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Diffstat (limited to 'Doc/library/urllib.parse.rst')
| -rw-r--r-- | Doc/library/urllib.parse.rst | 267 |
1 files changed, 201 insertions, 66 deletions
diff --git a/Doc/library/urllib.parse.rst b/Doc/library/urllib.parse.rst index 0ed27ba409..a6d72672ab 100644 --- a/Doc/library/urllib.parse.rst +++ b/Doc/library/urllib.parse.rst @@ -24,7 +24,15 @@ following URL schemes: ``file``, ``ftp``, ``gopher``, ``hdl``, ``http``, ``rsync``, ``rtsp``, ``rtspu``, ``sftp``, ``shttp``, ``sip``, ``sips``, ``snews``, ``svn``, ``svn+ssh``, ``telnet``, ``wais``. -The :mod:`urllib.parse` module defines the following functions: +The :mod:`urllib.parse` module defines functions that fall into two broad +categories: URL parsing and URL quoting. These are covered in detail in +the following sections. + +URL Parsing +----------- + +The URL parsing functions focus on splitting a URL string into its components, +or on combining URL components into a URL string. .. function:: urlparse(urlstring, scheme='', allow_fragments=True) @@ -104,8 +112,11 @@ The :mod:`urllib.parse` module defines the following functions: See section :ref:`urlparse-result-object` for more information on the result object. + .. versionchanged:: 3.2 + Added IPv6 URL parsing capabilities. + -.. function:: parse_qs(qs, keep_blank_values=False, strict_parsing=False) +.. function:: parse_qs(qs, keep_blank_values=False, strict_parsing=False, encoding='utf-8', errors='replace') Parse a query string given as a string argument (data of type :mimetype:`application/x-www-form-urlencoded`). Data are returned as a @@ -122,11 +133,19 @@ The :mod:`urllib.parse` module defines the following functions: parsing errors. If false (the default), errors are silently ignored. If true, errors raise a :exc:`ValueError` exception. + The optional *encoding* and *errors* parameters specify how to decode + percent-encoded sequences into Unicode characters, as accepted by the + :meth:`bytes.decode` method. + Use the :func:`urllib.parse.urlencode` function to convert such dictionaries into query strings. -.. function:: parse_qsl(qs, keep_blank_values=False, strict_parsing=False) + .. versionchanged:: 3.2 + Add *encoding* and *errors* parameters. + + +.. function:: parse_qsl(qs, keep_blank_values=False, strict_parsing=False, encoding='utf-8', errors='replace') Parse a query string given as a string argument (data of type :mimetype:`application/x-www-form-urlencoded`). Data are returned as a list of @@ -142,9 +161,16 @@ The :mod:`urllib.parse` module defines the following functions: parsing errors. If false (the default), errors are silently ignored. If true, errors raise a :exc:`ValueError` exception. + The optional *encoding* and *errors* parameters specify how to decode + percent-encoded sequences into Unicode characters, as accepted by the + :meth:`bytes.decode` method. + Use the :func:`urllib.parse.urlencode` function to convert such lists of pairs into query strings. + .. versionchanged:: 3.2 + Add *encoding* and *errors* parameters. + .. function:: urlunparse(parts) @@ -239,6 +265,162 @@ The :mod:`urllib.parse` module defines the following functions: string. If there is no fragment identifier in *url*, return *url* unmodified and an empty string. + The return value is actually an instance of a subclass of :class:`tuple`. This + class has the following additional read-only convenience attributes: + + +------------------+-------+-------------------------+----------------------+ + | Attribute | Index | Value | Value if not present | + +==================+=======+=========================+======================+ + | :attr:`url` | 0 | URL with no fragment | empty string | + +------------------+-------+-------------------------+----------------------+ + | :attr:`fragment` | 1 | Fragment identifier | empty string | + +------------------+-------+-------------------------+----------------------+ + + See section :ref:`urlparse-result-object` for more information on the result + object. + + .. versionchanged:: 3.2 + Result is a structured object rather than a simple 2-tuple. + +.. _parsing-ascii-encoded-bytes: + +Parsing ASCII Encoded Bytes +--------------------------- + +The URL parsing functions were originally designed to operate on character +strings only. In practice, it is useful to be able to manipulate properly +quoted and encoded URLs as sequences of ASCII bytes. Accordingly, the +URL parsing functions in this module all operate on :class:`bytes` and +:class:`bytearray` objects in addition to :class:`str` objects. + +If :class:`str` data is passed in, the result will also contain only +:class:`str` data. If :class:`bytes` or :class:`bytearray` data is +passed in, the result will