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                 "PROPPATCH": true,
 150                 "PUT":       true,
 151                 "RMCOL":     true,
 152                 "UNLOCK":    true,
 153         }
 154         webdavMethod = map[string]bool{
 155                 "COPY":      true,
 156                 "DELETE":    true,
 157                 "LOCK":      true,
 158                 "MKCOL":     true,
 159                 "MOVE":      true,
 160                 "OPTIONS":   true,
 161                 "PROPFIND":  true,
 162                 "PROPPATCH": true,
 163                 "PUT":       true,
 164                 "RMCOL":     true,
 165                 "UNLOCK":    true,
 166         }
 167         browserMethod = map[string]bool{
 168                 "GET":  true,
 169                 "HEAD": true,
 170                 "POST": true,
 171         }
 172         // top-level dirs to serve with siteFS
 173         siteFSDir = map[string]bool{
 174                 "":      true, // root directory
 175                 "by_id": true,
 176                 "users": true,
 177         }
 178 )
 179
 180 // ServeHTTP implements http.Handler.
 181 func (h *handler) ServeHTTP(wOrig http.ResponseWriter, r *http.Request) {
 182         h.setupOnce.Do(h.setup)
 183
 184         var statusCode = 0
 185         var statusText string
 186
 187         remoteAddr := r.RemoteAddr
 188         if xff := r.Header.Get("X-Forwarded-For"); xff != "" {
 189                 remoteAddr = xff + "," + remoteAddr
 190         }
 191         if xfp := r.Header.Get("X-Forwarded-Proto"); xfp != "" && xfp != "http" {
 192                 r.URL.Scheme = xfp
 193         }
 194
 195         w := httpserver.WrapResponseWriter(wOrig)
 196         defer func() {
 197                 if statusCode == 0 {
 198                         statusCode = w.WroteStatus()
 199                 } else if w.WroteStatus() == 0 {
 200                         w.WriteHeader(statusCode)
 201                 } else if w.WroteStatus() != statusCode {
 202                         log.WithField("RequestID", r.Header.Get("X-Request-Id")).Warn(
 203                                 fmt.Sprintf("Our status changed from %d to %d after we sent headers", w.WroteStatus(), statusCode))
 204                 }
 205                 if statusText == "" {
 206                         statusText = http.StatusText(statusCode)
 207                 }
 208         }()
 209
 210         if strings.HasPrefix(r.URL.Path, "/_health/") && r.Method == "GET" {
 211                 h.healthHandler.ServeHTTP(w, r)
 212                 return
 213         }
 214
 215         if method := r.Header.Get("Access-Control-Request-Method"); method != "" && r.Method == "OPTIONS" {
 216                 if !browserMethod[method] && !webdavMethod[method] {
 217                         statusCode = http.StatusMethodNotAllowed
 218                         return
 219                 }
 220                 w.Header().Set("Access-Control-Allow-Headers", corsAllowHeadersHeader)
 221                 w.Header().Set("Access-Control-Allow-Methods", "COPY, DELETE, GET, LOCK, MKCOL, MOVE, OPTIONS, POST, PROPFIND, PROPPATCH, PUT, RMCOL, UNLOCK")
 222                 w.Header().Set("Access-Control-Allow-Origin", "*")
 223                 w.Header().Set("Access-Control-Max-Age", "86400")
 224                 statusCode = http.StatusOK
 225                 return
 226         }
 227
 228         if !browserMethod[r.Method] && !webdavMethod[r.Method] {
 229                 statusCode, statusText = http.StatusMethodNotAllowed, r.Method
 230                 return
 231         }
 232
 233         if r.Header.Get("Origin") != "" {
 234                 // Allow simple cross-origin requests without user
 235                 // credentials ("user credentials" as defined by CORS,
 236                 // i.e., cookies, HTTP authentication, and client-side
 237                 // SSL certificates. See
 238                 // http://www.w3.org/TR/cors/#user-credentials).
 239                 w.Header().Set("Access-Control-Allow-Origin", "*")
 240                 w.Header().Set("Access-Control-Expose-Headers", "Content-Range")
 241         }
 242
 243         pathParts := strings.Split(r.URL.Path[1:], "/")
 244
 245         var stripParts int
 246         var collectionID string
 247         var tokens []string
 248         var reqTokens []string
 249         var pathToken bool
 250         var attachment bool
 251         var useSiteFS bool
 252         credentialsOK := h.Config.TrustAllContent
 253
 254         if r.Host != "" && r.Host == h.Config.AttachmentOnlyHost {
 255                 credentialsOK = true
 256                 attachment = true
 257         } else if r.FormValue("disposition") == "attachment" {
 258                 attachment = true
 259         }
 260
 261         if collectionID = parseCollectionIDFromDNSName(r.Host); collectionID != "" {
 262                 // http://ID.collections.example/PATH...
