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Python 3.6.5 Documentation > "urllib.parse" — Parse URLs into components

"urllib.parse" — Parse URLs into components
*******************************************

**Source code:** Lib/urllib/parse.py

======================================================================

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. It supports the following URL schemes:
"file", "ftp", "gopher", "hdl", "http", "https", "imap", "mailto",
"mms", "news", "nntp", "prospero", "rsync", "rtsp", "rtspu", "sftp",
"shttp", "sip", "sips", "snews", "svn", "svn+ssh", "telnet", "wais",
"ws", "wss".

The "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.

urllib.parse.urlparse(urlstring, scheme='', allow_fragments=True)

Parse a URL into six components, returning a 6-tuple. This
corresponds to the general structure of a URL:
"scheme://netloc/path;parameters?query#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
*path* component, which is retained if present. For example:

>>> from urllib.parse import urlparse
>>> o = urlparse('http://www.cwi.nl:80/%7Eguido/Python.html')
>>> o # doctest: +NORMALIZE_WHITESPACE
ParseResult(scheme='http', netloc='www.cwi.nl:80', path='/%7Eguido/Python.html',
params='', query='', fragment='')
>>> o.scheme
'http'
>>> o.port
80
>>> o.geturl()
'http://www.cwi.nl:80/%7Eguido/Python.html'

Following the syntax specifications in **RFC 1808**, urlparse
recognizes a netloc only if it is properly introduced by ‘//’.
Otherwise the input is presumed to be a relative URL and thus to
start with a path component.

>>> from urllib.parse import urlparse
>>> urlparse('//www.cwi.nl:80/%7Eguido/Python.html')
ParseResult(scheme='', netloc='www.cwi.nl:80', path='/%7Eguido/Python.html',
params='', query='', fragment='')
>>> urlparse('www.cwi.nl/%7Eguido/Python.html')
ParseResult(scheme='', netloc='', path='www.cwi.nl/%7Eguido/Python.html',
params='', query='', fragment='')
>>> urlparse('help/Python.html')
ParseResult(scheme='', netloc='', path='help/Python.html', params='',
query='', fragment='')

The *scheme* argument gives the default addressing scheme, to be
used only if the URL does not specify one. It should be the same
type (text or bytes) as *urlstring*, except that the default value
"''" is always allowed, and is automatically converted to "b''" if
appropriate.

If the *allow_fragments* argument is false, fragment identifiers
are not recognized. Instead, they are parsed as part of the path,
parameters or query component, and "fragment" is set to the empty
string in the return value.

The return value is actually an instance of a subclass of "tuple".
This class has the following additional read-only convenience
attributes:

Reading the "port" attribute will raise a "ValueError" if an
invalid port is specified in the URL. See section Structured Parse
Results for more information on the result object.

Unmatched square brackets in the "netloc" attribute will raise a
"ValueError".

Changed in version 3.2: Added IPv6 URL parsing capabilities.

Changed in version 3.3: The fragment is now parsed for all URL
schemes (unless *allow_fragment* is false), in accordance with
**RFC 3986**. Previously, a whitelist of schemes that support
fragments existed.

Changed in version 3.6: Out-of-range port numbers now raise
"ValueError", instead of returning "None".

urllib.parse.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
*application/x-www-form-urlencoded*). Data are returned as a
dictionary. The dictionary keys are the unique query variable
names and the values are lists of values for each name.

The optional argument *keep_blank_values* is a flag indicating
whether blank values in percent-encoded queries should be treated
as blank strings. A true value indicates that blanks should be
retained as blank strings. The default false value indicates that
blank values are to be ignored and treated as if they were not
included.

The optional argument *strict_parsing* is a flag indicating what to
do with parsing errors. If false (the default), errors are
silently ignored. If true, errors raise a "ValueError" exception.

The optional *encoding* and *errors* parameters specify how to
decode percent-encoded sequences into Unicode characters, as
accepted by the "bytes.decode()" method.

Use the "urllib.parse.urlencode()" function (with the "doseq"
parameter set to "True") to convert such dictionaries into query
strings.

Changed in version 3.2: Add *encoding* and *errors* parameters.

urllib.parse.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
*application/x-www-form-urlencoded*). Data are returned as a list
of name, value pairs.

The optional argument *strict_parsing* is a flag indicating what to
do with parsing errors. If false (the default), errors are
silently ignored. If true, errors raise a "ValueError" exception.

The optional *encoding* and *errors* parameters specify how to
decode percent-encoded sequences into Unicode characters, as
accepted by the "bytes.decode()" method.

Use the "urllib.parse.urlencode()" function to convert such lists
of pairs into query strings.

