Removing remaining CDP generic

Follow up to https://github.com/lightpanda-io/browser/pull/1990 which makes
both BrowserContext and Command non-generic.

src/cdp/CDP.zig

@@ -63,7 +63,7 @@ target_id_gen: TargetIdGen = .{},
 session_id_gen: SessionIdGen = .{},
 browser_context_id_gen: BrowserContextIdGen = .{},
 
-browser_context: ?BrowserContext(CDP),
+browser_context: ?BrowserContext,
 
 // Re-used arena for processing a message. We're assuming that we're getting
 // 1 message at a time.
@@ -120,7 +120,7 @@ pub fn handleMessage(self: *CDP, msg: []const u8) bool {
 pub fn processMessage(self: *CDP, msg: []const u8) !void {
     const arena = &self.message_arena;
     defer _ = arena.reset(.{ .retain_with_limit = 1024 * 16 });
-    return self.dispatch(arena.allocator(), self, msg);
+    return self.dispatch(arena.allocator(), .{ .cdp = self }, msg);
 }
 
 // @newhttp
@@ -136,12 +136,12 @@ pub fn pageWait(self: *CDP, ms: u32) !Session.Runner.CDPWaitResult {
 // Called from above, in processMessage which handles client messages
 // but can also be called internally. For example, Target.sendMessageToTarget
 // calls back into dispatch to capture the response.
-pub fn dispatch(self: *CDP, arena: Allocator, sender: anytype, str: []const u8) !void {
+pub fn dispatch(self: *CDP, arena: Allocator, sender: Command.Sender, str: []const u8) !void {
     const input = json.parseFromSliceLeaky(InputMessage, arena, str, .{
         .ignore_unknown_fields = true,
     }) catch return error.InvalidJSON;
 
-    var command = Command(CDP, @TypeOf(sender)){
+    var command = Command{
         .input = .{
             .json = str,
             .id = input.id,
@@ -186,7 +186,7 @@ pub fn dispatch(self: *CDP, arena: Allocator, sender: anytype, str: []const u8)
 // "special" handling - the bare minimum we need to do until the driver
 // switches to a real BrowserContext.
 // (I can imagine this logic will become driver-specific)
-fn dispatchStartupCommand(command: anytype, method: []const u8) !void {
+fn dispatchStartupCommand(command: *Command, method: []const u8) !void {
     // Stagehand parses the response and error if we don't return a
     // correct one for Page.getFrameTree on startup call.
     if (std.mem.eql(u8, method, "Page.getFrameTree")) {
@@ -197,7 +197,7 @@ fn dispatchStartupCommand(command: anytype, method: []const u8) !void {
     return command.sendResult(null, .{});
 }
 
-fn dispatchCommand(command: anytype, method: []const u8) !void {
+fn dispatchCommand(command: *Command, method: []const u8) !void {
     const domain = blk: {
         const i = std.mem.indexOfScalarPos(u8, method, 0, '.') orelse {
             return error.InvalidMethod;
@@ -273,10 +273,10 @@ pub fn createBrowserContext(self: *CDP) ![]const u8 {
     }
     const id = self.browser_context_id_gen.next();
 
-    self.browser_context = @as(BrowserContext(CDP), undefined);
+    self.browser_context = @as(BrowserContext, undefined);
     const browser_context = &self.browser_context.?;
 
-    try BrowserContext(CDP).init(browser_context, id, self);
+    try BrowserContext.init(browser_context, id, self);
     return id;
 }
 
@@ -308,7 +308,7 @@ pub fn sendJSON(self: *CDP, message: anytype) !void {
     });
 }
 
-pub fn BrowserContext(comptime CDP_T: type) type {
+pub const BrowserContext = struct {
     const Node = @import("Node.zig");
     const AXNode = @import("AXNode.zig");
 
@@ -317,9 +317,8 @@ pub fn BrowserContext(comptime CDP_T: type) type {
         data: std.ArrayList(u8),
     };
 
-    return struct {
     id: []const u8,
-        cdp: *CDP_T,
+    cdp: *CDP,
 
     // Represents the browser session. There is no equivalent in CDP. For
     // all intents and purpose, from CDP's point of view our Browser and
@@ -386,9 +385,7 @@ pub fn BrowserContext(comptime CDP_T: type) type {
 
     notification: *Notification,
 
-        const Self = @This();
+    fn init(self: *BrowserContext, id: []const u8, cdp: *CDP) !void {
-
-        fn init(self: *Self, id: []const u8, cdp: *CDP_T) !void {
         const allocator = cdp.allocator;
 
         // Create notification for this BrowserContext
@@ -434,7 +431,7 @@ pub fn BrowserContext(comptime CDP_T: type) type {
         try notification.register(.page_frame_created, self, onPageFrameCreated);
     }
 
-        pub fn deinit(self: *Self) void {
+    pub fn deinit(self: *BrowserContext) void {
         const browser = &self.cdp.browser;
         const env = &browser.env;
 
@@ -480,12 +477,12 @@ pub fn BrowserContext(comptime CDP_T: type) type {
         self.intercept_state.deinit();
     }
 
-        pub fn reset(self: *Self) void {
+    pub fn reset(self: *BrowserContext) void {
         self.node_registry.reset();
         self.node_search_list.reset();
     }
 
-        pub fn createIsolatedWorld(self: *Self, world_name: []const u8, grant_universal_access: bool) !*IsolatedWorld {
+    pub fn createIsolatedWorld(self: *BrowserContext, world_name: []const u8, grant_universal_access: bool) !*IsolatedWorld {
         const browser = &self.cdp.browser;
         const arena = try browser.arena_pool.acquire(.{ .debug = "IsolatedWorld" });
         errdefer browser.arena_pool.release(arena);
@@ -508,7 +505,7 @@ pub fn BrowserContext(comptime CDP_T: type) type {
         return world;
     }
 
-        pub fn nodeWriter(self: *Self, root: *const Node, opts: Node.Writer.Opts) Node.Writer {
+    pub fn nodeWriter(self: *BrowserContext, root: *const Node, opts: Node.Writer.Opts) Node.Writer {
         return .{
             .root = root,
             .depth = opts.depth,
@@ -517,7 +514,7 @@ pub fn BrowserContext(comptime CDP_T: type) type {
         };
     }
 
-        pub fn axnodeWriter(self: *Self, root: *const Node, opts: AXNode.Writer.Opts) !AXNode.Writer {
+    pub fn axnodeWriter(self: *BrowserContext, root: *const Node, opts: AXNode.Writer.Opts) !AXNode.Writer {
         const page = self.session.currentPage() orelse return error.PageNotLoaded;
         _ = opts;
         return .{
@@ -527,13 +524,13 @@ pub fn BrowserContext(comptime CDP_T: type) type {
         };
     }
 
-        pub fn getURL(self: *const Self) ?[:0]const u8 {
+    pub fn getURL(self: *const BrowserContext) ?[:0]const u8 {
         const page = self.session.currentPage() orelse return null;
         const url = page.url;
         return if (url.len == 0) null else url;
     }
 
-        pub fn getTitle(self: *const Self) ?[]const u8 {
+    pub fn getTitle(self: *const BrowserContext) ?[]const u8 {
         const page = self.session.currentPage() orelse return null;
         return page.getTitle() catch |err| {
             log.err(.cdp, "page title", .{ .err = err });
@@ -541,7 +538,7 @@ pub fn BrowserContext(comptime CDP_T: type) type {
         };
     }
 
-        pub fn networkEnable(self: *Self) !void {
+    pub fn networkEnable(self: *BrowserContext) !void {
         try self.notification.register(.http_request_fail, self, onHttpRequestFail);
         try self.notification.register(.http_request_start, self, onHttpRequestStart);
         try self.notification.register(.http_request_done, self, onHttpRequestDone);
@@ -549,7 +546,7 @@ pub fn BrowserContext(comptime CDP_T: type) type {
         try self.notification.register(.http_response_header_done, self, onHttpResponseHeadersDone);
     }
 
-        pub fn networkDisable(self: *Self) void {
+    pub fn networkDisable(self: *BrowserContext) void {
         self.notification.unregister(.http_request_fail, self);
         self.notification.unregister(.http_request_start, self);
         self.notification.unregister(.http_request_done, self);
@@ -557,83 +554,83 @@ pub fn BrowserContext(comptime CDP_T: type) type {
         self.notification.unregister(.http_response_header_done, self);
     }
 
