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Network.URI | Portability | portable | Stability | provisional | Maintainer | Graham Klyne <gk@ninebynine.org> |
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Description |
This module defines functions for handling URIs. It presents substantially the
same interface as the older GHC Network.URI module, but is implemented using
Parsec rather than a Regex library that is not available with Hugs. The internal
representation of URI has been changed so that URI strings are more
completely preserved when round-tripping to a URI value and back.
In addition, four methods are provided for parsing different
kinds of URI string (as noted in RFC3986):
parseURI,
parseURIReference,
parseRelativeReference and
parseAbsoluteURI.
Further, four methods are provided for classifying different
kinds of URI string (as noted in RFC3986):
isURI,
isURIReference,
isRelativeReference and
isAbsoluteURI.
The long-standing official reference for URI handling was RFC2396 [1],
as updated by RFC 2732 [2], but this was replaced by a new specification,
RFC3986 [3] in January 2005. This latter specification has been used
as the primary reference for constructing the URI parser implemented
here, and it is intended that there is a direct relationship between
the syntax definition in that document and this parser implementation.
RFC 1808 [4] contains a number of test cases for relative URI handling.
Dan Connolly's Python module uripath.py [5] also contains useful details
and test cases.
Some of the code has been copied from the previous GHC implementation,
but the parser is replaced with one that performs more complete
syntax checking of the URI itself, according to RFC3986 [3].
References
- http://www.ietf.org/rfc/rfc2396.txt
- http://www.ietf.org/rfc/rfc2732.txt
- http://www.ietf.org/rfc/rfc3986.txt
- http://www.ietf.org/rfc/rfc1808.txt
- http://www.w3.org/2000/10/swap/uripath.py
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Synopsis |
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The URI type
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Represents a general universal resource identifier using
its component parts.
For example, for the URI
foo://anonymous@www.haskell.org:42/ghc?query#frag
the components are:
| Constructors | | Instances | |
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Type for authority value within a URI
| Constructors | | Instances | |
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Blank URI
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Parsing
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Turn a string containing a URI into a URI.
Returns Nothing if the string is not a valid URI;
(an absolute URI with optional fragment identifier).
NOTE: this is different from the previous network.URI,
whose parseURI function works like parseURIReference
in this module.
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Parse a URI reference to a URI value.
Returns Nothing if the string is not a valid URI reference.
(an absolute or relative URI with optional fragment identifier).
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Parse a relative URI to a URI value.
Returns Nothing if the string is not a valid relative URI.
(a relative URI with optional fragment identifier).
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Parse an absolute URI to a URI value.
Returns Nothing if the string is not a valid absolute URI.
(an absolute URI without a fragment identifier).
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Test for strings containing various kinds of URI
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Test if string contains a valid URI
(an absolute URI with optional fragment identifier).
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Test if string contains a valid URI reference
(an absolute or relative URI with optional fragment identifier).
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Test if string contains a valid relative URI
(a relative URI with optional fragment identifier).
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Test if string contains a valid absolute URI
(an absolute URI without a fragment identifier).
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Test if string contains a valid IPv6 address
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Test if string contains a valid IPv4 address
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Relative URIs
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Compute an absolute URI for a supplied URI
relative to a given base.
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Returns a new URI which represents the value of the
first URI interpreted as relative to the second URI.
For example:
"foo" `relativeTo` "http://bar.org/" = "http://bar.org/foo"
"http:foo" `nonStrictRelativeTo` "http://bar.org/" = "http://bar.org/foo"
Algorithm from RFC3986 [3], section 5.2.2
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Returns a new URI which represents the relative location of
the first URI with respect to the second URI. Thus, the
values supplied are expected to be absolute URIs, and the result
returned may be a relative URI.
Example:
"http://example.com/Root/sub1/name2#frag"
`relativeFrom` "http://example.com/Root/sub2/name2#frag"
== "../sub2/name2#frag"
There is no single correct implementation of this function,
but any acceptable implementation must satisfy the following:
(uabs `relativeFrom` ubase) `relativeTo` ubase == uabs
For any valid absolute URI.
(cf. http://lists.w3.org/Archives/Public/uri/2003Jan/0008.html
http://lists.w3.org/Archives/Public/uri/2003Jan/0005.html)
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Operations on URI strings
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Support for putting strings into URI-friendly
escaped format and getting them back again.
This can't be done transparently in all cases, because certain
characters have different meanings in different kinds of URI.
The URI spec [3], section 2.4, indicates that all URI components
should be escaped before they are assembled as a URI:
"Once produced, a URI is always in its percent-encoded form"
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Turn a URI into a string.
Uses a supplied function to map the userinfo part of the URI.
The Show instance for URI uses a mapping that hides any password
that may be present in the URI. Use this function with argument id
to preserve the password in the formatted output.
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Returns True if the character is a "reserved" character in a
URI. To include a literal instance of one of these characters in a
component of a URI, it must be escaped.
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Returns True if the character is an "unreserved" character in
a URI. These characters do not need to be escaped in a URI. The
only characters allowed in a URI are either "reserved",
"unreserved", or an escape sequence (% followed by two hex digits).
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Returns True if the character is allowed in a URI.
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Returns True if the character is allowed unescaped in a URI.
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Escape character if supplied predicate is not satisfied,
otherwise return character as singleton string.
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:: (Char -> Bool) | a predicate which returns False
if the character should be escaped
| -> String | the string to process
| -> String | the resulting URI string
| Can be used to make a string valid for use in a URI.
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Turns all instances of escaped characters in the string back
into literal characters.
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URI Normalization functions
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Case normalization; cf. RFC3986 section 6.2.2.1
NOTE: authority case normalization is not performed
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Encoding normalization; cf. RFC3986 section 6.2.2.2
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Path segment normalization; cf. RFC3986 section 6.2.2.4
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Deprecated functions
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Produced by Haddock version 0.9 |