Changed in version 3.2: Add *encoding* and *errors* parameters.

urllib.parse.urlunparse(parts)

Construct a URL from a tuple as returned by "urlparse()". The
*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).

urllib.parse.urlsplit(urlstring, scheme='', allow_fragments=True)

This is similar to "urlparse()", but does not split the params from
the URL. This should generally be used instead of "urlparse()" if
the more recent URL syntax allowing parameters to be applied to
each segment of the *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 "tuple".
This class has the following additional read-only convenience
attributes:

Reading the "port" attribute will raise a "ValueError" if an
invalid port is specified in the URL. See section Structured Parse
Results for more information on the result object.

Unmatched square brackets in the "netloc" attribute will raise a
"ValueError".

Changed in version 3.6: Out-of-range port numbers now raise
"ValueError", instead of returning "None".

urllib.parse.urlunsplit(parts)

Combine the elements of a tuple as returned by "urlsplit()" into a
complete URL as a string. The *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).

urllib.parse.urljoin(base, url, allow_fragments=True)

Construct a full (“absolute”) URL by combining a “base URL”
(*base*) with another URL (*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:

>>> from urllib.parse import urljoin
>>> urljoin('http://www.cwi.nl/%7Eguido/Python.html', 'FAQ.html')
'http://www.cwi.nl/%7Eguido/FAQ.html'

The *allow_fragments* argument has the same meaning and default as
for "urlparse()".

Note: If *url* is an absolute URL (that is, starting with "//" or
"scheme://"), the *url*’s host name and/or scheme will be present
in the result. For example:

>>> urljoin('http://www.cwi.nl/%7Eguido/Python.html',
... '//www.python.org/%7Eguido')
'http://www.python.org/%7Eguido'

If you do not want that behavior, preprocess the *url* with
"urlsplit()" and "urlunsplit()", removing possible *scheme* and
*netloc* parts.

Changed in version 3.5: Behaviour updated to match the semantics
defined in **RFC 3986**.

urllib.parse.urldefrag(url)

If *url* contains a fragment identifier, return a modified version
of *url* with no fragment identifier, and the fragment identifier
as a separate 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 "tuple".
This class has the following additional read-only convenience
attributes:

See section Structured Parse Results for more information on the
result object.

Changed in version 3.2: Result is a structured object rather than a
simple 2-tuple.

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 "bytes" and "bytearray" objects in addition to "str"
objects.

If "str" data is passed in, the result will also contain only "str"
data. If "bytes" or "bytearray" data is passed in, the result will
contain only "bytes" data.

Attempting to mix "str" data with "bytes" or "bytearray" in a single
function call will result in a "TypeError" being raised, while
attempting to pass in non-ASCII byte values will trigger
"UnicodeDecodeError".

To support easier conversion of result objects between "str" and
"bytes", all return values from URL parsing functions provide either
an "encode()" method (when the result contains "str" data) or a
"decode()" method (when the result contains "bytes" data). The
signatures of these methods match those of the corresponding "str" and
"bytes" methods (except that the default encoding is "'ascii'" rather
than "'utf-8'"). Each produces a value of a corresponding type that
contains either "bytes" data (for "encode()" methods) or "str" data
(for "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.

Changed in version 3.2: URL parsing functions now accept ASCII encoded
byte sequences

Structured Parse Results
========================

The result objects from the "urlparse()", "urlsplit()" and
"urldefrag()" functions are subclasses of the "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:

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 "urldefrag()" results, only empty fragment identifiers will be
removed. For "urlsplit()" and "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 "str" objects:

class urllib.parse.DefragResult(url, fragment)

Concrete class for "urldefrag()" results containing "str" data. The
"encode()" method returns a "DefragResultBytes" instance.

New in version 3.2.

class urllib.parse.ParseResult(scheme, netloc, path, params, query, fragment)

Concrete class for "urlparse()" results containing "str" data. The
"encode()" method returns a "ParseResultBytes" instance.

class urllib.parse.SplitResult(scheme, netloc, path, query, fragment)

Concrete class for "urlsplit()" results containing "str" data. The
"encode()" method returns a "SplitResultBytes" instance.

The following classes provide the implementations of the parse results
when operating on "bytes" or "bytearray" objects:

class urllib.parse.DefragResultBytes(url, fragment)

Concrete class for "urldefrag()" results containing "bytes" data.
The "decode()" method returns a "DefragResult" instance.

New in version 3.2.

class urllib.parse.ParseResultBytes(scheme, netloc, path, params, query, fragment)

Concrete class for "urlparse()" results containing "bytes" data.
The "decode()" method returns a "ParseResult" instance.

