source: project/wiki/eggref/4/uri-common @ 13255

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1[[tags: eggs]]
2[[toc:]]
3
4== uri-common
5
6=== Description
7
8The {{uri-common}} library provides simple and easy-to-use parsing
9and manipulation procedures for URIs using common schemes.
10
11These "common schemes" all have the following rules:
12
13* An empty path after the hostname is considered to be identical to the root path.
14* All components are to be fully URI-decoded (so no percent-encoded characters in it).
15* The query argument will be in
16   [[http://www.w3.org/TR/xforms/#structure-model-submission|application/x-www-form-urlencoded]] form.
17* The port is automatically determined if it is omitted and the URI scheme is known.
18
19=== Library Procedures
20
21This library replaces most of the procedures in [[uri-generic]]. If
22you need to work with URIs on the uri-generic level or need to work
23with both uri-generic and uri-common URI objects, you will have to
24import and prefix or rename procedures.
25
26==== Constructors and predicates
27
28These constructors fully decode their arguments, so afterwards it is
29impossible to distinguish between encoded delimiters and unencoded
30delimiters.  This makes uri-common objects decoding endpoints; no
31further decoding on the URI level is possible (of course, applications
32are free to decode further information inside the URI).  If for some
33reason, the original URI is still needed, it can be converted to a
34uri-generic.  However, updating a URI component causes this
35component's original encoding to be lost, so be careful!
36
37<procedure>(uri-reference STRING) => URI</procedure>
38
39A URI reference is either a URI or a relative reference (RFC 3986,
40Section 4.1).  If the given string's prefix does not match the syntax
41of a scheme followed by a colon separator, then the given string is
42parsed as a relative reference.
43
44<procedure>(uri-reference? URI) => BOOL</procedure>
45
46Is the given object a URI reference?  '''All objects created by
47URI-generic constructors are URI references'''; they are either URIs
48or relative references.  The constructors below are just more strict
49checking versions of {{uri-reference}}.  They all create
50URI references.
51
52<procedure>(absolute-uri STRING) => URI</procedure>
53
54Parses the given string as an absolute URI, in which no fragments are
55allowed.  If no URI scheme is found, or a fragment is detected, this
56raises an error.
57
58Absolute URIs are defined by RFC 3986 as non-relative URI references
59without a fragment (RFC 3986, Section 4.2).  Absolute URIs can be used
60as a base URI to resolve a relative-ref against, using
61{{uri-relative-to}} (see below).
62
63<procedure>(absolute-uri? URI) => BOOL</procedure>
64
65Is the given object an absolute URI?
66
67<procedure>(uri? URI) => BOOL</procedure>
68
69Is the given object a URI?  URIs are all URI references that include
70a scheme part.  The other type of URI references are relative
71references.
72
73<procedure>(relative-ref? URI) => BOOL</procedure>
74
75Is the given object a relative reference?  Relative references are
76defined by RFC 3986 as URI references which are not URIs; they contain
77no URI scheme and can be resolved against an absolute URI to obtain
78a complete URI using {{uri-relative-to}}.
79
80==== uri-generic and string representation
81
82<procedure>(uri->uri-generic uri-common) => uri-generic</procedure>
83<procedure>(uri-generic->uri uri-common) => uri-common</procedure>
84
85To convert between uri-generic and uri-common objects, use these
86procedures.  As stated above, this will allow you to retrieve the
87original encoding of the URI components, but once you update a
88component from the uri-common side, the original encoding is no longer
89available (the updated value replaces the original value).
90
91<procedure>(uri->string uri-common userinfo) => string</procedure>
92
93Reconstructs the given URI into a string; uses a supplied function
94{{LAMBDA USERNAME PASSWORD -> STRING}} to map the userinfo part of the
95URI.
96
97==== Accessors
98
99* <procedure>(uri-scheme uri-common) => symbol</procedure>
100* <procedure>(uri-path uri-common) => list</procedure>
101* <procedure>(uri-query uri-common) => alist</procedure>
102* <procedure>(uri-fragment uri-common) => string</procedure>
103* <procedure>(uri-host uri-common) => string</procedure>
104* <procedure>(uri-port uri-common) => integer</procedure>
105* <procedure>(uri-username uri-common) => string</procedure>
106* <procedure>(uri-password uri-common) => string</procedure>
107
108If a component is not defined in the given URI-common, then the
109corresponding accessor returns {{#f}}.
