urllib.parse — Parse URLs into components

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: 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.

The urllib.parse module defines the following functions:

urllib.parse.urlparse(urlstring[, default_scheme[, allow_fragments]])

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'

If the 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 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 True.

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

Attribute	Index	Value	Value if not present
scheme	0	URL scheme specifier	empty string
netloc	1	Network location part	empty string
path	2	Hierarchical path	empty string
params	3	Parameters for last path element	empty string
query	4	Query component	empty string
fragment	5	Fragment identifier	empty string
username		User name	None
password		Password	None
hostname		Host name (lower case)	None
port		Port number as integer, if present	None

See section Results of urlparse() and urlsplit() for more information on the result object.

urllib.parse.parse_qs(qs[, keep_blank_values[, strict_parsing]])

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 URL 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.

Use the urllib.parse.urlencode() function to convert such dictionaries into query strings.

urllib.parse.parse_qsl(qs[, keep_blank_values[, strict_parsing]])

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 keep_blank_values is a flag indicating whether blank values in URL 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.

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

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[, default_scheme[, allow_fragments]])

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:

Attribute	Index	Value	Value if not present
scheme	0	URL scheme specifier	empty string
netloc	1	Network location part	empty string
path	2	Hierarchical path	empty string
query	3	Query component	empty string
fragment	4	Fragment identifier	empty string
username		User name	None
password		Password	None
hostname		Host name (lower case)	None
port		Port number as integer, if present	None

See section Results of urlparse() and urlsplit() for more information on the result object.

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])

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.

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.

urllib.parse.quote(string[, safe[, encoding[, errors]]])

Replace special characters in string using the %xx escape. Letters, digits, and the characters '_.-' are never quoted. 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[, errors]]])

Like quote(), but also replace spaces by plus signs, as required for quoting HTML form values. 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[, errors]])

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[, errors]])

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])

Convert a mapping object or a sequence of two-element tuples to a “url-encoded” string, suitable to pass to urlopen() above as the optional data argument. This is useful to pass a dictionary of form fields to a POST request. The resulting string is a series of key=value pairs separated by '&' characters, where both key and value are quoted using quote_plus() above. If the optional parameter doseq is present and evaluates to true, individual key=value pairs are generated for each element of the sequence. 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 order of parameters in the encoded string will match the order of parameter tuples in the sequence. This module provides the functions parse_qs() and parse_qsl() which are used to parse query strings into Python data structures.

See also

RFC 1738 - Uniform Resource Locators (URL)

This specifies the formal syntax and semantics of absolute URLs.

RFC 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.

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).

Results of urlparse() and urlsplit()

The result objects from the urlparse() and urlsplit() functions are subclasses of the tuple type. These subclasses add the attributes described in those functions, as well as provide an additional 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 urllib.parse.BaseResult

Base class for the concrete result classes. This provides most of the attribute definitions. It does not provide a geturl() method. It is derived from tuple, but does not override the __init__() or __new__() methods.

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

Concrete class for urlparse() results. The __new__() method is overridden to support checking that the right number of arguments are passed.

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

Concrete class for urlsplit() results. The __new__() method is overridden to support checking that the right number of arguments are passed.