urllib.parse —- Parse URLs into components
- URL 解析
- 解析ASCII编码字节
- 结构化解析结果
- URL Quoting

urllib.parse —- Parse URLs into components

源代码: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.), tocombine 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 UniformResource 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 broadcategories: URL parsing and URL quoting. These are covered in detail inthe following sections.

URL 解析

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-item named tuple. Thiscorresponds 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 insmaller parts (for example, the network location is a single string), and %escapes are not expanded. The delimiters as shown above are not part of theresult, except for a leading slash in the path component, which is retained ifpresent. 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 recognizesa netloc only if it is properly introduced by '//'. Otherwise theinput is presumed to be a relative URL and thus to start witha 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 beused only if the URL does not specify one. It should be the same type(text or bytes) as urlstring, except that the default value '' isalways allowed, and is automatically converted to b'' if appropriate.

If the allow_fragments argument is false, fragment identifiers are notrecognized. Instead, they are parsed as part of the path, parametersor query component, and fragment is set to the empty string inthe return value.

The return value is a named tuple, which means that its items canbe accessed by index or as named attributes, which are:

属性

索引

值

值（如果不存在）

scheme

URL方案说明符

scheme parameter

netloc

网络位置部分

空字符串

path

分层路径

空字符串

params

最后路径元素的参数

空字符串

query

查询组件

空字符串

fragment

片段识别

空字符串

username

用户名

None

password

密码

None

hostname

主机名（小写）

None

port

端口号为整数（如果存在）

None

Reading the port attribute will raise a ValueError ifan invalid port is specified in the URL. See section结构化解析结果 for more information on the result object.

Unmatched square brackets in the netloc attribute will raise aValueError.

Characters in the netloc attribute that decompose under NFKCnormalization (as used by the IDNA encoding) into any of /, ?,#, @, or : will raise a ValueError. If the URL isdecomposed before parsing, no error will be raised.

As is the case with all named tuples, the subclass has a few additional methodsand attributes that are particularly useful. One such method is _replace().The _replace() method will return a new ParseResult object replacing specifiedfields with new values.

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

在 3.2 版更改: 添加了IPv6 URL解析功能。

在 3.3 版更改: The fragment is now parsed for all URL schemes (unless allow_fragment isfalse), in accordance with RFC 3986. Previously, a whitelist ofschemes that support fragments existed.

在 3.6 版更改: Out-of-range port numbers now raise ValueError, instead ofreturning None.

在 3.8 版更改: Characters that affect netloc parsing under NFKC normalization willnow raise ValueError.

urllib.parse.parseqs(_qs, keep_blank_values=False, strict_parsing=False, encoding='utf-8', errors='replace', max_num_fields=None)
Parse a query string given as a string argument (data of typeapplication/x-www-form-urlencoded). Data are returned as adictionary. The dictionary keys are the unique query variable names and thevalues are lists of values for each name.

The optional argument keep_blank_values is a flag indicating whether blankvalues in percent-encoded queries should be treated as blank strings. A true valueindicates that blanks should be retained as blank strings. The default falsevalue indicates that blank values are to be ignored and treated as if they werenot included.

The optional argument strict_parsing is a flag indicating what to do withparsing 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 decodepercent-encoded sequences into Unicode characters, as accepted by thebytes.decode() method.

The optional argument max_num_fields is the maximum number of fields toread. If set, then throws a ValueError if there are more thanmax_num_fields fields read.

Use the urllib.parse.urlencode() function (with the doseqparameter set to True) to convert such dictionaries into querystrings.

在 3.2 版更改: Add encoding and errors parameters.

在 3.8 版更改: Added max_num_fields parameter.

urllib.parse.parseqsl(_qs, keep_blank_values=False, strict_parsing=False, encoding='utf-8', errors='replace', max_num_fields=None)
Parse a query string given as a string argument (data of typeapplication/x-www-form-urlencoded). Data are returned as a list ofname, value pairs.

The optional argument strict_parsing is a flag indicating what to do withparsing 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 decodepercent-encoded sequences into Unicode characters, as accepted by thebytes.decode() method.

The optional argument max_num_fields is the maximum number of fields toread. If set, then throws a ValueError if there are more thanmax_num_fields fields read.

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

在 3.2 版更改: Add encoding and errors parameters.

在 3.8 版更改: Added max_num_fields parameter.