-        pub fn fetchEnable(self: *Self, authRequests: bool) !void {
+    pub fn fetchEnable(self: *BrowserContext, authRequests: bool) !void {
         try self.notification.register(.http_request_intercept, self, onHttpRequestIntercept);
         if (authRequests) {
             try self.notification.register(.http_request_auth_required, self, onHttpRequestAuthRequired);
         }
     }
 
-        pub fn fetchDisable(self: *Self) void {
+    pub fn fetchDisable(self: *BrowserContext) void {
         self.notification.unregister(.http_request_intercept, self);
         self.notification.unregister(.http_request_auth_required, self);
     }
 
-        pub fn lifecycleEventsEnable(self: *Self) !void {
+    pub fn lifecycleEventsEnable(self: *BrowserContext) !void {
         self.page_life_cycle_events = true;
         try self.notification.register(.page_network_idle, self, onPageNetworkIdle);
         try self.notification.register(.page_network_almost_idle, self, onPageNetworkAlmostIdle);
     }
 
-        pub fn lifecycleEventsDisable(self: *Self) void {
+    pub fn lifecycleEventsDisable(self: *BrowserContext) void {
         self.page_life_cycle_events = false;
         self.notification.unregister(.page_network_idle, self);
         self.notification.unregister(.page_network_almost_idle, self);
     }
 
     pub fn onPageRemove(ctx: *anyopaque, _: Notification.PageRemove) !void {
-            const self: *Self = @ptrCast(@alignCast(ctx));
+        const self: *BrowserContext = @ptrCast(@alignCast(ctx));
         try @import("domains/page.zig").pageRemove(self);
     }
 
     pub fn onPageCreated(ctx: *anyopaque, page: *Page) !void {
-            const self: *Self = @ptrCast(@alignCast(ctx));
+        const self: *BrowserContext = @ptrCast(@alignCast(ctx));
         return @import("domains/page.zig").pageCreated(self, page);
     }
 
     pub fn onPageNavigate(ctx: *anyopaque, msg: *const Notification.PageNavigate) !void {
-            const self: *Self = @ptrCast(@alignCast(ctx));
+        const self: *BrowserContext = @ptrCast(@alignCast(ctx));
         return @import("domains/page.zig").pageNavigate(self, msg);
     }
 
     pub fn onPageNavigated(ctx: *anyopaque, msg: *const Notification.PageNavigated) !void {
-            const self: *Self = @ptrCast(@alignCast(ctx));
+        const self: *BrowserContext = @ptrCast(@alignCast(ctx));
         defer self.resetNotificationArena();
         return @import("domains/page.zig").pageNavigated(self.notification_arena, self, msg);
     }
 
     pub fn onPageFrameCreated(ctx: *anyopaque, msg: *const Notification.PageFrameCreated) !void {
-            const self: *Self = @ptrCast(@alignCast(ctx));
+        const self: *BrowserContext = @ptrCast(@alignCast(ctx));
         return @import("domains/page.zig").pageFrameCreated(self, msg);
     }
 
     pub fn onPageNetworkIdle(ctx: *anyopaque, msg: *const Notification.PageNetworkIdle) !void {
-            const self: *Self = @ptrCast(@alignCast(ctx));
+        const self: *BrowserContext = @ptrCast(@alignCast(ctx));
         return @import("domains/page.zig").pageNetworkIdle(self, msg);
     }
 
     pub fn onPageNetworkAlmostIdle(ctx: *anyopaque, msg: *const Notification.PageNetworkAlmostIdle) !void {
-            const self: *Self = @ptrCast(@alignCast(ctx));
+        const self: *BrowserContext = @ptrCast(@alignCast(ctx));
         return @import("domains/page.zig").pageNetworkAlmostIdle(self, msg);
     }
 
     pub fn onHttpRequestStart(ctx: *anyopaque, msg: *const Notification.RequestStart) !void {
-            const self: *Self = @ptrCast(@alignCast(ctx));
+        const self: *BrowserContext = @ptrCast(@alignCast(ctx));
         try @import("domains/network.zig").httpRequestStart(self, msg);
     }
 
     pub fn onHttpRequestIntercept(ctx: *anyopaque, msg: *const Notification.RequestIntercept) !void {
-            const self: *Self = @ptrCast(@alignCast(ctx));
+        const self: *BrowserContext = @ptrCast(@alignCast(ctx));
         try @import("domains/fetch.zig").requestIntercept(self, msg);
     }
 
     pub fn onHttpRequestFail(ctx: *anyopaque, msg: *const Notification.RequestFail) !void {
-            const self: *Self = @ptrCast(@alignCast(ctx));
+        const self: *BrowserContext = @ptrCast(@alignCast(ctx));
         return @import("domains/network.zig").httpRequestFail(self, msg);
     }
 
     pub fn onHttpResponseHeadersDone(ctx: *anyopaque, msg: *const Notification.ResponseHeaderDone) !void {
-            const self: *Self = @ptrCast(@alignCast(ctx));
+        const self: *BrowserContext = @ptrCast(@alignCast(ctx));
         defer self.resetNotificationArena();
 
         const arena = self.page_arena;
@@ -668,12 +665,12 @@ pub fn BrowserContext(comptime CDP_T: type) type {
     }
 
     pub fn onHttpRequestDone(ctx: *anyopaque, msg: *const Notification.RequestDone) !void {
-            const self: *Self = @ptrCast(@alignCast(ctx));
+        const self: *BrowserContext = @ptrCast(@alignCast(ctx));
         return @import("domains/network.zig").httpRequestDone(self, msg);
     }
 
     pub fn onHttpResponseData(ctx: *anyopaque, msg: *const Notification.ResponseData) !void {
-            const self: *Self = @ptrCast(@alignCast(ctx));
+        const self: *BrowserContext = @ptrCast(@alignCast(ctx));
         const arena = self.page_arena;
 
         const id = msg.transfer.id;
@@ -683,16 +680,16 @@ pub fn BrowserContext(comptime CDP_T: type) type {
     }
 
     pub fn onHttpRequestAuthRequired(ctx: *anyopaque, data: *const Notification.RequestAuthRequired) !void {
-            const self: *Self = @ptrCast(@alignCast(ctx));
+        const self: *BrowserContext = @ptrCast(@alignCast(ctx));
         defer self.resetNotificationArena();
         try @import("domains/fetch.zig").requestAuthRequired(self, data);
     }
 
-        fn resetNotificationArena(self: *Self) void {
+    fn resetNotificationArena(self: *BrowserContext) void {
         defer _ = self.cdp.notification_arena.reset(.{ .retain_with_limit = 1024 * 64 });
     }
 
-        pub fn callInspector(self: *const Self, msg: []const u8) void {
+    pub fn callInspector(self: *const BrowserContext, msg: []const u8) void {
         self.inspector_session.send(msg);
         self.session.browser.env.runMicrotasks();
     }
@@ -723,7 +720,7 @@ pub fn BrowserContext(comptime CDP_T: type) type {
     // This is hacky x 2. First, we create the JSON payload by gluing our
     // session_id onto it. Second, we're much more client/websocket aware than
     // we should be.
-        fn sendInspectorMessage(self: *Self, msg: []const u8) !void {
+    fn sendInspectorMessage(self: *BrowserContext, msg: []const u8) !void {
         const session_id = self.session_id orelse {
             // We no longer have an active session. What should we do
             // in this case?
@@ -759,8 +756,7 @@ pub fn BrowserContext(comptime CDP_T: type) type {
 
         try cdp.client.sendJSONRaw(buf);
     }
-    };
+};
-}
 
 /// see: https://chromium.googlesource.com/chromium/src/+/master/third_party/blink/renderer/bindings/core/v8/V8BindingDesign.md#world
 /// The current understanding. An isolated world lives in the same isolate, but a separated context.
@@ -832,17 +828,16 @@ const IsolatedWorld = struct {
 // behaviors. Normally, we're sending the result to the client. But in some cases
 // we want to capture the result. So we want the command.sendResult to be
 // generic.
-pub fn Command(comptime CDP_T: type, comptime Sender: type) type {
+pub const Command = struct {
-    return struct {
     // A misc arena that can be used for any allocation for processing
     // the message
     arena: Allocator,
 
