229 lines
7.0 KiB
TeX
229 lines
7.0 KiB
TeX
\section{\module{httplib} ---
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HTTP protocol client}
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\declaremodule{standard}{httplib}
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\modulesynopsis{HTTP and HTTPS protocol client (requires sockets).}
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\indexii{HTTP}{protocol}
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\index{HTTP!\module{httplib} (standard module)}
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This module defines classes which implement the client side of the
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HTTP and HTTPS protocols. It is normally not used directly --- the
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module \refmodule{urllib}\refstmodindex{urllib} uses it to handle URLs
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that use HTTP and HTTPS. \note{HTTPS support is only
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available if the \refmodule{socket} module was compiled with SSL
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support.}
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The constants defined in this module are:
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\begin{datadesc}{HTTP_PORT}
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The default port for the HTTP protocol (always \code{80}).
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\end{datadesc}
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\begin{datadesc}{HTTPS_PORT}
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The default port for the HTTPS protocol (always \code{443}).
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\end{datadesc}
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The module provides the following classes:
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\begin{classdesc}{HTTPConnection}{host\optional{, port}}
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An \class{HTTPConnection} instance represents one transaction with an HTTP
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server. It should be instantiated passing it a host and optional port number.
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If no port number is passed, the port is extracted from the host string if it
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has the form \code{\var{host}:\var{port}}, else the default HTTP port (80) is
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used. For example, the following calls all create instances that connect to
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the server at the same host and port:
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\begin{verbatim}
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>>> h1 = httplib.HTTPConnection('www.cwi.nl')
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>>> h2 = httplib.HTTPConnection('www.cwi.nl:80')
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>>> h3 = httplib.HTTPConnection('www.cwi.nl', 80)
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\end{verbatim}
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\end{classdesc}
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\begin{classdesc}{HTTPSConnection}{host\optional{, port}}
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A subclass of \class{HTTPConnection} that uses SSL for communication with
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secure servers. Default port is \code{443}.
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\end{classdesc}
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The following exceptions are raised as appropriate:
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\begin{excdesc}{HTTPException}
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The base class of the other exceptions in this module. It is a
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subclass of \exception{Exception}.
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\end{excdesc}
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\begin{excdesc}{NotConnected}
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A subclass of \exception{HTTPException}.
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\end{excdesc}
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\begin{excdesc}{InvalidURL}
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A subclass of \exception{HTTPException}, raised if a port is given and is
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either non-numeric or empty.
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\end{excdesc}
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\begin{excdesc}{UnknownProtocol}
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A subclass of \exception{HTTPException}.
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\end{excdesc}
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\begin{excdesc}{UnknownTransferEncoding}
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A subclass of \exception{HTTPException}.
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\end{excdesc}
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\begin{excdesc}{IllegalKeywordArgument}
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A subclass of \exception{HTTPException}.
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\end{excdesc}
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\begin{excdesc}{UnimplementedFileMode}
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A subclass of \exception{HTTPException}.
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\end{excdesc}
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\begin{excdesc}{IncompleteRead}
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A subclass of \exception{HTTPException}.
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\end{excdesc}
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\begin{excdesc}{ImproperConnectionState}
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A subclass of \exception{HTTPException}.
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\end{excdesc}
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\begin{excdesc}{CannotSendRequest}
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A subclass of \exception{ImproperConnectionState}.
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\end{excdesc}
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\begin{excdesc}{CannotSendHeader}
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A subclass of \exception{ImproperConnectionState}.
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\end{excdesc}
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\begin{excdesc}{ResponseNotReady}
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A subclass of \exception{ImproperConnectionState}.
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\end{excdesc}
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\begin{excdesc}{BadStatusLine}
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A subclass of \exception{HTTPException}. Raised if a server responds with a
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HTTP status code that we don't understand.
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\end{excdesc}
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\subsection{HTTPConnection Objects \label{httpconnection-objects}}
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\class{HTTPConnection} instances have the following methods:
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\begin{methoddesc}{request}{method, url\optional{, body\optional{, headers}}}
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This will send a request to the server using the HTTP request method
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\var{method} and the selector \var{url}. If the \var{body} argument is
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present, it should be a string of data to send after the headers are finished.
