libhttplib2.tex - platform/external/python/httplib2 - Git at Google

 % Template for a library manual section.
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 % Complete documentation on the extended LaTeX markup used for Python
 % documentation is available in ``Documenting Python'', which is part
 % of the standard documentation for Python.  It may be found online
 % at:
 %
 %     http://www.python.org/doc/current/doc/doc.html

 % ==== 0. ====
 % Copy this file to <mydir>/lib<mymodule>.tex, and edit that file
 % according to the instructions below.


 % ==== 1. ====
 % The section prologue.  Give the section a title and provide some
 % meta-information.  References to the module should use
 % \refbimodindex, \refstmodindex, \refexmodindex or \refmodindex, as
 % appropriate.


 \section{\module{httplib2}
          A comprehensive HTTP client library.  }

 % Choose one of these to specify the module module name.  If there's
 % an underscore in the name, use
 % \declaremodule[modname]{...}{mod_name} instead.
 %
 \declaremodule{}{httplib2}                     % not standard, in Python

 % Portability statement:  Uncomment and fill in the parameter to specify the
 % availability of the module.  The parameter can be Unix, IRIX, SunOS, Mac,
 % Windows, or lots of other stuff.  When ``Mac'' is specified, the availability
 % statement will say ``Macintosh'' and the Module Index may say ``Mac''.
 % Please use a name that has already been used whenever applicable.  If this
 % is omitted, no availability statement is produced or implied.
 %
 %   \platform{Unix}

 % These apply to all modules, and may be given more than once:

 \moduleauthor{Joe Gregorio}{joe@bitworking.org}         % Author of the module code;
                                         % omit if not known.
 \sectionauthor{Joe Gregorio}{joe@bitworking.org}                % Author of the documentation,
                                         % even if not a module section.


 % Leave at least one blank line after this, to simplify ad-hoc tools
 % that are sometimes used to massage these files.
 \modulesynopsis{A comprehensive HTTP client library, \module{httplib2} supports many features left out of other HTTP libraries.}


 % ==== 2. ====
 % Give a short overview of what the module does.
 % If it is platform specific, mention this.
 % Mention other important restrictions or general operating principles.
 % For example:

 The \module{httplib2} module is a comprehensive HTTP client library with the following features:

 \begin{description}
 \item[HTTP and HTTPS]  HTTPS support is only available if the socket module was compiled with SSL support.
 \item[Keep-Alive]    Supports HTTP 1.1 Keep-Alive, keeping the socket open and performing multiple requests over the same connection if possible.
 \item[Authentication] The following three types of HTTP Authentication are supported. These can be used over both HTTP and HTTPS.
     \begin{itemize}
         \item Digest
         \item Basic
         \item WSSE
     \end{itemize}
 \item[Caching]
     The module can optionally operate with a private cache that understands the Cache-Control: header and uses both the ETag and Last-Modified cache validators.
 \item[All Methods]
     The module can handle any HTTP request method, not just GET and POST.
 \item[Redirects]
     Automatically follows 3XX redirects on GETs.
 \item[Compression]
     Handles both 'deflate' and 'gzip' types of compression.
 \item[Proxies]
     If the Socksipy module is installed then httplib2 can handle sock4, sock5 and http proxies.
 \item[Lost update support]
     Automatically adds back ETags into PUT requests to resources we have already cached. This implements Section 3.2 of Detecting the Lost Update Problem Using Unreserved Checkout
 \end{description}

 % ==== 3. ====
 % List the public functions defined by the module.  Begin with a
 % standard phrase.  You may also list the exceptions and other data
 % items defined in the module, insofar as they are important for the
 % user.

 The \module{httplib2} module defines the following variables:
 % ---- 3.2. ----
 % Data items are described using a ``datadesc'' block.  This has only
 % one parameter: the item's name.

 \begin{datadesc}{debuglevel}
 The amount of debugging information to print. The default is 0.
 \end{datadesc}

 \begin{datadesc}{RETRIES}
 A request will be tried 'RETRIES' times if it fails at the socket/connection level.
 The default is 2.
 \end{datadesc}

 % --- 3.3. ---
 % Exceptions are described using a ``excdesc'' block.  This has only
 % one parameter: the exception name.  Exceptions defined as classes in
 % the source code should be documented using this environment, but
 % constructor parameters must be omitted.

