feat: add WebView support for extension (#1359)

internal/webview/goprovider/mainthread_darwin.go

@@ -0,0 +1,36 @@
+//go:build darwin
+
+package goprovider
+
+var mainThreadTasks chan func()
+
+func RunMainThreadLoop(run func() int) int {
+	if mainThreadTasks != nil {
+		return run()
+	}
+
+	mainThreadTasks = make(chan func())
+	resultCh := make(chan int, 1)
+
+	go func() {
+		resultCh <- run()
+	}()
+
+	for {
+		select {
+		case task := <-mainThreadTasks:
+			task()
+		case code := <-resultCh:
+			mainThreadTasks = nil
+			return code
+		}
+	}
+}
+
+func postMainThreadTask(task func()) bool {
+	if mainThreadTasks == nil {
+		return false
+	}
+	mainThreadTasks <- task
+	return true
+}

internal/webview/goprovider/mainthread_other.go

@@ -0,0 +1,11 @@
+//go:build !darwin
+
+package goprovider
+
+func RunMainThreadLoop(run func() int) int {
+	return run()
+}
+
+func postMainThreadTask(func()) bool {
+	return false
+}

internal/webview/goprovider/provider_integration_test.go

@@ -0,0 +1,15 @@
+//go:build cgo && webview && !darwin
+
+package goprovider
+
+import (
+	"testing"
+
+	"github.com/GopeedLab/gopeed/internal/webview/integrationtest"
+)
+
+func TestProviderContract(t *testing.T) {
+	integrationtest.RunProviderContract(t, New(), integrationtest.ContractOptions{
+		CookieDomainMode: integrationtest.CookieDomainModeRequired,
+	})
+}

internal/webview/goprovider/provider_stub.go

@@ -0,0 +1,9 @@
+//go:build !cgo
+
+package goprovider
+
+import enginewebview "github.com/GopeedLab/gopeed/pkg/download/engine/webview"
+
+func New() enginewebview.Provider {
+	return enginewebview.NewUnavailableProvider()
+}

internal/webview/goprovider/window_darwin.go

@@ -0,0 +1,38 @@
+//go:build cgo && darwin
+
+package goprovider
+
+/*
+#cgo darwin CFLAGS: -x objective-c
+#cgo darwin LDFLAGS: -framework Cocoa
+
+#include <Cocoa/Cocoa.h>
+
+static void gopeedApplyHeadlessWindowOptions(void *windowPtr, int headless) {
+  if (windowPtr == NULL) {
+    return;
+  }
+
+  NSWindow *window = (__bridge NSWindow *)windowPtr;
+  if (headless) {
+    [window orderOut:nil];
+  }
+}
+*/
+import "C"
+
+import (
+	enginewebview "github.com/GopeedLab/gopeed/pkg/download/engine/webview"
+	webview "github.com/GopeedLab/webview_go"
+)
+
+func applyWindowOptions(w webview.WebView, opts enginewebview.OpenOptions) {
+	C.gopeedApplyHeadlessWindowOptions(w.Window(), C.int(boolToInt(opts.Headless)))
+}
+
+func boolToInt(value bool) int {
+	if value {
+		return 1
+	}
+	return 0
+}

internal/webview/goprovider/window_other.go

@@ -0,0 +1,10 @@
+//go:build cgo && !darwin
+
+package goprovider
+
+import (
+	enginewebview "github.com/GopeedLab/gopeed/pkg/download/engine/webview"
+	webview "github.com/GopeedLab/webview_go"
+)
+
+func applyWindowOptions(_ webview.WebView, _ enginewebview.OpenOptions) {}