 263                 credentialsOK = true
 264         } else if r.URL.Path == "/status.json" {
 265                 h.serveStatus(w, r)
 266                 return
 267         } else if strings.HasPrefix(r.URL.Path, "/metrics") {
 268                 h.MetricsAPI.ServeHTTP(w, r)
 269                 return
 270         } else if siteFSDir[pathParts[0]] {
 271                 useSiteFS = true
 272         } else if len(pathParts) >= 1 && strings.HasPrefix(pathParts[0], "c=") {
 273                 // /c=ID[/PATH...]
 274                 collectionID = parseCollectionIDFromURL(pathParts[0][2:])
 275                 stripParts = 1
 276         } else if len(pathParts) >= 2 && pathParts[0] == "collections" {
 277                 if len(pathParts) >= 4 && pathParts[1] == "download" {
 278                         // /collections/download/ID/TOKEN/PATH...
 279                         collectionID = parseCollectionIDFromURL(pathParts[2])
 280                         tokens = []string{pathParts[3]}
 281                         stripParts = 4
 282                         pathToken = true
 283                 } else {
 284                         // /collections/ID/PATH...
 285                         collectionID = parseCollectionIDFromURL(pathParts[1])
 286                         stripParts = 2
 287                         // This path is only meant to work for public
 288                         // data. Tokens provided with the request are
 289                         // ignored.
 290                         credentialsOK = false
 291                 }
 292         }
 293
 294         if collectionID == "" && !useSiteFS {
 295                 statusCode = http.StatusNotFound
 296                 return
 297         }
 298
 299         forceReload := false
 300         if cc := r.Header.Get("Cache-Control"); strings.Contains(cc, "no-cache") || strings.Contains(cc, "must-revalidate") {
 301                 forceReload = true
 302         }
 303
 304         if credentialsOK {
 305                 reqTokens = auth.CredentialsFromRequest(r).Tokens
 306         }
 307
 308         formToken := r.FormValue("api_token")
 309         if formToken != "" && r.Header.Get("Origin") != "" && attachment && r.URL.Query().Get("api_token") == "" {
 310                 // The client provided an explicit token in the POST
 311                 // body. The Origin header indicates this *might* be
 312                 // an AJAX request, in which case redirect-with-cookie
 313                 // won't work: we should just serve the content in the
 314                 // POST response. This is safe because:
 315                 //
 316                 // * We're supplying an attachment, not inline
 317                 //   content, so we don't need to convert the POST to
 318                 //   a GET and avoid the "really resubmit form?"
 319                 //   problem.
 320                 //
 321                 // * The token isn't embedded in the URL, so we don't
 322                 //   need to worry about bookmarks and copy/paste.
 323                 reqTokens = append(reqTokens, formToken)
 324         } else if formToken != "" && browserMethod[r.Method] {
 325                 // The client provided an explicit token in the query
 326                 // string, or a form in POST body. We must put the
 327                 // token in an HttpOnly cookie, and redirect to the
 328                 // same URL with the query param redacted and method =
 329                 // GET.
 330                 h.seeOtherWithCookie(w, r, "", credentialsOK)
 331                 return
 332         }
 333
 334         if useSiteFS {
 335                 h.serveSiteFS(w, r, reqTokens, credentialsOK, attachment)
 336                 return
 337         }
 338
 339         targetPath := pathParts[stripParts:]
 340         if tokens == nil && len(targetPath) > 0 && strings.HasPrefix(targetPath[0], "t=") {
 341                 // http://ID.example/t=TOKEN/PATH...
 342                 // /c=ID/t=TOKEN/PATH...
 343                 //
 344                 // This form must only be used to pass scoped tokens
 345                 // that give permission for a single collection. See
 346                 // FormValue case above.
 347                 tokens = []string{targetPath[0][2:]}
 348                 pathToken = true
 349                 targetPath = targetPath[1:]
 350                 stripParts++
 351         }
 352
 353         if tokens == nil {
 354                 tokens = append(reqTokens, h.Config.AnonymousTokens...)
