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feat(gateway): JSON and CBOR response formats (IPIP-328) (#9335)
ipfs/kubo#9335 ipfs/specs#328 Co-authored-by: Marcin Rataj <lidel@lidel.org> This commit was moved from ipfs/kubo@fdd1965
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,258 @@ | ||
| package corehttp | ||
|
|
||
| import ( | ||
| "bytes" | ||
| "context" | ||
| "fmt" | ||
| "html" | ||
| "io" | ||
| "net/http" | ||
| "strings" | ||
| "time" | ||
|
|
||
| cid "github.com/ipfs/go-cid" | ||
| ipldlegacy "github.com/ipfs/go-ipld-legacy" | ||
| ipath "github.com/ipfs/interface-go-ipfs-core/path" | ||
| "github.com/ipfs/kubo/assets" | ||
| dih "github.com/ipfs/kubo/assets/dag-index-html" | ||
| "github.com/ipfs/kubo/tracing" | ||
| "github.com/ipld/go-ipld-prime" | ||
| "github.com/ipld/go-ipld-prime/multicodec" | ||
| mc "github.com/multiformats/go-multicodec" | ||
| "go.opentelemetry.io/otel/attribute" | ||
| "go.opentelemetry.io/otel/trace" | ||
| ) | ||
|
|
||
| // codecToContentType maps the supported IPLD codecs to the HTTP Content | ||
| // Type they should have. | ||
| var codecToContentType = map[uint64]string{ | ||
| uint64(mc.Json): "application/json", | ||
| uint64(mc.Cbor): "application/cbor", | ||
| uint64(mc.DagJson): "application/vnd.ipld.dag-json", | ||
| uint64(mc.DagCbor): "application/vnd.ipld.dag-cbor", | ||
| } | ||
|
|
||
| // contentTypeToCodecs maps the HTTP Content Type to the respective | ||
| // possible codecs. If the original data is in one of those codecs, | ||
| // we stream the raw bytes. Otherwise, we encode in the last codec | ||
| // of the list. | ||
| var contentTypeToCodecs = map[string][]uint64{ | ||
| "application/json": {uint64(mc.Json), uint64(mc.DagJson)}, | ||
| "application/vnd.ipld.dag-json": {uint64(mc.DagJson)}, | ||
| "application/cbor": {uint64(mc.Cbor), uint64(mc.DagCbor)}, | ||
| "application/vnd.ipld.dag-cbor": {uint64(mc.DagCbor)}, | ||
| } | ||
|
|
||
| // contentTypeToExtension maps the HTTP Content Type to the respective file | ||
| // extension, used in Content-Disposition header when downloading the file. | ||
| var contentTypeToExtension = map[string]string{ | ||
| "application/json": ".json", | ||
| "application/vnd.ipld.dag-json": ".json", | ||
| "application/cbor": ".cbor", | ||
| "application/vnd.ipld.dag-cbor": ".cbor", | ||
| } | ||
|
|
||
| func (i *gatewayHandler) serveCodec(ctx context.Context, w http.ResponseWriter, r *http.Request, resolvedPath ipath.Resolved, contentPath ipath.Path, begin time.Time, requestedContentType string) { | ||
| ctx, span := tracing.Span(ctx, "Gateway", "ServeCodec", trace.WithAttributes(attribute.String("path", resolvedPath.String()), attribute.String("requestedContentType", requestedContentType))) | ||
| defer span.End() | ||
|
|
||
| cidCodec := resolvedPath.Cid().Prefix().Codec | ||
| responseContentType := requestedContentType | ||
|
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||
| // If the resolved path still has some remainder, return error for now. | ||
| // TODO: handle this when we have IPLD Patch (https://ipld.io/specs/patch/) via HTTP PUT | ||
| // TODO: (depends on https://github.com/ipfs/kubo/issues/4801 and https://github.com/ipfs/kubo/issues/4782) | ||
| if resolvedPath.Remainder() != "" { | ||
| path := strings.TrimSuffix(resolvedPath.String(), resolvedPath.Remainder()) | ||
| err := fmt.Errorf("%q of %q could not be returned: reading IPLD Kinds other than Links (CBOR Tag 42) is not implemented: try reading %q instead", resolvedPath.Remainder(), resolvedPath.String(), path) | ||
| webError(w, "unsupported pathing", err, http.StatusNotImplemented) | ||
| return | ||
| } | ||
|
|
||
| // If no explicit content type was requested, the response will have one based on the codec from the CID | ||
| if requestedContentType == "" { | ||
| cidContentType, ok := codecToContentType[cidCodec] | ||
| if !ok { | ||
| // Should not happen unless function is called with wrong parameters. | ||