internal/webview/integrationtest/contract.go

@@ -0,0 +1,378 @@
+package integrationtest
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strings"
+	"testing"
+	"time"
+
+	enginewebview "github.com/GopeedLab/gopeed/pkg/download/engine/webview"
+)
+
+const TestUserAgent = "GopeedWebViewIntegration/1.0"
+
+type ContractOptions struct {
+	AvailabilityTimeout time.Duration
+	CookieDomainMode    CookieDomainMode
+	CookieTestURL       string
+}
+
+type CookieDomainMode int
+
+const (
+	CookieDomainModeRequired CookieDomainMode = iota
+	CookieDomainModeOmit
+)
+
+func RunProviderContract(t *testing.T, provider enginewebview.Provider, opts ContractOptions) {
+	t.Helper()
+
+	timeout := opts.AvailabilityTimeout
+	if timeout <= 0 {
+		timeout = 10 * time.Second
+	}
+	waitForProviderAvailable(t, provider, timeout)
+
+	page, server, testURL := openTestPage(t, provider, enginewebview.OpenOptions{
+		Headless:  true,
+		Title:     "Gopeed WebView Integration",
+		Width:     640,
+		Height:    480,
+		UserAgent: TestUserAgent,
+	})
+
+	if err := page.Goto(testURL, map[string]any{"timeoutMs": 10000}); err != nil {
+		t.Fatalf("goto failed: %v", err)
+	}
+
+	ua, err := page.Execute(`() => navigator.userAgent`)
+	if err != nil {
+		t.Fatalf("navigator.userAgent execute failed: %v", err)
+	}
+	if ua != TestUserAgent {
+		t.Fatalf("unexpected user agent: got %v want %q", ua, TestUserAgent)
+	}
+
+	if err := page.Focus("#name"); err != nil {
+		t.Fatalf("focus failed: %v", err)
+	}
+	activeElement, err := page.Execute(`() => document.activeElement && document.activeElement.id`)
+	if err != nil {
+		t.Fatalf("activeElement execute failed: %v", err)
+	}
+	if activeElement != "name" {
+		t.Fatalf("expected active element to be #name, got %v", activeElement)
+	}
+
+	if err := page.Type("#name", "Gopeed", map[string]any{"delay": 5}); err != nil {
+		t.Fatalf("type failed: %v", err)
+	}
+	typeState, err := page.Execute(`() => ({
+		value: document.querySelector('#name').value,
+		mirror: document.querySelector('#name-value').textContent,
+		inputCount: window.__inputEvents.length
+	})`)
+	if err != nil {
+		t.Fatalf("type state execute failed: %v", err)
+	}
+	stateMap, ok := typeState.(map[string]any)
+	if !ok {
+		t.Fatalf("unexpected type state payload: %T", typeState)
+	}
+	if stateMap["value"] != "Gopeed" || stateMap["mirror"] != "Gopeed" {
+		t.Fatalf("unexpected type state: %#v", stateMap)
+	}
+	if stateMap["inputCount"] != float64(len("Gopeed")) {
+		t.Fatalf("unexpected input event count: %#v", stateMap["inputCount"])
+	}
+
+	if err := page.Click("#clicker"); err != nil {
+		t.Fatalf("click failed: %v", err)
+	}
+	clickCount, err := page.Execute(`() => document.querySelector('#click-count').textContent`)
+	if err != nil {
+		t.Fatalf("click count execute failed: %v", err)
+	}
+	if clickCount != "1" {
+		t.Fatalf("expected click count to be 1, got %v", clickCount)
+	}
+
+	found, err := page.WaitForSelector("#delayed", map[string]any{
+		"timeoutMs":      5000,
+		"pollIntervalMs": 25,
+		"visible":        true,
+	})
+	if err != nil {
+		t.Fatalf("waitForSelector failed: %v", err)
+	}
+	if !found {
+		t.Fatal("expected delayed selector to appear")
+	}
+
+	value, err := page.WaitForFunction(`() => window.__readyValue`, map[string]any{
+		"timeoutMs":      5000,
+		"pollIntervalMs": 25,
+	})
+	if err != nil {
+		t.Fatalf("waitForFunction failed: %v", err)
+	}
+	readyValue, ok := value.(map[string]any)
+	if !ok {
+		t.Fatalf("unexpected waitForFunction value: %T", value)
+	}
+	if readyValue["status"] != "ready" {
+		t.Fatalf("unexpected waitForFunction payload: %#v", readyValue)
+	}
+
+	found, err = page.WaitForSelector("#missing", map[string]any{
+		"timeoutMs":      200,
+		"pollIntervalMs": 25,
+	})
+	if err != nil {
+		t.Fatalf("waitForSelector timeout case failed: %v", err)
+	}
+	if found {
+		t.Fatal("expected missing selector wait to time out")
+	}
+
+	cookieTestURL := opts.CookieTestURL
+	if cookieTestURL == "" {
+		cookieTestURL = testURL
+	}
+	runCookieLifecycleAssertions(t, page, server, cookieTestURL, opts.CookieDomainMode)
+}
+
+func waitForProviderAvailable(t *testing.T, provider enginewebview.Provider, timeout time.Duration) {
+	t.Helper()
+	deadline := time.Now().Add(timeout)
+	for time.Now().Before(deadline) {
+		if provider != nil && provider.IsAvailable() {
+			return
+		}
+		time.Sleep(200 * time.Millisecond)
+	}
+	t.Fatalf("provider did not become available within %s", timeout)
+}
+
+func openTestPage(t *testing.T, provider enginewebview.Provider, opts enginewebview.OpenOptions) (*enginewebview.PageHandle, *httptest.Server, string) {
+	t.Helper()
+
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "text/html; charset=utf-8")
+		switch r.URL.Path {
+		case "/next":
+			fmt.Fprint(w, `<!DOCTYPE html>
+<html>
+  <head><title>Next Page</title></head>
+  <body>
+    <h1 id="next-page">Navigation complete</h1>
+  </body>
+</html>`)
+		default:
+			fmt.Fprint(w, `<!DOCTYPE html>
+<html>
+  <head><title>Test Page</title></head>
+  <body>
+    <input id="name" type="text" />
+    <div id="name-value"></div>
+    <button id="clicker" type="button">Click me</button>
+    <div id="click-count">0</div>
+    <button id="nav-btn" type="button">Navigate</button>
+    <script>
+      window.__inputEvents = [];
+      window.__readyValue = null;
+      const nameInput = document.getElementById('name');
+      const nameValue = document.getElementById('name-value');
+      nameInput.addEventListener('input', () => {
+        nameValue.textContent = nameInput.value;
+        window.__inputEvents.push(nameInput.value);
+      });
+      document.getElementById('clicker').addEventListener('click', () => {
+        const counter = document.getElementById('click-count');