     // reference to our CDP instance
-        cdp: *CDP_T,
+    cdp: *CDP,
 
     // The browser context this command targets
-        browser_context: ?*BrowserContext(CDP_T),
+    browser_context: ?*BrowserContext,
 
     // The command input (the id, optional session_id, params, ...)
     input: Input,
@@ -853,9 +848,23 @@ pub fn Command(comptime CDP_T: type, comptime Sender: type) type {
     // be code to capture the data that we were "sending".
     sender: Sender,
 
-        const Self = @This();
+    const Sender = union(enum) {
+        cdp: *CDP,
+        capture: *std.Io.Writer,
 
-        pub fn params(self: *const Self, comptime T: type) !?T {
+        pub fn sendJSON(self: Sender, message: anytype) !void {
+            switch (self) {
+                .cdp => |cdp| return cdp.sendJSON(message),
+                .capture => |writer| {
+                    return std.json.Stringify.value(message, .{
+                        .emit_null_optional_fields = false,
+                    }, writer);
+                },
+            }
+        }
+    };
+
+    pub fn params(self: *const Command, comptime T: type) !?T {
         if (self.input.params) |p| {
             return try json.parseFromSliceLeaky(
                 T,
@@ -867,7 +876,7 @@ pub fn Command(comptime CDP_T: type, comptime Sender: type) type {
         return null;
     }
 
-        pub fn createBrowserContext(self: *Self) !*BrowserContext(CDP_T) {
+    pub fn createBrowserContext(self: *Command) !*BrowserContext {
         _ = try self.cdp.createBrowserContext();
         self.browser_context = &(self.cdp.browser_context.?);
         return self.browser_context.?;
@@ -876,7 +885,7 @@ pub fn Command(comptime CDP_T: type, comptime Sender: type) type {
     const SendResultOpts = struct {
         include_session_id: bool = true,
     };
-        pub fn sendResult(self: *Self, result: anytype, opts: SendResultOpts) !void {
+    pub fn sendResult(self: *Command, result: anytype, opts: SendResultOpts) !void {
         return self.sender.sendJSON(.{
             .id = self.input.id,
             .result = if (comptime @typeInfo(@TypeOf(result)) == .null) struct {}{} else result,
@@ -884,10 +893,7 @@ pub fn Command(comptime CDP_T: type, comptime Sender: type) type {
         });
     }
 
-        const SendEventOpts = struct {
+    pub fn sendEvent(self: *Command, method: []const u8, p: anytype, opts: SendEventOpts) !void {
-            session_id: ?[]const u8 = null,
-        };
-        pub fn sendEvent(self: *Self, method: []const u8, p: anytype, opts: CDP_T.SendEventOpts) !void {
         // Events ALWAYS go to the client. self.sender should not be used
         return self.cdp.sendEvent(method, p, opts);
     }
@@ -895,7 +901,7 @@ pub fn Command(comptime CDP_T: type, comptime Sender: type) type {
     const SendErrorOpts = struct {
         include_session_id: bool = true,
     };
-        pub fn sendError(self: *Self, code: i32, message: []const u8, opts: SendErrorOpts) !void {
+    pub fn sendError(self: *Command, code: i32, message: []const u8, opts: SendErrorOpts) !void {
         return self.sender.sendJSON(.{
             .id = self.input.id,
             .@"error" = .{ .code = code, .message = message },
@@ -920,8 +926,7 @@ pub fn Command(comptime CDP_T: type, comptime Sender: type) type {
         // The full raw json input
         json: []const u8,
     };
-    };
+};
-}
 
 // When we parse a JSON message from the client, this is the structure
 // we always expect

src/cdp/domains/accessibility.zig

@@ -18,8 +18,9 @@
 
 const std = @import("std");
 const id = @import("../id.zig");
+const CDP = @import("../CDP.zig");
 
-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
     const action = std.meta.stringToEnum(enum {
         enable,
         disable,
@@ -32,15 +33,15 @@ pub fn processMessage(cmd: anytype) !void {
         .getFullAXTree => return getFullAXTree(cmd),
     }
 }
-fn enable(cmd: anytype) !void {
+fn enable(cmd: *CDP.Command) !void {
     return cmd.sendResult(null, .{});
 }
 
-fn disable(cmd: anytype) !void {
+fn disable(cmd: *CDP.Command) !void {
     return cmd.sendResult(null, .{});
 }
 
-fn getFullAXTree(cmd: anytype) !void {
+fn getFullAXTree(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         depth: ?i32 = null,
         frameId: ?[]const u8 = null,

src/cdp/domains/browser.zig

@@ -17,6 +17,7 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
+const CDP = @import("../CDP.zig");
 
 // TODO: hard coded data
 const PROTOCOL_VERSION = "1.3";
@@ -35,7 +36,7 @@ const PRODUCT = "Chrome/124.0.6367.29";
 const JS_VERSION = "12.4.254.8";
 const DEV_TOOLS_WINDOW_ID = 1923710101;
 
-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
     const action = std.meta.stringToEnum(enum {
         getVersion,
         setPermission,
@@ -57,7 +58,7 @@ pub fn processMessage(cmd: anytype) !void {
     }
 }
 
-fn getVersion(cmd: anytype) !void {
+fn getVersion(cmd: *CDP.Command) !void {
     // TODO: pre-serialize?
     return cmd.sendResult(.{
         .protocolVersion = PROTOCOL_VERSION,
@@ -69,7 +70,7 @@ fn getVersion(cmd: anytype) !void {
 }
 
 // TODO: noop method
-fn setDownloadBehavior(cmd: anytype) !void {
+fn setDownloadBehavior(cmd: *CDP.Command) !void {
     // const params = (try cmd.params(struct {
     //     behavior: []const u8,
     //     browserContextId: ?[]const u8 = null,
@@ -80,7 +81,7 @@ fn setDownloadBehavior(cmd: anytype) !void {
     return cmd.sendResult(null, .{ .include_session_id = false });
 }
 
-fn getWindowForTarget(cmd: anytype) !void {
+fn getWindowForTarget(cmd: *CDP.Command) !void {
     // const params = (try cmd.params(struct {
     //     targetId: ?[]const u8 = null,
     // })) orelse return error.InvalidParams;
@@ -91,22 +92,22 @@ fn getWindowForTarget(cmd: anytype) !void {
 }
 
 // TODO: noop method
-fn setWindowBounds(cmd: anytype) !void {
+fn setWindowBounds(cmd: *CDP.Command) !void {
     return cmd.sendResult(null, .{});
 }
 
 // TODO: noop method
-fn grantPermissions(cmd: anytype) !void {
+fn grantPermissions(cmd: *CDP.Command) !void {
     return cmd.sendResult(null, .{});
 }
 
 // TODO: noop method
-fn setPermission(cmd: anytype) !void {
+fn setPermission(cmd: *CDP.Command) !void {
     return cmd.sendResult(null, .{});
 }
 
 // TODO: noop method
-fn resetPermissions(cmd: anytype) !void {
+fn resetPermissions(cmd: *CDP.Command) !void {
     return cmd.sendResult(null, .{});
 }
 

src/cdp/domains/css.zig

@@ -17,8 +17,9 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
+const CDP = @import("../CDP.zig");
 
-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
     const action = std.meta.stringToEnum(enum {
         enable,
     }, cmd.input.action) orelse return error.UnknownMethod;

src/cdp/domains/dom.zig

@@ -18,17 +18,18 @@
 
 const std = @import("std");
 const id = @import("../id.zig");
-const log = @import("../../log.zig");
+const CDP = @import("../CDP.zig");
 const Node = @import("../Node.zig");
+
+const log = @import("../../log.zig");
+const dump = @import("../../browser/dump.zig");
+const js = @import("../../browser/js/js.zig");
 const DOMNode = @import("../../browser/webapi/Node.zig");
 const Selector = @import("../../browser/webapi/selector/Selector.zig");
 
-const dump = @import("../../browser/dump.zig");
-const js = @import("../../browser/js/js.zig");
-
 const Allocator = std.mem.Allocator;
 
-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
     const action = std.meta.stringToEnum(enum {
         enable,
         getDocument,
@@ -69,7 +70,7 @@ pub fn processMessage(cmd: anytype) !void {
 }
 