 The \module{httplib2} module may raise the following Exceptions. Note that
 there is an option that turns exceptions into
 normal responses with an HTTP status code indicating
 an error occured. See \member{Http.force_exception_to_status_code}

 \begin{excdesc}{HttpLib2Error}
 The Base Exception for all exceptions raised by httplib2.
 \end{excdesc}

 \begin{excdesc}{RedirectMissingLocation}
 A 3xx redirect response code was provided but no Location: header
 was provided to point to the new location.
 \end{excdesc}

 \begin{excdesc}{RedirectLimit}
 The maximum number of redirections was reached without coming to a final URI.
 \end{excdesc}


 \begin{excdesc}{ServerNotFoundError}
 Unable to resolve the host name given.
 \end{excdesc}

 \begin{excdesc}{RelativeURIError}
 A relative, as opposed to an absolute URI, was passed into request().
 \end{excdesc}

 \begin{excdesc}{FailedToDecompressContent}
 The headers claimed that the content of the response was compressed but the
 decompression algorithm applied to the content failed.
 \end{excdesc}

 \begin{excdesc}{UnimplementedDigestAuthOptionError}
 The server requested a type of Digest authentication that we
 are unfamiliar with.
 \end{excdesc}

 \begin{excdesc}{UnimplementedHmacDigestAuthOptionError}
 The server requested a type of HMACDigest authentication that we
 are unfamiliar with.
 \end{excdesc}

 % ---- 3.4. ----
 % Other standard environments:
 %
 %  classdesc    - Python classes; same arguments are funcdesc
 %  methoddesc   - methods, like funcdesc but has an optional parameter
 %                 to give the type name: \begin{methoddesc}[mytype]{name}{args}
 %                 By default, the type name will be the name of the
 %                 last class defined using classdesc.  The type name
 %                 is required if the type is implemented in C (because
 %                 there's no classdesc) or if the class isn't directly
 %                 documented (if it's private).
 %  memberdesc   - data members, like datadesc, but with an optional
 %                 type name like methoddesc.

 \begin{classdesc}{Http}{\optional{cache=None}, \optional{timeout=None}, \optional{proxy_info=None}}
 The class that represents a client HTTP interface.
 The \var{cache} parameter is either the name of a directory
 to be used as a flat file cache, or it must an object that
 implements the required caching interface.
 The \var{timeout} parameter is the socket level timeout.
 The \var{proxy_info} is an instance of \class{ProxyInfo} and is supplied
 if a proxy is to be used. Note that the Socksipy module must be
 installed for proxy support to work.
 \end{classdesc}

 \begin{classdesc}{Response}{info}
 Response is a subclass of \class{dict} and instances of this
 class are returned from calls
 to Http.request. The \var{info} parameter is either
 an \class{rfc822.Message} or an \class{httplib.HTTPResponse} object.
 \end{classdesc}

 \begin{classdesc}{FileCache}{dir_name, \optional{safe=safename}}
 FileCache implements a Cache as a directory of files.
 The \var{dir_name} parameter is
 the name of the directory to use. If the directory does
 not exist then FileCache attempts to create the directory.
 The optional \var{safe} parameter is a funtion which generates
 the cache filename for each URI. A FileCache object is
 constructed and used for caching when you pass a directory name
 into the constructor of \class{Http}.
 \end{classdesc}

 \begin{classdesc}{ProxyInfo}{proxy_type, proxy_host, proxy_port, \optional{proxy_rdns=None}, \optional{proxy_user=None}, \optional{proxy_pass=None}}
 The parameter \var{proxy_type} must be set to one of socks.PROXY_TYPE_XXX
 constants. The \var{proxy_host} and \var{proxy_port} must be set to the location
 of the proxy. The optional \var{proxy_rdns} should be set to True if
 the DNS server on the proxy should be used. The \var{proxy_user} and
 \var{proxy_pass} are supplied when the proxy is protected by authentication.
 \end{classdesc}


 % If your module defines new object types (for a built-in module) or
 % classes (for a module written in Python), you should list the
 % methods and instance variables (if any) of each type or class in a
 % separate subsection.

 \subsection{Http Objects}
 \label{http-objects}
 % This label is generally useful for referencing this section, but is
 % also used to give a filename when generating HTML.

 Http objects have the following methods:

 \begin{methoddesc}[Http]{request}{uri, \optional{method="GET", body=None, headers=None, redirections=DEFAULT_MAX_REDIRECTS, connection_type=None}}
 Performs a single HTTP request.
 The \var{uri} is the URI of the HTTP resource and can begin with either \code{http} or \code{https}. The value of \var{uri} must be an absolute URI.

