *http.Request, tokens []string, credentialsOK, attachment bool) {
 522         if len(tokens) == 0 {
 523                 w.Header().Add("WWW-Authenticate", "Basic realm=\"collections\"")
 524                 http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
 525                 return
 526         }
 527         if writeMethod[r.Method] {
 528                 http.Error(w, errReadOnly.Error(), http.StatusMethodNotAllowed)
 529                 return
 530         }
 531         arv := h.clientPool.Get()
 532         if arv == nil {
 533                 http.Error(w, "Pool failed: "+h.clientPool.Err().Error(), http.StatusInternalServerError)
 534                 return
 535         }
 536         defer h.clientPool.Put(arv)
 537         arv.ApiToken = tokens[0]
 538
 539         kc, err := keepclient.MakeKeepClient(arv)
 540         if err != nil {
 541                 http.Error(w, err.Error(), http.StatusInternalServerError)
 542                 return
 543         }
 544         kc.RequestID = r.Header.Get("X-Request-Id")
 545         client := (&arvados.Client{
 546                 APIHost:   arv.ApiServer,
 547                 AuthToken: arv.ApiToken,
 548                 Insecure:  arv.ApiInsecure,
 549         }).WithRequestID(r.Header.Get("X-Request-Id"))
 550         fs := client.SiteFileSystem(kc)
 551         f, err := fs.Open(r.URL.Path)
 552         if os.IsNotExist(err) {
 553                 http.Error(w, err.Error(), http.StatusNotFound)
 554                 return
 555         } else if err != nil {
 556                 http.Error(w, err.Error(), http.StatusInternalServerError)
 557                 return
 558         }
 559         defer f.Close()
 560         if fi, err := f.Stat(); err == nil && fi.IsDir() && r.Method == "GET" {
 561                 if !strings.HasSuffix(r.URL.Path, "/") {
 562                         h.seeOtherWithCookie(w, r, r.URL.Path+"/", credentialsOK)
 563                 } else {
 564                         h.serveDirectory(w, r, fi.Name(), fs, r.URL.Path, false)
 565                 }
 566                 return
 567         }
 568         if r.Method == "GET" {
 569                 _, basename := filepath.Split(r.URL.Path)
 570                 applyContentDispositionHdr(w, r, basename, attachment)
 571         }
 572         wh := webdav.Handler{
 573                 Prefix: "/",
 574                 FileSystem: &webdavFS{
 575                         collfs:        fs,
 576                         writing:       writeMethod[r.Method],
 577                         alwaysReadEOF: r.Method == "PROPFIND",
 578                 },
 579                 LockSystem: h.webdavLS,
 580                 Logger: func(_ *http.Request, err error) {
 581                         if err != nil {
 582                                 log.Printf("error from webdav handler: %q", err)
 583                         }
 584                 },
 585         }
 586         wh.ServeHTTP(w, r)
 587 }
 588
 589 var dirListingTemplate = `<!DOCTYPE HTML>
 590 <HTML><HEAD>
 591   <META name="robots" content="NOINDEX">
 592   <TITLE>{{ .CollectionName }}</TITLE>
 593   <STYLE type="text/css">
 594     body {
 595       margin: 1.5em;
 596     }
 597     pre {
 598       background-color: #D9EDF7;
 599       border-radius: .25em;
 600       padding: .75em;
 601       overflow: auto;
 602     }
 603     .footer p {
 604       font-size: 82%;
 605     }
 606     ul {
 607       padding: 0;
 608     }
 609     ul li {
 610       font-family: monospace;
 611       list-style: none;
 612     }
 613   </STYLE>
 614 </HEAD>
 615 <BODY>
 616
 617 <H1>{{ .CollectionName }}</H1>
 618
 619 <P>This collection of data files is being shared with you through
 620 Arvados.  You can download individual files listed below.  To download
 621 the entire directory tree with wget, try:</P>
 622
 623 <PRE>$ wget --mirror --no-parent --no-host --cut-dirs={{ .StripParts }} https://{{ .Request.Host }}{{ .Request.URL.Path }}</PRE>
 624
 625 <H2>File Listing</H2>
 626
 627 {{if .Files}}
 628 <UL>
 629 {{range .Files}}
 630 {{if .IsDir }}
 631   <LI>{{" " | printf "%15s  " | nbsp}}<A href="{{print "./" .Name}}/">{{.Name}}/</A></LI>
 632 {{else}}
 633   <LI>{{.Size | printf "%15d  " | nbsp}}<A href="{{print "./" .Name}}">{{.Name}}</A></LI>
