Parsing and validation of URIs (RFC 3896) and IRIs (RFC 3987)
Project description
This module provides regular expressions according to RFC 3986 “Uniform Resource Identifier (URI): Generic Syntax” and RFC 3987 “Internationalized Resource Identifiers (IRIs)”, and utilities for composition and relative resolution of references.
API
- patterns
A dict of regular expressions (patterns) keyed by rule names for URIs and rule names for IRIs.
Patterns are str instances (be it in python 2.x or 3.x) containing ASCII characters only. They can be compiled with regex, without need for any particular compilation flag:
>>> import regex >>> uri = regex.compile('^%s$' % patterns['URI']) >>> m = uri.match('http://tools.ietf.org/html/rfc3986#appendix-A') >>> d = m.groupdict() >>> assert all([ d['scheme'] == 'http', ... d['authority'] == 'tools.ietf.org', ... d['path'] == '/html/rfc3986', ... d['query'] == None, ... d['fragment'] == 'appendix-A' ]) >>> from unicodedata import lookup >>> smp = 'urn:' + lookup('OLD ITALIC LETTER A') # U+00010300 >>> assert not uri.match(smp) >>> assert regex.match('^%s$' % patterns['IRI'], smp) >>> assert not regex.match('^%s$' % patterns['relative_ref'], '#f#g')
Alternatively, the standard library re module can be used provided that:
\u and \U escapes are preprocessed (see issue3665):
>>> import re, sys, ast >>> re.compile(patterns['ucschar']) #doctest:+IGNORE_EXCEPTION_DETAIL Traceback (most recent call last): ... File "/usr/lib/python2.6/re.py", line 245, in _compile raise error, v # invalid expression error: bad character range >>> tpl = 'u"%s"' if sys.version_info[0] < 3 else '"%s"' >>> utext_pattern = ast.literal_eval(tpl % patterns['ucschar']) >>> assert re.compile(utext_pattern)
named capture groups do not occur on multiple branches of an alternation:
>>> re.compile(patterns['path']) #doctest:+IGNORE_EXCEPTION_DETAIL Traceback (most recent call last): ... File "/usr/lib/python2.6/re.py", line 245, in _compile raise error, v # invalid expression error: redefinition of group name 'path' as group 2; was group 1 >>> pat = format_patterns(path='outermost_group_name')['path'] >>> assert re.compile(pat)
- format_patterns
Returns a dict of regular expressions keyed by rule name.
By default, the formatted patterns contain no named capture groups. To wrap the pattern of a rule in a named group, pass a keyword argument of the form rule_name=’group_name’. For a useful set of group names, see also patterns.
- compose
Returns an URI composed from named parts.
- resolve
Resolves an URI reference relative to a base URI.
>>> base = "http://a/b/c/d;p?q" >>> for relative, resolved in { ... "g:h" : "g:h", ... "g" : "http://a/b/c/g", ... "./g" : "http://a/b/c/g", ... "g/" : "http://a/b/c/g/", ... "/g" : "http://a/g", ... "//g" : "http://g", ... "?y" : "http://a/b/c/d;p?y", ... "g?y" : "http://a/b/c/g?y", ... "#s" : "http://a/b/c/d;p?q#s", ... "g#s" : "http://a/b/c/g#s", ... "g?y#s" : "http://a/b/c/g?y#s", ... ";x" : "http://a/b/c/;x", ... "g;x" : "http://a/b/c/g;x", ... "g;x?y#s" : "http://a/b/c/g;x?y#s", ... "" : "http://a/b/c/d;p?q", ... "." : "http://a/b/c/", ... "./" : "http://a/b/c/", ... ".." : "http://a/b/", ... "../" : "http://a/b/", ... "../g" : "http://a/b/g", ... "../.." : "http://a/", ... "../../" : "http://a/", ... "../../g" : "http://a/g", ... "../../../g" : "http://a/g", ... "../../../../g" : "http://a/g", ... "/./g" : "http://a/g", ... "/../g" : "http://a/g", ... "g." : "http://a/b/c/g.", ... ".g" : "http://a/b/c/.g", ... "g.." : "http://a/b/c/g..", ... "..g" : "http://a/b/c/..g", ... "./../g" : "http://a/b/g", ... "./g/." : "http://a/b/c/g/", ... "g/./h" : "http://a/b/c/g/h", ... "g/../h" : "http://a/b/c/h", ... "g;x=1/./y" : "http://a/b/c/g;x=1/y", ... "g;x=1/../y" : "http://a/b/c/y", ... }.items(): ... assert resolve(base, relative) == resolved
If return_parts is True, returns a dict of named parts instead of a string.
What’s new
version 1.3.0:
python 3.x compatibility
format_patterns
version 1.2.1:
compose, resolve
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