 The \var{method} is the HTTP method to perform, such as \code{GET}, \code{POST}, \code{DELETE}, etc. There is no restriction
 on the methods allowed.

 The \var{body} is the entity body to be sent with the request. It is a string
 object.

 Any extra headers that are to be sent with the request should be provided in the
 \var{headers} dictionary.

 The maximum number of redirect to follow before raising an exception is \var{redirections}. The default is 5.

 The \var{connection_type} is the type of connection object to use. The supplied class
 should implement the interface of httplib.HTTPConnection.

 The return value is a tuple of (response, content), the first being and instance of the
 \class{Response} class, the second being a string that contains the response entity body.
 \end{methoddesc}

 \begin{methoddesc}[Http]{add_credentials}{name, password, \optional{domain=None}}
 Adds a name and password that will be used when a request
 requires authentication. Supplying the optional \var{domain} name will
 restrict these credentials to only be sent to the specified
 domain. If \var{domain} is not specified then the given credentials will
 be used to try to satisfy every HTTP 401 challenge.
 \end{methoddesc}

 \begin{methoddesc}[Http]{add_certificate}{key, cert, domain}
 Add a \var{key} and \var{cert} that will be used for an SSL connection
 to the specified domain. \var{keyfile} is the name of a PEM formatted
 file that contains your private key. \var{certfile} is a PEM formatted certificate chain file.
 \end{methoddesc}

 \begin{methoddesc}[Http]{clear_credentials}{}
 Remove all the names and passwords used for authentication.
 \end{methoddesc}

 \begin{memberdesc}[Http]{follow_redirects}
 If \code{True}, which is the default, safe redirects are followed, where
 safe means that the client is only doing a \code{GET} or \code{HEAD} on the
 URI to which it is being redirected. If \code{False} then no redirects are followed.
 Note that a False 'follow_redirects' takes precedence over a True 'follow_all_redirects'.
 Another way of saying that is for 'follow_all_redirects' to have any affect, 'follow_redirects'
 must be True.
 \end{memberdesc}

 \begin{memberdesc}[Http]{forward_authorization_headers}
 If \code{False}, which is the default, then Authorization: headers are
 stripped from redirects. If \code{True} then Authorization: headers are left
 in place when following redirects. This parameter only applies if following
 redirects is turned on. Note that turning this on could cause your credentials
 to leak, so carefully consider the consequences.
 \end{memberdesc}

 \begin{memberdesc}[Http]{follow_all_redirects}
 If \code{False}, which is the default, only safe redirects are followed, where
 safe means that the client is only doing a \code{GET} or \code{HEAD} on the
 URI to which it is being redirected. If \code{True} then all redirects are followed.
 Note that a False 'follow_redirects' takes precedence over a True 'follow_all_redirects'.
 Another way of saying that is for 'follow_all_redirects' to have any affect, 'follow_redirects'
 must be True.
 \end{memberdesc}

 \begin{memberdesc}[Http]{force_exception_to_status_code}
 If \code{True}, which is the default, then no \module{httplib2} exceptions will be thrown. Instead,
 those error conditions will be turned into \class{Response} objects
 that will be returned normally.

 If \code{False}, then exceptions will be thrown.
 \end{memberdesc}

 \begin{memberdesc}[Http]{ignore_etag}
 Defaults to \code{False}. If \code{True}, then any etags present in the cached response
 are ignored when processing the current request, i.e. httplib2 does \strong{not} use
 'if-match' for PUT or 'if-none-match' when GET or HEAD requests are made. This
 is mainly to deal with broken servers which supply an etag, but change it capriciously.
 \end{memberdesc}

 \subsection{Cache Objects}
 \label{cache-objects}
 % This label is generally useful for referencing this section, but is
 % also used to give a filename when generating HTML.

 If you wish to supply your own caching implementation
 then you will need to pass in an object that supports the
 following methods. Note that the \module{memcache} module
 supports this interface natively.

 \begin{methoddesc}[Cache]{get}{key}
 Takes a string \var{key} and returns the value as a string.
 \end{methoddesc}

 \begin{methoddesc}[Cache]{set}{key, value}
 Takes a string \var{key} and \var{value} and stores it in the cache.
 \end{methoddesc}

 \begin{methoddesc}[Cache]{delete}{key}
 Deletes the cached value stored at \var{key}. The value
 of \var{key} is a string.
 \end{methoddesc}


 \subsection{Response Objects}
 \label{response-objects}
 % This label is generally useful for referencing this section, but is
 % also used to give a filename when generating HTML.

