Merge pull request ipfs/kubo#7262 from gowthamgts/fix/http/content-type

Fixes #7252 - Uses gabriel-vasile/mimetype to support additional content types

This commit was moved from ipfs/kubo@01e27f9

gateway/core/corehttp/gateway_handler.go

@@ -15,6 +15,7 @@ import (
 	"time"
 
 	humanize "github.com/dustin/go-humanize"
+	"github.com/gabriel-vasile/mimetype"
 	"github.com/ipfs/go-cid"
 	files "github.com/ipfs/go-ipfs-files"
 	dag "github.com/ipfs/go-merkledag"
@@ -376,10 +377,16 @@ func (i *gatewayHandler) serveFile(w http.ResponseWriter, req *http.Request, nam
 	} else {
 		ctype = mime.TypeByExtension(gopath.Ext(name))
 		if ctype == "" {
-			buf := make([]byte, 512)
-			n, _ := io.ReadFull(content, buf[:])
-			ctype = http.DetectContentType(buf[:n])
-			_, err := content.Seek(0, io.SeekStart)
+			// uses https://github.com/gabriel-vasile/mimetype library to determine the content type.
+			// Fixes https://github.com/ipfs/go-ipfs/issues/7252
+			mimeType, err := mimetype.DetectReader(content)
+			if err != nil {
+				http.Error(w, fmt.Sprintf("cannot detect content-type: %s", err.Error()), http.StatusInternalServerError)
+				return
+			}
+
+			ctype = mimeType.String()
+			_, err = content.Seek(0, io.SeekStart)
 			if err != nil {
 				http.Error(w, "seeker can't seek", http.StatusInternalServerError)
 				return