contain only :class:`bytes` data. + +Attempting to mix :class:`str` data with :class:`bytes` or +:class:`bytearray` in a single function call will result in a +:exc:`TypeError` being raised, while attempting to pass in non-ASCII +byte values will trigger :exc:`UnicodeDecodeError`. + +To support easier conversion of result objects between :class:`str` and +:class:`bytes`, all return values from URL parsing functions provide +either an :meth:`encode` method (when the result contains :class:`str` +data) or a :meth:`decode` method (when the result contains :class:`bytes` +data). The signatures of these methods match those of the corresponding +:class:`str` and :class:`bytes` methods (except that the default encoding +is ``'ascii'`` rather than ``'utf-8'``). Each produces a value of a +corresponding type that contains either :class:`bytes` data (for +:meth:`encode` methods) or :class:`str` data (for +:meth:`decode` methods). + +Applications that need to operate on potentially improperly quoted URLs +that may contain non-ASCII data will need to do their own decoding from +bytes to characters before invoking the URL parsing methods. + +The behaviour described in this section applies only to the URL parsing +functions. The URL quoting functions use their own rules when producing +or consuming byte sequences as detailed in the documentation of the +individual URL quoting functions. + +.. versionchanged:: 3.2 + URL parsing functions now accept ASCII encoded byte sequences + + +.. _urlparse-result-object: + +Structured Parse Results +------------------------ + +The result objects from the :func:`urlparse`, :func:`urlsplit` and +:func:`urldefrag` functions are subclasses of the :class:`tuple` type. +These subclasses add the attributes listed in the documentation for +those functions, the encoding and decoding support described in the +previous section, as well as an additional method: + +.. method:: urllib.parse.SplitResult.geturl() + + Return the re-combined version of the original URL as a string. This may + differ from the original URL in that the scheme may be normalized to lower + case and empty components may be dropped. Specifically, empty parameters, + queries, and fragment identifiers will be removed. + + For :func:`urldefrag` results, only empty fragment identifiers will be removed. + For :func:`urlsplit` and :func:`urlparse` results, all noted changes will be + made to the URL returned by this method. + + The result of this method remains unchanged if passed back through the original + parsing function: + + >>> from urllib.parse import urlsplit + >>> url = 'HTTP://www.Python.org/doc/#' + >>> r1 = urlsplit(url) + >>> r1.geturl() + 'http://www.Python.org/doc/' + >>> r2 = urlsplit(r1.geturl()) + >>> r2.geturl() + 'http://www.Python.org/doc/' + + +The following classes provide the implementations of the structured parse +results when operating on :class:`str` objects: + +.. class:: DefragResult(url, fragment) + + Concrete class for :func:`urldefrag` results containing :class:`str` + data. The :meth:`encode` method returns a :class:`DefragResultBytes` + instance. + + .. versionadded:: 3.2 + +.. class:: ParseResult(scheme, netloc, path, params, query, fragment) + + Concrete class for :func:`urlparse` results containing :class:`str` + data. The :meth:`encode` method returns a :class:`ParseResultBytes` + instance. + +.. class:: SplitResult(scheme, netloc, path, query, fragment) + + Concrete class for :func:`urlsplit` results containing :class:`str` + data. The :meth:`encode` method returns a :class:`SplitResultBytes` + instance. + + +The following classes provide the implementations of the parse results when +operating on :class:`bytes` or :class:`bytearray` objects: + +.. class:: DefragResultBytes(url, fragment) + + Concrete class for :func:`urldefrag` results containing :class:`bytes` + data. The :meth:`decode` method returns a :class:`DefragResult` + instance. + + .. versionadded:: 3.2 + +.. class:: ParseResultBytes(scheme, netloc, path, params, query, fragment) + + Concrete class for :func:`urlparse` results containing :class:`bytes` + data. The :meth:`decode` method returns a :class:`ParseResult` + instance. + + .. versionadded:: 3.2 + +.. class:: SplitResultBytes(scheme, netloc, path, query, fragment) + + Concrete class for :func:`urlsplit` results containing :class:`bytes` + data. The :meth:`decode` method returns a :class:`SplitResult` + instance. + + .. versionadded:: 3.2 + + +URL Quoting +----------- + +The URL quoting functions focus on taking program data and making it safe +for use as URL components by quoting special characters and appropriately +encoding non-ASCII text. They also support reversing these operations to +recreate the original data