 Response objects are derived from \class{dict} and map
 header names (lower case with the trailing colon removed)
 to header values. In addition to the dict methods
 a Response object also has:

 \begin{memberdesc}[Response]{fromcache}
 If \code{true} the the response was returned from the cache.
 \end{memberdesc}

 \begin{memberdesc}[Response]{version}
 The version of HTTP that the server supports. A value
 of 11 means '1.1'.
 \end{memberdesc}

 \begin{memberdesc}[Response]{status}
 The numerical HTTP status code returned in the response.
 \end{memberdesc}

 \begin{memberdesc}[Response]{reason}
 The human readable component of the HTTP response status code.
 \end{memberdesc}

 \begin{memberdesc}[Response]{previous}
 If redirects are followed then the \class{Response} object returned
 is just for the very last HTTP request and \var{previous} points to
 the previous \class{Response} object. In this manner they form a chain
 going back through the responses to the very first response.
 Will be \code{None} if there are no previous respones.
 \end{memberdesc}

 The Response object also populates the header \code{content-location}, that
 contains the URI that was ultimately requested. This is useful if
 redirects were encountered, you can determine the ultimate URI that
 the request was sent to. All Response objects contain this key value,
 including \code{previous} responses so you can determine the entire
 chain of redirects. If \member{Http.force_exception_to_status_code} is \code{True}
 and the number of redirects has exceeded the number of allowed number
 of redirects then the \class{Response} object will report the error
 in the status code, but the complete chain of previous responses will
 still be in tact.


 % ==== 4. ====
 % Now is probably a good time for a complete example.  (Alternatively,
 % an example giving the flavor of the module may be given before the
 % detailed list of functions.)

 \subsection{Examples \label{httplib2-example}}

 To do a simple \code{GET} request just supply the absolute URI
 of the resource:

 \begin{verbatim}
 import httplib2
 h = httplib2.Http()
 resp, content = h.request("http://bitworking.org/")
 assert resp.status == 200
 assert resp['content-type'] == 'text/html'
 \end{verbatim}

 Here is more complex example that does a PUT
 of some text to a resource that requires authentication.
 The Http instance also uses a file cache
 in the directory \code{.cache}.

 \begin{verbatim}
 import httplib2
 h = httplib2.Http(".cache")
 h.add_credentials('name', 'password')
 resp, content = h.request("https://example.org/chap/2",
     "PUT", body="This is text",
     headers={'content-type':'text/plain'} )
 \end{verbatim}

 Here is an example that connects to a server that
 supports the Atom Publishing Protocol.

 \begin{verbatim}
 import httplib2
 h = httplib2.Http()
 h.add_credentials(myname, mypasswd)
 h.follow_all_redirects = True
 headers = {'Content-Type': 'application/atom+xml'}
 body    = """<?xml version="1.0" ?>
     <entry xmlns="http://www.w3.org/2005/Atom">
       <title>Atom-Powered Robots Run Amok</title>
       <id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id>
       <updated>2003-12-13T18:30:02Z</updated>
       <author><name>John Doe</name></author>
       <content>Some text.</content>
 </entry>
 """
 uri     = "http://www.example.com/collection/"
 resp, content = h.request(uri, "POST", body=body, headers=headers)
 \end{verbatim}
 % Note that there is no trailing ">>> " prompt shown.

 Here is an example of providing data to an HTML form processor.
 In this case we presume this is a POST form. We need to take our
 data and format it as "application/x-www-form-urlencoded" data and use that as a
 body for a POST request.

 \begin{verbatim}
 >>> import httplib2
 >>> import urllib
 >>> data = {'name': 'fred', 'address': '123 shady lane'}
 >>> body = urllib.urlencode(data)
 >>> body
 'name=fred&address=123+shady+lane'
 >>> h = httplib2.Http()
 >>> resp, content = h.request("http://example.com", method="POST", body=body)
 \end{verbatim}
 % Note that there is no trailing ">>> " prompt shown.

