urllib.parse — 将 URL 剖析成组件 ¶

URL 剖析 ¶

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 命名元组 . 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 into 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
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'
										

遵循的句法规范在 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='')
										

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'' 若合适。

若 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.

返回值为 命名元组 , which means that its items can be accessed by index or as named attributes, which are:

属性	索引	值	值若不存在
scheme	0	URL 方案说明符	scheme parameter
netloc	1	网络位置部分	空字符串
path	2	分层路径	空字符串
params	3	用于最后路径元素的参数	空字符串
query	4	查询组件	空字符串
fragment	5	片段标识符	空字符串
username		用户名	None
password		口令	None
hostname		主机名 (小写)	None
port		整数形式的端口号 (若存在)	None

读取 port 属性将引发 ValueError if an invalid port is specified in the URL. See section 结构化剖析结果 for more information on the result object.

Unmatched square brackets in the netloc 属性将引发 ValueError .

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

As is the case with all named tuples, the subclass has a few additional methods and attributes that are particularly useful. One such method is _replace() . _replace() method will return a new ParseResult object replacing specified fields 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='')
										

3.2 版改变： Added IPv6 URL parsing capabilities.

3.3 版改变： 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.

3.6 版改变： Out-of-range port numbers now raise ValueError , instead of returning None .

3.8 版改变： Characters that affect netloc parsing under NFKC normalization will now raise ValueError .

urllib.parse. parse_qs ( qs , keep_blank_values=False , strict_parsing=False , encoding='utf-8' , errors='replace' , max_num_fields=None , separator='&' ) ¶

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.

可选自变量 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.

可选自变量 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 异常。

可选 encoding and errors parameters specify how to decode percent-encoded sequences into Unicode characters, as accepted by the bytes.decode() 方法。

可选自变量 max_num_fields is the maximum number of fields to read. If set, then throws a ValueError if there are more than max_num_fields fields read.

可选自变量 separator is the symbol to use for separating the query arguments. It defaults to & .

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

3.2 版改变： 添加 encoding and errors 参数。

3.8 版改变： 添加 max_num_fields 参数。

Changed in version 3.9.2: 添加 separator parameter with the default value of & . Python versions earlier than Python 3.9.2 allowed using both ; and & as query parameter separator. This has been changed to allow only a single separator key, with & as the default separator.

urllib.parse. parse_qsl ( qs , keep_blank_values=False , strict_parsing=False , encoding='utf-8' , errors='replace' , max_num_fields=None , separator='&' ) ¶

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.

可选自变量 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.

可选自变量 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 异常。

可选 encoding and errors parameters specify how to decode percent-encoded sequences into Unicode characters, as accepted by the bytes.decode() 方法。

可选自变量 max_num_fields is the maximum number of fields to read. If set, then throws a ValueError if there are more than max_num_fields fields read.

可选自变量 separator is the symbol to use for separating the query arguments. It defaults to & .

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

3.2 版改变： 添加 encoding and errors 参数。

3.8 版改变： 添加 max_num_fields 参数。

Changed in version 3.9.2: 添加 separator parameter with the default value of & . Python versions earlier than Python 3.9.2 allowed using both ; and & as query parameter separator. This has been changed to allow only a single separator key, with & as the default separator.

urllib.parse. urlunparse ( parts ) ¶

Construct a URL from a tuple as returned by urlparse() 。 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-item 命名元组 :

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

返回值为 命名元组 , its items can be accessed by index or as named attributes:

属性	索引	值	值若不存在
scheme	0	URL 方案说明符	scheme parameter
netloc	1	网络位置部分	空字符串
path	2	分层路径	空字符串
query	3	查询组件	空字符串
fragment	4	片段标识符	空字符串
username		用户名	None
password		口令	None
hostname		主机名 (小写)	None
port		整数形式的端口号 (若存在)	None

读取 port 属性将引发 ValueError if an invalid port is specified in the URL. See section 结构化剖析结果 for more information on the result object.

Unmatched square brackets in the netloc 属性将引发 ValueError .

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

Following the WHATWG spec that updates RFC 3986, ASCII newline \n , \r and tab \t characters are stripped from the URL.

3.6 版改变： Out-of-range port numbers now raise ValueError , instead of returning None .

3.8 版改变： Characters that affect netloc parsing under NFKC normalization will now raise ValueError .

3.9.5 版改变： ASCII newline and tab characters are stripped from the URL.

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'
										

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

注意

若 url is an absolute URL (that is, it starts with // or scheme:// ), the url ’s hostname 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.

3.5 版改变： Behavior updated to match the semantics defined in RFC 3986 .

urllib.parse. urldefrag ( url ) ¶

若 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 ，返回 url unmodified and an empty string.

返回值为 命名元组 , its items can be accessed by index or as named attributes:

属性	索引	值	值若不存在
url	0	URL with no fragment	空字符串
fragment	1	片段标识符	空字符串

见章节 结构化剖析结果 for more information on the result object.

3.2 版改变： 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/path or scheme://host/path )。若 url is not a wrapped URL, it is returned without changes.

解析 ASCII 编码字节 ¶

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 对象。

若 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 数据。

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' 而不是 'utf-8' ). Each produces a value of a corresponding type that contains either bytes data (for encode() methods) or str data (for decode() 方法)。

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.

结构化剖析结果 ¶

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 对象：

class urllib.parse. DefragResult ( url , fragment ) ¶

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

3.2 版新增。

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

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

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

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

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

class urllib.parse. DefragResultBytes ( url , fragment ) ¶

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

3.2 版新增。

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

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

3.2 版新增。

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

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

3.2 版新增。

URL 引用 ¶

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

string may be either a str 或 bytes 对象。

3.7 版改变： Moved from RFC 2396 to RFC 3986 for quoting URL strings. “~” is now included in the set of unreserved characters.

可选 encoding and errors parameters specify how to deal with non-ASCII characters, as accepted by the str.encode() 方法。 encoding 默认为 'utf-8' . errors 默认为 'strict' , meaning unsupported characters raise a UnicodeEncodeError . encoding and errors must not be supplied if string 是 bytes ，或 TypeError 被引发。

注意， quote(string, safe, encoding, errors) 相当于 quote_from_bytes(string.encode(encoding, errors), safe) .

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

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

像 quote() , but also replace spaces with 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 '/' .

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

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

像 quote() ，但接受 bytes 对象而不是 str , and does not perform string-to-bytes encoding.

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

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

替换 %xx escapes with 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() 方法。

string may be either a str 或 bytes 对象。

encoding 默认为 'utf-8' . errors 默认为 'replace' , meaning invalid sequences are replaced by a placeholder character.

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

3.9 版改变： string parameter supports bytes and str objects (previously only str).

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

像 unquote() , but also replace plus signs with spaces, as required for unquoting HTML form values.

string 必须是 str .

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

urllib.parse. unquote_to_bytes ( string ) ¶

替换 %xx escapes with their single-octet equivalent, and return a bytes 对象。

string may be either a str 或 bytes 对象。

若它是 str , unescaped non-ASCII characters in string are encoded into UTF-8 bytes.

范例： 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 ) ¶

转换映射对象或 2 元素元组序列，其中可能包含 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 评估为 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.

safe , encoding ，和 errors parameters are passed down to quote_via ( 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.

参考 urllib 范例 to find out how the urllib.parse.urlencode() method can be used for generating the query string of a URL or data for a POST request.

3.2 版改变： query supports bytes and string objects.

3.5 版新增： quote_via 参数。