Merge pull request ipfs/kubo#4177 from Voker57/feat/gw-filename-option

Set filename in Content-Disposition if filename=x is passed in URI query

This commit was moved from ipfs/kubo@fcc96a3

gateway/core/corehttp/gateway_handler.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"net/url"
 	"os"
 	gopath "path"
 	"runtime/debug"
@@ -259,7 +260,14 @@ func (i *gatewayHandler) getOrHeadHandler(ctx context.Context, w http.ResponseWr
 	}
 
 	if !dir {
-		name := gopath.Base(urlPath)
+		urlFilename := r.URL.Query().Get("filename")
+		var name string
+		if urlFilename != "" {
+			w.Header().Set("Content-Disposition", fmt.Sprintf("inline; filename*=UTF-8''%s", url.PathEscape(urlFilename)))
+			name = urlFilename
+		} else {
+			name = gopath.Base(urlPath)
+		}
 		i.serveFile(w, r, name, modtime, dr)
 		return
 	}