v1.7.3 前端新增后端选择器 + 暴露 /api/backends + 接通 chrome-cdp 后端

- 新增 GET /api/backends 返回可用后端/默认顺序/说明，供前端动态渲染
- 前端表单新增「捕获后端」下拉框: 自动(默认,优先agent-browser超时自动回退playwright)/agent-browser/playwright/chrome-cdp，不可用的置灰
- 接通 chrome-cdp 后端: 之前函数已实现但 capture_webpage 未接线(传 backend=chrome-cdp 会报 Unknown backend)，现支持 screenshot/html/text，连接已开的 Chrome(--remote-debugging-port)
- 前端 currentData 携带 backend 字段

app.py

@@ -708,6 +708,14 @@ async def capture_with_cdp(
                                 "html": html
                             })
             
+                        elif action == "text":
+                            text = await page.evaluate("document.body.innerText")
+                            result_data.append({
+                                "url": current_url,
+                                "title": title,
+                                "text": clean_text(text)
+                            })
+
             if result_data:
                 return {"success": True, "pages": result_data}
             else:
@@ -983,13 +991,14 @@ def capture_webpage(
     full_page: bool = False,
     viewport: dict = None,
     wait_time: int = 2000,
-    backend: str = "auto"
+    backend: str = "auto",
+    cdp_port: int = 9222
 ):
     """
     捕获网页
     
     Args:
-        backend: "auto", "agent-browser", "playwright"
+        backend: "auto", "agent-browser", "playwright", "chrome-cdp"
     """
     # 选择后端
     if backend == "auto":
@@ -1044,6 +1053,33 @@ def capture_webpage(
         except Exception as e:
             return {"success": False, "error": str(e)}
     
+    elif backend == "chrome-cdp":
+        # 连接已打开的 Chrome（需 --remote-debugging-port=<cdp_port>），归一化为单结果
+        if not PLAYWRIGHT_AVAILABLE:
+            return {"success": False, "error": "Playwright not installed (chrome-cdp 依赖 playwright)"}
+        try:
+            loop = asyncio.new_event_loop()
+            asyncio.set_event_loop(loop)
+            r = loop.run_until_complete(
+                capture_with_cdp(url_hint=url, action=action, cdp_port=cdp_port)
+            )
+            loop.close()
+        except Exception as e:
+            return {"success": False, "error": str(e)}
+        if not r.get("success"):
+            return r
+        if not r.get("pages"):
+            return {"success": False, "error": "chrome-cdp 未找到匹配页面（请确认 Chrome 已开 --remote-debugging-port）"}
+        p0 = r["pages"][0]
+        res = {"success": True, "title": p0.get("title", ""), "backend": "chrome-cdp"}
+        if action == "screenshot":
+            res["file_path"] = p0["file_path"]
+        elif action == "html":
+            res["html"] = p0["html"]
+        elif action == "text":
+            res["text"] = p0["text"]
+        return res
+    
     else:
         return {"success": False, "error": f"Unknown backend: {backend}"}
 
@@ -1054,6 +1090,37 @@ def index():
     return render_template('index.html')
 
 
+@app.route('/api/backends')
+def api_backends():
+    """返回可用后端及默认选择顺序，供前端渲染选择器"""
+    available = []
+    if AGENT_BROWSER_AVAILABLE:
+        available.append("agent-browser")
+    if PLAYWRIGHT_AVAILABLE:
+        available.append("playwright")
+        # chrome-cdp 依赖 playwright 的 connect_over_cdp
+        available.append("chrome-cdp")
+    unavailable = []
+    if not AGENT_BROWSER_AVAILABLE:
+        unavailable.append("agent-browser")
+    if not PLAYWRIGHT_AVAILABLE:
+        unavailable.append("playwright")
+        unavailable.append("chrome-cdp")
+    return jsonify({
+        "success": True,
+        "default": "auto",
+        "available": available,
+        "unavailable": unavailable,
+        "priority": available + unavailable,
+        "labels": {
+            "auto": "自动（推荐：优先 agent-browser，打开超时自动回退 Playwright）",
+            "agent-browser": "agent-browser（Rust 版，反爬强、快，默认首选）",
+            "playwright": "Playwright（Python 版，domcontentloaded 更宽容，慢页面更稳）",
+            "chrome-cdp": "Chrome CDP（连接已打开的 Chrome，需 --remote-debugging-port 启动）"
+        }
+    })
+
+
 @app.route('/api')
 def api_info():
     """API信息"""
@@ -1066,6 +1133,7 @@ def api_info():
         },
         "endpoints": {
             "/api/capture": "POST - Capture webpage (screenshot/html/text/smart) + 自动入库历史(记录调用者/方式/原始HTML)",
+            "/api/backends": "GET - 可用后端列表与默认顺序(供前端渲染后端选择器)",
             "/api/history": "GET - 历史记录分页列表 (?page&page_size&action&search)",
             "/api/history/<id>": "GET - 历史记录详情 / DELETE - 删除记录",
             "/api/history/<id>/file": "GET - 读取历史截图文件",
@@ -1320,7 +1388,8 @@ def capture():
         full_page=full_page,
         viewport=viewport,
         wait_time=wait_time,
-        backend=backend
+        backend=backend,
+        cdp_port=cdp_port
     )
     
     backend_used = result.get("backend", backend)