Python HTTP 服务器保持连接

Question

我正在尝试测试用 C 编写的 HTTP 客户端，它向我计算机上的本地服务器发送 HTTP POST 请求。我在我的 POST 请求中添加了 headers keep-alive，在我计算机上的 python3 HTTP 服务器运行上看起来像这样：

<ip-address-1> - - [29/Apr/2018 18:27:49] "POST /html HTTP/1.1" 200 -
Host: <ip-address-2>
Content-Type: application/json
Content-Length: 168
Connection: Keep-Alive
Keep-Alive: timeout=5, max=100


INFO:root:POST request,
Body:
{
"field": "abc",
"time": "2018-04-29T01:27:50.322000Z" 
}

HTTP 服务器 POST 处理程序如下所示：

class S(BaseHTTPRequestHandler):
    def _set_response(self):
        self.send_response(200)
        self.send_header('Content-type', 'text/html')
        self.send_header("Connection", "keep-alive")
        self.send_header("keep-alive", "timeout=5, max=30")
        self.end_headers()

    def do_POST(self):
        content_length = int(self.headers['Content-Length']) # <--- Gets the size of data
        post_data = self.rfile.read(content_length) # <--- Gets the data itself
        print(self.headers)
        logging.info("POST request,\nBody:\n%s\n", post_data.decode('utf-8'))

        self._set_response()
        self.wfile.write("POST request for {}".format(self.path).encode('utf-8'))

def run(server_class=HTTPServer, handler_class=S, port=8080):
    logging.basicConfig(level=logging.INFO)
    server_address = ('', port)
    httpd = server_class(server_address, handler_class)
    logging.info('Starting httpd...\n')
    try:
        httpd.serve_forever()
    except KeyboardInterrupt:
        pass
    httpd.server_close()
    logging.info('Stopping httpd...\n')

我在客户端看到的header响应是：

HTTP/1.0 200 OK
Server: BaseHTTP/0.6 Python/3.5.2
Date: Tue, 29 April 2018 16:07:42 GMT
Content-type: text/html
Connection: keep-alive
keep-alive: timeout=5, max=30

我仍然会收到断开连接回调，所以我的问题是如何从服务器端设置 keep-alive 连接参数？

Answer 1

默认情况下，BaseHTTPRequestHandler 发出 HTTP/1.0 响应，如您在 HTTP/1.0 200 OK 中所见。 HTTP/1.1 是 keep alive 响应所必需的，如 the doc (or for v3):

所示

protocol_version

This specifies the HTTP protocol version used in responses. If set to 'HTTP/1.1', the server will permit HTTP persistent connections; however, your server must then include an accurate Content-Length header (using send_header()) in all of its responses to clients. For backwards compatibility, the setting defaults to 'HTTP/1.0'.

然后正如您在引用中看到的那样，您还必须为您的回复设置正确的 Content-Length。

请注意，目前您发送的回复没有 body，您应该为此使用 204（无内容）代码并添加 Content-length: 0 header，或添加一个小的 body（Content-Length 中的字节数正确，警告，这不是字符计数器，而是字节计数器，在 ascii7 中几乎相同，但与其他编码不同）。

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