Merge pull request #3558 from lightpanda-io/cdp-frame-owner

cdp: DOM.getFrameOwner returns the owner <iframe>, nodes carry frameId

src/server/cdp/Node.zig

@@ -22,8 +22,10 @@
 const std = @import("std");
 const lp = @import("lightpanda");
 
+const id = @import("id.zig");
 const Frame = @import("../../browser/Frame.zig");
 const DOMNode = @import("../../browser/webapi/Node.zig");
+const IFrame = @import("../../browser/webapi/element/html/IFrame.zig");
 const NodeRegistry = @import("../../NodeRegistry.zig");
 
 const log = lp.log;
@@ -67,12 +69,12 @@ pub const Search = struct {
         }
 
         pub fn create(self: *List, nodes: []const *DOMNode) !Search {
-            const id = self.search_id;
-            defer self.search_id = id +% 1;
+            const search_id = self.search_id;
+            defer self.search_id = search_id +% 1;
 
             const arena = self.arena.allocator();
 
-            const name = switch (id) {
+            const name = switch (search_id) {
                 0 => "0",
                 1 => "1",
                 2 => "2",
@@ -83,7 +85,7 @@ pub const Search = struct {
                 7 => "7",
                 8 => "8",
                 9 => "9",
-                else => try std.fmt.allocPrint(arena, "{d}", .{id}),
+                else => try std.fmt.allocPrint(arena, "{d}", .{search_id}),
             };
 
             var registry = self.registry;
@@ -217,6 +219,25 @@ pub const Writer = struct {
 
             try w.objectField("localName");
             try w.write(element.getLocalName());
+
+            // Chrome names the hosted frame on frame-owner elements and the own
+            // frame on the document element; that's how clients pair an <iframe>
+            // with its Page.frameAttached id.
+            if (element.is(IFrame)) |iframe| {
+                if (iframe.getContentDocument()) |document| {
+                    if (document._frame) |child| {
+                        try w.objectField("frameId");
+                        try w.write(&id.toFrameId(child._frame_id));
+                    }
+                }
+            } else if (dom_node._parent) |dom_parent| {
+                if (dom_parent._type == .document) {
+                    if (dom_parent.subtype(DOMNode.Document)._frame) |frame| {
+                        try w.objectField("frameId");
+                        try w.write(&id.toFrameId(frame._frame_id));
+                    }
+                }
+            }
         } else {
             try w.objectField("localName");
             try w.write("");

src/server/cdp/domains/dom.zig

@@ -610,7 +610,14 @@ fn getFrameOwner(cmd: *CDP.Command) !void {
         return cmd.sendError(-32000, "Frame with the given id does not belong to the target.", .{});
     };
 
-    const node = try bc.node_registry.register(frame.window._document.asNode());
+    // The element hosting the frame, as in Chrome; the main frame has none.
+    // Clients (Stagehand's frameLocator, Playwright's contentFrame) match this
+    // backendNodeId against the <iframe> they resolved in the parent.
+    const iframe = frame.iframe orelse {
+        return cmd.sendError(-32000, "Frame with the given id does not belong to the target.", .{});
+    };
+
+    const node = try bc.node_registry.register(iframe.asNode());
     return cmd.sendResult(.{ .nodeId = node.id, .backendNodeId = node.id }, .{});
 }
 
@@ -1313,6 +1320,46 @@ test "cdp.dom: resolveNode into a child frame's context" {
     try ctx.expectSentError(-31998, "ContextNotFound", .{ .id = 15 });
 }
 
+test "cdp.dom: getFrameOwner returns the owner iframe element" {
+    var ctx = try testing.context();
+    defer ctx.deinit();
+
+    const bc = try ctx.loadBrowserContext(.{ .id = "BID-FO", .url = "cdp/isolated_world.html", .target_id = "FID-000000000X".* });
+    const root = bc.mainFrame() orelse unreachable;
+    const child = root.child_frames.items[0];
+    const iframe_node = try bc.node_registry.register(child.iframe.?.asNode());
+
+    try ctx.processMessage(.{ .id = 10, .method = "DOM.getFrameOwner", .sessionId = "SID-X", .params = .{
+        .frameId = &id.toFrameId(child._frame_id),
+    } });
+    try ctx.expectSentResult(.{ .nodeId = iframe_node.id, .backendNodeId = iframe_node.id }, .{ .id = 10 });
+
+    // The owner element names the frame it hosts.
+    try ctx.processMessage(.{ .id = 11, .method = "DOM.describeNode", .sessionId = "SID-X", .params = .{
+        .backendNodeId = iframe_node.id,
+    } });
+    try ctx.expectSentResult(.{ .node = .{
+        .localName = "iframe",
+        .frameId = &id.toFrameId(child._frame_id),
+    } }, .{ .id = 11 });
+
+    // So does the document element, for its own frame.
+    const child_html = try bc.node_registry.register(child.window._document.getDocumentElement().?.asNode());
+    try ctx.processMessage(.{ .id = 12, .method = "DOM.describeNode", .sessionId = "SID-X", .params = .{
+        .backendNodeId = child_html.id,
+    } });
+    try ctx.expectSentResult(.{ .node = .{
+        .localName = "html",
+        .frameId = &id.toFrameId(child._frame_id),
+    } }, .{ .id = 12 });
+
+    // The main frame has no owner.
+    try ctx.processMessage(.{ .id = 13, .method = "DOM.getFrameOwner", .sessionId = "SID-X", .params = .{
+        .frameId = &id.toFrameId(root._frame_id),
+    } });
+    try ctx.expectSentError(-32000, "Frame with the given id does not belong to the target.", .{ .id = 13 });
+}
+
 fn mainWorldContextId(bc: *CDP.BrowserContext, frame: *const Frame) !i32 {
     var ls: js.Local.Scope = undefined;
     frame.js.localScope(&ls);