110
111* <procedure>(update-uri URI-common #!key scheme path query fragment host port username password) => URI-common</procedure>
112
113Update the specified keys in the URI-common object in a functional way
114(ie, it creates a new copy with the modifications).
115
116==== Reference Resolution
117
118<procedure>(uri-relative-to URI URI) => URI</procedure>
119
120Resolve the first URI as a reference relative to the second URI,
121returning a new URI (RFC 3986, Section 5.2.2).
122
123<procedure>(uri-relative-from URI URI) => URI</procedure>
124
125Constructs a new, possibly relative, URI which represents the location
126of the first URI with respect to the second URI.
127
128<examples>
129<example>
130<init>(use uri-common)</init>
131<expr>(uri->string (uri-relative-to (uri-reference "../qux") (uri-reference "http://example.com/foo/bar/")))</expr>
132<result>"http://example.com/foo/qux"</result>
133</example>
134<example>
135<init>(use uri-common)</init>
136<expr>(uri->string (uri-relative-from (uri-reference "http://example.com/foo/qux") (uri-reference "http://example.com/foo/bar/")))</expr>
137<result>"../qux"</result>
138</example>
139</examples>
140
141==== Query encoding and decoding
142
143* <parameter>(form-urlencoded-separator [char-set/char/string])</parameter>
144* <procedure>(form-urlencode alist #!key (separator (form-urlencoded-separator))) => string</procedure>
145* <procedure>(form-urldecode string #!key (separator (form-urlencoded-separator))) => alist</procedure>
146
147Encode or decode an alist using the encoding corresponding to the
148[[http://www.w3.org/TR/html401/interact/forms.html#h-17.13.4.1|form-urlencoded]]
149media type, using the given separator character(s).
150
151When encoding, if {{separator}} is a string, the first character will
152be used as the separator in the resulting querystring.  If it is a
153char-set, it will be converted to a string and its first character
154will be taken.  In either case, all of these characters are encoded if
155they occur inside the key/value pairs.
156
157When decoding, any character in the set (or string) will be seen as
158a separator.
159
160The separator defaults to the string {{";&"}}.  This means that
161either semicolons or ampersands are allowed as separators when decoding
162an URI string, but semicolons are used when generating strings.
163
164If you would like to use a different separator, you should parameterize
165''all'' calls to procedures that return an uri-common object.
166
167
168==== Normalization 
169
170<procedure>(uri-normalize-case URI) => URI</procedure>
171
172URI case normalization (RFC 3986 section 6.2.2.1)
173
174<procedure>(uri-normalize-path-segments URI) => URI</procedure>
175
176URI path segment normalization (RFC 3986 section 6.2.2.3)
177
178
179=== Requires
180
181* [[uri-generic]]
182* [[matchable]]
183* [[defstruct]]
184
185=== Version History
186
187* 0.2 Add predicates for URIs, absolute URIs and relative references, matching the ones in uri-generic.
188* 0.1 Initial Release
189
190=== License
191
192  Copyright 2008-2009 Peter Bex
193  All rights reserved.
194 
195  Redistribution and use in source and binary forms, with or without
196  modification, are permitted provided that the following conditions are
197  met:
198 
199  Redistributions of source code must retain the above copyright
200  notice, this list of conditions and the following disclaimer.
201 
202  Redistributions in binary form must reproduce the above copyright
203  notice, this list of conditions and the following disclaimer in the
204  documentation and/or other materials provided with the distribution.
205 
206  Neither the name of the author nor the names of its contributors may
207  be used to endorse or promote products derived from this software
208  without specific prior written permission.
209 
210  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
211  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
212  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
213  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
214  COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
215  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
216  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
217  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
218  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
219  STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
220  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
221  OF THE POSSIBILITY OF SUCH DAMAGE.
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