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

1. http://www.ietf.org/rfc/rfc2396.txt
2. http://www.ietf.org/rfc/rfc2732.txt
3. http://www.ietf.org/rfc/rfc3986.txt
4. http://www.ietf.org/rfc/rfc1808.txt
5. http://www.w3.org/2000/10/swap/uripath.py

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.

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

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)

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.