+        counter.textContent = String(Number(counter.textContent || '0') + 1);
+      });
+      document.getElementById('nav-btn').addEventListener('click', () => {
+        setTimeout(() => {
+          window.location.href = '/next';
+        }, 50);
+      });
+      setTimeout(() => {
+        const marker = document.createElement('div');
+        marker.id = 'delayed';
+        marker.textContent = 'Loaded later';
+        document.body.appendChild(marker);
+      }, 150);
+      setTimeout(() => {
+        window.__readyValue = { status: 'ready', source: 'timer' };
+      }, 200);
+    </script>
+  </body>
+</html>`)
+		}
+	}))
+	t.Cleanup(server.Close)
+
+	runtime := enginewebview.NewRuntime(provider, true)
+	page, err := runtime.Open(map[string]any{
+		"headless":  opts.Headless,
+		"debug":     opts.Debug,
+		"title":     opts.Title,
+		"width":     opts.Width,
+		"height":    opts.Height,
+		"userAgent": opts.UserAgent,
+	})
+	if err != nil {
+		t.Fatalf("failed to open webview: %v", err)
+	}
+	t.Cleanup(func() {
+		_ = runtime.Close()
+	})
+
+	return page, server, server.URL
+}
+
+func runCookieLifecycleAssertions(t *testing.T, page *enginewebview.PageHandle, _ *httptest.Server, testURL string, domainMode CookieDomainMode) {
+	t.Helper()
+
+	parsedURL, err := url.Parse(testURL)
+	if err != nil {
+		t.Fatalf("parse cookie test url failed: %v", err)
+	}
+	cookieDomain := parsedURL.Hostname()
+
+	if err := page.ClearCookies(); err != nil {
+		t.Fatalf("clearCookies before cookie assertions failed: %v", err)
+	}
+
+	visibleCookie := map[string]any{
+		"name":  "visible",
+		"value": "1",
+		"path":  "/",
+	}
+	secretCookie := map[string]any{
+		"name":     "secret",
+		"value":    "2",
+		"path":     "/",
+		"httpOnly": true,
+		"expires":  time.Now().Add(time.Hour).UTC().Format(time.RFC3339Nano),
+	}
+	deleteCookie := map[string]any{
+		"name": "visible",
+		"path": "/",
+	}
+	if domainMode == CookieDomainModeRequired {
+		visibleCookie["domain"] = cookieDomain
+		secretCookie["domain"] = cookieDomain
+		deleteCookie["domain"] = cookieDomain
+	}
+
+	if err := page.SetCookie(visibleCookie); err != nil {
+		t.Fatalf("set visible cookie failed: %v", err)
+	}
+	if err := page.SetCookie(secretCookie); err != nil {
+		t.Fatalf("set secret cookie failed: %v", err)
+	}
+
+	if err := page.Goto(testURL, map[string]any{"timeoutMs": 10000}); err != nil {
+		t.Fatalf("goto after setCookie failed: %v", err)
+	}
+
+	documentCookie, err := page.Execute(`() => document.cookie`)
+	if err != nil {
+		t.Fatalf("document.cookie execute failed: %v", err)
+	}
+	documentCookieText, ok := documentCookie.(string)
+	if !ok {
+		t.Fatalf("unexpected document.cookie payload: %T", documentCookie)
+	}
+	if !strings.Contains(documentCookieText, "visible=1") {
+		t.Fatalf("expected visible cookie in document.cookie, got %q", documentCookieText)
+	}
+	if strings.Contains(documentCookieText, "secret=2") {
+		t.Fatalf("expected httpOnly cookie to be hidden from document.cookie, got %q", documentCookieText)
+	}
+
+	cookies, err := page.GetCookies()
+	if err != nil {
+		t.Fatalf("getCookies failed: %v", err)
+	}
+	if len(cookies) < 2 {
+		t.Fatalf("expected at least 2 cookies, got %#v", cookies)
+	}
+	if !hasCookie(cookies, "visible", "1") {
+		t.Fatalf("expected visible cookie in native cookie store, got %#v", cookies)
+	}
+	if !hasCookie(cookies, "secret", "2") {
+		t.Fatalf("expected secret cookie in native cookie store, got %#v", cookies)
+	}
+
+	if err := page.DeleteCookie(deleteCookie); err != nil {
+		t.Fatalf("deleteCookie failed: %v", err)
+	}
+	if err := page.Goto(testURL, map[string]any{"timeoutMs": 10000}); err != nil {
+		t.Fatalf("goto after deleteCookie failed: %v", err)
+	}
+
+	documentCookie, err = page.Execute(`() => document.cookie`)
+	if err != nil {
+		t.Fatalf("document.cookie execute after delete failed: %v", err)
+	}
+	documentCookieText, ok = documentCookie.(string)
+	if !ok {
+		t.Fatalf("unexpected document.cookie payload after delete: %T", documentCookie)
+	}
+	if strings.Contains(documentCookieText, "visible=1") {
+		t.Fatalf("expected visible cookie to be deleted, got %q", documentCookieText)
+	}
+	if strings.Contains(documentCookieText, "secret=2") {
+		t.Fatalf("expected httpOnly cookie to remain hidden after delete, got %q", documentCookieText)
+	}
+
+	cookies, err = page.GetCookies()
+	if err != nil {
+		t.Fatalf("getCookies after delete failed: %v", err)
+	}
+	if hasCookie(cookies, "visible", "1") {
+		t.Fatalf("expected visible cookie to be removed from native store, got %#v", cookies)
+	}
+	if !hasCookie(cookies, "secret", "2") {
+		t.Fatalf("expected secret cookie to remain in native store after delete, got %#v", cookies)
+	}
+
+	if err := page.ClearCookies(); err != nil {
+		t.Fatalf("clearCookies failed: %v", err)
+	}
+	if err := page.Goto(testURL, map[string]any{"timeoutMs": 10000}); err != nil {
+		t.Fatalf("goto after clearCookies failed: %v", err)
+	}
+	documentCookie, err = page.Execute(`() => document.cookie`)
+	if err != nil {
+		t.Fatalf("document.cookie execute after clear failed: %v", err)
+	}
+	documentCookieText, ok = documentCookie.(string)
+	if !ok {
+		t.Fatalf("unexpected document.cookie payload after clear: %T", documentCookie)
+	}
+	if documentCookieText != "" {
+		t.Fatalf("expected document.cookie to be empty after clear, got %q", documentCookieText)
+	}
+	cookies, err = page.GetCookies()
+	if err != nil {
+		t.Fatalf("getCookies after clear failed: %v", err)
+	}
+	if len(cookies) != 0 {
+		t.Fatalf("expected cookie store to be empty after clear, got %#v", cookies)
+	}
+}
+
+func hasCookie(cookies []enginewebview.Cookie, name string, value string) bool {
+	for _, cookie := range cookies {
+		if cookie.Name == name && cookie.Value == value {
+			return true
+		}
+	}
+	return false
+}