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 slightlydifferent, but equivalent URL, if the URL that was parsed originally hadunnecessary delimiters (for example, a ? with an empty query; the RFCstates 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 URLsyntax allowing parameters to be applied to each segment of the path portionof the URL (see RFC 2396) is wanted. A separate function is needed toseparate the path segments and parameters. This function returns a 5-itemnamed tuple:

(addressing scheme, network location, path, query, fragment identifier).

The return value is a named tuple, its items can be accessed by indexor as named attributes:

属性

索引

值

值（如果不存在）

scheme

URL方案说明符

scheme parameter

netloc

网络位置部分

空字符串

path

分层路径

空字符串

query

查询组件

空字符串

fragment

片段识别

空字符串

username

用户名

None

password

密码

None

hostname

主机名（小写）

None

port

端口号为整数（如果存在）

None

Reading the port attribute will raise a ValueError ifan invalid port is specified in the URL. See section结构化解析结果 for more information on the result object.

Unmatched square brackets in the netloc attribute will raise aValueError.

在 3.6 版更改: Out-of-range port numbers now raise ValueError, instead ofreturning None.

在 3.8 版更改: Characters that affect netloc parsing under NFKC normalization willnow raise ValueError.

urllib.parse.urlunsplit(parts)
Combine the elements of a tuple as returned by urlsplit() into acomplete URL as a string. The parts argument can be any five-itemiterable. This may result in a slightly different, but equivalent URL, if theURL 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) withanother URL (url). Informally, this uses components of the base URL, inparticular the addressing scheme, the network location and (part of) thepath, 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 forurlparse().

注解

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() andurlunsplit(), removing possible scheme and netloc parts.

在 3.5 版更改: 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 separatestring. If there is no fragment identifier in _url, return url unmodifiedand an empty string.

The return value is a named tuple, its items can be accessed by indexor as named attributes:

属性

索引

值

值（如果不存在）

url

URL with no fragment

空字符串

fragment

片段识别

空字符串

See section 结构化解析结果 for more information on the resultobject.

在 3.2 版更改: Result is a structured object rather than a simple 2-tuple.

urllib.parse.unwrap(url)
Extract the url from a wrapped URL (that is, a string formatted as<URL:scheme://host/path>, <scheme://host/path>, URL:scheme://host/pathor scheme://host/path). If url is not a wrapped URL, it is returnedwithout changes.

解析ASCII编码字节

The URL parsing functions were originally designed to operate on characterstrings only. In practice, it is useful to be able to manipulate properlyquoted and encoded URLs as sequences of ASCII bytes. Accordingly, theURL parsing functions in this module all operate on bytes andbytearray objects in addition to str objects.

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

Attempting to mix str data with bytes orbytearray in a single function call will result in aTypeError being raised, while attempting to pass in non-ASCIIbyte values will trigger UnicodeDecodeError.

To support easier conversion of result objects between str andbytes, all return values from URL parsing functions provideeither an encode() method (when the result contains strdata) or a decode() method (when the result contains bytesdata). The signatures of these methods match those of the correspondingstr and bytes methods (except that the default encodingis 'ascii' rather than 'utf-8'). Each produces a value of acorresponding type that contains either bytes data (forencode() methods) or str data (fordecode() methods).

Applications that need to operate on potentially improperly quoted URLsthat may contain non-ASCII data will need to do their own decoding frombytes to characters before invoking the URL parsing methods.

The behaviour described in this section applies only to the URL parsingfunctions. The URL quoting functions use their own rules when producingor consuming byte sequences as detailed in the documentation of theindividual URL quoting functions.

在 3.2 版更改: URL parsing functions now accept ASCII encoded byte sequences

结构化解析结果

The result objects from the urlparse(), urlsplit() andurldefrag() functions are subclasses of the tuple type.These subclasses add the attributes listed in the documentation forthose functions, the encoding and decoding support described in theprevious section, as well as an additional method:

urllib.parse.SplitResult.geturl()
Return the re-combined version of the original URL as a string. This maydiffer from the original URL in that the scheme may be normalized to lowercase 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 bemade to the URL returned by this method.

The result of this method remains unchanged if passed back through the originalparsing 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 parseresults when operating on str objects:

class urllib.parse.DefragResult(url, fragment)
Concrete class for urldefrag() results containing strdata. The encode() method returns a DefragResultBytesinstance.