 Here is an example of using a proxy server:
 \begin{verbatim}
 import httplib2
 import socks

 httplib2.debuglevel=4
 h = httplib2.Http(proxy_info = httplib2.ProxyInfo(socks.PROXY_TYPE_HTTP, 'localhost', 8000))
 r,c = h.request("http://bitworking.org/news/")
 \end{verbatim}
	% Template for a library manual section.
	% PLEASE REMOVE THE COMMENTS AFTER USING THE TEMPLATE
	%
	% Complete documentation on the extended LaTeX markup used for Python
	% documentation is available in ``Documenting Python'', which is part
	% of the standard documentation for Python. It may be found online
	% at:
	%
	% http://www.python.org/doc/current/doc/doc.html

	% ==== 0. ====
	% Copy this file to <mydir>/lib<mymodule>.tex, and edit that file
	% according to the instructions below.


	% ==== 1. ====
	% The section prologue. Give the section a title and provide some
	% meta-information. References to the module should use
	% \refbimodindex, \refstmodindex, \refexmodindex or \refmodindex, as
	% appropriate.


	\section{\module{httplib2}
	A comprehensive HTTP client library. }

	% Choose one of these to specify the module module name. If there's
	% an underscore in the name, use
	% \declaremodule[modname]{...}{mod_name} instead.
	%
	\declaremodule{}{httplib2} % not standard, in Python

	% Portability statement: Uncomment and fill in the parameter to specify the
	% availability of the module. The parameter can be Unix, IRIX, SunOS, Mac,
	% Windows, or lots of other stuff. When ``Mac'' is specified, the availability
	% statement will say ``Macintosh'' and the Module Index may say ``Mac''.
	% Please use a name that has already been used whenever applicable. If this
	% is omitted, no availability statement is produced or implied.
	%
	% \platform{Unix}

	% These apply to all modules, and may be given more than once:

	\moduleauthor{Joe Gregorio}{joe@bitworking.org} % Author of the module code;
	% omit if not known.
	\sectionauthor{Joe Gregorio}{joe@bitworking.org} % Author of the documentation,
	% even if not a module section.


	% Leave at least one blank line after this, to simplify ad-hoc tools
	% that are sometimes used to massage these files.
	\modulesynopsis{A comprehensive HTTP client library, \module{httplib2} supports many features left out of other HTTP libraries.}


	% ==== 2. ====
	% Give a short overview of what the module does.
	% If it is platform specific, mention this.
	% Mention other important restrictions or general operating principles.
	% For example:

	The \module{httplib2} module is a comprehensive HTTP client library with the following features:

	\begin{description}
	\item[HTTP and HTTPS] HTTPS support is only available if the socket module was compiled with SSL support.
	\item[Keep-Alive] Supports HTTP 1.1 Keep-Alive, keeping the socket open and performing multiple requests over the same connection if possible.
	\item[Authentication] The following three types of HTTP Authentication are supported. These can be used over both HTTP and HTTPS.
	\begin{itemize}
	\item Digest
	\item Basic
	\item WSSE
	\end{itemize}
	\item[Caching]
	The module can optionally operate with a private cache that understands the Cache-Control: header and uses both the ETag and Last-Modified cache validators.
	\item[All Methods]
	The module can handle any HTTP request method, not just GET and POST.
	\item[Redirects]
	Automatically follows 3XX redirects on GETs.
	\item[Compression]
	Handles both 'deflate' and 'gzip' types of compression.
	\item[Proxies]
	If the Socksipy module is installed then httplib2 can handle sock4, sock5 and http proxies.
	\item[Lost update support]
	Automatically adds back ETags into PUT requests to resources we have already cached. This implements Section 3.2 of Detecting the Lost Update Problem Using Unreserved Checkout
	\end{description}

	% ==== 3. ====
	% List the public functions defined by the module. Begin with a
	% standard phrase. You may also list the exceptions and other data
	% items defined in the module, insofar as they are important for the
	% user.

	The \module{httplib2} module defines the following variables:
	% ---- 3.2. ----
	% Data items are described using a ``datadesc'' block. This has only
	% one parameter: the item's name.

	\begin{datadesc}{debuglevel}
	The amount of debugging information to print. The default is 0.
	\end{datadesc}

	\begin{datadesc}{RETRIES}
	A request will be tried 'RETRIES' times if it fails at the socket/connection level.
	The default is 2.
	\end{datadesc}

	% --- 3.3. ---
	% Exceptions are described using a ``excdesc'' block. This has only
	% one parameter: the exception name. Exceptions defined as classes in
	% the source code should be documented using this environment, but
	% constructor parameters must be omitted.