New in version 3.2.

class urllib.parse.SplitResultBytes(scheme, netloc, path, query, fragment)

Concrete class for "urlsplit()" results containing "bytes" data.
The "decode()" method returns a "SplitResult" instance.

New in version 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.

urllib.parse.quote(string, safe='/', encoding=None, errors=None)

Replace special characters in *string* using the "%xx" escape.
Letters, digits, and the characters "'_.-'" are never quoted. By
default, this function is intended for quoting the path section of
URL. The optional *safe* parameter specifies additional ASCII
characters that should not be quoted — its default value is "'/'".

*string* may be either a "str" or a "bytes".

The optional *encoding* and *errors* parameters specify how to deal
with non-ASCII characters, as accepted by the "str.encode()"
method. *encoding* defaults to "'utf-8'". *errors* defaults to
"'strict'", meaning unsupported characters raise a
"UnicodeEncodeError". *encoding* and *errors* must not be supplied
if *string* is a "bytes", or a "TypeError" is raised.

Note that "quote(string, safe, encoding, errors)" is equivalent to
"quote_from_bytes(string.encode(encoding, errors), safe)".

Example: "quote('/El Niño/')" yields "'/El%20Ni%C3%B1o/'".

urllib.parse.quote_plus(string, safe='', encoding=None, errors=None)

Like "quote()", but also replace spaces by plus signs, as required
for quoting HTML form values when building up a query string to go
into a URL. Plus signs in the original string are escaped unless
they are included in *safe*. It also does not have *safe* default
to "'/'".

Example: "quote_plus('/El Niño/')" yields "'%2FEl+Ni%C3%B1o%2F'".

urllib.parse.quote_from_bytes(bytes, safe='/')

Like "quote()", but accepts a "bytes" object rather than a "str",
and does not perform string-to-bytes encoding.

Example: "quote_from_bytes(b'a&\xef')" yields "'a%26%EF'".

urllib.parse.unquote(string, encoding='utf-8', errors='replace')

Replace "%xx" escapes by their single-character equivalent. The
optional *encoding* and *errors* parameters specify how to decode
percent-encoded sequences into Unicode characters, as accepted by
the "bytes.decode()" method.

*string* must be a "str".

*encoding* defaults to "'utf-8'". *errors* defaults to "'replace'",
meaning invalid sequences are replaced by a placeholder character.

Example: "unquote('/El%20Ni%C3%B1o/')" yields "'/El Niño/'".

urllib.parse.unquote_plus(string, encoding='utf-8', errors='replace')

Like "unquote()", but also replace plus signs by spaces, as
required for unquoting HTML form values.

*string* must be a "str".

Example: "unquote_plus('/El+Ni%C3%B1o/')" yields "'/El Niño/'".

urllib.parse.unquote_to_bytes(string)

Replace "%xx" escapes by their single-octet equivalent, and return
a "bytes" object.

*string* may be either a "str" or a "bytes".

If it is a "str", unescaped non-ASCII characters in *string* are
encoded into UTF-8 bytes.

Example: "unquote_to_bytes('a%26%EF')" yields "b'a&\xef'".

urllib.parse.urlencode(query, doseq=False, safe='', encoding=None, errors=None, quote_via=quote_plus)

Convert a mapping object or a sequence of two-element tuples, which
may contain "str" or "bytes" objects, to a percent-encoded ASCII
text string. If the resultant string is to be used as a *data* for
POST operation with the "urlopen()" function, then it should be
encoded to bytes, otherwise it would result in a "TypeError".

The resulting string is a series of "key=value" pairs separated by
"'&'" characters, where both *key* and *value* are quoted using the
*quote_via* function. By default, "quote_plus()" is used to quote
the values, which means spaces are quoted as a "'+'" character and
‘/’ characters are encoded as "%2F", which follows the standard for
GET requests ("application/x-www-form-urlencoded"). An alternate
function that can be passed as *quote_via* is "quote()", which will
encode spaces as "%20" and not encode ‘/’ characters. For maximum
control of what is quoted, use "quote" and specify a value for
*safe*.

When a sequence of two-element tuples is used as the *query*
argument, the first element of each tuple is a key and the second
is a value. The value element in itself can be a sequence and in
that case, if 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.

The *safe*, *encoding*, and *errors* parameters are passed down to
*quote_via* (the *encoding* and *errors* parameters are only passed
when a query element is a "str").

To reverse this encoding process, "parse_qs()" and "parse_qsl()"
are provided in this module to parse query strings into Python data
structures.

Refer to urllib examples to find out how urlencode method can be
used for generating query string for a URL or data for POST.

Changed in version 3.2: Query parameter supports bytes and string
objects.

New in version 3.5: *quote_via* parameter.