3.2 新版功能.

class urllib.parse.ParseResult(scheme, netloc, path, params, query, fragment)
Concrete class for urlparse() results containing strdata. The encode() method returns a ParseResultBytesinstance.
class urllib.parse.SplitResult(scheme, netloc, path, query, fragment)
Concrete class for urlsplit() results containing strdata. The encode() method returns a SplitResultBytesinstance.

The following classes provide the implementations of the parse results whenoperating on bytes or bytearray objects:

class urllib.parse.DefragResultBytes(url, fragment)
Concrete class for urldefrag() results containing bytesdata. The decode() method returns a DefragResultinstance.

3.2 新版功能.

class urllib.parse.ParseResultBytes(scheme, netloc, path, params, query, fragment)
Concrete class for urlparse() results containing bytesdata. The decode() method returns a ParseResultinstance.

3.2 新版功能.

class urllib.parse.SplitResultBytes(scheme, netloc, path, query, fragment)
Concrete class for urlsplit() results containing bytesdata. The decode() method returns a SplitResultinstance.

3.2 新版功能.

URL Quoting

The URL quoting functions focus on taking program data and making it safefor use as URL components by quoting special characters and appropriatelyencoding non-ASCII text. They also support reversing these operations torecreate the original data from the contents of a URL component if thattask 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, thisfunction 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.

在 3.7 版更改: Moved from RFC 2396 to RFC 3986 for quoting URL strings. "~" is nowincluded in the set of unreserved characters.

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

Note that quote(string, safe, encoding, errors) is equivalent toquote_from_bytes(string.encode(encoding, errors), safe).

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

urllib.parse.quoteplus(_string, safe='', encoding=None, errors=None)
Like quote(), but also replace spaces by plus signs, as required forquoting 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 insafe. It also does not have safe default to '/'.

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

urllib.parse.quotefrom_bytes(_bytes, safe='/')
Like quote(), but accepts a bytes object rather than astr, 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 decodepercent-encoded sequences into Unicode characters, as accepted by thebytes.decode() method.

string must be a str.

encoding defaults to 'utf-8'.errors defaults to 'replace', meaning invalid sequences are replacedby a placeholder character.

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

urllib.parse.unquoteplus(_string, encoding='utf-8', errors='replace')
Like unquote(), but also replace plus signs by spaces, as required forunquoting HTML form values.

string must be a str.

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

urllib.parse.unquoteto_bytes(_string)
Replace %xx escapes by their single-octet equivalent, and return abytes 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 maycontain str or bytes objects, to a percent-encoded ASCIItext string. If the resultant string is to be used as a data for POSToperation with the urlopen() function, thenit should be encoded to bytes, otherwise it would result in aTypeError.

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, whichmeans spaces are quoted as a '+' character and '/' characters areencoded as %2F, which follows the standard for GET requests(application/x-www-form-urlencoded). An alternate function that can bepassed as _quote_via is quote(), which will encode spaces as %20and not encode '/' characters. For maximum control of what is quoted, usequote 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 avalue. The value element in itself can be a sequence and in that case, ifthe optional parameter _doseq is evaluates to True, individualkey=value pairs separated by '&' are generated for each element ofthe value sequence for the key. The order of parameters in the encodedstring will match the order of parameter tuples in the sequence.

The safe, encoding, and errors parameters are passed down toquote_via (the encoding and errors parameters are only passedwhen a query element is a str).

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

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

在 3.2 版更改: 查询参数支持字节和字符串对象。

3.5 新版功能: quote_via 参数.

参见

RFC 3986 - 统一资源标识符
This is the current standard (STD66). Any changes to urllib.parse moduleshould conform to this. Certain deviations could be observed, which aremostly for backward compatibility purposes and for certain de-factoparsing 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 - 统一资源标识符（URI）：通用语法
Document describing the generic syntactic requirements for both Uniform ResourceNames (URNs) and Uniform Resource Locators (URLs).
RFC 2368 - The mailto URL scheme.
Parsing requirements for mailto URL schemes.
RFC 1808 - Relative Uniform Resource Locators
This Request For Comments includes the rules for joining an absolute and arelative URL, including a fair number of "Abnormal Examples" which govern thetreatment of border cases.
RFC 1738 - Uniform Resource Locators (URL)
This specifies the formal syntax and semantics of absolute URLs.