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dir: /sys/src/cmd/python/Doc/lib/liburlparse.tex/
\section{\module{urlparse} --- Parse URLs into components} \declaremodule{standard}{urlparse} \modulesynopsis{Parse URLs into components.} \index{WWW} \index{World Wide Web} \index{URL} \indexii{URL}{parsing} \indexii{relative}{URL} This module defines a standard interface to break Uniform Resource Locator (URL) strings up in components (addressing scheme, network location, path etc.), to combine the components back into a URL string, and to convert a ``relative URL'' to an absolute URL given a ``base URL.'' The module has been designed to match the Internet RFC on Relative Uniform Resource Locators (and discovered a bug in an earlier draft!). It supports the following URL schemes: \code{file}, \code{ftp}, \code{gopher}, \code{hdl}, \code{http}, \code{https}, \code{imap}, \code{mailto}, \code{mms}, \code{news}, \code{nntp}, \code{prospero}, \code{rsync}, \code{rtsp}, \code{rtspu}, \code{sftp}, \code{shttp}, \code{sip}, \code{sips}, \code{snews}, \code{svn}, \code{svn+ssh}, \code{telnet}, \code{wais}. \versionadded[Support for the \code{sftp} and \code{sips} schemes]{2.5} The \module{urlparse} module defines the following functions: \begin{funcdesc}{urlparse}{urlstring\optional{, default_scheme\optional{, allow_fragments}}} Parse a URL into six components, returning a 6-tuple. This corresponds to the general structure of a URL: \code{\var{scheme}://\var{netloc}/\var{path};\var{parameters}?\var{query}\#\var{fragment}}. Each tuple item is a string, possibly empty. The components are not broken up in smaller parts (for example, the network location is a single string), and \% escapes are not expanded. The delimiters as shown above are not part of the result, except for a leading slash in the \var{path} component, which is retained if present. For example: \begin{verbatim} >>> from urlparse import urlparse >>> o = urlparse('http://www.cwi.nl:80/%7Eguido/Python.html') >>> o ('http', 'www.cwi.nl:80', '/%7Eguido/Python.html', '', '', '') >>> o.scheme 'http' >>> o.port 80 >>> o.geturl() 'http://www.cwi.nl:80/%7Eguido/Python.html' \end{verbatim} If the \var{default_scheme} argument is specified, it gives the default addressing scheme, to be used only if the URL does not specify one. The default value for this argument is the empty string. If the \var{allow_fragments} argument is false, fragment identifiers are not allowed, even if the URL's addressing scheme normally does support them. The default value for this argument is \constant{True}. The return value is actually an instance of a subclass of \pytype{tuple}. This class has the following additional read-only convenience attributes: \begin{tableiv}{l|c|l|c}{member}{Attribute}{Index}{Value}{Value if not present} \lineiv{scheme} {0} {URL scheme specifier} {empty string} \lineiv{netloc} {1} {Network location part} {empty string} \lineiv{path} {2} {Hierarchical path} {empty string} \lineiv{params} {3} {Parameters for last path element} {empty string} \lineiv{query} {4} {Query component} {empty string} \lineiv{fragment}{5} {Fragment identifier} {empty string} \lineiv{username}{ } {User name} {\constant{None}} \lineiv{password}{ } {Password} {\constant{None}} \lineiv{hostname}{ } {Host name (lower case)} {\constant{None}} \lineiv{port} { } {Port number as integer, if present} {\constant{None}} \end{tableiv} See section~\ref{urlparse-result-object}, ``Results of \function{urlparse()} and \function{urlsplit()},'' for more information on the result object. \versionchanged[Added attributes to return value]{2.5} \end{funcdesc} \begin{funcdesc}{urlunparse}{parts} Construct a URL from a tuple as returned by \code{urlparse()}. The \var{parts} argument can be any six-item iterable. This may result in a slightly different, but equivalent URL, if the URL that was parsed originally had unnecessary delimiters (for example, a ? with an empty query; the RFC states that these are equivalent). \end{funcdesc} \begin{funcdesc}{urlsplit}{urlstring\optional{, default_scheme\optional{, allow_fragments}}} This is similar to \function{urlparse()}, but does not split the params from the URL. This should generally be used instead of \function{urlparse()} if the more recent URL syntax allowing parameters to be applied to each segment of the \var{path} portion of the URL (see \rfc{2396}) is wanted. A separate function is needed to separate the path segments and parameters. This function returns a 5-tuple: (addressing scheme, network location, path, query, fragment identifier). The return value is actually an instance of a subclass of \pytype{tuple}. This class has the following additional read-only convenience attributes: \begin{tableiv}{l|c|l|c}{member}{Attribute}{Index}{Value}{Value if not present} \lineiv{scheme} {0} {URL scheme specifier} {empty string} \lineiv{netloc} {1} {Network location part} {empty string} \lineiv{path} {2} {Hierarchical path} {empty string} \lineiv{query} {3} {Query