aboutsummaryrefslogtreecommitdiffstats
path: root/swarm/api/http/server.go
blob: 2055bda589de133be2bbbfc6a8cfa462cb0b3df5 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

/*
A simple http server interface to Swarm
*/
package http

import (
    "bufio"
    "bytes"
    "encoding/json"
    "fmt"
    "io"
    "io/ioutil"
    "mime"
    "mime/multipart"
    "net/http"
    "os"
    "path"
    "strconv"
    "strings"
    "time"

    "github.com/dexon-foundation/dexon/common"
    "github.com/dexon-foundation/dexon/metrics"
    "github.com/dexon-foundation/dexon/swarm/api"
    "github.com/dexon-foundation/dexon/swarm/log"
    "github.com/dexon-foundation/dexon/swarm/storage"
    "github.com/dexon-foundation/dexon/swarm/storage/feed"
    "github.com/rs/cors"
)

var (
    postRawCount    = metrics.NewRegisteredCounter("api.http.post.raw.count", nil)
    postRawFail     = metrics.NewRegisteredCounter("api.http.post.raw.fail", nil)
    postFilesCount  = metrics.NewRegisteredCounter("api.http.post.files.count", nil)
    postFilesFail   = metrics.NewRegisteredCounter("api.http.post.files.fail", nil)
    deleteCount     = metrics.NewRegisteredCounter("api.http.delete.count", nil)
    deleteFail      = metrics.NewRegisteredCounter("api.http.delete.fail", nil)
    getCount        = metrics.NewRegisteredCounter("api.http.get.count", nil)
    getFail         = metrics.NewRegisteredCounter("api.http.get.fail", nil)
    getFileCount    = metrics.NewRegisteredCounter("api.http.get.file.count", nil)
    getFileNotFound = metrics.NewRegisteredCounter("api.http.get.file.notfound", nil)
    getFileFail     = metrics.NewRegisteredCounter("api.http.get.file.fail", nil)
    getListCount    = metrics.NewRegisteredCounter("api.http.get.list.count", nil)
    getListFail     = metrics.NewRegisteredCounter("api.http.get.list.fail", nil)
)

type methodHandler map[string]http.Handler

func (m methodHandler) ServeHTTP(rw http.ResponseWriter, r *http.Request) {
    v, ok := m[r.Method]
    if ok {
        v.ServeHTTP(rw, r)
        return
    }
    rw.WriteHeader(http.StatusMethodNotAllowed)
}

func NewServer(api *api.API, corsString string) *Server {
    var allowedOrigins []string
    for _, domain := range strings.Split(corsString, ",") {
        allowedOrigins = append(allowedOrigins, strings.TrimSpace(domain))
    }
    c := cors.New(cors.Options{
        AllowedOrigins: allowedOrigins,
        AllowedMethods: []string{http.MethodPost, http.MethodGet, http.MethodDelete, http.MethodPatch, http.MethodPut},
        MaxAge:         600,
        AllowedHeaders: []string{"*"},
    })

    server := &Server{api: api}

    defaultMiddlewares := []Adapter{
        RecoverPanic,
        SetRequestID,
        SetRequestHost,
        InitLoggingResponseWriter,
        ParseURI,
        InstrumentOpenTracing,
    }

    mux := http.NewServeMux()
    mux.Handle("/bzz:/", methodHandler{
        "GET": Adapt(
            http.HandlerFunc(server.HandleBzzGet),
            defaultMiddlewares...,
        ),
        "POST": Adapt(
            http.HandlerFunc(server.HandlePostFiles),
            defaultMiddlewares...,
        ),
        "DELETE": Adapt(
            http.HandlerFunc(server.HandleDelete),
            defaultMiddlewares...,
        ),
    })
    mux.Handle("/bzz-raw:/", methodHandler{
        "GET": Adapt(
            http.HandlerFunc(server.HandleGet),
            defaultMiddlewares...,
        ),
        "POST": Adapt(
            http.HandlerFunc(server.HandlePostRaw),
            defaultMiddlewares...,
        ),
    })
    mux.Handle("/bzz-immutable:/", methodHandler{
        "GET": Adapt(
            http.HandlerFunc(server.HandleBzzGet),
            defaultMiddlewares...,
        ),
    })
    mux.Handle("/bzz-hash:/", methodHandler{
        "GET": Adapt(
            http.HandlerFunc(server.HandleGet),
            defaultMiddlewares...,
        ),
    })
    mux.Handle("/bzz-list:/", methodHandler{
        "GET": Adapt(
            http.HandlerFunc(server.HandleGetList),
            defaultMiddlewares...,
        ),
    })
    mux.Handle("/bzz-feed:/", methodHandler{
        "GET": Adapt(
            http.HandlerFunc(server.HandleGetFeed),
            defaultMiddlewares...,
        ),
        "POST": Adapt(
            http.HandlerFunc(server.HandlePostFeed),
            defaultMiddlewares...,
        ),
    })