internal/webview/rpcprovider/README.md

@@ -0,0 +1,488 @@
+# rpcprovider
+
+`rpcprovider` is the RPC-backed implementation of Gopeed's `webview.Provider` interface.
+
+It is intended for environments where WebView capability is owned by another process, most notably mobile hosts. This package does not implement a WebView itself. Instead, it translates the `pkg/download/engine/webview` page API into single-request `POST + JSON` calls sent to a local host-side RPC service.
+
+## When to use it
+
+Use `rpcprovider` for entrypoints such as `bind/mobile`, where the Go process cannot directly own a native WebView.
+
+Do not use it for desktop or `cmd/web` local WebView integration. Those entrypoints should use `internal/webview/goprovider` instead.
+
+## Configuration
+
+The provider is configured through `pkg/download/engine/webview.RPCConfig`:
+
+```go
+type RPCConfig struct {
+	Network string `json:"network"`
+	Address string `json:"address"`
+	Token   string `json:"token,omitempty"`
+}
+```
+
+Notes:
+
+- `Network` currently supports `tcp` and `unix`.
+- `Address` examples:
+  - `127.0.0.1:38765`
+  - `/path/to/webview.sock`
+- `Token` is optional. When set, the client sends `Authorization: Bearer <token>`.
+
+Example:
+
+```go
+provider := rpcprovider.New(webview.RPCConfig{
+	Network: "tcp",
+	Address: "127.0.0.1:38765",
+	Token:   "secret-token",
+})
+```
+
+## Transport
+
+- Endpoint: `POST /webview`
+- Content type: `application/json`
+- One request, one response
+- No `id` field yet
+- The envelope is intentionally close to JSON-RPC so it can evolve later without renaming the methods or reshaping the payloads
+
+Request example:
+
+```json
+{
+  "method": "page.execute",
+  "params": {
+    "pageId": "page-1",
+    "expression": "document.title",
+    "args": []
+  }
+}
+```
+
+Successful response:
+
+```json
+{
+  "result": {
+    "title": "Example"
+  },
+  "error": null
+}
+```
+
+Failure response:
+
+```json
+{
+  "result": null,
+  "error": {
+    "code": "PAGE_NOT_FOUND",
+    "message": "page not found"
+  }
+}
+```
+
+## Supported methods
+
+- `webview.isAvailable`
+- `page.open`
+- `page.addInitScript`
+- `page.goto`
+- `page.execute`
+- `page.getCookies`
+- `page.setCookie`
+- `page.deleteCookie`
+- `page.clearCookies`
+- `page.close`
+
+The canonical wire models for these methods are defined in:
+
+- [pkg/download/engine/webview/rpc.go](../../../pkg/download/engine/webview/rpc.go)
+- [pkg/download/engine/webview/runtime.go](../../../pkg/download/engine/webview/runtime.go)
+
+The README is only a guide. The Go source above is the authoritative protocol reference.
+
+## Method reference
+
+Each method below uses the common envelope:
+
+```json
+{
+  "method": "<method-name>",
+  "params": { ... }
+}
+```
+
+and returns:
+
+```json
+{
+  "result": ...,
+  "error": null
+}
+```
+
+or:
+
+```json
+{
+  "result": null,
+  "error": {
+    "code": "<ERROR_CODE>",
+    "message": "<message>"
+  }
+}
+```
+
+### `webview.isAvailable`
+
+Request:
+
+```json
+{
+  "method": "webview.isAvailable",
+  "params": {}
+}
+```
+
+Success:
+
+```json
+{
+  "result": {
+    "available": true
+  },
+  "error": null
+}
+```
+
+### `page.open`
+
+Request:
+
+```json
+{
+  "method": "page.open",
+  "params": {
+    "headless": true,
+    "debug": false,
+    "title": "Gopeed WebView",
+    "width": 1280,
+    "height": 720,
+    "userAgent": "Mozilla/5.0 ..."
+  }
+}
+```
+
+Success:
+
+```json
+{
+  "result": {
+    "pageId": "page-1"
+  },
+  "error": null
+}
+```
+
+### `page.addInitScript`
+
+Request:
+
+```json
+{
+  "method": "page.addInitScript",
+  "params": {
+    "pageId": "page-1",
+    "script": "window.__READY__ = true;"
+  }
+}
+```
+
+Success:
+
+```json
+{
+  "result": {},
+  "error": null
+}
+```
+
+### `page.goto`
+
+Request:
+
+```json
+{
+  "method": "page.goto",
+  "params": {
+    "pageId": "page-1",
+    "url": "https://example.com",
+    "timeoutMs": 15000,
+    "waitUntil": "domcontentloaded"
+  }
+}
+```
+
+Success:
+
+```json
+{
+  "result": {},
+  "error": null
+}
+```
+
+`waitUntil` currently supports `load` and `domcontentloaded`. The default is `load`.
+
+### `page.execute`
+
+Request:
+
+```json
+{
+  "method": "page.execute",
+  "params": {
+    "pageId": "page-1",
+    "expression": "document.title",
+    "args": []