from the contents of a URL component if that +task isn't already covered by the URL parsing functions above. .. function:: quote(string, safe='/', encoding=None, errors=None) @@ -319,16 +501,16 @@ The :mod:`urllib.parse` module defines the following functions: If it is a :class:`str`, unescaped non-ASCII characters in *string* are encoded into UTF-8 bytes. - Example: ``unquote_to_bytes('a%26%EF')`` yields - ``b'a&\xef'``. + Example: ``unquote_to_bytes('a%26%EF')`` yields ``b'a&\xef'``. .. function:: urlencode(query, doseq=False, safe='', encoding=None, errors=None) Convert a mapping object or a sequence of two-element tuples, which may - either be a :class:`str` or a :class:`bytes`, to a "percent-encoded" string, - suitable to pass to :func:`urlopen` above as the optional *data* argument. - This is useful to pass a dictionary of form fields to a ``POST`` request. + either be a :class:`str` or a :class:`bytes`, to a "percent-encoded" + string. The resultant string must be converted to bytes using the + user-specified encoding before it is sent to :func:`urlopen` as the optional + *data* argument. The resulting string is a series of ``key=value`` pairs separated by ``'&'`` characters, where both *key* and *value* are quoted using :func:`quote_plus` above. When a sequence of two-element tuples is used as the *query* @@ -337,12 +519,16 @@ The :mod:`urllib.parse` module defines the following functions: the optional parameter *doseq* is evaluates to *True*, individual ``key=value`` pairs separated by ``'&'`` are generated for each element of the value sequence for the key. The order of parameters in the encoded - string will match the order of parameter tuples in the sequence. This module - provides the functions :func:`parse_qs` and :func:`parse_qsl` which are used - to parse query strings into Python data structures. + string will match the order of parameter tuples in the sequence. When *query* parameter is a :class:`str`, the *safe*, *encoding* and *error* - parameters are sent the :func:`quote_plus` for encoding. + parameters are passed down to :func:`quote_plus` for encoding. + + To reverse this encoding process, :func:`parse_qs` and :func:`parse_qsl` are + provided in this module to parse query strings into Python data structures. + + Refer to :ref:`urllib examples <urllib-examples>` to find out how urlencode + method can be used for generating query string for a URL or data for POST. .. versionchanged:: 3.2 Query parameter supports bytes and string objects. @@ -356,6 +542,9 @@ The :mod:`urllib.parse` module defines the following functions: mostly for backward compatibility purposes and for certain de-facto parsing requirements as commonly observed in major browsers. + :rfc:`2732` - Format for Literal IPv6 Addresses in URL's. + This specifies the parsing requirements of IPv6 URLs. + :rfc:`2396` - Uniform Resource Identifiers (URI): Generic Syntax Document describing the generic syntactic requirements for both Uniform Resource Names (URNs) and Uniform Resource Locators (URLs). @@ -370,57 +559,3 @@ The :mod:`urllib.parse` module defines the following functions: :rfc:`1738` - Uniform Resource Locators (URL) This specifies the formal syntax and semantics of absolute URLs. - - -.. _urlparse-result-object: - -Results of :func:`urlparse` and :func:`urlsplit` ------------------------------------------------- - -The result objects from the :func:`urlparse` and :func:`urlsplit` functions are -subclasses of the :class:`tuple` type. These subclasses add the attributes -described in those functions, as well as provide an additional method: - -.. method:: 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: - - >>> import urllib.parse - >>> url = 'HTTP://www.Python.org/doc/#' - - >>> r1 = urllib.parse.urlsplit(url) - >>> r1.geturl() - 'http://www.Python.org/doc/' - - >>> r2 = urllib.parse.urlsplit(r1.geturl()) - >>> r2.geturl() - 'http://www.Python.org/doc/' - - -The following classes provide the implementations of the parse results: - -.. class:: BaseResult - - Base class for the concrete result classes. This provides most of the - attribute definitions. It does not provide a :meth:`geturl` method. It is - derived from :class:`tuple`, but does not override the :meth:`__init__` or - :meth:`__new__` methods. - - -.. class:: ParseResult(scheme, netloc, path, params, query, fragment) - - Concrete class for :func:`urlparse` results. The :meth:`__new__` method is - overridden to support checking that the right number of arguments are passed. - - -.. class:: SplitResult(scheme, netloc, path, query, fragment) - - Concrete class for :func:`urlsplit` results. The :meth:`__new__` method is - overridden to support checking that the right number of arguments are passed. - |