    mux.Handle("/", methodHandler{
        "GET": Adapt(
            http.HandlerFunc(server.HandleRootPaths),
            SetRequestID,
            InitLoggingResponseWriter,
        ),
    })
    server.Handler = c.Handler(mux)

    return server
}

func (s *Server) ListenAndServe(addr string) error {
    s.listenAddr = addr
    return http.ListenAndServe(addr, s)
}

// browser API for registering bzz url scheme handlers:
// https://developer.mozilla.org/en/docs/Web-based_protocol_handlers
// electron (chromium) api for registering bzz url scheme handlers:
// https://github.com/atom/electron/blob/master/docs/api/protocol.md
type Server struct {
    http.Handler
    api        *api.API
    listenAddr string
}

func (s *Server) HandleBzzGet(w http.ResponseWriter, r *http.Request) {
    log.Debug("handleBzzGet", "ruid", GetRUID(r.Context()), "uri", r.RequestURI)
    if r.Header.Get("Accept") == "application/x-tar" {
        uri := GetURI(r.Context())
        _, credentials, _ := r.BasicAuth()
        reader, err := s.api.GetDirectoryTar(r.Context(), s.api.Decryptor(r.Context(), credentials), uri)
        if err != nil {
            if isDecryptError(err) {
                w.Header().Set("WWW-Authenticate", fmt.Sprintf("Basic realm=%q", uri.Address().String()))
                respondError(w, r, err.Error(), http.StatusUnauthorized)
                return
            }
            respondError(w, r, fmt.Sprintf("Had an error building the tarball: %v", err), http.StatusInternalServerError)
            return
        }
        defer reader.Close()

        w.Header().Set("Content-Type", "application/x-tar")

        fileName := uri.Addr
        if found := path.Base(uri.Path); found != "" && found != "." && found != "/" {
            fileName = found
        }
        w.Header().Set("Content-Disposition", fmt.Sprintf("inline; filename=\"%s.tar\"", fileName))

        w.WriteHeader(http.StatusOK)
        io.Copy(w, reader)
        return
    }

    s.HandleGetFile(w, r)
}

func (s *Server) HandleRootPaths(w http.ResponseWriter, r *http.Request) {
    switch r.RequestURI {
    case "/":
        respondTemplate(w, r, "landing-page", "Swarm: Please request a valid ENS or swarm hash with the appropriate bzz scheme", 200)
        return
    case "/robots.txt":
        w.Header().Set("Last-Modified", time.Now().Format(http.TimeFormat))
        fmt.Fprintf(w, "User-agent: *\nDisallow: /")
    case "/favicon.ico":
        w.WriteHeader(http.StatusOK)
        w.Write(faviconBytes)
    default:
        respondError(w, r, "Not Found", http.StatusNotFound)
    }
}

// HandlePostRaw handles a POST request to a raw bzz-raw:/ URI, stores the request
// body in swarm and returns the resulting storage address as a text/plain response
func (s *Server) HandlePostRaw(w http.ResponseWriter, r *http.Request) {
    ruid := GetRUID(r.Context())
    log.Debug("handle.post.raw", "ruid", ruid)

    postRawCount.Inc(1)

    toEncrypt := false
    uri := GetURI(r.Context())
    if uri.Addr == "encrypt" {
        toEncrypt = true
    }

    if uri.Path != "" {
        postRawFail.Inc(1)
        respondError(w, r, "raw POST request cannot contain a path", http.StatusBadRequest)
        return
    }