 355         }
 356
 357         if len(targetPath) > 0 && targetPath[0] == "_" {
 358                 // If a collection has a directory called "t=foo" or
 359                 // "_", it can be served at
 360                 // //collections.example/_/t=foo/ or
 361                 // //collections.example/_/_/ respectively:
 362                 // //collections.example/t=foo/ won't work because
 363                 // t=foo will be interpreted as a token "foo".
 364                 targetPath = targetPath[1:]
 365                 stripParts++
 366         }
 367
 368         arv := h.clientPool.Get()
 369         if arv == nil {
 370                 statusCode, statusText = http.StatusInternalServerError, "Pool failed: "+h.clientPool.Err().Error()
 371                 return
 372         }
 373         defer h.clientPool.Put(arv)
 374
 375         var collection *arvados.Collection
 376         tokenResult := make(map[string]int)
 377         for _, arv.ApiToken = range tokens {
 378                 var err error
 379                 collection, err = h.Config.Cache.Get(arv, collectionID, forceReload)
 380                 if err == nil {
 381                         // Success
 382                         break
 383                 }
 384                 if srvErr, ok := err.(arvadosclient.APIServerError); ok {
 385                         switch srvErr.HttpStatusCode {
 386                         case 404, 401:
 387                                 // Token broken or insufficient to
 388                                 // retrieve collection
 389                                 tokenResult[arv.ApiToken] = srvErr.HttpStatusCode
 390                                 continue
 391                         }
 392                 }
 393                 // Something more serious is wrong
 394                 statusCode, statusText = http.StatusInternalServerError, err.Error()
 395                 return
 396         }
 397         if collection == nil {
 398                 if pathToken || !credentialsOK {
 399                         // Either the URL is a "secret sharing link"
 400                         // that didn't work out (and asking the client
 401                         // for additional credentials would just be
 402                         // confusing), or we don't even accept
 403                         // credentials at this path.
 404                         statusCode = http.StatusNotFound
 405                         return
 406                 }
 407                 for _, t := range reqTokens {
 408                         if tokenResult[t] == 404 {
 409                                 // The client provided valid token(s), but the
 410                                 // collection was not found.
 411                                 statusCode = http.StatusNotFound
 412                                 return
 413                         }
 414                 }
 415                 // The client's token was invalid (e.g., expired), or
 416                 // the client didn't even provide one.  Propagate the
 417                 // 401 to encourage the client to use a [different]
 418                 // token.
 419                 //
 420                 // TODO(TC): This response would be confusing to
 421                 // someone trying (anonymously) to download public
 422                 // data that has been deleted.  Allow a referrer to
 423                 // provide this context somehow?
 424                 w.Header().Add("WWW-Authenticate", "Basic realm=\"collections\"")
 425                 statusCode = http.StatusUnauthorized
 426                 return
 427         }
 428
 429         kc, err := keepclient.MakeKeepClient(arv)
 430         if err != nil {
 431                 statusCode, statusText = http.StatusInternalServerError, err.Error()
 432                 return
 433         }
 434         kc.RequestID = r.Header.Get("X-Request-Id")
 435
 436         var basename string
 437         if len(targetPath) > 0 {
 438                 basename = targetPath[len(targetPath)-1]
 439         }
 440         applyContentDispositionHdr(w, r, basename, attachment)
 441
 442         client := (&arvados.Client{
 443                 APIHost:   arv.ApiServer,
 444                 AuthToken: arv.ApiToken,
 445                 Insecure:  arv.ApiInsecure,
 446         }).WithRequestID(r.Header.Get("X-Request-Id"))
 447
 448         fs, err := collection.FileSystem(client, kc)
 449         if err != nil {
 450                 statusCode, statusText = http.StatusInternalServerError, err.Error()
 451                 return
 452         }
 453
 454         writefs, writeOK := fs.(arvados.CollectionFileSystem)
 455         targetIsPDH := arvadosclient.PDHMatch(collectionID)
 456         if (targetIsPDH || !writeOK) && writeMethod[r.Method] {
 457                 statusCode, statusText = http.StatusMethodNotAllowed, errReadOnly.Error()
 458                 return
 459         }
 460
 461         if webdavMethod[r.Method] {
 462                 if writeMethod[r.Method] {
 463                         // Save the collection only if/when all
 464                         // webdav->filesystem operations succeed --
 465                         // and send a 500 error if the modified
 466                         // collection can't be saved.