 // https://chromedevtools.github.io/devtools-protocol/tot/DOM/#method-getDocument
-fn getDocument(cmd: anytype) !void {
+fn getDocument(cmd: *CDP.Command) !void {
     const Params = struct {
         // CDP documentation implies that 0 isn't valid, but it _does_ work in Chrome
         depth: i32 = 3,
@@ -89,7 +90,7 @@ fn getDocument(cmd: anytype) !void {
 }
 
 // https://chromedevtools.github.io/devtools-protocol/tot/DOM/#method-performSearch
-fn performSearch(cmd: anytype) !void {
+fn performSearch(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         query: []const u8,
         includeUserAgentShadowDOM: ?bool = null,
@@ -116,7 +117,7 @@ fn performSearch(cmd: anytype) !void {
 // hierarchy of each nodes.
 // We dispatch event in the reverse order: from the top level to the direct parents.
 // We should dispatch a node only if it has never been sent.
-fn dispatchSetChildNodes(cmd: anytype, dom_nodes: []const *DOMNode) !void {
+fn dispatchSetChildNodes(cmd: *CDP.Command, dom_nodes: []const *DOMNode) !void {
     const arena = cmd.arena;
     const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
     const session_id = bc.session_id orelse return error.SessionIdNotLoaded;
@@ -172,7 +173,7 @@ fn dispatchSetChildNodes(cmd: anytype, dom_nodes: []const *DOMNode) !void {
 }
 
 // https://chromedevtools.github.io/devtools-protocol/tot/DOM/#method-discardSearchResults
-fn discardSearchResults(cmd: anytype) !void {
+fn discardSearchResults(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         searchId: []const u8,
     })) orelse return error.InvalidParams;
@@ -184,7 +185,7 @@ fn discardSearchResults(cmd: anytype) !void {
 }
 
 // https://chromedevtools.github.io/devtools-protocol/tot/DOM/#method-getSearchResults
-fn getSearchResults(cmd: anytype) !void {
+fn getSearchResults(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         searchId: []const u8,
         fromIndex: u32,
@@ -209,7 +210,7 @@ fn getSearchResults(cmd: anytype) !void {
     return cmd.sendResult(.{ .nodeIds = node_ids[params.fromIndex..params.toIndex] }, .{});
 }
 
-fn querySelector(cmd: anytype) !void {
+fn querySelector(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         nodeId: Node.Id,
         selector: []const u8,
@@ -235,7 +236,7 @@ fn querySelector(cmd: anytype) !void {
     }, .{});
 }
 
-fn querySelectorAll(cmd: anytype) !void {
+fn querySelectorAll(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         nodeId: Node.Id,
         selector: []const u8,
@@ -266,7 +267,7 @@ fn querySelectorAll(cmd: anytype) !void {
     }, .{});
 }
 
-fn resolveNode(cmd: anytype) !void {
+fn resolveNode(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         nodeId: ?Node.Id = null,
         backendNodeId: ?u32 = null,
@@ -327,7 +328,7 @@ fn resolveNode(cmd: anytype) !void {
     } }, .{});
 }
 
-fn describeNode(cmd: anytype) !void {
+fn describeNode(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         nodeId: ?Node.Id = null,
         backendNodeId: ?Node.Id = null,
@@ -374,7 +375,7 @@ fn rectToQuad(rect: DOMNode.Element.DOMRect) Quad {
     };
 }
 
-fn scrollIntoViewIfNeeded(cmd: anytype) !void {
+fn scrollIntoViewIfNeeded(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         nodeId: ?Node.Id = null,
         backendNodeId: ?u32 = null,
@@ -397,7 +398,7 @@ fn scrollIntoViewIfNeeded(cmd: anytype) !void {
     return cmd.sendResult(null, .{});
 }
 
-fn getNode(arena: Allocator, bc: anytype, node_id: ?Node.Id, backend_node_id: ?Node.Id, object_id: ?[]const u8) !*Node {
+fn getNode(arena: Allocator, bc: *CDP.BrowserContext, node_id: ?Node.Id, backend_node_id: ?Node.Id, object_id: ?[]const u8) !*Node {
     const input_node_id = node_id orelse backend_node_id;
     if (input_node_id) |input_node_id_| {
         return bc.node_registry.lookup_by_id.get(input_node_id_) orelse return error.NodeNotFound;
@@ -417,7 +418,7 @@ fn getNode(arena: Allocator, bc: anytype, node_id: ?Node.Id, backend_node_id: ?N
 
 // https://chromedevtools.github.io/devtools-protocol/tot/DOM/#method-getContentQuads
 // Related to: https://drafts.csswg.org/cssom-view/#the-geometryutils-interface
-fn getContentQuads(cmd: anytype) !void {
+fn getContentQuads(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         nodeId: ?Node.Id = null,
         backendNodeId: ?Node.Id = null,
@@ -443,7 +444,7 @@ fn getContentQuads(cmd: anytype) !void {
     return cmd.sendResult(.{ .quads = &.{quad} }, .{});
 }
 
-fn getBoxModel(cmd: anytype) !void {
+fn getBoxModel(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         nodeId: ?Node.Id = null,
         backendNodeId: ?u32 = null,
@@ -472,7 +473,7 @@ fn getBoxModel(cmd: anytype) !void {
     } }, .{});
 }
 
-fn requestChildNodes(cmd: anytype) !void {
+fn requestChildNodes(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         nodeId: Node.Id,
         depth: i32 = 1,
@@ -496,7 +497,7 @@ fn requestChildNodes(cmd: anytype) !void {
     return cmd.sendResult(null, .{});
 }
 
-fn getFrameOwner(cmd: anytype) !void {
+fn getFrameOwner(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         frameId: []const u8,
     })) orelse return error.InvalidParams;
@@ -512,7 +513,7 @@ fn getFrameOwner(cmd: anytype) !void {
     return cmd.sendResult(.{ .nodeId = node.id, .backendNodeId = node.id }, .{});
 }
 
-fn getOuterHTML(cmd: anytype) !void {
+fn getOuterHTML(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         nodeId: ?Node.Id = null,
         backendNodeId: ?Node.Id = null,
@@ -534,7 +535,7 @@ fn getOuterHTML(cmd: anytype) !void {
     return cmd.sendResult(.{ .outerHTML = aw.written() }, .{});
 }
 
-fn requestNode(cmd: anytype) !void {
+fn requestNode(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         objectId: []const u8,
     })) orelse return error.InvalidParams;

src/cdp/domains/emulation.zig

@@ -17,9 +17,10 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
+const CDP = @import("../CDP.zig");
 const log = @import("../../log.zig");
 
-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
     const action = std.meta.stringToEnum(enum {
         setEmulatedMedia,
         setFocusEmulationEnabled,
@@ -38,7 +39,7 @@ pub fn processMessage(cmd: anytype) !void {
 }
 
 // TODO: noop method
-fn setEmulatedMedia(cmd: anytype) !void {
+fn setEmulatedMedia(cmd: *CDP.Command) !void {
     // const input = (try const incoming.params(struct {
     //     media: ?[]const u8 = null,
     //     features: ?[]struct{
@@ -51,7 +52,7 @@ fn setEmulatedMedia(cmd: anytype) !void {
 }
 
 // TODO: noop method
-fn setFocusEmulationEnabled(cmd: anytype) !void {
+fn setFocusEmulationEnabled(cmd: *CDP.Command) !void {
     // const input = (try const incoming.params(struct {
     //     enabled: bool,
     // })) orelse return error.InvalidParams;
@@ -59,16 +60,16 @@ fn setFocusEmulationEnabled(cmd: anytype) !void {
 }
 
 // TODO: noop method
-fn setDeviceMetricsOverride(cmd: anytype) !void {
+fn setDeviceMetricsOverride(cmd: *CDP.Command) !void {
     return cmd.sendResult(null, .{});
 }
 
 // TODO: noop method
-fn setTouchEmulationEnabled(cmd: anytype) !void {
+fn setTouchEmulationEnabled(cmd: *CDP.Command) !void {
     return cmd.sendResult(null, .{});
 }
 
-fn setUserAgentOverride(cmd: anytype) !void {
+fn setUserAgentOverride(cmd: *CDP.Command) !void {
     log.info(.app, "setUserAgentOverride ignored", .{});
     return cmd.sendResult(null, .{});
 }

src/cdp/domains/fetch.zig

@@ -17,17 +17,19 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
-const Allocator = std.mem.Allocator;
 
 const id = @import("../id.zig");
+const CDP = @import("../CDP.zig");
 const log = @import("../../log.zig");
-const network = @import("network.zig");
 
 const HttpClient = @import("../../browser/HttpClient.zig");
 const net_http = @import("../../network/http.zig");
 const Notification = @import("../../Notification.zig");
 