	The \module{httplib2} module may raise the following Exceptions. Note that
	there is an option that turns exceptions into
	normal responses with an HTTP status code indicating
	an error occured. See \member{Http.force_exception_to_status_code}

	\begin{excdesc}{HttpLib2Error}
	The Base Exception for all exceptions raised by httplib2.
	\end{excdesc}

	\begin{excdesc}{RedirectMissingLocation}
	A 3xx redirect response code was provided but no Location: header
	was provided to point to the new location.
	\end{excdesc}

	\begin{excdesc}{RedirectLimit}
	The maximum number of redirections was reached without coming to a final URI.
	\end{excdesc}


	\begin{excdesc}{ServerNotFoundError}
	Unable to resolve the host name given.
	\end{excdesc}

	\begin{excdesc}{RelativeURIError}
	A relative, as opposed to an absolute URI, was passed into request().
	\end{excdesc}

	\begin{excdesc}{FailedToDecompressContent}
	The headers claimed that the content of the response was compressed but the
	decompression algorithm applied to the content failed.
	\end{excdesc}

	\begin{excdesc}{UnimplementedDigestAuthOptionError}
	The server requested a type of Digest authentication that we
	are unfamiliar with.
	\end{excdesc}

	\begin{excdesc}{UnimplementedHmacDigestAuthOptionError}
	The server requested a type of HMACDigest authentication that we
	are unfamiliar with.
	\end{excdesc}

	% ---- 3.4. ----
	% Other standard environments:
	%
	% classdesc - Python classes; same arguments are funcdesc
	% methoddesc - methods, like funcdesc but has an optional parameter
	% to give the type name: \begin{methoddesc}[mytype]{name}{args}
	% By default, the type name will be the name of the
	% last class defined using classdesc. The type name
	% is required if the type is implemented in C (because
	% there's no classdesc) or if the class isn't directly
	% documented (if it's private).
	% memberdesc - data members, like datadesc, but with an optional
	% type name like methoddesc.

	\begin{classdesc}{Http}{\optional{cache=None}, \optional{timeout=None}, \optional{proxy_info=None}}
	The class that represents a client HTTP interface.
	The \var{cache} parameter is either the name of a directory
	to be used as a flat file cache, or it must an object that
	implements the required caching interface.
	The \var{timeout} parameter is the socket level timeout.
	The \var{proxy_info} is an instance of \class{ProxyInfo} and is supplied
	if a proxy is to be used. Note that the Socksipy module must be
	installed for proxy support to work.
	\end{classdesc}

	\begin{classdesc}{Response}{info}
	Response is a subclass of \class{dict} and instances of this
	class are returned from calls
	to Http.request. The \var{info} parameter is either
	an \class{rfc822.Message} or an \class{httplib.HTTPResponse} object.
	\end{classdesc}

	\begin{classdesc}{FileCache}{dir_name, \optional{safe=safename}}
	FileCache implements a Cache as a directory of files.
	The \var{dir_name} parameter is
	the name of the directory to use. If the directory does
	not exist then FileCache attempts to create the directory.
	The optional \var{safe} parameter is a funtion which generates
	the cache filename for each URI. A FileCache object is
	constructed and used for caching when you pass a directory name
	into the constructor of \class{Http}.
	\end{classdesc}

	\begin{classdesc}{ProxyInfo}{proxy_type, proxy_host, proxy_port, \optional{proxy_rdns=None}, \optional{proxy_user=None}, \optional{proxy_pass=None}}
	The parameter \var{proxy_type} must be set to one of socks.PROXY_TYPE_XXX
	constants. The \var{proxy_host} and \var{proxy_port} must be set to the location
	of the proxy. The optional \var{proxy_rdns} should be set to True if
	the DNS server on the proxy should be used. The \var{proxy_user} and
	\var{proxy_pass} are supplied when the proxy is protected by authentication.
	\end{classdesc}


	% If your module defines new object types (for a built-in module) or
	% classes (for a module written in Python), you should list the
	% methods and instance variables (if any) of each type or class in a
	% separate subsection.

	\subsection{Http Objects}
	\label{http-objects}
	% This label is generally useful for referencing this section, but is
	% also used to give a filename when generating HTML.

	Http objects have the following methods:

	\begin{methoddesc}[Http]{request}{uri, \optional{method="GET", body=None, headers=None, redirections=DEFAULT_MAX_REDIRECTS, connection_type=None}}
	Performs a single HTTP request.
	The \var{uri} is the URI of the HTTP resource and can begin with either \code{http} or \code{https}. The value of \var{uri} must be an absolute URI.

