如何向Chrome WebDriver端点发送HTTP请求？Python代码报错解决

问题场景 #

用Python原生http.client.HTTPConnection向Chrome WebDriver端点发送请求时触发域名解析错误，但Postman中请求完全正常。

原代码 #

import http.client
import json

connection = http.client.HTTPConnection("http://localhost:9515")
headers = {"Content-type" : "application/json"}
json_data = json.dumps({
    "capabilities " : {
        "browsername" : "chrome",
        "browserVersion" : "12"
    }
})
connection.request("POST", "/session", json_data, headers)
response = connection.getresponse()
connection.close()

报错信息 #

PS C:\Users\Coder\Desktop\Ayman\automation> python main.py
Traceback (most recent call last):
  File "C:\Users\Coder\Desktop\Ayman\automation\main.py", line 12, in <module>
    connection.request("POST", "/session", json_data, headers)
  File "C:\Python310\lib\http\client.py", line 1282, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "C:\Python310\lib\http\client.py", line 1328, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
  File "C:\Python310\lib\http\client.py", line 1277, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "C:\Python310\lib\http\client.py", line 1037, in _send_output
    self.send(msg)
  File "C:\Python310\lib\http\client.py", line 975, in send
    self.connect()
  File "C:\Python310\lib\http\client.py", line 941, in connect
    self.sock = self._create_connection(
  File "C:\Python310\lib\socket.py", line 824, in create_connection
    for res in getaddrinfo(host, port, 0, SOCK_STREAM):
  File "C:\Python310\lib\socket.py", line 955, in getaddrinfo
    for res in _socket.getaddrinfo(host, port, family, type, proto, flags):
socket.gaierror: [Errno 11001] getaddrinfo failed

错误原因 #

1. HTTPConnection参数格式错误：HTTPConnection的主机参数不能带http://前缀，否则会被当作域名解析，触发socket.gaierror。
2. WebDriver协议字段不规范：
   • "capabilities "末尾多了空格，WebDriver无法识别该字段
   • "browsername"不符合协议要求的驼峰命名，正确写法是"browserName"
   • "browserVersion"值仅写"12"过于模糊，需对应你的Chrome实际版本号，也可直接省略该字段让Driver自动适配。

修复后的代码 #

import http.client
import json

# 正确传入主机和端口，去掉http://前缀
connection = http.client.HTTPConnection("localhost", 9515)
headers = {"Content-type": "application/json"}
json_data = json.dumps({
    "capabilities": {
        "browserName": "chrome"
        # 如需指定版本，替换为实际Chrome版本，例如：
        # "browserVersion": "124.0.6367.60"
    }
})
connection.request("POST", "/session", json_data, headers)
response = connection.getresponse()

# 打印响应内容便于调试
print(f"响应状态: {response.status} {response.reason}")
print(f"响应内容: {response.read().decode('utf-8')}")

connection.close()

额外注意事项 #

• 确保ChromeDriver已经启动，且监听端口为9515（默认端口，若自定义需同步修改代码）
• Postman能正常工作是因为它自动处理了协议前缀和部分字段格式问题，而Python原生库需要严格遵循参数规范

内容的提问来源于stack exchange，提问作者Ayman Benyahia