gateway: fix seeker can't seek on specific files

License: MIT
Signed-off-by: Łukasz Magiera <magik6k@gmail.com>

core/corehttp/gateway_handler.go

@@ -268,7 +268,7 @@ func (i *gatewayHandler) getOrHeadHandler(ctx context.Context, w http.ResponseWr
 
 	if !dir {
 		name := gopath.Base(urlPath)
-		http.ServeContent(w, r, name, modtime, dr)
+		i.serverFile(w, r, name, modtime, dr)
 		return
 	}
 
@@ -372,6 +372,17 @@ func (i *gatewayHandler) getOrHeadHandler(ctx context.Context, w http.ResponseWr
 	}
 }
 
+func (i *gatewayHandler) serverFile(w http.ResponseWriter, req *http.Request, name string, modtime time.Time, content io.ReadSeeker) {
+	http.ServeContent(w, req, name, modtime, content)
+	//TODO: check for errors in ServeContent.. somehow
+
+	// If http.ServeContent can't figure out content size it won't write it to the
+	// responseWriter, Content-Length not being set is a good indicator of this
+	if req.Method != "HEAD" && w.Header().Get("Content-Length") == "" {
+		io.Copy(w, content)
+	}
+}
+
 func (i *gatewayHandler) postHandler(ctx context.Context, w http.ResponseWriter, r *http.Request) {
 	p, err := i.api.Unixfs().Add(ctx, r.Body)
 	if err != nil {

test/sharness/t0110-gateway.sh

@@ -124,7 +124,7 @@ test_expect_success "HEAD 'index.html' has no content" '
 # test ipfs readonly api
 
 test_curl_gateway_api() {
-    curl -sfo actual "http://127.0.0.1:$port/api/v0/$1"
+  curl -sfo actual "http://127.0.0.1:$port/api/v0/$1"
 }
 
 test_expect_success "get IPFS directory file through readonly API succeeds" '
@@ -140,7 +140,7 @@ test_expect_success "refs IPFS directory file through readonly API succeeds" '
 '
 
 test_expect_success "test gateway api is sanitized" '
-for cmd in "add" "block/put" "bootstrap" "config" "dht" "diag" "dns" "get" "id" "mount" "name/publish" "object/put" "object/new" "object/patch" "pin" "ping" "refs/local" "repo" "resolve" "stats" "swarm"  "file" "update" "version" "bitswap"; do
+  for cmd in "add" "block/put" "bootstrap" "config" "dht" "diag" "dns" "get" "id" "mount" "name/publish" "object/put" "object/new" "object/patch" "pin" "ping" "refs/local" "repo" "resolve" "stats" "swarm"  "file" "update" "version" "bitswap"; do
     test_curl_resp_http_code "http://127.0.0.1:$port/api/v0/$cmd" "HTTP/1.1 404 Not Found"
   done
 '
@@ -155,6 +155,17 @@ test_expect_success "try fetching it from gateway" '
   test_cmp rfile ffile
 '
 
+test_expect_success "Add compact blocks" '
+  ipfs block put ../t0110-gateway-data/foo.block &&
+  FOO2_HASH=$(ipfs block put ../t0110-gateway-data/foofoo.block) &&
+  printf "foofoo" > expected
+'
+
+test_expect_success "GET compact blocks succeeds" '
+  curl -o actual "http://127.0.0.1:$port/ipfs/$FOO2_HASH" &&
+  test_cmp expected actual
+'
+
 test_kill_ipfs_daemon
 
 test_done

unixfs/io/pbdagreader.go

@@ -243,7 +243,16 @@ func (dr *pbDagReader) Seek(offset int64, whence int) (int64, error) {
 		return dr.Seek(noffset, io.SeekStart)
 	case io.SeekEnd:
 		noffset := int64(dr.pbdata.GetFilesize()) - offset
-		return dr.Seek(noffset, io.SeekStart)
+		n, err := dr.Seek(noffset, io.SeekStart)
+
+		// Return negative number if we can't figure out the file size. Using io.EOF
+		// for this seems to be good(-enough) solution as it's only returned by
+		// precalcNextBuf when we step out of file range.
+		// This is needed for gateway to function properly
+		if err == io.EOF && *dr.pbdata.Type == ftpb.Data_File {
+			return -1, nil
+		}
+		return n, err
 	default:
 		return 0, errors.New("invalid whence")
 	}