| err := fmt.Errorf("content type not found for codec: %v", cidCodec) | ||
| webError(w, "internal error", err, http.StatusInternalServerError) | ||
| return | ||
| } | ||
| responseContentType = cidContentType | ||
| } | ||
|
|
||
| // Set HTTP headers (for caching etc) | ||
| modtime := addCacheControlHeaders(w, r, contentPath, resolvedPath.Cid()) | ||
| name := setCodecContentDisposition(w, r, resolvedPath, responseContentType) | ||
| w.Header().Set("Content-Type", responseContentType) | ||
| w.Header().Set("X-Content-Type-Options", "nosniff") | ||
|
|
||
| // No content type is specified by the user (via Accept, or format=). However, | ||
| // we support this format. Let's handle it. | ||
| if requestedContentType == "" { | ||
| isDAG := cidCodec == uint64(mc.DagJson) || cidCodec == uint64(mc.DagCbor) | ||
| acceptsHTML := strings.Contains(r.Header.Get("Accept"), "text/html") | ||
| download := r.URL.Query().Get("download") == "true" | ||
|
|
||
| if isDAG && acceptsHTML && !download { | ||
| i.serveCodecHTML(ctx, w, r, resolvedPath, contentPath) | ||
| } else { | ||
| i.serveCodecRaw(ctx, w, r, resolvedPath, contentPath, name, modtime) | ||
| } | ||
|
|
||
| return | ||
| } | ||
|
|
||
| // Otherwise, the user has requested a specific content type. Let's first get | ||
| // the codecs that can be used with this content type. | ||
| codecs, ok := contentTypeToCodecs[requestedContentType] | ||
| if !ok { | ||
| // This is never supposed to happen unless function is called with wrong parameters. | ||
| err := fmt.Errorf("unsupported content type: %s", requestedContentType) | ||
| webError(w, err.Error(), err, http.StatusInternalServerError) | ||
| return | ||
| } | ||
|
|
||
| // If we need to convert, use the last codec (strict dag- variant) | ||
| toCodec := codecs[len(codecs)-1] | ||
|
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||
| // If the requested content type has "dag-", ALWAYS go through the encoding | ||
| // process in order to validate the content. | ||
| if strings.Contains(requestedContentType, "dag-") { | ||
| i.serveCodecConverted(ctx, w, r, resolvedPath, contentPath, toCodec, modtime) | ||
| return | ||
| } | ||
|
|
||
| // Otherwise, check if the data is encoded with the requested content type. | ||
| // If so, we can directly stream the raw data. serveRawBlock cannot be directly | ||
| // used here as it sets different headers. | ||
| for _, codec := range codecs { | ||
| if resolvedPath.Cid().Prefix().Codec == codec { | ||
| i.serveCodecRaw(ctx, w, r, resolvedPath, contentPath, name, modtime) | ||
| return | ||
| } | ||
| } | ||
|
|
||
| // Finally, if nothing of the above is true, we have to actually convert the codec. | ||
| i.serveCodecConverted(ctx, w, r, resolvedPath, contentPath, toCodec, modtime) | ||
| } | ||
|
|
||
| func (i *gatewayHandler) serveCodecHTML(ctx context.Context, w http.ResponseWriter, r *http.Request, resolvedPath ipath.Resolved, contentPath ipath.Path) { | ||
| // A HTML directory index will be presented, be sure to set the correct | ||
| // type instead of relying on autodetection (which may fail). | ||
| w.Header().Set("Content-Type", "text/html") | ||
|
|
||
| // Clear Content-Disposition -- we want HTML to be rendered inline | ||
| w.Header().Del("Content-Disposition") | ||
|
|
||
| // Generated index requires custom Etag (output may change between Kubo versions) | ||
| dagEtag := getDagIndexEtag(resolvedPath.Cid()) | ||
| w.Header().Set("Etag", dagEtag) | ||
|
|
||
| // Remove Cache-Control for now to match UnixFS dir-index-html responses | ||
| // (we don't want browser to cache HTML forever) | ||
| // TODO: if we ever change behavior for UnixFS dir listings, same changes should be applied here | ||
| w.Header().Del("Cache-Control") | ||
|
|
||
| cidCodec := mc.Code(resolvedPath.Cid().Prefix().Codec) | ||
| if err := dih.DagIndexTemplate.Execute(w, dih.DagIndexTemplateData{ | ||
| Path: contentPath.String(), | ||
| CID: resolvedPath.Cid().String(), | ||