	The \var{method} is the HTTP method to perform, such as \code{GET}, \code{POST}, \code{DELETE}, etc. There is no restriction
	on the methods allowed.

	The \var{body} is the entity body to be sent with the request. It is a string
	object.

	Any extra headers that are to be sent with the request should be provided in the
	\var{headers} dictionary.

	The maximum number of redirect to follow before raising an exception is \var{redirections}. The default is 5.

	The \var{connection_type} is the type of connection object to use. The supplied class
	should implement the interface of httplib.HTTPConnection.

	The return value is a tuple of (response, content), the first being and instance of the
	\class{Response} class, the second being a string that contains the response entity body.
	\end{methoddesc}

	\begin{methoddesc}[Http]{add_credentials}{name, password, \optional{domain=None}}
	Adds a name and password that will be used when a request
	requires authentication. Supplying the optional \var{domain} name will
	restrict these credentials to only be sent to the specified
	domain. If \var{domain} is not specified then the given credentials will
	be used to try to satisfy every HTTP 401 challenge.
	\end{methoddesc}

	\begin{methoddesc}[Http]{add_certificate}{key, cert, domain}
	Add a \var{key} and \var{cert} that will be used for an SSL connection
	to the specified domain. \var{keyfile} is the name of a PEM formatted
	file that contains your private key. \var{certfile} is a PEM formatted certificate chain file.
	\end{methoddesc}

	\begin{methoddesc}[Http]{clear_credentials}{}
	Remove all the names and passwords used for authentication.
	\end{methoddesc}

	\begin{memberdesc}[Http]{follow_redirects}
	If \code{True}, which is the default, safe redirects are followed, where
	safe means that the client is only doing a \code{GET} or \code{HEAD} on the
	URI to which it is being redirected. If \code{False} then no redirects are followed.
	Note that a False 'follow_redirects' takes precedence over a True 'follow_all_redirects'.
	Another way of saying that is for 'follow_all_redirects' to have any affect, 'follow_redirects'
	must be True.
	\end{memberdesc}

	\begin{memberdesc}[Http]{forward_authorization_headers}
	If \code{False}, which is the default, then Authorization: headers are
	stripped from redirects. If \code{True} then Authorization: headers are left
	in place when following redirects. This parameter only applies if following
	redirects is turned on. Note that turning this on could cause your credentials
	to leak, so carefully consider the consequences.
	\end{memberdesc}

	\begin{memberdesc}[Http]{follow_all_redirects}
	If \code{False}, which is the default, only safe redirects are followed, where
	safe means that the client is only doing a \code{GET} or \code{HEAD} on the
	URI to which it is being redirected. If \code{True} then all redirects are followed.
	Note that a False 'follow_redirects' takes precedence over a True 'follow_all_redirects'.
	Another way of saying that is for 'follow_all_redirects' to have any affect, 'follow_redirects'
	must be True.
	\end{memberdesc}

	\begin{memberdesc}[Http]{force_exception_to_status_code}
	If \code{True}, which is the default, then no \module{httplib2} exceptions will be thrown. Instead,
	those error conditions will be turned into \class{Response} objects
	that will be returned normally.

	If \code{False}, then exceptions will be thrown.
	\end{memberdesc}

	\begin{memberdesc}[Http]{ignore_etag}
	Defaults to \code{False}. If \code{True}, then any etags present in the cached response
	are ignored when processing the current request, i.e. httplib2 does \strong{not} use
	'if-match' for PUT or 'if-none-match' when GET or HEAD requests are made. This
	is mainly to deal with broken servers which supply an etag, but change it capriciously.
	\end{memberdesc}

	\subsection{Cache Objects}
	\label{cache-objects}
	% This label is generally useful for referencing this section, but is
	% also used to give a filename when generating HTML.

	If you wish to supply your own caching implementation
	then you will need to pass in an object that supports the
	following methods. Note that the \module{memcache} module
	supports this interface natively.

	\begin{methoddesc}[Cache]{get}{key}
	Takes a string \var{key} and returns the value as a string.
	\end{methoddesc}

	\begin{methoddesc}[Cache]{set}{key, value}
	Takes a string \var{key} and \var{value} and stores it in the cache.
	\end{methoddesc}

	\begin{methoddesc}[Cache]{delete}{key}
	Deletes the cached value stored at \var{key}. The value
	of \var{key} is a string.
	\end{methoddesc}




	\subsection{Response Objects}
	\label{response-objects}
	% This label is generally useful for referencing this section, but is
	% also used to give a filename when generating HTML.