+  }
+}
+```
+
+Success:
+
+```json
+{
+  "result": "Example Domain",
+  "error": null
+}
+```
+
+### `page.getCookies`
+
+Request:
+
+```json
+{
+  "method": "page.getCookies",
+  "params": {
+    "pageId": "page-1"
+  }
+}
+```
+
+Success:
+
+```json
+{
+  "result": [
+    {
+      "name": "session",
+      "value": "abc",
+      "domain": ".example.com",
+      "path": "/",
+      "expires": "2026-03-26T12:00:00Z",
+      "secure": true,
+      "httpOnly": true
+    }
+  ],
+  "error": null
+}
+```
+
+### `page.setCookie`
+
+Request:
+
+```json
+{
+  "method": "page.setCookie",
+  "params": {
+    "pageId": "page-1",
+    "cookie": {
+      "name": "session",
+      "value": "abc",
+      "domain": ".example.com",
+      "path": "/",
+      "expires": "2026-03-26T12:00:00Z",
+      "secure": true,
+      "httpOnly": true
+    }
+  }
+}
+```
+
+Success:
+
+```json
+{
+  "result": {},
+  "error": null
+}
+```
+
+### `page.deleteCookie`
+
+Request:
+
+```json
+{
+  "method": "page.deleteCookie",
+  "params": {
+    "pageId": "page-1",
+    "cookie": {
+      "name": "session",
+      "domain": ".example.com",
+      "path": "/"
+    }
+  }
+}
+```
+
+Success:
+
+```json
+{
+  "result": {},
+  "error": null
+}
+```
+
+### `page.clearCookies`
+
+Request:
+
+```json
+{
+  "method": "page.clearCookies",
+  "params": {
+    "pageId": "page-1"
+  }
+}
+```
+
+Success:
+
+```json
+{
+  "result": {},
+  "error": null
+}
+```
+
+### `page.close`
+
+Request:
+
+```json
+{
+  "method": "page.close",
+  "params": {
+    "pageId": "page-1"
+  }
+}
+```
+
+Success:
+
+```json
+{
+  "result": {},
+  "error": null
+}
+```
+
+## Method semantics
+
+- `page.open`
+  - Creates a page session
+  - Returns `pageId`
+- `page.addInitScript`
+  - Registers a page initialization script
+- `page.goto`
+  - Goes to the target URL
+  - The server should return only after navigation completes or fails
+- `page.execute`
+  - Executes an expression or serialized function body
+  - The returned value must be JSON-serializable
+- `page.getCookies`
+  - Returns cookies from the underlying native WebView cookie store
+- `page.setCookie`
+  - Inserts or updates a cookie
+- `page.deleteCookie`
+  - Deletes a cookie using `name/domain/path`
+- `page.clearCookies`
+  - Clears the current cookie store
+- `page.close`
+  - Closes the page and releases related resources
+
+## Cookie model
+
+Cookies use `runtime/webview.Cookie`.
+
+Example payload:
+
+```json
+{
+  "name": "session",
+  "value": "abc",
+  "domain": ".example.com",
+  "path": "/",
+  "expires": "2026-03-26T12:00:00Z",
+  "secure": true,
+  "httpOnly": true
+}
+```
+
+Notes:
+
+- `expires` uses RFC3339 / RFC3339Nano string form.
+- If the host platform supports a full native cookie store, it should return fields such as `httpOnly` and `secure`.
+- `setCookie -> goto` is a valid pattern for preloading authenticated session state.
+
+## Error codes
+
+The current error code set is defined in `pkg/download/engine/webview/rpc.go`:
+
+- `INVALID_REQUEST`
+- `UNKNOWN_METHOD`
+- `UNAVAILABLE`
+- `BROWSER_NOT_FOUND`
+- `PAGE_NOT_FOUND`
+- `NAVIGATION_FAILED`
+- `EVALUATION_FAILED`
+- `TIMEOUT`
+- `INTERNAL_ERROR`
+
+`BROWSER_NOT_FOUND` is a historical leftover from an earlier shape of the protocol. The current protocol no longer has a separate browser model, so this can be cleaned up later if the protocol is tightened further.
+
+## Current protocol boundary
+
+This protocol is intentionally limited:
+
+- Single-direction request/response only
+- Not REST-style resource routing
+- No bidirectional events
+- No streaming event subscriptions
+- No host-initiated push channel
+
+If the protocol needs to evolve toward full JSON-RPC later, the intended migration path is to keep the existing `method/params/result/error` structure and add:
+
+- `id`
+- notifications
+- a bidirectional transport model
+
+## Host implementation guidance
+
+A host implementation should usually:
+
+- Listen on a local `tcp` address or `unix socket`
+- Expose `POST /webview`
+- Validate the bearer token if configured
+- Maintain `pageId -> native webview/session`
+- Own page lifecycle, cleanup, and timeout handling
+
+With that split, Gopeed stays a pure RPC client and does not need to know how the host's native WebView is implemented.