-pub fn processMessage(cmd: anytype) !void {
+const network = @import("network.zig");
+const Allocator = std.mem.Allocator;
+
+pub fn processMessage(cmd: *CDP.Command) !void {
     const action = std.meta.stringToEnum(enum {
         disable,
         enable,
@@ -135,13 +137,13 @@ const ErrorReason = enum {
     BlockedByResponse,
 };
 
-fn disable(cmd: anytype) !void {
+fn disable(cmd: *CDP.Command) !void {
     const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
     bc.fetchDisable();
     return cmd.sendResult(null, .{});
 }
 
-fn enable(cmd: anytype) !void {
+fn enable(cmd: *CDP.Command) !void {
     const params = (try cmd.params(EnableParam)) orelse EnableParam{};
     if (!arePatternsSupported(params.patterns)) {
         log.warn(.not_implemented, "Fetch.enable", .{ .params = "pattern" });
@@ -180,7 +182,7 @@ fn arePatternsSupported(patterns: []RequestPattern) bool {
     return true;
 }
 
-pub fn requestIntercept(bc: anytype, intercept: *const Notification.RequestIntercept) !void {
+pub fn requestIntercept(bc: *CDP.BrowserContext, intercept: *const Notification.RequestIntercept) !void {
     // detachTarget could be called, in which case, we still have a page doing
     // things, but no session.
     const session_id = bc.session_id orelse return;
@@ -215,7 +217,7 @@ pub fn requestIntercept(bc: anytype, intercept: *const Notification.RequestInter
     intercept.wait_for_interception.* = true;
 }
 
-fn continueRequest(cmd: anytype) !void {
+fn continueRequest(cmd: *CDP.Command) !void {
     const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
     const params = (try cmd.params(struct {
         requestId: []const u8, // INT-{d}"
@@ -275,7 +277,7 @@ const AuthChallengeResponse = enum {
     ProvideCredentials,
 };
 
-fn continueWithAuth(cmd: anytype) !void {
+fn continueWithAuth(cmd: *CDP.Command) !void {
     const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
     const params = (try cmd.params(struct {
         requestId: []const u8, // "INT-{d}"
@@ -318,7 +320,7 @@ fn continueWithAuth(cmd: anytype) !void {
     return cmd.sendResult(null, .{});
 }
 
-fn fulfillRequest(cmd: anytype) !void {
+fn fulfillRequest(cmd: *CDP.Command) !void {
     const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
 
     const params = (try cmd.params(struct {
@@ -360,7 +362,7 @@ fn fulfillRequest(cmd: anytype) !void {
     return cmd.sendResult(null, .{});
 }
 
-fn failRequest(cmd: anytype) !void {
+fn failRequest(cmd: *CDP.Command) !void {
     const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
     const params = (try cmd.params(struct {
         requestId: []const u8, // "INT-{d}"
@@ -382,7 +384,7 @@ fn failRequest(cmd: anytype) !void {
     return cmd.sendResult(null, .{});
 }
 
-pub fn requestAuthRequired(bc: anytype, intercept: *const Notification.RequestAuthRequired) !void {
+pub fn requestAuthRequired(bc: *CDP.BrowserContext, intercept: *const Notification.RequestAuthRequired) !void {
     // detachTarget could be called, in which case, we still have a page doing
     // things, but no session.
     const session_id = bc.session_id orelse return;

src/cdp/domains/input.zig

@@ -17,8 +17,9 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
+const CDP = @import("../CDP.zig");
 
-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
     const action = std.meta.stringToEnum(enum {
         dispatchKeyEvent,
         dispatchMouseEvent,
@@ -33,7 +34,7 @@ pub fn processMessage(cmd: anytype) !void {
 }
 
 // https://chromedevtools.github.io/devtools-protocol/tot/Input/#method-dispatchKeyEvent
-fn dispatchKeyEvent(cmd: anytype) !void {
+fn dispatchKeyEvent(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         type: Type,
         key: []const u8 = "",
@@ -74,7 +75,7 @@ fn dispatchKeyEvent(cmd: anytype) !void {
 }
 
 // https://chromedevtools.github.io/devtools-protocol/tot/Input/#method-dispatchMouseEvent
-fn dispatchMouseEvent(cmd: anytype) !void {
+fn dispatchMouseEvent(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         x: f64,
         y: f64,
@@ -104,7 +105,7 @@ fn dispatchMouseEvent(cmd: anytype) !void {
 }
 
 // https://chromedevtools.github.io/devtools-protocol/tot/Input/#method-insertText
-fn insertText(cmd: anytype) !void {
+fn insertText(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         text: []const u8, // The text to insert
     })) orelse return error.InvalidParams;

src/cdp/domains/inspector.zig

@@ -17,8 +17,9 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
+const CDP = @import("../CDP.zig");
 
-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
     const action = std.meta.stringToEnum(enum {
         enable,
         disable,

src/cdp/domains/log.zig

@@ -17,8 +17,9 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
+const CDP = @import("../CDP.zig");
 
-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
     const action = std.meta.stringToEnum(enum {
         enable,
         disable,

src/cdp/domains/lp.zig

@@ -18,14 +18,18 @@
 
 const std = @import("std");
 const lp = @import("lightpanda");
+
+const CDP = @import("../CDP.zig");
+const Node = @import("../Node.zig");
+
+const DOMNode = @import("../../browser/webapi/Node.zig");
+
 const markdown = lp.markdown;
 const SemanticTree = lp.SemanticTree;
 const interactive = lp.interactive;
 const structured_data = lp.structured_data;
-const Node = @import("../Node.zig");
-const DOMNode = @import("../../browser/webapi/Node.zig");
 
-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
     const action = std.meta.stringToEnum(enum {
         getMarkdown,
         getSemanticTree,
@@ -51,7 +55,7 @@ pub fn processMessage(cmd: anytype) !void {
     }
 }
 
-fn getSemanticTree(cmd: anytype) !void {
+fn getSemanticTree(cmd: *CDP.Command) !void {
     const Params = struct {
         format: ?enum { text } = null,
         prune: ?bool = null,
@@ -96,7 +100,7 @@ fn getSemanticTree(cmd: anytype) !void {
     }, .{});
 }
 
-fn getMarkdown(cmd: anytype) !void {
+fn getMarkdown(cmd: *CDP.Command) !void {
     const Params = struct {
         nodeId: ?Node.Id = null,
     };
@@ -119,7 +123,7 @@ fn getMarkdown(cmd: anytype) !void {
     }, .{});
 }
 
-fn getInteractiveElements(cmd: anytype) !void {
+fn getInteractiveElements(cmd: *CDP.Command) !void {
     const Params = struct {
         nodeId: ?Node.Id = null,
     };
@@ -141,7 +145,7 @@ fn getInteractiveElements(cmd: anytype) !void {
     }, .{});
 }
 
-fn getStructuredData(cmd: anytype) !void {
+fn getStructuredData(cmd: *CDP.Command) !void {
     const bc = cmd.browser_context orelse return error.NoBrowserContext;
     const page = bc.session.currentPage() orelse return error.PageNotLoaded;
 
@@ -156,7 +160,7 @@ fn getStructuredData(cmd: anytype) !void {
     }, .{});
 }
 
-fn detectForms(cmd: anytype) !void {
+fn detectForms(cmd: *CDP.Command) !void {
     const bc = cmd.browser_context orelse return error.NoBrowserContext;
     const page = bc.session.currentPage() orelse return error.PageNotLoaded;
 
@@ -173,7 +177,7 @@ fn detectForms(cmd: anytype) !void {
     }, .{});
 }
 
-fn clickNode(cmd: anytype) !void {
+fn clickNode(cmd: *CDP.Command) !void {
     const Params = struct {
         nodeId: ?Node.Id = null,
         backendNodeId: ?Node.Id = null,
@@ -194,7 +198,7 @@ fn clickNode(cmd: anytype) !void {
     return cmd.sendResult(.{}, .{});
 }
 
-fn fillNode(cmd: anytype) !void {
+fn fillNode(cmd: *CDP.Command) !void {
     const Params = struct {
         nodeId: ?Node.Id = null,
         backendNodeId: ?Node.Id = null,
@@ -216,7 +220,7 @@ fn fillNode(cmd: anytype) !void {
     return cmd.sendResult(.{}, .{});
 }
 