    if uri.Addr != "" && uri.Addr != "encrypt" {
        postRawFail.Inc(1)
        respondError(w, r, "raw POST request addr can only be empty or \"encrypt\"", http.StatusBadRequest)
        return
    }

    if r.Header.Get("Content-Length") == "" {
        postRawFail.Inc(1)
        respondError(w, r, "missing Content-Length header in request", http.StatusBadRequest)
        return
    }

    addr, _, err := s.api.Store(r.Context(), r.Body, r.ContentLength, toEncrypt)
    if err != nil {
        postRawFail.Inc(1)
        respondError(w, r, err.Error(), http.StatusInternalServerError)
        return
    }

    log.Debug("stored content", "ruid", ruid, "key", addr)

    w.Header().Set("Content-Type", "text/plain")
    w.WriteHeader(http.StatusOK)
    fmt.Fprint(w, addr)
}

// HandlePostFiles handles a POST request to
// bzz:/<hash>/<path> which contains either a single file or multiple files
// (either a tar archive or multipart form), adds those files either to an
// existing manifest or to a new manifest under <path> and returns the
// resulting manifest hash as a text/plain response
func (s *Server) HandlePostFiles(w http.ResponseWriter, r *http.Request) {
    ruid := GetRUID(r.Context())
    log.Debug("handle.post.files", "ruid", ruid)
    postFilesCount.Inc(1)

    contentType, params, err := mime.ParseMediaType(r.Header.Get("Content-Type"))
    if err != nil {
        postFilesFail.Inc(1)
        respondError(w, r, err.Error(), http.StatusBadRequest)
        return
    }

    toEncrypt := false
    uri := GetURI(r.Context())
    if uri.Addr == "encrypt" {
        toEncrypt = true
    }

    var addr storage.Address
    if uri.Addr != "" && uri.Addr != "encrypt" {
        addr, err = s.api.Resolve(r.Context(), uri.Addr)
        if err != nil {
            postFilesFail.Inc(1)
            respondError(w, r, fmt.Sprintf("cannot resolve %s: %s", uri.Addr, err), http.StatusInternalServerError)
            return
        }
        log.Debug("resolved key", "ruid", ruid, "key", addr)
    } else {
        addr, err = s.api.NewManifest(r.Context(), toEncrypt)
        if err != nil {
            postFilesFail.Inc(1)
            respondError(w, r, err.Error(), http.StatusInternalServerError)
            return
        }
        log.Debug("new manifest", "ruid", ruid, "key", addr)
    }

    newAddr, err := s.api.UpdateManifest(r.Context(), addr, func(mw *api.ManifestWriter) error {
        switch contentType {
        case "application/x-tar":
            _, err := s.handleTarUpload(r, mw)
            if err != nil {
                respondError(w, r, fmt.Sprintf("error uploading tarball: %v", err), http.StatusInternalServerError)
                return err
            }
            return nil
        case "multipart/form-data":
            return s.handleMultipartUpload(r, params["boundary"], mw)

        default:
            return s.handleDirectUpload(r, mw)
        }
    })
    if err != nil {
        postFilesFail.Inc(1)
        respondError(w, r, fmt.Sprintf("cannot create manifest: %s", err), http.StatusInternalServerError)
        return
    }

    log.Debug("stored content", "ruid", ruid, "key", newAddr)

    w.Header().Set("Content-Type", "text/plain")
    w.WriteHeader(http.StatusOK)
    fmt.Fprint(w, newAddr)
}

func (s *Server) handleTarUpload(r *http.Request, mw *api.ManifestWriter) (storage.Address, error) {
    log.Debug("handle.tar.upload", "ruid", GetRUID(r.Context()))

    defaultPath := r.URL.Query().Get("defaultpath")

    key, err := s.api.UploadTar(r.Context(), r.Body, GetURI(r.Context()).Path, defaultPath, mw)
    if err != nil {
        return nil, err
    }
    return key, nil
}

func (s *Server) handleMultipartUpload(r *http.Request, boundary string, mw *api.ManifestWriter) error {
    ruid := GetRUID(r.Context())
    log.Debug("handle.multipart.upload", "ruid", ruid)
    mr := multipart.NewReader(r.Body, boundary)
    for {
        part, err := mr.NextPart()
        if err == io.EOF {
            return nil
        } else if err != nil {
            return fmt.Errorf("error reading multipart form: %s", err)
        }