	Response objects are derived from \class{dict} and map
	header names (lower case with the trailing colon removed)
	to header values. In addition to the dict methods
	a Response object also has:

	\begin{memberdesc}[Response]{fromcache}
	If \code{true} the the response was returned from the cache.
	\end{memberdesc}

	\begin{memberdesc}[Response]{version}
	The version of HTTP that the server supports. A value
	of 11 means '1.1'.
	\end{memberdesc}

	\begin{memberdesc}[Response]{status}
	The numerical HTTP status code returned in the response.
	\end{memberdesc}

	\begin{memberdesc}[Response]{reason}
	The human readable component of the HTTP response status code.
	\end{memberdesc}

	\begin{memberdesc}[Response]{previous}
	If redirects are followed then the \class{Response} object returned
	is just for the very last HTTP request and \var{previous} points to
	the previous \class{Response} object. In this manner they form a chain
	going back through the responses to the very first response.
	Will be \code{None} if there are no previous respones.
	\end{memberdesc}

	The Response object also populates the header \code{content-location}, that
	contains the URI that was ultimately requested. This is useful if
	redirects were encountered, you can determine the ultimate URI that
	the request was sent to. All Response objects contain this key value,
	including \code{previous} responses so you can determine the entire
	chain of redirects. If \member{Http.force_exception_to_status_code} is \code{True}
	and the number of redirects has exceeded the number of allowed number
	of redirects then the \class{Response} object will report the error
	in the status code, but the complete chain of previous responses will
	still be in tact.


	% ==== 4. ====
	% Now is probably a good time for a complete example. (Alternatively,
	% an example giving the flavor of the module may be given before the
	% detailed list of functions.)

	\subsection{Examples \label{httplib2-example}}

	To do a simple \code{GET} request just supply the absolute URI
	of the resource:

	\begin{verbatim}
	import httplib2
	h = httplib2.Http()
	resp, content = h.request("http://bitworking.org/")
	assert resp.status == 200
	assert resp['content-type'] == 'text/html'
	\end{verbatim}

	Here is more complex example that does a PUT
	of some text to a resource that requires authentication.
	The Http instance also uses a file cache
	in the directory \code{.cache}.

	\begin{verbatim}
	import httplib2
	h = httplib2.Http(".cache")
	h.add_credentials('name', 'password')
	resp, content = h.request("https://example.org/chap/2",
	"PUT", body="This is text",
	headers={'content-type':'text/plain'} )
	\end{verbatim}

	Here is an example that connects to a server that
	supports the Atom Publishing Protocol.

	\begin{verbatim}
	import httplib2
	h = httplib2.Http()
	h.add_credentials(myname, mypasswd)
	h.follow_all_redirects = True
	headers = {'Content-Type': 'application/atom+xml'}
	body = """<?xml version="1.0" ?>
	<entry xmlns="http://www.w3.org/2005/Atom">
	<title>Atom-Powered Robots Run Amok</title>
	<id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id>
	<updated>2003-12-13T18:30:02Z</updated>
	<author><name>John Doe</name></author>
	<content>Some text.</content>
	</entry>
	"""
	uri = "http://www.example.com/collection/"
	resp, content = h.request(uri, "POST", body=body, headers=headers)
	\end{verbatim}
	% Note that there is no trailing ">>> " prompt shown.

	Here is an example of providing data to an HTML form processor.
	In this case we presume this is a POST form. We need to take our
	data and format it as "application/x-www-form-urlencoded" data and use that as a
	body for a POST request.

	\begin{verbatim}
	>>> import httplib2
	>>> import urllib
	>>> data = {'name': 'fred', 'address': '123 shady lane'}
	>>> body = urllib.urlencode(data)
	>>> body
	'name=fred&address=123+shady+lane'
	>>> h = httplib2.Http()
	>>> resp, content = h.request("http://example.com", method="POST", body=body)
	\end{verbatim}
	% Note that there is no trailing ">>> " prompt shown.

	Here is an example of using a proxy server:
	\begin{verbatim}
	import httplib2
	import socks

	httplib2.debuglevel=4
	h = httplib2.Http(proxy_info = httplib2.ProxyInfo(socks.PROXY_TYPE_HTTP, 'localhost', 8000))
	r,c = h.request("http://bitworking.org/news/")
	\end{verbatim}