internal/webview/rpcprovider/provider.go

@@ -0,0 +1,195 @@
+package rpcprovider
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net"
+	"net/http"
+	"strings"
+
+	enginewebview "github.com/GopeedLab/gopeed/pkg/download/engine/webview"
+)
+
+type Provider struct {
+	client *Client
+}
+
+func New(cfg enginewebview.RPCConfig) enginewebview.Provider {
+	return &Provider{
+		client: NewClient(cfg),
+	}
+}
+
+func (p *Provider) IsAvailable() bool {
+	if p == nil || p.client == nil || !p.client.Enabled() {
+		return false
+	}
+	var result enginewebview.IsAvailableResult
+	if err := p.client.Call(enginewebview.MethodIsAvailable, enginewebview.IsAvailableParams{}, &result); err != nil {
+		return false
+	}
+	return result.Available
+}
+
+func (p *Provider) Open(opts enginewebview.OpenOptions) (enginewebview.Page, error) {
+	if p == nil || p.client == nil || !p.IsAvailable() {
+		return nil, enginewebview.ErrUnavailable
+	}
+	var result enginewebview.PageOpenResult
+	if err := p.client.Call(enginewebview.MethodPageOpen, enginewebview.NewPageOpenParams(opts), &result); err != nil {
+		return nil, err
+	}
+	return &page{
+		client: p.client,
+		id:     result.PageID,
+	}, nil
+}
+
+type page struct {
+	client *Client
+	id     string
+}
+
+func (p *page) AddInitScript(script string) error {
+	return p.client.Call(enginewebview.MethodPageAddInitScript, enginewebview.PageAddInitScriptParams{
+		PageID: p.id,
+		Script: script,
+	}, nil)
+}
+
+func (p *page) Goto(url string, opts enginewebview.GotoOptions) error {
+	return p.client.Call(enginewebview.MethodPageGoto, enginewebview.NewPageGotoParams(p.id, url, opts), nil)
+}
+
+func (p *page) Execute(expression string, args ...any) (any, error) {
+	var result any
+	if err := p.client.Call(enginewebview.MethodPageExecute, enginewebview.PageExecuteParams{
+		PageID:     p.id,
+		Expression: expression,
+		Args:       args,
+	}, &result); err != nil {
+		return nil, err
+	}
+	return result, nil
+}
+
+func (p *page) GetCookies() ([]enginewebview.Cookie, error) {
+	var result []enginewebview.Cookie
+	if err := p.client.Call(enginewebview.MethodPageGetCookies, enginewebview.PageGetCookiesParams{
+		PageID: p.id,
+	}, &result); err != nil {
+		return nil, err
+	}
+	if result == nil {
+		return []enginewebview.Cookie{}, nil
+	}
+	return result, nil
+}
+
+func (p *page) SetCookie(cookie enginewebview.Cookie) error {
+	return p.client.Call(enginewebview.MethodPageSetCookie, enginewebview.PageSetCookieParams{
+		PageID: p.id,
+		Cookie: cookie,
+	}, nil)
+}
+
+func (p *page) DeleteCookie(cookie enginewebview.Cookie) error {
+	return p.client.Call(enginewebview.MethodPageDeleteCookie, enginewebview.PageDeleteCookieParams{
+		PageID: p.id,
+		Cookie: cookie,
+	}, nil)
+}
+
+func (p *page) ClearCookies() error {
+	return p.client.Call(enginewebview.MethodPageClearCookies, enginewebview.PageClearCookiesParams{
+		PageID: p.id,
+	}, nil)
+}
+
+func (p *page) Close() error {
+	return p.client.Call(enginewebview.MethodPageClose, enginewebview.PageCloseParams{
+		PageID: p.id,
+	}, nil)
+}
+
+type Client struct {
+	endpoint string
+	token    string
+	http     *http.Client
+}
+
+func NewClient(cfg enginewebview.RPCConfig) *Client {
+	client := &Client{token: cfg.Token}
+	if !cfg.Enabled() {
+		return client
+	}
+	switch strings.ToLower(cfg.Network) {
+	case "unix":
+		client.endpoint = "http://unix" + enginewebview.RPCEndpointPath
+		client.http = &http.Client{
+			Transport: &http.Transport{
+				DialContext: func(ctx context.Context, _, _ string) (net.Conn, error) {
+					var d net.Dialer
+					return d.DialContext(ctx, "unix", cfg.Address)
+				},
+			},
+		}
+	default:
+		client.endpoint = "http://" + cfg.Address + enginewebview.RPCEndpointPath
+		client.http = &http.Client{}
+	}
+	return client
+}
+
+func (c *Client) Enabled() bool {
+	return c != nil && c.endpoint != "" && c.http != nil
+}
+
+func (c *Client) Call(method string, params any, result any) error {
+	if !c.Enabled() {
+		return enginewebview.ErrUnavailable
+	}
+	payload, err := json.Marshal(enginewebview.RPCRequest{
+		Method: method,
+		Params: params,
+	})
+	if err != nil {
+		return err
+	}
+
+	req, err := http.NewRequest(http.MethodPost, c.endpoint, bytes.NewReader(payload))
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Content-Type", "application/json")
+	if c.token != "" {
+		req.Header.Set("Authorization", "Bearer "+c.token)
+	}
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("webview rpc status %d", resp.StatusCode)
+	}
+
+	var body enginewebview.RPCResponse
+	if err := json.NewDecoder(resp.Body).Decode(&body); err != nil {
+		return err
+	}
+	if body.Error != nil {
+		return body.Error
+	}
+	if result == nil {
+		return nil
+	}
+	if len(body.Result) == 0 || string(body.Result) == "null" {
+		return nil
+	}
+	return json.Unmarshal(body.Result, result)
+}