-fn scrollNode(cmd: anytype) !void {
+fn scrollNode(cmd: *CDP.Command) !void {
     const Params = struct {
         nodeId: ?Node.Id = null,
         backendNodeId: ?Node.Id = null,
@@ -244,7 +248,7 @@ fn scrollNode(cmd: anytype) !void {
     return cmd.sendResult(.{}, .{});
 }
 
-fn waitForSelector(cmd: anytype) !void {
+fn waitForSelector(cmd: *CDP.Command) !void {
     const Params = struct {
         selector: []const u8,
         timeout: ?u32 = null,

src/cdp/domains/network.zig

@@ -18,18 +18,21 @@
 
 const std = @import("std");
 const lp = @import("lightpanda");
-const Allocator = std.mem.Allocator;
+
 const log = @import("../../log.zig");
 
-const CdpStorage = @import("storage.zig");
-
 const id = @import("../id.zig");
+const CDP = @import("../CDP.zig");
+
 const URL = @import("../../browser/URL.zig");
 const Transfer = @import("../../browser/HttpClient.zig").Transfer;
 const Notification = @import("../../Notification.zig");
 const Mime = @import("../../browser/Mime.zig");
 
-pub fn processMessage(cmd: anytype) !void {
+const CdpStorage = @import("storage.zig");
+const Allocator = std.mem.Allocator;
+
+pub fn processMessage(cmd: *CDP.Command) !void {
     const action = std.meta.stringToEnum(enum {
         enable,
         disable,
@@ -59,19 +62,19 @@ pub fn processMessage(cmd: anytype) !void {
     }
 }
 
-fn enable(cmd: anytype) !void {
+fn enable(cmd: *CDP.Command) !void {
     const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
     try bc.networkEnable();
     return cmd.sendResult(null, .{});
 }
 
-fn disable(cmd: anytype) !void {
+fn disable(cmd: *CDP.Command) !void {
     const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
     bc.networkDisable();
     return cmd.sendResult(null, .{});
 }
 
-fn setExtraHTTPHeaders(cmd: anytype) !void {
+fn setExtraHTTPHeaders(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         headers: std.json.ArrayHashMap([]const u8),
     })) orelse return error.InvalidParams;
@@ -110,7 +113,7 @@ fn cookieMatches(cookie: *const Cookie, name: []const u8, domain: ?[]const u8, p
     return true;
 }
 
-fn deleteCookies(cmd: anytype) !void {
+fn deleteCookies(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         name: []const u8,
         url: ?[:0]const u8 = null,
@@ -144,14 +147,14 @@ fn deleteCookies(cmd: anytype) !void {
     return cmd.sendResult(null, .{});
 }
 
-fn clearBrowserCookies(cmd: anytype) !void {
+fn clearBrowserCookies(cmd: *CDP.Command) !void {
     if (try cmd.params(struct {}) != null) return error.InvalidParams;
     const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
     bc.session.cookie_jar.clearRetainingCapacity();
     return cmd.sendResult(null, .{});
 }
 
-fn setCookie(cmd: anytype) !void {
+fn setCookie(cmd: *CDP.Command) !void {
     const params = (try cmd.params(
         CdpStorage.CdpCookie,
     )) orelse return error.InvalidParams;
@@ -162,7 +165,7 @@ fn setCookie(cmd: anytype) !void {
     try cmd.sendResult(.{ .success = true }, .{});
 }
 
-fn setCookies(cmd: anytype) !void {
+fn setCookies(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         cookies: []const CdpStorage.CdpCookie,
     })) orelse return error.InvalidParams;
@@ -178,7 +181,7 @@ fn setCookies(cmd: anytype) !void {
 const GetCookiesParam = struct {
     urls: ?[]const [:0]const u8 = null,
 };
-fn getCookies(cmd: anytype) !void {
+fn getCookies(cmd: *CDP.Command) !void {
     const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
     const params = (try cmd.params(GetCookiesParam)) orelse GetCookiesParam{};
 
@@ -201,7 +204,7 @@ fn getCookies(cmd: anytype) !void {
     try cmd.sendResult(.{ .cookies = writer }, .{});
 }
 
-fn getResponseBody(cmd: anytype) !void {
+fn getResponseBody(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         requestId: []const u8, // "REQ-{d}"
     })) orelse return error.InvalidParams;
@@ -227,7 +230,7 @@ fn getResponseBody(cmd: anytype) !void {
     }, .{});
 }
 
-pub fn httpRequestFail(bc: anytype, msg: *const Notification.RequestFail) !void {
+pub fn httpRequestFail(bc: *CDP.BrowserContext, msg: *const Notification.RequestFail) !void {
     // It's possible that the request failed because we aborted when the client
     // sent Target.closeTarget. In that case, bc.session_id will be cleared
     // already, and we can skip sending these messages to the client.
@@ -247,7 +250,7 @@ pub fn httpRequestFail(bc: anytype, msg: *const Notification.RequestFail) !void
     }, .{ .session_id = session_id });
 }
 
-pub fn httpRequestStart(bc: anytype, msg: *const Notification.RequestStart) !void {
+pub fn httpRequestStart(bc: *CDP.BrowserContext, msg: *const Notification.RequestStart) !void {
     // detachTarget could be called, in which case, we still have a page doing
     // things, but no session.
     const session_id = bc.session_id orelse return;
@@ -276,7 +279,7 @@ pub fn httpRequestStart(bc: anytype, msg: *const Notification.RequestStart) !voi
     }, .{ .session_id = session_id });
 }
 
-pub fn httpResponseHeaderDone(arena: Allocator, bc: anytype, msg: *const Notification.ResponseHeaderDone) !void {
+pub fn httpResponseHeaderDone(arena: Allocator, bc: *CDP.BrowserContext, msg: *const Notification.ResponseHeaderDone) !void {
     // detachTarget could be called, in which case, we still have a page doing
     // things, but no session.
     const session_id = bc.session_id orelse return;
@@ -293,7 +296,7 @@ pub fn httpResponseHeaderDone(arena: Allocator, bc: anytype, msg: *const Notific
     }, .{ .session_id = session_id });
 }
 
-pub fn httpRequestDone(bc: anytype, msg: *const Notification.RequestDone) !void {
+pub fn httpRequestDone(bc: *CDP.BrowserContext, msg: *const Notification.RequestDone) !void {
     // detachTarget could be called, in which case, we still have a page doing
     // things, but no session.
     const session_id = bc.session_id orelse return;

src/cdp/domains/page.zig

@@ -1,4 +1,5 @@
 // Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+
 //
 // Francis Bouvier <francis@lightpanda.io>
 // Pierre Tachoire <pierre@lightpanda.io>
@@ -22,6 +23,8 @@ const lp = @import("lightpanda");
 const screenshot_png = @embedFile("screenshot.png");
 
 const id = @import("../id.zig");
+const CDP = @import("../CDP.zig");
+
 const log = @import("../../log.zig");
 const js = @import("../../browser/js/js.zig");
 const URL = @import("../../browser/URL.zig");
@@ -31,7 +34,7 @@ const Notification = @import("../../Notification.zig");
 
 const Allocator = std.mem.Allocator;
 
-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
     const action = std.meta.stringToEnum(enum {
         enable,
         getFrameTree,
@@ -78,7 +81,7 @@ const Frame = struct {
     gatedAPIFeatures: [][]const u8 = &[0][]const u8{},
 };
 
-fn getFrameTree(cmd: anytype) !void {
+fn getFrameTree(cmd: *CDP.Command) !void {
     // Stagehand parses the response and error if we don't return a
     // correct one for this call when browser context or target id are missing.
     const startup = .{
@@ -108,7 +111,7 @@ fn getFrameTree(cmd: anytype) !void {
     }, .{});
 }
 
-fn setLifecycleEventsEnabled(cmd: anytype) !void {
+fn setLifecycleEventsEnabled(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         enabled: bool,
     })) orelse return error.InvalidParams;
@@ -149,7 +152,7 @@ fn setLifecycleEventsEnabled(cmd: anytype) !void {
     return cmd.sendResult(null, .{});
 }
 
