Python Language Python HTTP Server Programmatic API of SimpleHTTPServer


Example

What happens when we execute python -m SimpleHTTPServer 9000?

To answer this question we should understand the construct of SimpleHTTPServer (https://hg.python.org/cpython/file/2.7/Lib/SimpleHTTPServer.py) and BaseHTTPServer(https://hg.python.org/cpython/file/2.7/Lib/BaseHTTPServer.py).

Firstly, Python invokes the SimpleHTTPServer module with 9000 as an argument. Now observing the SimpleHTTPServer code,

def test(HandlerClass = SimpleHTTPRequestHandler,
         ServerClass = BaseHTTPServer.HTTPServer):
    BaseHTTPServer.test(HandlerClass, ServerClass)


if __name__ == '__main__':
    test()

The test function is invoked following request handlers and ServerClass. Now BaseHTTPServer.test is invoked

def test(HandlerClass = BaseHTTPRequestHandler,
         ServerClass = HTTPServer, protocol="HTTP/1.0"):
"""Test the HTTP request handler class.

This runs an HTTP server on port 8000 (or the first command line
argument).

"""

if sys.argv[1:]:
    port = int(sys.argv[1])
else:
    port = 8000
server_address = ('', port)

HandlerClass.protocol_version = protocol
httpd = ServerClass(server_address, HandlerClass)

sa = httpd.socket.getsockname()
print "Serving HTTP on", sa[0], "port", sa[1], "..."
httpd.serve_forever()

Hence here the port number, which the user passed as argument is parsed and is bound to the host address. Further basic steps of socket programming with given port and protocol is carried out. Finally socket server is initiated.

This is a basic overview of inheritance from SocketServer class to other classes:

    +------------+
    | BaseServer |
    +------------+
          |
          v
    +-----------+        +------------------+
    | TCPServer |------->| UnixStreamServer |
    +-----------+        +------------------+
          |
          v
    +-----------+        +--------------------+
    | UDPServer |------->| UnixDatagramServer |
    +-----------+        +--------------------+

The links https://hg.python.org/cpython/file/2.7/Lib/BaseHTTPServer.py and https://hg.python.org/cpython/file/2.7/Lib/SocketServer.py are useful for finding further information.