internal/webview/rpcprovider/provider_integration_test.go

@@ -0,0 +1,41 @@
+//go:build webview && darwin
+
+package rpcprovider
+
+import (
+	"flag"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/GopeedLab/gopeed/internal/webview/integrationtest"
+	enginewebview "github.com/GopeedLab/gopeed/pkg/download/engine/webview"
+)
+
+var (
+	webViewRPCNetwork = flag.String("webview-rpc-network", "unix", "WebView RPC network for integration tests")
+	webViewRPCAddress = flag.String("webview-rpc-address", defaultWebViewRPCAddress(), "WebView RPC address for integration tests")
+	webViewRPCToken   = flag.String("webview-rpc-token", "", "WebView RPC token for integration tests")
+)
+
+func TestProviderContract(t *testing.T) {
+	provider := New(enginewebview.RPCConfig{
+		Network: *webViewRPCNetwork,
+		Address: *webViewRPCAddress,
+		Token:   *webViewRPCToken,
+	})
+	integrationtest.RunProviderContract(t, provider, integrationtest.ContractOptions{
+		AvailabilityTimeout: 5 * time.Minute,
+		CookieDomainMode:    integrationtest.CookieDomainModeRequired,
+		CookieTestURL:       "https://example.com/",
+	})
+}
+
+func defaultWebViewRPCAddress() string {
+	homeDir, err := os.UserHomeDir()
+	if err != nil {
+		return ""
+	}
+	return filepath.Join(homeDir, "Library", "Application Support", "com.gopeed.gopeed", "gopeed_webview.sock")
+}

internal/webview/rpcprovider/provider_socket_test.go

@@ -0,0 +1,50 @@
+package rpcprovider
+
+import (
+	"encoding/json"
+	"net"
+	"net/http"
+	"os"
+	"path/filepath"
+	"testing"
+
+	enginewebview "github.com/GopeedLab/gopeed/pkg/download/engine/webview"
+)
+
+func TestProviderIsAvailableOverUnixSocket(t *testing.T) {
+	socketPath := filepath.Join("/tmp", "gopeed-rpcwebview-"+t.Name()+".sock")
+	listener, err := net.Listen("unix", socketPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer listener.Close()
+	defer os.Remove(socketPath)
+
+	server := &http.Server{
+		Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			var req enginewebview.RPCRequest
+			if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+				t.Fatal(err)
+			}
+			if req.Method != enginewebview.MethodIsAvailable {
+				t.Fatalf("unexpected unix method: %s", req.Method)
+			}
+			if err := json.NewEncoder(w).Encode(map[string]any{
+				"result": enginewebview.IsAvailableResult{Available: true},
+				"error":  nil,
+			}); err != nil {
+				t.Fatal(err)
+			}
+		}),
+	}
+	defer server.Close()
+	go server.Serve(listener)
+
+	provider := New(enginewebview.RPCConfig{
+		Network: "unix",
+		Address: socketPath,
+	})
+	if !provider.IsAvailable() {
+		t.Fatal("expected unix provider to be available")
+	}
+}