        var size int64
        var reader io.Reader
        if contentLength := part.Header.Get("Content-Length"); contentLength != "" {
            size, err = strconv.ParseInt(contentLength, 10, 64)
            if err != nil {
                return fmt.Errorf("error parsing multipart content length: %s", err)
            }
            reader = part
        } else {
            // copy the part to a tmp file to get its size
            tmp, err := ioutil.TempFile("", "swarm-multipart")
            if err != nil {
                return err
            }
            defer os.Remove(tmp.Name())
            defer tmp.Close()
            size, err = io.Copy(tmp, part)
            if err != nil {
                return fmt.Errorf("error copying multipart content: %s", err)
            }
            if _, err := tmp.Seek(0, io.SeekStart); err != nil {
                return fmt.Errorf("error copying multipart content: %s", err)
            }
            reader = tmp
        }

        // add the entry under the path from the request
        name := part.FileName()
        if name == "" {
            name = part.FormName()
        }
        uri := GetURI(r.Context())
        path := path.Join(uri.Path, name)
        entry := &api.ManifestEntry{
            Path:        path,
            ContentType: part.Header.Get("Content-Type"),
            Size:        size,
        }
        log.Debug("adding path to new manifest", "ruid", ruid, "bytes", entry.Size, "path", entry.Path)
        contentKey, err := mw.AddEntry(r.Context(), reader, entry)
        if err != nil {
            return fmt.Errorf("error adding manifest entry from multipart form: %s", err)
        }
        log.Debug("stored content", "ruid", ruid, "key", contentKey)
    }
}

func (s *Server) handleDirectUpload(r *http.Request, mw *api.ManifestWriter) error {
    ruid := GetRUID(r.Context())
    log.Debug("handle.direct.upload", "ruid", ruid)
    key, err := mw.AddEntry(r.Context(), r.Body, &api.ManifestEntry{
        Path:        GetURI(r.Context()).Path,
        ContentType: r.Header.Get("Content-Type"),
        Mode:        0644,
        Size:        r.ContentLength,
    })
    if err != nil {
        return err
    }
    log.Debug("stored content", "ruid", ruid, "key", key)
    return nil
}

// HandleDelete handles a DELETE request to bzz:/<manifest>/<path>, removes
// <path> from <manifest> and returns the resulting manifest hash as a
// text/plain response
func (s *Server) HandleDelete(w http.ResponseWriter, r *http.Request) {
    ruid := GetRUID(r.Context())
    uri := GetURI(r.Context())
    log.Debug("handle.delete", "ruid", ruid)
    deleteCount.Inc(1)
    newKey, err := s.api.Delete(r.Context(), uri.Addr, uri.Path)
    if err != nil {
        deleteFail.Inc(1)
        respondError(w, r, fmt.Sprintf("could not delete from manifest: %v", err), http.StatusInternalServerError)
        return
    }

    w.Header().Set("Content-Type", "text/plain")
    w.WriteHeader(http.StatusOK)
    fmt.Fprint(w, newKey)
}

// Handles feed manifest creation and feed updates
// The POST request admits a JSON structure as defined in the feeds package: `feed.updateRequestJSON`
// The requests can be to a) create a feed manifest, b) update a feed or c) both a+b: create a feed manifest and publish a first update
func (s *Server) HandlePostFeed(w http.ResponseWriter, r *http.Request) {
    ruid := GetRUID(r.Context())
    uri := GetURI(r.Context())
    log.Debug("handle.post.feed", "ruid", ruid)
    var err error

