unknown method 错误码
unknown method 错误是一种 WebDriver 错误，当驱动程序无法识别该端点所用的 HTTP 请求方法时会出现。
WebDriver 提供的 API 大体上类似 REST，该 API 中并非所有端点都有 GET、POST 和 DELETE 方法。当你使用端点不支持的 HTTP 请求方法调用它时，就会出现此错误。
示例
New Session 命令提供一个 POST 请求端点，让你创建新的 WebDriver 会话：
bash
% curl -d '{}' http://localhost:4444/session
{"sessionId":"d4605710-5a4e-4d64-a52a-778bb0c31e00","value":{"XULappId":"{ec8030f7-c20a-464f-9b0e-13a3a9e97384}","acceptSslCerts":false,"appBuildId":"20160913030425","browserName":"firefox","browserVersion":"51.0a1","command_id":1,"platform":"LINUX","platformName":"linux","platformVersion":"4.9.0-1-amd64","processId":17474,"proxy":{},"raisesAccessibilityExceptions":false,"rotatable":false,"specificationLevel":0,"takesElementScreenshot":true,"takesScreenshot":true,"version":"51.0a1"}}
它也实现了用于结束会话的 DELETE 方法：
bash
% curl -X DELETE http://localhost:4444/session/d4605710-5a4e-4d64-a52a-778bb0c31e00
{}
但它并不提供 GET 方法，因此这会返回 unknown method 错误：
bash
% curl http://localhost:4444/session/650f9df3-740e-314c-958d-307e41752fae
{"value":{"error":"unknown command","message":"GET /session/650f9df3-740e-314c-958d-307e41752fae did not match a known command","stacktrace":""}}%