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The header Content-Length is automatically set to the correct value.
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The \var{headers} argument should be a mapping of extra HTTP headers to send
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with the request.
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\end{methoddesc}
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\begin{methoddesc}{getresponse}{}
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Should be called after a request is sent to get the response from the server.
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Returns an \class{HTTPResponse} instance.
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\end{methoddesc}
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\begin{methoddesc}{set_debuglevel}{level}
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Set the debugging level (the amount of debugging output printed).
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The default debug level is \code{0}, meaning no debugging output is
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printed.
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\end{methoddesc}
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\begin{methoddesc}{connect}{}
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Connect to the server specified when the object was created.
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\end{methoddesc}
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\begin{methoddesc}{close}{}
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Close the connection to the server.
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\end{methoddesc}
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\begin{methoddesc}{send}{data}
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Send data to the server. This should be used directly only after the
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\method{endheaders()} method has been called and before
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\method{getreply()} has been called.
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\end{methoddesc}
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\begin{methoddesc}{putrequest}{request, selector}
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This should be the first call after the connection to the server has
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been made. It sends a line to the server consisting of the
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\var{request} string, the \var{selector} string, and the HTTP version
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(\code{HTTP/1.1}).
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\end{methoddesc}
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\begin{methoddesc}{putheader}{header, argument\optional{, ...}}
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Send an \rfc{822}-style header to the server. It sends a line to the
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server consisting of the header, a colon and a space, and the first
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argument. If more arguments are given, continuation lines are sent,
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each consisting of a tab and an argument.
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\end{methoddesc}
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\begin{methoddesc}{endheaders}{}
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Send a blank line to the server, signalling the end of the headers.
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\end{methoddesc}
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\subsection{HTTPResponse Objects \label{httpresponse-objects}}
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\class{HTTPResponse} instances have the following methods and attributes:
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\begin{methoddesc}{read}{}
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Reads and returns the response body.
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\end{methoddesc}
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\begin{methoddesc}{getheader}{name\optional{, default}}
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Get the contents of the header \var{name}, or \var{default} if there is no
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matching header.
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\end{methoddesc}
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\begin{datadesc}{msg}
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A \class{mimetools.Message} instance containing the response headers.
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\end{datadesc}
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\begin{datadesc}{version}
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HTTP protocol version used by server. 10 for HTTP/1.0, 11 for HTTP/1.1.
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\end{datadesc}
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\begin{datadesc}{status}
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Status code returned by server.
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\end{datadesc}
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\begin{datadesc}{reason}
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Reason phrase returned by server.
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\end{datadesc}
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\subsection{Examples \label{httplib-examples}}
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Here is an example session that uses the \samp{GET} method:
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\begin{verbatim}
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>>> import httplib
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>>> conn = httplib.HTTPConnection("www.python.org")
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>>> conn.request("GET", "/index.html")
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>>> r1 = conn.getresponse()
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>>> print r1.status, r1.reason
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200 OK
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>>> data1 = r1.read()
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>>> conn.request("GET", "/parrot.spam")
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>>> r2 = conn.getresponse()
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>>> print r2.status, r2.reason
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404 Not Found
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>>> data2 = r2.read()
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>>> conn.close()
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\end{verbatim}
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Here is an example session that shows how to \samp{POST} requests:
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\begin{verbatim}
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>>> import httplib, urllib
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>>> params = urllib.urlencode({'spam': 1, 'eggs': 2, 'bacon': 0})
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>>> headers = {"Content-type": "application/x-www-form-urlencoded",
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... "Accept": "text/plain"}
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>>> conn = httplib.HTTPConnection("musi-cal.mojam.com:80")
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>>> conn.request("POST", "/cgi-bin/query", params, headers)
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>>> response = conn.getresponse()
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>>> print response.status, response.reason
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200 OK
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>>> data = response.read()
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>>> conn.close()
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\end{verbatim}
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