    // Creation and update must send feed.updateRequestJSON JSON structure
    body, err := ioutil.ReadAll(r.Body)
    if err != nil {
        respondError(w, r, err.Error(), http.StatusInternalServerError)
        return
    }

    fd, err := s.api.ResolveFeed(r.Context(), uri, r.URL.Query())
    if err != nil { // couldn't parse query string or retrieve manifest
        getFail.Inc(1)
        httpStatus := http.StatusBadRequest
        if err == api.ErrCannotLoadFeedManifest || err == api.ErrCannotResolveFeedURI {
            httpStatus = http.StatusNotFound
        }
        respondError(w, r, fmt.Sprintf("cannot retrieve feed from manifest: %s", err), httpStatus)
        return
    }

    var updateRequest feed.Request
    updateRequest.Feed = *fd
    query := r.URL.Query()

    if err := updateRequest.FromValues(query, body); err != nil { // decodes request from query parameters
        respondError(w, r, err.Error(), http.StatusBadRequest)
        return
    }

    switch {
    case updateRequest.IsUpdate():
        // Verify that the signature is intact and that the signer is authorized
        // to update this feed
        // Check this early, to avoid creating a feed and then not being able to set its first update.
        if err = updateRequest.Verify(); err != nil {
            respondError(w, r, err.Error(), http.StatusForbidden)
            return
        }
        _, err = s.api.FeedsUpdate(r.Context(), &updateRequest)
        if err != nil {
            respondError(w, r, err.Error(), http.StatusInternalServerError)
            return
        }
        fallthrough
    case query.Get("manifest") == "1":
        // we create a manifest so we can retrieve feed updates with bzz:// later
        // this manifest has a special "feed type" manifest, and saves the
        // feed identification used to retrieve feed updates later
        m, err := s.api.NewFeedManifest(r.Context(), &updateRequest.Feed)
        if err != nil {
            respondError(w, r, fmt.Sprintf("failed to create feed manifest: %v", err), http.StatusInternalServerError)
            return
        }
        // the key to the manifest will be passed back to the client
        // the client can access the feed  directly through its Feed member
        // the manifest key can be set as content in the resolver of the ENS name
        outdata, err := json.Marshal(m)
        if err != nil {
            respondError(w, r, fmt.Sprintf("failed to create json response: %s", err), http.StatusInternalServerError)
            return
        }
        fmt.Fprint(w, string(outdata))

        w.Header().Add("Content-type", "application/json")
    default:
        respondError(w, r, "Missing signature in feed update request", http.StatusBadRequest)
    }
}

// HandleGetFeed retrieves Swarm feeds updates:
// bzz-feed://<manifest address or ENS name> - get latest feed update, given a manifest address
// - or -
// specify user + topic (optional), subtopic name (optional) directly, without manifest:
// bzz-feed://?user=0x...&topic=0x...&name=subtopic name
// topic defaults to 0x000... if not specified.
// name defaults to empty string if not specified.
// thus, empty name and topic refers to the user's default feed.
//
// Optional parameters:
// time=xx - get the latest update before time (in epoch seconds)
// hint.time=xx - hint the lookup algorithm looking for updates at around that time
// hint.level=xx - hint the lookup algorithm looking for updates at around this frequency level
// meta=1 - get feed metadata and status information instead of performing a feed query
// NOTE: meta=1 will be deprecated in the near future
func (s *Server) HandleGetFeed(w http.ResponseWriter, r *http.Request) {
    ruid := GetRUID(r.Context())
    uri := GetURI(r.Context())
    log.Debug("handle.get.feed", "ruid", ruid)
    var err error

    fd, err := s.api.ResolveFeed(r.Context(), uri, r.URL.Query())
    if err != nil { // couldn't parse query string or retrieve manifest
        getFail.Inc(1)
        httpStatus := http.StatusBadRequest
        if err == api.ErrCannotLoadFeedManifest || err == api.ErrCannotResolveFeedURI {
            httpStatus = http.StatusNotFound
        }
        respondError(w, r, fmt.Sprintf("cannot retrieve feed information from manifest: %s", err), httpStatus)
        return
    }

    // determine if the query specifies period and version or it is a metadata query
    if r.URL.Query().Get("meta") == "1" {
        unsignedUpdateRequest, err := s.api.FeedsNewRequest(r.Context(), fd)
        if err != nil {
            getFail.Inc(1)
            respondError(w, r, fmt.Sprintf("cannot retrieve feed metadata for feed=%s: %s", fd.Hex(), err), http.StatusNotFound)
            return
        }
        rawResponse, err := unsignedUpdateRequest.MarshalJSON()
        if err != nil {
            respondError(w, r, fmt.Sprintf("cannot encode unsigned feed update request: %v", err), http.StatusInternalServerError)
            return
        }
        w.Header().Add("Content-type", "application/json")
        w.WriteHeader(http.StatusOK)
        fmt.Fprint(w, string(rawResponse))
        return
    }

    lookupParams := &feed.Query{Feed: *fd}
    if err = lookupParams.FromValues(r.URL.Query()); err != nil { // parse period, version
        respondError(w, r, fmt.Sprintf("invalid feed update request:%s", err), http.StatusBadRequest)
        return
    }

    data, err := s.api.FeedsLookup(r.Context(), lookupParams)