internal/webview/rpcprovider/provider_test.go

@@ -0,0 +1,186 @@
+package rpcprovider
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+
+	enginewebview "github.com/GopeedLab/gopeed/pkg/download/engine/webview"
+)
+
+func TestProviderLifecycleOverHTTP(t *testing.T) {
+	var calls []enginewebview.RPCRequest
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPost {
+			t.Fatalf("unexpected method: %s", r.Method)
+		}
+		if r.URL.Path != enginewebview.RPCEndpointPath {
+			t.Fatalf("unexpected path: %s", r.URL.Path)
+		}
+		if got := r.Header.Get("Authorization"); got != "Bearer secret-token" {
+			t.Fatalf("unexpected auth header: %q", got)
+		}
+		var req enginewebview.RPCRequest
+		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+			t.Fatal(err)
+		}
+		calls = append(calls, req)
+
+		var body any
+		switch req.Method {
+		case enginewebview.MethodIsAvailable:
+			body = map[string]any{
+				"result": enginewebview.IsAvailableResult{Available: true},
+				"error":  nil,
+			}
+		case enginewebview.MethodPageOpen:
+			body = map[string]any{
+				"result": enginewebview.PageOpenResult{PageID: "page-open-1"},
+				"error":  nil,
+			}
+		case enginewebview.MethodPageAddInitScript, enginewebview.MethodPageGoto:
+			body = map[string]any{
+				"result": enginewebview.EmptyResult{},
+				"error":  nil,
+			}
+		case enginewebview.MethodPageExecute:
+			body = map[string]any{
+				"result": map[string]any{"title": "Example"},
+				"error":  nil,
+			}
+		case enginewebview.MethodPageClose:
+			body = map[string]any{
+				"result": enginewebview.EmptyResult{},
+				"error":  nil,
+			}
+		default:
+			t.Fatalf("unexpected method: %s", req.Method)
+		}
+		if err := json.NewEncoder(w).Encode(body); err != nil {
+			t.Fatal(err)
+		}
+	}))
+	defer server.Close()
+
+	cfg := enginewebview.RPCConfig{
+		Network: "tcp",
+		Address: server.Listener.Addr().String(),
+		Token:   "secret-token",
+	}
+	provider := New(cfg)
+	if !provider.IsAvailable() {
+		t.Fatal("expected provider to be available")
+	}
+
+	opener, ok := provider.(enginewebview.Opener)
+	if !ok {
+		t.Fatal("expected provider to implement runtime webview opener")
+	}
+	opened, err := opener.Open(enginewebview.OpenOptions{
+		Headless:  true,
+		Width:     1280,
+		Height:    720,
+		Title:     "Gopeed",
+		UserAgent: "UA",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := opened.AddInitScript("window.__TEST__ = true"); err != nil {
+		t.Fatal(err)
+	}
+	if err := opened.Goto("https://example.com", enginewebview.GotoOptions{
+		TimeoutMS: 3210,
+		WaitUntil: "domcontentloaded",
+	}); err != nil {
+		t.Fatal(err)
+	}
+	value, err := opened.Execute("document.title")
+	if err != nil {
+		t.Fatal(err)
+	}
+	got, ok := value.(map[string]any)
+	if !ok || got["title"] != "Example" {
+		t.Fatalf("unexpected evaluate result: %#v", value)
+	}
+	if err := opened.Close(); err != nil {
+		t.Fatal(err)
+	}
+
+	expectedMethods := []string{
+		enginewebview.MethodIsAvailable,
+		enginewebview.MethodIsAvailable,
+		enginewebview.MethodPageOpen,
+		enginewebview.MethodPageAddInitScript,
+		enginewebview.MethodPageGoto,
+		enginewebview.MethodPageExecute,
+		enginewebview.MethodPageClose,
+	}
+	if len(calls) != len(expectedMethods) {
+		t.Fatalf("unexpected call count: got %d want %d", len(calls), len(expectedMethods))
+	}
+	for i, method := range expectedMethods {
+		if calls[i].Method != method {
+			t.Fatalf("unexpected method at %d: got %s want %s", i, calls[i].Method, method)
+		}
+	}
+	gotoParamsJSON, err := json.Marshal(calls[4].Params)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var gotoParams enginewebview.PageGotoParams
+	if err := json.Unmarshal(gotoParamsJSON, &gotoParams); err != nil {
+		t.Fatal(err)
+	}
+	if gotoParams.WaitUntil != "domcontentloaded" {
+		t.Fatalf("unexpected waitUntil: %q", gotoParams.WaitUntil)
+	}
+}
+
+func TestProviderLaunchUnavailableWithoutEndpoint(t *testing.T) {
+	provider := New(enginewebview.RPCConfig{})
+	if provider.IsAvailable() {
+		t.Fatal("expected empty provider to be unavailable")
+	}
+	opener, ok := provider.(enginewebview.Opener)
+	if !ok {
+		t.Fatal("expected provider to implement runtime webview opener")
+	}
+	if _, err := opener.Open(enginewebview.OpenOptions{}); err == nil || err.Error() != enginewebview.ErrUnavailable.Error() {
+		t.Fatalf("unexpected launch error: %v", err)
+	}
+}
+
+func TestPageSetCookieParamsOmitsZeroExpires(t *testing.T) {
+	params := enginewebview.PageSetCookieParams{
+		PageID: "page-1",
+		Cookie: enginewebview.Cookie{
+			Name:   "visible",
+			Value:  "1",
+			Domain: "example.com",
+			Path:   "/",
+		},
+	}
+	payload, err := json.Marshal(params)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(payload) == "" {
+		t.Fatal("expected non-empty json payload")
+	}
+	if got := string(payload); strings.Contains(got, `"expires"`) {
+		t.Fatalf("unexpected zero expires in payload: %s", got)
+	}
+
+	params.Cookie.Expires = time.Now().UTC().Truncate(time.Second)
+	payload, err = json.Marshal(params)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := string(payload); !strings.Contains(got, `"expires"`) {
+		t.Fatalf("expected expires in payload: %s", got)
+	}
+}