| CodecName: cidCodec.String(), | ||
| CodecHex: fmt.Sprintf("0x%x", uint64(cidCodec)), | ||
| }); err != nil { | ||
| webError(w, "failed to generate HTML listing for this DAG: try fetching raw block with ?format=raw", err, http.StatusInternalServerError) | ||
| } | ||
| } | ||
|
|
||
| func (i *gatewayHandler) serveCodecRaw(ctx context.Context, w http.ResponseWriter, r *http.Request, resolvedPath ipath.Resolved, contentPath ipath.Path, name string, modtime time.Time) { | ||
| blockCid := resolvedPath.Cid() | ||
| blockReader, err := i.api.Block().Get(ctx, resolvedPath) | ||
| if err != nil { | ||
| webError(w, "ipfs block get "+blockCid.String(), err, http.StatusInternalServerError) | ||
| return | ||
| } | ||
| block, err := io.ReadAll(blockReader) | ||
| if err != nil { | ||
| webError(w, "ipfs block get "+blockCid.String(), err, http.StatusInternalServerError) | ||
| return | ||
| } | ||
| content := bytes.NewReader(block) | ||
|
|
||
| // ServeContent will take care of | ||
| // If-None-Match+Etag, Content-Length and range requests | ||
| _, _, _ = ServeContent(w, r, name, modtime, content) | ||
| } | ||
|
|
||
| func (i *gatewayHandler) serveCodecConverted(ctx context.Context, w http.ResponseWriter, r *http.Request, resolvedPath ipath.Resolved, contentPath ipath.Path, toCodec uint64, modtime time.Time) { | ||
| obj, err := i.api.Dag().Get(ctx, resolvedPath.Cid()) | ||
| if err != nil { | ||
| webError(w, "ipfs dag get "+html.EscapeString(resolvedPath.String()), err, http.StatusInternalServerError) | ||
| return | ||
| } | ||
|
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||
| universal, ok := obj.(ipldlegacy.UniversalNode) | ||
| if !ok { | ||
| err = fmt.Errorf("%T is not a valid IPLD node", obj) | ||
| webError(w, err.Error(), err, http.StatusInternalServerError) | ||
| return | ||
| } | ||
| finalNode := universal.(ipld.Node) | ||
|
|
||
| encoder, err := multicodec.LookupEncoder(toCodec) | ||
| if err != nil { | ||
| webError(w, err.Error(), err, http.StatusInternalServerError) | ||
| return | ||
| } | ||
|
|
||
| // Ensure IPLD node conforms to the codec specification. | ||
| var buf bytes.Buffer | ||
| err = encoder(finalNode, &buf) | ||
| if err != nil { | ||
| webError(w, err.Error(), err, http.StatusInternalServerError) | ||
| return | ||
| } | ||
|
|
||
| // Sets correct Last-Modified header. This code is borrowed from the standard | ||
| // library (net/http/server.go) as we cannot use serveFile. | ||
| if !(modtime.IsZero() || modtime.Equal(unixEpochTime)) { | ||
| w.Header().Set("Last-Modified", modtime.UTC().Format(http.TimeFormat)) | ||
| } | ||
|
|
||
| _, _ = w.Write(buf.Bytes()) | ||
| } | ||
|
|
||
| func setCodecContentDisposition(w http.ResponseWriter, r *http.Request, resolvedPath ipath.Resolved, contentType string) string { | ||
| var dispType, name string | ||
|
|
||
| ext, ok := contentTypeToExtension[contentType] | ||
| if !ok { | ||
| // Should never happen. | ||
| ext = ".bin" | ||
| } | ||
|
|
||
| if urlFilename := r.URL.Query().Get("filename"); urlFilename != "" { | ||
| name = urlFilename | ||
| } else { | ||
| name = resolvedPath.Cid().String() + ext | ||
| } | ||
|
|
||
| // JSON should be inlined, but ?download=true should still override | ||
| if r.URL.Query().Get("download") == "true" { | ||
| dispType = "attachment" | ||
| } else { | ||
| switch ext { | ||
| case ".json": // codecs that serialize to JSON can be rendered by browsers | ||
| dispType = "inline" | ||
| default: // everything else is assumed binary / opaque bytes | ||
| dispType = "attachment" | ||
| } | ||
| } | ||
|
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||
| setContentDispositionHeader(w, name, dispType) | ||
| return name | ||
| } | ||
|
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||
| func getDagIndexEtag(dagCid cid.Cid) string { | ||
| return `"DagIndex-` + assets.AssetHash + `_CID-` + dagCid.String() + `"` | ||
| } |
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