    // any error from the switch statement will end up here
    if err != nil {
        code, err2 := s.translateFeedError(w, r, "feed lookup fail", err)
        respondError(w, r, err2.Error(), code)
        return
    }

    // All ok, serve the retrieved update
    log.Debug("Found update", "feed", fd.Hex(), "ruid", ruid)
    w.Header().Set("Content-Type", api.MimeOctetStream)
    http.ServeContent(w, r, "", time.Now(), bytes.NewReader(data))
}

func (s *Server) translateFeedError(w http.ResponseWriter, r *http.Request, supErr string, err error) (int, error) {
    code := 0
    defaultErr := fmt.Errorf("%s: %v", supErr, err)
    rsrcErr, ok := err.(*feed.Error)
    if !ok && rsrcErr != nil {
        code = rsrcErr.Code()
    }
    switch code {
    case storage.ErrInvalidValue:
        return http.StatusBadRequest, defaultErr
    case storage.ErrNotFound, storage.ErrNotSynced, storage.ErrNothingToReturn, storage.ErrInit:
        return http.StatusNotFound, defaultErr
    case storage.ErrUnauthorized, storage.ErrInvalidSignature:
        return http.StatusUnauthorized, defaultErr
    case storage.ErrDataOverflow:
        return http.StatusRequestEntityTooLarge, defaultErr
    }

    return http.StatusInternalServerError, defaultErr
}

// HandleGet handles a GET request to
// - bzz-raw://<key> and responds with the raw content stored at the
//   given storage key
// - bzz-hash://<key> and responds with the hash of the content stored
//   at the given storage key as a text/plain response
func (s *Server) HandleGet(w http.ResponseWriter, r *http.Request) {
    ruid := GetRUID(r.Context())
    uri := GetURI(r.Context())
    log.Debug("handle.get", "ruid", ruid, "uri", uri)
    getCount.Inc(1)
    _, pass, _ := r.BasicAuth()

    addr, err := s.api.ResolveURI(r.Context(), uri, pass)
    if err != nil {
        getFail.Inc(1)
        respondError(w, r, fmt.Sprintf("cannot resolve %s: %s", uri.Addr, err), http.StatusNotFound)
        return
    }
    w.Header().Set("Cache-Control", "max-age=2147483648, immutable") // url was of type bzz://<hex key>/path, so we are sure it is immutable.

    log.Debug("handle.get: resolved", "ruid", ruid, "key", addr)

    // if path is set, interpret <key> as a manifest and return the
    // raw entry at the given path

    etag := common.Bytes2Hex(addr)
    noneMatchEtag := r.Header.Get("If-None-Match")
    w.Header().Set("ETag", fmt.Sprintf("%q", etag)) // set etag to manifest key or raw entry key.
    if noneMatchEtag != "" {
        if bytes.Equal(storage.Address(common.Hex2Bytes(noneMatchEtag)), addr) {
            w.WriteHeader(http.StatusNotModified)
            return
        }
    }

    // check the root chunk exists by retrieving the file's size
    reader, isEncrypted := s.api.Retrieve(r.Context(), addr)
    if _, err := reader.Size(r.Context(), nil); err != nil {
        getFail.Inc(1)
        respondError(w, r, fmt.Sprintf("root chunk not found %s: %s", addr, err), http.StatusNotFound)
        return
    }

    w.Header().Set("X-Decrypted", fmt.Sprintf("%v", isEncrypted))

    switch {
    case uri.Raw():
        // allow the request to overwrite the content type using a query
        // parameter
        if typ := r.URL.Query().Get("content_type"); typ != "" {
            w.Header().Set("Content-Type", typ)
        }
        http.ServeContent(w, r, "", time.Now(), reader)
    case uri.Hash():
        w.Header().Set("Content-Type", "text/plain")
        w.WriteHeader(http.StatusOK)
        fmt.Fprint(w, addr)
    }
}