 467                         w = &updateOnSuccess{
 468                                 ResponseWriter: w,
 469                                 update: func() error {
 470                                         return h.Config.Cache.Update(client, *collection, writefs)
 471                                 }}
 472                 }
 473                 h := webdav.Handler{
 474                         Prefix: "/" + strings.Join(pathParts[:stripParts], "/"),
 475                         FileSystem: &webdavFS{
 476                                 collfs:        fs,
 477                                 writing:       writeMethod[r.Method],
 478                                 alwaysReadEOF: r.Method == "PROPFIND",
 479                         },
 480                         LockSystem: h.webdavLS,
 481                         Logger: func(_ *http.Request, err error) {
 482                                 if err != nil {
 483                                         log.Printf("error from webdav handler: %q", err)
 484                                 }
 485                         },
 486                 }
 487                 h.ServeHTTP(w, r)
 488                 return
 489         }
 490
 491         openPath := "/" + strings.Join(targetPath, "/")
 492         if f, err := fs.Open(openPath); os.IsNotExist(err) {
 493                 // Requested non-existent path
 494                 statusCode = http.StatusNotFound
 495         } else if err != nil {
 496                 // Some other (unexpected) error
 497                 statusCode, statusText = http.StatusInternalServerError, err.Error()
 498         } else if stat, err := f.Stat(); err != nil {
 499                 // Can't get Size/IsDir (shouldn't happen with a collectionFS!)
 500                 statusCode, statusText = http.StatusInternalServerError, err.Error()
 501         } else if stat.IsDir() && !strings.HasSuffix(r.URL.Path, "/") {
 502                 // If client requests ".../dirname", redirect to
 503                 // ".../dirname/". This way, relative links in the
 504                 // listing for "dirname" can always be "fnm", never
 505                 // "dirname/fnm".
 506                 h.seeOtherWithCookie(w, r, r.URL.Path+"/", credentialsOK)
 507         } else if stat.IsDir() {
 508                 h.serveDirectory(w, r, collection.Name, fs, openPath, true)
 509         } else {
 510                 http.ServeContent(w, r, basename, stat.ModTime(), f)
 511                 if r.Header.Get("Range") == "" && int64(w.WroteBodyBytes()) != stat.Size() {
 512                         // If we wrote fewer bytes than expected, it's
 513                         // too late to change the real response code
 514                         // or send an error message to the client, but
 515                         // at least we can try to put some useful
 516                         // debugging info in the logs.
 517                         n, err := f.Read(make([]byte, 1024))
 518                         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)
 519
 520                 }
 521         }
 522 }
 523
 524 func (h *handler) serveSiteFS(w http.ResponseWriter, r *http.Request, tokens []string, credentialsOK, attachment bool) {
 525         if len(tokens) == 0 {
 526                 w.Header().Add("WWW-Authenticate", "Basic realm=\"collections\"")
 527                 http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
 528                 return
 529         }
 530         if writeMethod[r.Method] {
 531                 http.Error(w, errReadOnly.Error(), http.StatusMethodNotAllowed)
 532                 return
 533         }
 534         arv := h.clientPool.Get()
 535         if arv == nil {