-fn addScriptToEvaluateOnNewDocument(cmd: anytype) !void {
+fn addScriptToEvaluateOnNewDocument(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         source: []const u8,
         worldName: ?[]const u8 = null,
@@ -179,7 +182,7 @@ fn addScriptToEvaluateOnNewDocument(cmd: anytype) !void {
     }, .{});
 }
 
-fn removeScriptToEvaluateOnNewDocument(cmd: anytype) !void {
+fn removeScriptToEvaluateOnNewDocument(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         identifier: []const u8,
     })) orelse return error.InvalidParams;
@@ -198,7 +201,7 @@ fn removeScriptToEvaluateOnNewDocument(cmd: anytype) !void {
     return cmd.sendResult(null, .{});
 }
 
-fn close(cmd: anytype) !void {
+fn close(cmd: *CDP.Command) !void {
     const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
 
     const target_id = bc.target_id orelse return error.TargetNotLoaded;
@@ -235,7 +238,7 @@ fn close(cmd: anytype) !void {
     bc.target_id = null;
 }
 
-fn createIsolatedWorld(cmd: anytype) !void {
+fn createIsolatedWorld(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         frameId: []const u8,
         worldName: []const u8,
@@ -255,7 +258,7 @@ fn createIsolatedWorld(cmd: anytype) !void {
     return cmd.sendResult(.{ .executionContextId = js_context.id }, .{});
 }
 
-fn navigate(cmd: anytype) !void {
+fn navigate(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         url: [:0]const u8,
         // referrer: ?[]const u8 = null,
@@ -289,7 +292,7 @@ fn navigate(cmd: anytype) !void {
     });
 }
 
-fn doReload(cmd: anytype) !void {
+fn doReload(cmd: *CDP.Command) !void {
     const params = try cmd.params(struct {
         ignoreCache: ?bool = null,
         scriptToEvaluateOnLoad: ?[]const u8 = null,
@@ -319,7 +322,7 @@ fn doReload(cmd: anytype) !void {
     });
 }
 
-pub fn pageNavigate(bc: anytype, event: *const Notification.PageNavigate) !void {
+pub fn pageNavigate(bc: *CDP.BrowserContext, event: *const Notification.PageNavigate) !void {
     // detachTarget could be called, in which case, we still have a page doing
     // things, but no session.
     const session_id = bc.session_id orelse return;
@@ -371,7 +374,7 @@ pub fn pageNavigate(bc: anytype, event: *const Notification.PageNavigate) !void
     }, .{ .session_id = session_id });
 }
 
-pub fn pageRemove(bc: anytype) !void {
+pub fn pageRemove(bc: *CDP.BrowserContext) !void {
     // Clear all remote object mappings to prevent stale objectIds from being used
     // after the context is destroy
     bc.inspector_session.inspector.resetContextGroup();
@@ -382,7 +385,7 @@ pub fn pageRemove(bc: anytype) !void {
     }
 }
 
-pub fn pageCreated(bc: anytype, page: *Page) !void {
+pub fn pageCreated(bc: *CDP.BrowserContext, page: *Page) !void {
     _ = bc.cdp.page_arena.reset(.{ .retain_with_limit = 1024 * 512 });
 
     for (bc.isolated_worlds.items) |isolated_world| {
@@ -394,7 +397,7 @@ pub fn pageCreated(bc: anytype, page: *Page) !void {
     bc.captured_responses = .empty;
 }
 
-pub fn pageFrameCreated(bc: anytype, event: *const Notification.PageFrameCreated) !void {
+pub fn pageFrameCreated(bc: *CDP.BrowserContext, event: *const Notification.PageFrameCreated) !void {
     const session_id = bc.session_id orelse return;
 
     const cdp = bc.cdp;
@@ -415,7 +418,7 @@ pub fn pageFrameCreated(bc: anytype, event: *const Notification.PageFrameCreated
     }
 }
 
-pub fn pageNavigated(arena: Allocator, bc: anytype, event: *const Notification.PageNavigated) !void {
+pub fn pageNavigated(arena: Allocator, bc: *CDP.BrowserContext, event: *const Notification.PageNavigated) !void {
     // detachTarget could be called, in which case, we still have a page doing
     // things, but no session.
     const session_id = bc.session_id orelse return;
@@ -597,15 +600,15 @@ pub fn pageNavigated(arena: Allocator, bc: anytype, event: *const Notification.P
     }, .{ .session_id = session_id });
 }
 
-pub fn pageNetworkIdle(bc: anytype, event: *const Notification.PageNetworkIdle) !void {
+pub fn pageNetworkIdle(bc: *CDP.BrowserContext, event: *const Notification.PageNetworkIdle) !void {
     return sendPageLifecycle(bc, "networkIdle", event.timestamp, &id.toFrameId(event.frame_id), &id.toLoaderId(event.req_id));
 }
 
-pub fn pageNetworkAlmostIdle(bc: anytype, event: *const Notification.PageNetworkAlmostIdle) !void {
+pub fn pageNetworkAlmostIdle(bc: *CDP.BrowserContext, event: *const Notification.PageNetworkAlmostIdle) !void {
     return sendPageLifecycle(bc, "networkAlmostIdle", event.timestamp, &id.toFrameId(event.frame_id), &id.toLoaderId(event.req_id));
 }
 
-fn sendPageLifecycle(bc: anytype, name: []const u8, timestamp: u64, frame_id: []const u8, loader_id: []const u8) !void {
+fn sendPageLifecycle(bc: *CDP.BrowserContext, name: []const u8, timestamp: u64, frame_id: []const u8, loader_id: []const u8) !void {
     // detachTarget could be called, in which case, we still have a page doing
     // things, but no session.
     const session_id = bc.session_id orelse return;
@@ -640,7 +643,7 @@ fn base64Encode(comptime input: []const u8) [std.base64.standard.Encoder.calcSiz
     return buf;
 }
 
-fn captureScreenshot(cmd: anytype) !void {
+fn captureScreenshot(cmd: *CDP.Command) !void {
     const Params = struct {
         format: ?[]const u8 = "png",
         quality: ?u8 = null,
@@ -676,7 +679,7 @@ fn captureScreenshot(cmd: anytype) !void {
     }, .{});
 }
 
-fn getLayoutMetrics(cmd: anytype) !void {
+fn getLayoutMetrics(cmd: *CDP.Command) !void {
     const width = 1920;
     const height = 1080;
 

src/cdp/domains/performance.zig

@@ -17,8 +17,9 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
+const CDP = @import("../CDP.zig");
 
-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
     const action = std.meta.stringToEnum(enum {
         enable,
         disable,

src/cdp/domains/runtime.zig

@@ -19,7 +19,9 @@
 const std = @import("std");
 const builtin = @import("builtin");
 
-pub fn processMessage(cmd: anytype) !void {
+const CDP = @import("../CDP.zig");
+
+pub fn processMessage(cmd: *CDP.Command) !void {
     const action = std.meta.stringToEnum(enum {
         enable,
         runIfWaitingForDebugger,
@@ -36,7 +38,7 @@ pub fn processMessage(cmd: anytype) !void {
     }
 }
 
-fn sendInspector(cmd: anytype, action: anytype) !void {
+fn sendInspector(cmd: *CDP.Command, action: anytype) !void {
     // save script in file at debug mode
     if (builtin.mode == .Debug) {
         try logInspector(cmd, action);
@@ -48,7 +50,7 @@ fn sendInspector(cmd: anytype, action: anytype) !void {
     bc.callInspector(cmd.input.json);
 }
 
-fn logInspector(cmd: anytype, action: anytype) !void {
+fn logInspector(cmd: *CDP.Command, action: anytype) !void {
     const script = switch (action) {
         .evaluate => blk: {
             const params = (try cmd.params(struct {

src/cdp/domains/security.zig

@@ -17,8 +17,9 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
+const CDP = @import("../CDP.zig");
 
-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
     const action = std.meta.stringToEnum(enum {
         enable,
         disable,
@@ -32,7 +33,7 @@ pub fn processMessage(cmd: anytype) !void {
     }
 }
 
-fn setIgnoreCertificateErrors(cmd: anytype) !void {
+fn setIgnoreCertificateErrors(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         ignore: bool,
     })) orelse return error.InvalidParams;

src/cdp/domains/storage.zig

@@ -18,13 +18,16 @@
 
 const std = @import("std");
 