// HandleGetList handles a GET request to bzz-list:/<manifest>/<path> and returns
// a list of all files contained in <manifest> under <path> grouped into
// common prefixes using "/" as a delimiter
func (s *Server) HandleGetList(w http.ResponseWriter, r *http.Request) {
    ruid := GetRUID(r.Context())
    uri := GetURI(r.Context())
    _, credentials, _ := r.BasicAuth()
    log.Debug("handle.get.list", "ruid", ruid, "uri", uri)
    getListCount.Inc(1)

    // ensure the root path has a trailing slash so that relative URLs work
    if uri.Path == "" && !strings.HasSuffix(r.URL.Path, "/") {
        http.Redirect(w, r, r.URL.Path+"/", http.StatusMovedPermanently)
        return
    }

    addr, err := s.api.Resolve(r.Context(), uri.Addr)
    if err != nil {
        getListFail.Inc(1)
        respondError(w, r, fmt.Sprintf("cannot resolve %s: %s", uri.Addr, err), http.StatusNotFound)
        return
    }
    log.Debug("handle.get.list: resolved", "ruid", ruid, "key", addr)

    list, err := s.api.GetManifestList(r.Context(), s.api.Decryptor(r.Context(), credentials), addr, uri.Path)
    if err != nil {
        getListFail.Inc(1)
        if isDecryptError(err) {
            w.Header().Set("WWW-Authenticate", fmt.Sprintf("Basic realm=%q", addr.String()))
            respondError(w, r, err.Error(), http.StatusUnauthorized)
            return
        }
        respondError(w, r, err.Error(), http.StatusInternalServerError)
        return
    }

    // if the client wants HTML (e.g. a browser) then render the list as a
    // HTML index with relative URLs
    if strings.Contains(r.Header.Get("Accept"), "text/html") {
        w.Header().Set("Content-Type", "text/html")
        err := TemplatesMap["bzz-list"].Execute(w, &htmlListData{
            URI: &api.URI{
                Scheme: "bzz",
                Addr:   uri.Addr,
                Path:   uri.Path,
            },
            List: &list,
        })
        if err != nil {
            getListFail.Inc(1)
            log.Error(fmt.Sprintf("error rendering list HTML: %s", err))
        }
        return
    }

    w.Header().Set("Content-Type", "application/json")
    json.NewEncoder(w).Encode(&list)
}

// HandleGetFile handles a GET request to bzz://<manifest>/<path> and responds
// with the content of the file at <path> from the given <manifest>
func (s *Server) HandleGetFile(w http.ResponseWriter, r *http.Request) {
    ruid := GetRUID(r.Context())
    uri := GetURI(r.Context())
    _, credentials, _ := r.BasicAuth()
    log.Debug("handle.get.file", "ruid", ruid, "uri", r.RequestURI)
    getFileCount.Inc(1)

    // ensure the root path has a trailing slash so that relative URLs work
    if uri.Path == "" && !strings.HasSuffix(r.URL.Path, "/") {
        http.Redirect(w, r, r.URL.Path+"/", http.StatusMovedPermanently)
        return
    }
    var err error
    manifestAddr := uri.Address()

    if manifestAddr == nil {
        manifestAddr, err = s.api.Resolve(r.Context(), uri.Addr)
        if err != nil {
            getFileFail.Inc(1)
            respondError(w, r, fmt.Sprintf("cannot resolve %s: %s", uri.Addr, err), http.StatusNotFound)
            return
        }
    } else {
        w.Header().Set("Cache-Control", "max-age=2147483648, immutable") // url was of type bzz://<hex key>/path, so we are sure it is immutable.
    }

    log.Debug("handle.get.file: resolved", "ruid", ruid, "key", manifestAddr)

    reader, contentType, status, contentKey, err := s.api.Get(r.Context(), s.api.Decryptor(r.Context(), credentials), manifestAddr, uri.Path)