component} {empty string} \lineiv{fragment} {4} {Fragment identifier} {empty string} \lineiv{username} { } {User name} {\constant{None}} \lineiv{password} { } {Password} {\constant{None}} \lineiv{hostname} { } {Host name (lower case)} {\constant{None}} \lineiv{port} { } {Port number as integer, if present} {\constant{None}} \end{tableiv} See section~\ref{urlparse-result-object}, ``Results of \function{urlparse()} and \function{urlsplit()},'' for more information on the result object. \versionadded{2.2} \versionchanged[Added attributes to return value]{2.5} \end{funcdesc} \begin{funcdesc}{urlunsplit}{parts} Combine the elements of a tuple as returned by \function{urlsplit()} into a complete URL as a string. The \var{parts} argument can be any five-item iterable. This may result in a slightly different, but equivalent URL, if the URL that was parsed originally had unnecessary delimiters (for example, a ? with an empty query; the RFC states that these are equivalent). \versionadded{2.2} \end{funcdesc} \begin{funcdesc}{urljoin}{base, url\optional{, allow_fragments}} Construct a full (``absolute'') URL by combining a ``base URL'' (\var{base}) with another URL (\var{url}). Informally, this uses components of the base URL, in particular the addressing scheme, the network location and (part of) the path, to provide missing components in the relative URL. For example: \begin{verbatim} >>> from urlparse import urljoin >>> urljoin('http://www.cwi.nl/%7Eguido/Python.html', 'FAQ.html') 'http://www.cwi.nl/%7Eguido/FAQ.html' \end{verbatim} The \var{allow_fragments} argument has the same meaning and default as for \function{urlparse()}. \note{If \var{url} is an absolute URL (that is, starting with \code{//} or \code{scheme://}, the \var{url}'s host name and/or scheme will be present in the result. For example:} \begin{verbatim} >>> urljoin('http://www.cwi.nl/%7Eguido/Python.html', ... '//www.python.org/%7Eguido') 'http://www.python.org/%7Eguido' \end{verbatim} If you do not want that behavior, preprocess the \var{url} with \function{urlsplit()} and \function{urlunsplit()}, removing possible \emph{scheme} and \emph{netloc} parts. \end{funcdesc} \begin{funcdesc}{urldefrag}{url} If \var{url} contains a fragment identifier, returns a modified version of \var{url} with no fragment identifier, and the fragment identifier as a separate string. If there is no fragment identifier in \var{url}, returns \var{url} unmodified and an empty string. \end{funcdesc} \begin{seealso} \seerfc{1738}{Uniform Resource Locators (URL)}{ This specifies the formal syntax and semantics of absolute URLs.} \seerfc{1808}{Relative Uniform Resource Locators}{ This Request For Comments includes the rules for joining an absolute and a relative URL, including a fair number of ``Abnormal Examples'' which govern the treatment of border cases.} \seerfc{2396}{Uniform Resource Identifiers (URI): Generic Syntax}{ Document describing the generic syntactic requirements for both Uniform Resource Names (URNs) and Uniform Resource Locators (URLs).} \end{seealso} \subsection{Results of \function{urlparse()} and \function{urlsplit()} \label{urlparse-result-object}} The result objects from the \function{urlparse()} and \function{urlsplit()} functions are subclasses of the \pytype{tuple} type. These subclasses add the attributes described in those functions, as well as provide an additional method: \begin{methoddesc}[ParseResult]{geturl}{} Return the re-combined version of the original URL as a string. This may differ from the original URL in that the scheme will always be normalized to lower case and empty components may be dropped. Specifically, empty parameters, queries, and fragment identifiers will be removed. The result of this method is a fixpoint if passed back through the original parsing function: \begin{verbatim} >>> import urlparse >>> url = 'HTTP://www.Python.org/doc/#' >>> r1 = urlparse.urlsplit(url) >>> r1.geturl() 'http://www.Python.org/doc/' >>> r2 = urlparse.urlsplit(r1.geturl()) >>> r2.geturl() 'http://www.Python.org/doc/' \end{verbatim} \versionadded{2.5} \end{methoddesc} The following classes provide the implementations of the parse results:: \begin{classdesc*}{BaseResult} Base class for the concrete result classes. This provides most of the attribute definitions. It does not provide a \method{geturl()} method. It is derived from \class{tuple}, but does not override the \method{__init__()} or \method{__new__()} methods. \end{classdesc*} \begin{classdesc}{ParseResult}{scheme, netloc, path, params, query, fragment} Concrete class for \function{urlparse()} results. The \method{__new__()} method is overridden to support checking that the right number of arguments are passed. \end{classdesc} \begin{classdesc}{SplitResult}{scheme, netloc, path, query, fragment} Concrete class for \function{urlsplit()} results. The \method{__new__()} method is overridden to support checking that the right number of arguments are passed. \end{classdesc}