+const CDP = @import("../CDP.zig");
+
 const log = @import("../../log.zig");
 const URL = @import("../../browser/URL.zig");
 const Cookie = @import("../../browser/webapi/storage/storage.zig").Cookie;
+
 const CookieJar = Cookie.Jar;
 pub const PreparedUri = Cookie.PreparedUri;
 
-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
     const action = std.meta.stringToEnum(enum {
         clearCookies,
         setCookies,
@@ -40,7 +43,7 @@ pub fn processMessage(cmd: anytype) !void {
 
 const BrowserContextParam = struct { browserContextId: ?[]const u8 = null };
 
-fn clearCookies(cmd: anytype) !void {
+fn clearCookies(cmd: *CDP.Command) !void {
     const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
     const params = (try cmd.params(BrowserContextParam)) orelse BrowserContextParam{};
 
@@ -55,7 +58,7 @@ fn clearCookies(cmd: anytype) !void {
     return cmd.sendResult(null, .{});
 }
 
-fn getCookies(cmd: anytype) !void {
+fn getCookies(cmd: *CDP.Command) !void {
     const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
     const params = (try cmd.params(BrowserContextParam)) orelse BrowserContextParam{};
 
@@ -69,7 +72,7 @@ fn getCookies(cmd: anytype) !void {
     try cmd.sendResult(.{ .cookies = writer }, .{});
 }
 
-fn setCookies(cmd: anytype) !void {
+fn setCookies(cmd: *CDP.Command) !void {
     const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
     const params = (try cmd.params(struct {
         cookies: []const CdpCookie,

src/cdp/domains/target.zig

@@ -20,11 +20,13 @@ const std = @import("std");
 const lp = @import("lightpanda");
 
 const id = @import("../id.zig");
+const CDP = @import("../CDP.zig");
+
 const log = @import("../../log.zig");
 const URL = @import("../../browser/URL.zig");
 const js = @import("../../browser/js/js.zig");
 
-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
     const action = std.meta.stringToEnum(enum {
         getTargets,
         attachToTarget,
@@ -60,7 +62,7 @@ pub fn processMessage(cmd: anytype) !void {
     }
 }
 
-fn getTargets(cmd: anytype) !void {
+fn getTargets(cmd: *CDP.Command) !void {
     // If no context available, return an empty array.
     const bc = cmd.browser_context orelse {
         return cmd.sendResult(.{
@@ -86,7 +88,7 @@ fn getTargets(cmd: anytype) !void {
     }, .{ .include_session_id = false });
 }
 
-fn getBrowserContexts(cmd: anytype) !void {
+fn getBrowserContexts(cmd: *CDP.Command) !void {
     var browser_context_ids: []const []const u8 = undefined;
     if (cmd.browser_context) |bc| {
         browser_context_ids = &.{bc.id};
@@ -99,7 +101,7 @@ fn getBrowserContexts(cmd: anytype) !void {
     }, .{ .include_session_id = false });
 }
 
-fn createBrowserContext(cmd: anytype) !void {
+fn createBrowserContext(cmd: *CDP.Command) !void {
     const params = try cmd.params(struct {
         disposeOnDetach: bool = false,
         proxyServer: ?[:0]const u8 = null,
@@ -130,7 +132,7 @@ fn createBrowserContext(cmd: anytype) !void {
     }, .{});
 }
 
-fn disposeBrowserContext(cmd: anytype) !void {
+fn disposeBrowserContext(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         browserContextId: []const u8,
     })) orelse return error.InvalidParams;
@@ -141,7 +143,7 @@ fn disposeBrowserContext(cmd: anytype) !void {
     try cmd.sendResult(null, .{});
 }
 
-fn createTarget(cmd: anytype) !void {
+fn createTarget(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         url: [:0]const u8 = "about:blank",
         // width: ?u64 = null,
@@ -230,7 +232,7 @@ fn createTarget(cmd: anytype) !void {
     }, .{});
 }
 
-fn attachToTarget(cmd: anytype) !void {
+fn attachToTarget(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         targetId: []const u8,
         flatten: bool = true,
@@ -247,7 +249,7 @@ fn attachToTarget(cmd: anytype) !void {
     return cmd.sendResult(.{ .sessionId = bc.session_id }, .{});
 }
 
-fn attachToBrowserTarget(cmd: anytype) !void {
+fn attachToBrowserTarget(cmd: *CDP.Command) !void {
     const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
 
     const session_id = bc.session_id orelse cmd.cdp.session_id_gen.next();
@@ -269,7 +271,7 @@ fn attachToBrowserTarget(cmd: anytype) !void {
     return cmd.sendResult(.{ .sessionId = bc.session_id }, .{});
 }
 
-fn closeTarget(cmd: anytype) !void {
+fn closeTarget(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         targetId: []const u8,
     })) orelse return error.InvalidParams;
@@ -310,7 +312,7 @@ fn closeTarget(cmd: anytype) !void {
     bc.target_id = null;
 }
 
-fn getTargetInfo(cmd: anytype) !void {
+fn getTargetInfo(cmd: *CDP.Command) !void {
     const Params = struct {
         targetId: ?[]const u8 = null,
     };
@@ -347,7 +349,7 @@ fn getTargetInfo(cmd: anytype) !void {
     }, .{ .include_session_id = false });
 }
 
-fn sendMessageToTarget(cmd: anytype) !void {
+fn sendMessageToTarget(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         message: []const u8,
         sessionId: []const u8,
@@ -365,32 +367,19 @@ fn sendMessageToTarget(cmd: anytype) !void {
         return error.UnknownSessionId;
     }
 
-    const Capture = struct {
+    var aw = std.Io.Writer.Allocating.init(cmd.arena);
-        aw: std.Io.Writer.Allocating,
+    cmd.cdp.dispatch(cmd.arena, .{ .capture = &aw.writer }, params.message) catch |err| {
-
-        pub fn sendJSON(self: *@This(), message: anytype) !void {
-            return std.json.Stringify.value(message, .{
-                .emit_null_optional_fields = false,
-            }, &self.aw.writer);
-        }
-    };
-
-    var capture = Capture{
-        .aw = .init(cmd.arena),
-    };
-
-    cmd.cdp.dispatch(cmd.arena, &capture, params.message) catch |err| {
         log.err(.cdp, "internal dispatch error", .{ .err = err, .id = cmd.input.id, .message = params.message });
         return err;
     };
 
     try cmd.sendEvent("Target.receivedMessageFromTarget", .{
-        .message = capture.aw.written(),
+        .message = aw.written(),
         .sessionId = params.sessionId,
     }, .{});
 }
 
-fn detachFromTarget(cmd: anytype) !void {
+fn detachFromTarget(cmd: *CDP.Command) !void {
     if (cmd.browser_context) |bc| {
         if (bc.session_id) |session_id| {
             try cmd.sendEvent("Target.detachedFromTarget", .{
@@ -404,11 +393,11 @@ fn detachFromTarget(cmd: anytype) !void {
 }
 
 // TODO: noop method
-fn setDiscoverTargets(cmd: anytype) !void {
+fn setDiscoverTargets(cmd: *CDP.Command) !void {
     return cmd.sendResult(null, .{});
 }
 
-fn setAutoAttach(cmd: anytype) !void {
+fn setAutoAttach(cmd: *CDP.Command) !void {
     const params = (try cmd.params(struct {
         autoAttach: bool,
         waitForDebuggerOnStart: bool,
@@ -468,7 +457,7 @@ fn setAutoAttach(cmd: anytype) !void {
     try cmd.sendResult(null, .{});
 }
 
-fn doAttachtoTarget(cmd: anytype, target_id: []const u8) !void {
+fn doAttachtoTarget(cmd: *CDP.Command, target_id: []const u8) !void {
     const bc = cmd.browser_context.?;
     const session_id = bc.session_id orelse cmd.cdp.session_id_gen.next();
 

src/cdp/testing.zig

@@ -64,7 +64,7 @@ const TestContext = struct {
         session_id: ?[]const u8 = null,
         url: ?[:0]const u8 = null,
     };
-    pub fn loadBrowserContext(self: *TestContext, opts: BrowserContextOpts) !*CDP.BrowserContext(CDP) {
+    pub fn loadBrowserContext(self: *TestContext, opts: BrowserContextOpts) !*CDP.BrowserContext {
         var c = self.cdp();
         if (c.browser_context) |bc| {
             _ = c.disposeBrowserContext(bc.id);