    etag := common.Bytes2Hex(contentKey)
    noneMatchEtag := r.Header.Get("If-None-Match")
    w.Header().Set("ETag", fmt.Sprintf("%q", etag)) // set etag to actual content key.
    if noneMatchEtag != "" {
        if bytes.Equal(storage.Address(common.Hex2Bytes(noneMatchEtag)), contentKey) {
            w.WriteHeader(http.StatusNotModified)
            return
        }
    }

    if err != nil {
        if isDecryptError(err) {
            w.Header().Set("WWW-Authenticate", fmt.Sprintf("Basic realm=%q", manifestAddr))
            respondError(w, r, err.Error(), http.StatusUnauthorized)
            return
        }

        switch status {
        case http.StatusNotFound:
            getFileNotFound.Inc(1)
            respondError(w, r, err.Error(), http.StatusNotFound)
        default:
            getFileFail.Inc(1)
            respondError(w, r, err.Error(), http.StatusInternalServerError)
        }
        return
    }

    //the request results in ambiguous files
    //e.g. /read with readme.md and readinglist.txt available in manifest
    if status == http.StatusMultipleChoices {
        list, err := s.api.GetManifestList(r.Context(), s.api.Decryptor(r.Context(), credentials), manifestAddr, uri.Path)
        if err != nil {
            getFileFail.Inc(1)
            if isDecryptError(err) {
                w.Header().Set("WWW-Authenticate", fmt.Sprintf("Basic realm=%q", manifestAddr))
                respondError(w, r, err.Error(), http.StatusUnauthorized)
                return
            }
            respondError(w, r, err.Error(), http.StatusInternalServerError)
            return
        }

        log.Debug(fmt.Sprintf("Multiple choices! --> %v", list), "ruid", ruid)
        //show a nice page links to available entries
        ShowMultipleChoices(w, r, list)
        return
    }

    // check the root chunk exists by retrieving the file's size
    if _, err := reader.Size(r.Context(), nil); err != nil {
        getFileNotFound.Inc(1)
        respondError(w, r, fmt.Sprintf("file not found %s: %s", uri, err), http.StatusNotFound)
        return
    }

    if contentType != "" {
        w.Header().Set("Content-Type", contentType)
    }

    fileName := uri.Addr
    if found := path.Base(uri.Path); found != "" && found != "." && found != "/" {
        fileName = found
    }
    w.Header().Set("Content-Disposition", fmt.Sprintf("inline; filename=\"%s\"", fileName))

    http.ServeContent(w, r, fileName, time.Now(), newBufferedReadSeeker(reader, getFileBufferSize))
}

// The size of buffer used for bufio.Reader on LazyChunkReader passed to
// http.ServeContent in HandleGetFile.
// Warning: This value influences the number of chunk requests and chunker join goroutines
// per file request.
// Recommended value is 4 times the io.Copy default buffer value which is 32kB.
const getFileBufferSize = 4 * 32 * 1024

// bufferedReadSeeker wraps bufio.Reader to expose Seek method
// from the provied io.ReadSeeker in newBufferedReadSeeker.
type bufferedReadSeeker struct {
    r io.Reader
    s io.Seeker
}

// newBufferedReadSeeker creates a new instance of bufferedReadSeeker,
// out of io.ReadSeeker. Argument `size` is the size of the read buffer.
func newBufferedReadSeeker(readSeeker io.ReadSeeker, size int) bufferedReadSeeker {
    return bufferedReadSeeker{
        r: bufio.NewReaderSize(readSeeker, size),
        s: readSeeker,
    }
}

func (b bufferedReadSeeker) Read(p []byte) (n int, err error) {
    return b.r.Read(p)
}

func (b bufferedReadSeeker) Seek(offset int64, whence int) (int64, error) {
    return b.s.Seek(offset, whence)
}

type loggingResponseWriter struct {
    http.ResponseWriter
    statusCode int
}

func newLoggingResponseWriter(w http.ResponseWriter) *loggingResponseWriter {
    return &loggingResponseWriter{w, http.StatusOK}
}

func (lrw *loggingResponseWriter) WriteHeader(code int) {
    lrw.statusCode = code
    lrw.ResponseWriter.WriteHeader(code)
}

func isDecryptError(err error) bool {
    return strings.Contains(err.Error(), api.ErrDecrypt.Error())
}