1 files changed, 41 insertions, 0 deletions
diff --git a/routers/web/repo/editor_preview.go b/routers/web/repo/editor_preview.go
new file mode 100644
index 0000000000..14be5b72b6
--- /dev/null
+++ b/routers/web/repo/editor_preview.go
@@ -0,0 +1,41 @@
+// Copyright 2025 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package repo
+
+import (
+	"net/http"
+
+	"code.gitea.io/gitea/services/context"
+	files_service "code.gitea.io/gitea/services/repository/files"
+)
+
+func DiffPreviewPost(ctx *context.Context) {
+	content := ctx.FormString("content")
+	treePath := files_service.CleanGitTreePath(ctx.Repo.TreePath)
+	if treePath == "" {
+		ctx.HTTPError(http.StatusBadRequest, "file name to diff is invalid")
+		return
+	}
+
+	entry, err := ctx.Repo.Commit.GetTreeEntryByPath(treePath)
+	if err != nil {
+		ctx.ServerError("GetTreeEntryByPath", err)
+		return
+	} else if entry.IsDir() {
+		ctx.HTTPError(http.StatusUnprocessableEntity)
+		return
+	}
+
+	diff, err := files_service.GetDiffPreview(ctx, ctx.Repo.Repository, ctx.Repo.BranchName, treePath, content)
+	if err != nil {
+		ctx.ServerError("GetDiffPreview", err)
+		return
+	}
+
+	if len(diff.Files) != 0 {
+		ctx.Data["File"] = diff.Files[0]
+	}
+
+	ctx.HTML(http.StatusOK, tplEditDiffPreview)
+}