 536                 http.Error(w, "Pool failed: "+h.clientPool.Err().Error(), http.StatusInternalServerError)
 537                 return
 538         }
 539         defer h.clientPool.Put(arv)
 540         arv.ApiToken = tokens[0]
 541
 542         kc, err := keepclient.MakeKeepClient(arv)
 543         if err != nil {
 544                 http.Error(w, err.Error(), http.StatusInternalServerError)
 545                 return
 546         }
 547         kc.RequestID = r.Header.Get("X-Request-Id")
 548         client := (&arvados.Client{
 549                 APIHost:   arv.ApiServer,
 550                 AuthToken: arv.ApiToken,
 551                 Insecure:  arv.ApiInsecure,
 552         }).WithRequestID(r.Header.Get("X-Request-Id"))
 553         fs := client.SiteFileSystem(kc)
 554         f, err := fs.Open(r.URL.Path)
 555         if os.IsNotExist(err) {
 556                 http.Error(w, err.Error(), http.StatusNotFound)
 557                 return
 558         } else if err != nil {
 559                 http.Error(w, err.Error(), http.StatusInternalServerError)
 560                 return
 561         }
 562         defer f.Close()
 563         if fi, err := f.Stat(); err == nil && fi.IsDir() && r.Method == "GET" {
 564                 if !strings.HasSuffix(r.URL.Path, "/") {
 565                         h.seeOtherWithCookie(w, r, r.URL.Path+"/", credentialsOK)
 566                 } else {
 567                         h.serveDirectory(w, r, fi.Name(), fs, r.URL.Path, false)
 568                 }
 569                 return
 570         }
 571         if r.Method == "GET" {
 572                 _, basename := filepath.Split(r.URL.Path)
 573                 applyContentDispositionHdr(w, r, basename, attachment)
 574         }
 575         wh := webdav.Handler{
 576                 Prefix: "/",
 577                 FileSystem: &webdavFS{
 578                         collfs:        fs,
 579                         writing:       writeMethod[r.Method],
 580                         alwaysReadEOF: r.Method == "PROPFIND",
 581                 },
 582                 LockSystem: h.webdavLS,
 583                 Logger: func(_ *http.Request, err error) {
 584                         if err != nil {
 585                                 log.Printf("error from webdav handler: %q", err)
 586                         }
 587                 },
 588         }
 589         wh.ServeHTTP(w, r)
 590 }
 591
 592 var dirListingTemplate = `<!DOCTYPE HTML>
 593 <HTML><HEAD>
 594   <META name="robots" content="NOINDEX">
 595   <TITLE>{{ .CollectionName }}</TITLE>
 596   <STYLE type="text/css">
 597     body {
 598       margin: 1.5em;
 599     }
 600     pre {
 601       background-color: #D9EDF7;
 602       border-radius: .25em;
 603       padding: .75em;
 604       overflow: auto;
 605     }
 606     .footer p {
 607       font-size: 82%;
 608     }
 609     ul {
 610       padding: 0;
 611     }
 612     ul li {
 613       font-family: monospace;
 614       list-style: none;
 615     }
 616   </STYLE>
 617 </HEAD>
 618 <BODY>
 619
 620 <H1>{{ .CollectionName }}</H1>
 621
 622 <P>This collection of data files is being shared with you through
 623 Arvados.  You can download individual files listed below.  To download
 624 the entire directory tree with wget, try:</P>
 625
 626 <PRE>$ wget --mirror --no-parent --no-host --cut-dirs={{ .StripParts }} https://{{ .Request.Host }}{{ .Request.URL.Path }}</PRE>
 627
 628 <H2>File Listing</H2>
 629
 630 {{if .Files}}
 631 <UL>
 632 {{range .Files}}
 633 {{if .IsDir }}
 634   <LI>{{" " | printf "%15s  " | nbsp}}<A href="{{print "./" .Name}}/">{{.Name}}/</A></LI>
 635 {{else}}
 636   <LI>{{.Size | printf "%15d  " | nbsp}}<A href="{{print "./" .Name}}">{{.Name}}</A></LI>
