python+selenium+ Chrome 运行中更换userAgent

通常情况下用selenium开发爬虫时，会使用以下方式添加UA

chrome_options.add_argument('user-agent=' + self.ua)

但是每次更换需要重启浏览器，这会造成资源浪费。好在selenium支持CDP,于是翻了文档终于找到了解决方法。解决方法如下

driver.execute_cdp_cmd("Emulation.setUserAgentOverride", {
        "userAgent": "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:6.0) Gecko/20100101 Firefox/6.0"
    })

执行后打开控制台，输入navigator.userAgent查看，会发现userAgent已经改变，访问任何页面都会是目前设置的

同时官方文档中还有以下参数可以使用：

{
                    "name": "setUserAgentOverride",
                    "description": "Allows overriding user agent with the given string.",
                    "redirect": "Emulation",
                    "parameters": [
                        {
                            "name": "userAgent",
                            "description": "User agent to use.",
                            "type": "string"
                        },
                        {
                            "name": "acceptLanguage",
                            "description": "Browser langugage to emulate.",
                            "optional": true,
                            "type": "string"
                        },
                        {
                            "name": "platform",
                            "description": "The platform navigator.platform should return.",
                            "optional": true,
                            "type": "string"
                        },
                        {
                            "name": "userAgentMetadata",
                            "description": "To be sent in Sec-CH-UA-* headers and returned in navigator.userAgentData",
                            "experimental": true,
                            "optional": true,
                            "$ref": "Emulation.UserAgentMetadata"
                        }
                    ]
                }