Lib/http/client.py

Source:

cpython 3.14 @ ab2d84fe1023/Lib/http/client.py ↗

http.client (formerly httplib) is the low-level HTTP/1.1 client. It does not follow redirects or manage cookies; that is left to urllib.request. It is used directly by xmlrpc.client, smtplib, and other stdlib modules.

Map

Lines	Symbol	Role
1-100	Constants: HTTP_PORT, HTTPS_PORT, status codes	HTTPStatus enum
101-300	HTTPResponse	Parse the response status line, headers, and body
301-600	HTTPConnection	Manage the socket; send request headers and body
601-800	HTTPConnection.request, _send_request	Build and send an HTTP request
801-1000	Chunked encoding: _read_chunked, _send_output	Transfer-Encoding: chunked support
1001-1200	HTTPSConnection	TLS wrapper using ssl.wrap_socket
1201-1900	HTTPException hierarchy, UnknownProtocol, CannotSendHeader, etc.	Exception classes

Reading

HTTPConnection.request

# CPython: Lib/http/client.py:1063 HTTPConnection.request
def request(self, method, url, body=None, headers={}, *, encode_chunked=False):
    self._send_request(method, url, body, headers, encode_chunked)

_send_request formats the request line and headers, determines content-length or chunked encoding, then calls endheaders(body) which flushes the write buffer to the socket.

HTTPResponse.read

# CPython: Lib/http/client.py:465 HTTPResponse.read
def read(self, amt=None):
    ...
    if self.chunked:
        return self._read_chunked(amt)
    ...
    s = self.fp.read(amt)
    ...
    return s

The response body can be chunked (Transfer-Encoding: chunked) or length-delimited (Content-Length) or connection-close. _read_chunked parses the <size>\r\n<data>\r\n format.

HTTPSConnection

# CPython: Lib/http/client.py:1457 HTTPSConnection.connect
def connect(self):
    self.sock = self._context.wrap_socket(
        sock, server_hostname=self._server_hostname)

HTTPSConnection is a subclass that wraps the raw socket in an SSL context after connecting. The context parameter is an ssl.SSLContext.

Persistent connections

HTTPConnection reuses the socket across multiple requests (HTTP/1.1 persistent connections) via the keep-alive header. A new socket is created only on connect() or when the previous socket is closed.

gopy notes

Status: not yet ported. Go's net/http client covers most use cases at a higher level. A faithful http.client port would need net.Conn, bufio.ReadWriter, and an HTTP/1.1 request/response parser. The most useful immediate port is HTTPSConnection.getresponse() for urllib.request compatibility.