 637 {{end}}
 638 {{end}}
 639 </UL>
 640 {{else}}
 641 <P>(No files; this collection is empty.)</P>
 642 {{end}}
 643
 644 <HR noshade>
 645 <DIV class="footer">
 646   <P>
 647     About Arvados:
 648     Arvados is a free and open source software bioinformatics platform.
 649     To learn more, visit arvados.org.
 650     Arvados is not responsible for the files listed on this page.
 651   </P>
 652 </DIV>
 653
 654 </BODY>
 655 `
 656
 657 type fileListEnt struct {
 658         Name  string
 659         Size  int64
 660         IsDir bool
 661 }
 662
 663 func (h *handler) serveDirectory(w http.ResponseWriter, r *http.Request, collectionName string, fs http.FileSystem, base string, recurse bool) {
 664         var files []fileListEnt
 665         var walk func(string) error
 666         if !strings.HasSuffix(base, "/") {
 667                 base = base + "/"
 668         }
 669         walk = func(path string) error {
 670                 dirname := base + path
 671                 if dirname != "/" {
 672                         dirname = strings.TrimSuffix(dirname, "/")
 673                 }
 674                 d, err := fs.Open(dirname)
 675                 if err != nil {
 676                         return err
 677                 }
 678                 ents, err := d.Readdir(-1)
 679                 if err != nil {
 680                         return err
 681                 }
 682                 for _, ent := range ents {
 683                         if recurse && ent.IsDir() {
 684                                 err = walk(path + ent.Name() + "/")
 685                                 if err != nil {
 686                                         return err
 687                                 }
 688                         } else {
 689                                 files = append(files, fileListEnt{
 690                                         Name:  path + ent.Name(),
 691                                         Size:  ent.Size(),
 692                                         IsDir: ent.IsDir(),
 693                                 })
 694                         }
 695                 }
 696                 return nil
 697         }
 698         if err := walk(""); err != nil {
 699                 http.Error(w, err.Error(), http.StatusInternalServerError)
 700                 return
 701         }
 702
 703         funcs := template.FuncMap{
 704                 "nbsp": func(s string) template.HTML {
 705                         return template.HTML(strings.Replace(s, " ", "&nbsp;", -1))
 706                 },
 707         }
 708         tmpl, err := template.New("dir").Funcs(funcs).Parse(dirListingTemplate)
 709         if err != nil {
 710                 http.Error(w, err.Error(), http.StatusInternalServerError)
 711                 return
 712         }
 713         sort.Slice(files, func(i, j int) bool {
 714                 return files[i].Name < files[j].Name
 715         })
 716         w.WriteHeader(http.StatusOK)
 717         tmpl.Execute(w, map[string]interface{}{
 718                 "CollectionName": collectionName,
 719                 "Files":          files,
 720                 "Request":        r,
 721                 "StripParts":     strings.Count(strings.TrimRight(r.URL.Path, "/"), "/"),
 722         })
 723 }
 724
 725 func applyContentDispositionHdr(w http.ResponseWriter, r *http.Request, filename string, isAttachment bool) {
 726         disposition := "inline"
 727         if isAttachment {
 728                 disposition = "attachment"
 729         }
 730         if strings.ContainsRune(r.RequestURI, '?') {
 731                 // Help the UA realize that the filename is just
 732                 // "filename.txt", not
 733                 // "filename.txt?disposition=attachment".
 734                 //
 735                 // TODO(TC): Follow advice at RFC 6266 appendix D
 736                 disposition += "; filename=" + strconv.QuoteToASCII(filename)
 737         }
 738         if disposition != "inline" {
 739                 w.Header().Set("Content-Disposition", disposition)
 740         }
 741 }
 742
 743 func (h *handler) seeOtherWithCookie(w http.ResponseWriter, r *http.Request, location string, credentialsOK bool) {
 744         if formToken := r.FormValue("api_token"); formToken != "" {
 745                 if !credentialsOK {
 746                         // It is not safe to copy the provided token
 747                         // into a cookie unless the current vhost
 748                         // (origin) serves only a single collection or
 749                         // we are in TrustAllContent mode.
 750                         w.WriteHeader(http.StatusBadRequest)
 751                         return
 752                 }
 753
 754                 // The HttpOnly flag is necessary to prevent
 755                 // JavaScript code (included in, or loaded by, a page
 756                 // in the collection being served) from employing the
 757                 // user's token beyond reading other files in the same
 758                 // domain, i.e., same collection.
 759                 //
 760                 // The 303 redirect is necessary in the case of a GET
 761                 // request to avoid exposing the token in the Location
 762                 // bar, and in the case of a POST request to avoid
 763                 // raising warnings when the user refreshes the
 764                 // resulting page.
 765                 http.SetCookie(w, &http.Cookie{
 766                         Name:     "arvados_api_token",
 767                         Value:    auth.EncodeTokenCookie([]byte(formToken)),
 768                         Path:     "/",
 769                         HttpOnly: true,
 770                 })
 771         }
 772
 773         // Propagate query parameters (except api_token) from
 774         // the original request.
 775         redirQuery := r.URL.Query()
 776         redirQuery.Del("api_token")
 777
 778         u := r.URL
 779         if location != "" {
 780                 newu, err := u.Parse(location)
 781                 if err != nil {
 782                         w.WriteHeader(http.StatusInternalServerError)
 783                         return
 784                 }
 785                 u = newu
 786         }
 787         redir := (&url.URL{
 788                 Scheme:   r.URL.Scheme,
 789                 Host:     r.Host,
 790                 Path:     u.Path,
 791                 RawQuery: redirQuery.Encode(),
 792         }).String()
 793
 794         w.Header().Add("Location", redir)
 795         w.WriteHeader(http.StatusSeeOther)
 796         io.WriteString(w, `<A href="`)
 797         io.WriteString(w, html.EscapeString(redir))
 798         io.WriteString(w, `">Continue</A>`)
 799 }