 634 {{end}}
 635 {{end}}
 636 </UL>
 637 {{else}}
 638 <P>(No files; this collection is empty.)</P>
 639 {{end}}
 640
 641 <HR noshade>
 642 <DIV class="footer">
 643   <P>
 644     About Arvados:
 645     Arvados is a free and open source software bioinformatics platform.
 646     To learn more, visit arvados.org.
 647     Arvados is not responsible for the files listed on this page.
 648   </P>
 649 </DIV>
 650
 651 </BODY>
 652 `
 653
 654 type fileListEnt struct {
 655         Name  string
 656         Size  int64
 657         IsDir bool
 658 }
 659
 660 func (h *handler) serveDirectory(w http.ResponseWriter, r *http.Request, collectionName string, fs http.FileSystem, base string, recurse bool) {
 661         var files []fileListEnt
 662         var walk func(string) error
 663         if !strings.HasSuffix(base, "/") {
 664                 base = base + "/"
 665         }
 666         walk = func(path string) error {
 667                 dirname := base + path
 668                 if dirname != "/" {
 669                         dirname = strings.TrimSuffix(dirname, "/")
 670                 }
 671                 d, err := fs.Open(dirname)
 672                 if err != nil {
 673                         return err
 674                 }
 675                 ents, err := d.Readdir(-1)
 676                 if err != nil {
 677                         return err
 678                 }
 679                 for _, ent := range ents {
 680                         if recurse && ent.IsDir() {
 681                                 err = walk(path + ent.Name() + "/")
 682                                 if err != nil {
 683                                         return err
 684                                 }
 685                         } else {
 686                                 files = append(files, fileListEnt{
 687                                         Name:  path + ent.Name(),
 688                                         Size:  ent.Size(),
 689                                         IsDir: ent.IsDir(),
 690                                 })
 691                         }
 692                 }
 693                 return nil
 694         }
 695         if err := walk(""); err != nil {
 696                 http.Error(w, err.Error(), http.StatusInternalServerError)
 697                 return
 698         }
 699
 700         funcs := template.FuncMap{
 701                 "nbsp": func(s string) template.HTML {
 702                         return template.HTML(strings.Replace(s, " ", "&nbsp;", -1))
 703                 },
 704         }
 705         tmpl, err := template.New("dir").Funcs(funcs).Parse(dirListingTemplate)
 706         if err != nil {
 707                 http.Error(w, err.Error(), http.StatusInternalServerError)
 708                 return
 709         }
 710         sort.Slice(files, func(i, j int) bool {
 711                 return files[i].Name < files[j].Name
 712         })
 713         w.WriteHeader(http.StatusOK)
 714         tmpl.Execute(w, map[string]interface{}{
 715                 "CollectionName": collectionName,
 716                 "Files":          files,
 717                 "Request":        r,
 718                 "StripParts":     strings.Count(strings.TrimRight(r.URL.Path, "/"), "/"),
 719         })
 720 }
 721
 722 func applyContentDispositionHdr(w http.ResponseWriter, r *http.Request, filename string, isAttachment bool) {
 723         disposition := "inline"
 724         if isAttachment {
 725                 disposition = "attachment"
 726         }
 727         if strings.ContainsRune(r.RequestURI, '?') {
 728                 // Help the UA realize that the filename is just
 729                 // "filename.txt", not
 730                 // "filename.txt?disposition=attachment".
 731                 //
 732                 // TODO(TC): Follow advice at RFC 6266 appendix D
 733                 disposition += "; filename=" + strconv.QuoteToASCII(filename)
 734         }
 735         if disposition != "inline" {
 736                 w.Header().Set("Content-Disposition", disposition)
 737         }
 738 }
 739
 740 func (h *handler) seeOtherWithCookie(w http.ResponseWriter, r *http.Request, location string, credentialsOK bool) {
 741         if formToken := r.FormValue("api_token"); formToken != "" {
 742                 if !credentialsOK {
 743                         // It is not safe to copy the provided token
 744                         // into a cookie unless the current vhost
 745                         // (origin) serves only a single collection or
 746                         // we are in TrustAllContent mode.
 747                         w.WriteHeader(http.StatusBadRequest)
 748                         return
 749                 }
 750
 751                 // The HttpOnly flag is necessary to prevent
 752                 // JavaScript code (included in, or loaded by, a page
 753                 // in the collection being served) from employing the
 754                 // user's token beyond reading other files in the same
 755                 // domain, i.e., same collection.
 756                 //
 757                 // The 303 redirect is necessary in the case of a GET
 758                 // request to avoid exposing the token in the Location
 759                 // bar, and in the case of a POST request to avoid
 760                 // raising warnings when the user refreshes the
 761                 // resulting page.
 762                 http.SetCookie(w, &http.Cookie{
 763                         Name:     "arvados_api_token",
 764                         Value:    auth.EncodeTokenCookie([]byte(formToken)),
 765                         Path:     "/",
 766                         HttpOnly: true,
 767                 })
 768         }
 769
 770         // Propagate query parameters (except api_token) from
 771         // the original request.
 772         redirQuery := r.URL.Query()
 773         redirQuery.Del("api_token")
 774
 775         u := r.URL
 776         if location != "" {
 777                 newu, err := u.Parse(location)
 778                 if err != nil {
 779                         w.WriteHeader(http.StatusInternalServerError)
 780                         return
 781                 }
 782                 u = newu
 783         }
 784         redir := (&url.URL{
 785                 Scheme:   r.URL.Scheme,
 786                 Host:     r.Host,
 787                 Path:     u.Path,
 788                 RawQuery: redirQuery.Encode(),
 789         }).String()
 790
 791         w.Header().Add("Location", redir)
 792         w.WriteHeader(http.StatusSeeOther)
 793         io.WriteString(w, `<A href="`)
 794         io.WriteString(w, html.EscapeString(redir))
 795         io.WriteString(w, `">Continue</A>`)
 796 }