source: project/wiki/eggref/4/uri-common @ 14584

Last change on this file since 14584 was 14584, checked in by sjamaan, 12 years ago

Add uri->list description

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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, string and list 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<procedure>(uri->list URI USERINFO) => LIST</procedure>
98
99Returns a list of the form {{(SCHEME SPECIFIC FRAGMENT)}};
100{{SPECIFIC}} is of the form {{(AUTHORITY PATH QUERY)}}.
101
102
103==== Accessors
104
105* <procedure>(uri-scheme uri-common) => symbol</procedure>
106* <procedure>(uri-path uri-common) => list</procedure>
107* <procedure>(uri-query uri-common) => alist</procedure>
108* <procedure>(uri-fragment uri-common) => string</procedure>
109* <procedure>(uri-host uri-common) => string</procedure>
110* <procedure>(uri-port uri-common) => integer</procedure>
111* <procedure>(uri-username uri-common) => string</procedure>
112* <procedure>(uri-password uri-common) => string</procedure>
113
114If a component is not defined in the given URI-common, then the
115corresponding accessor returns {{#f}}.
116
117* <procedure>(update-uri URI-common #!key scheme path query fragment host port username password) => URI-common</procedure>
118
119Update the specified keys in the URI-common object in a functional way
120(ie, it creates a new copy with the modifications).
121
122==== Reference Resolution
123
124<procedure>(uri-relative-to URI URI) => URI</procedure>
125
126Resolve the first URI as a reference relative to the second URI,
127returning a new URI (RFC 3986, Section 5.2.2).
128
129<procedure>(uri-relative-from URI URI) => URI</procedure>
130
131Constructs a new, possibly relative, URI which represents the location
132of the first URI with respect to the second URI.
133
134<examples>
135<example>
136<init>(use uri-common)</init>
137<expr>(uri->string (uri-relative-to (uri-reference "../qux") (uri-reference "http://example.com/foo/bar/")))</expr>
138<result>"http://example.com/foo/qux"</result>
139</example>
140<example>
141<init>(use uri-common)</init>
142<expr>(uri->string (uri-relative-from (uri-reference "http://example.com/foo/qux") (uri-reference "http://example.com/foo/bar/")))</expr>
143<result>"../qux"</result>
144</example>
145</examples>
146
147==== Query encoding and decoding
148
149* <parameter>(form-urlencoded-separator [char-set/char/string])</parameter>
150* <procedure>(form-urlencode alist #!key (separator (form-urlencoded-separator))) => string</procedure>
151* <procedure>(form-urldecode string #!key (separator (form-urlencoded-separator))) => alist</procedure>
152
153Encode or decode an alist using the encoding corresponding to the
154[[http://www.w3.org/TR/html401/interact/forms.html#h-17.13.4.1|form-urlencoded]]
155media type, using the given separator character(s).
156
157When encoding, if {{separator}} is a string, the first character will
158be used as the separator in the resulting querystring.  If it is a
159char-set, it will be converted to a string and its first character
160will be taken.  In either case, all of these characters are encoded if
161they occur inside the key/value pairs.
162
163When decoding, any character in the set (or string) will be seen as
164a separator.
165
166The separator defaults to the string {{";&"}}.  This means that
167either semicolons or ampersands are allowed as separators when decoding
168an URI string, but semicolons are used when generating strings.
169
170If you would like to use a different separator, you should parameterize
171''all'' calls to procedures that return an uri-common object.
172
173
174==== Normalization 
175
176<procedure>(uri-normalize-case URI) => URI</procedure>
177
178URI case normalization (RFC 3986 section 6.2.2.1)
179
180<procedure>(uri-normalize-path-segments URI) => URI</procedure>
181
182URI path segment normalization (RFC 3986 section 6.2.2.3)
183
184
185=== Requires
186
187* [[uri-generic]]
188* [[matchable]]
189* [[defstruct]]
190
191=== Version History
192
193* 0.4 Add {{uri->list}} conversion procedure
194* 0.3 Fix dependency info (requires at least uri-generic 2.1)
195* 0.2 Add predicates for URIs, absolute URIs and relative references, matching the ones in uri-generic.
196* 0.1 Initial Release
197
198=== License
199
200  Copyright 2008-2009 Peter Bex
201  All rights reserved.
202 
203  Redistribution and use in source and binary forms, with or without
204  modification, are permitted provided that the following conditions are
205  met:
206 
207  Redistributions of source code must retain the above copyright
208  notice, this list of conditions and the following disclaimer.
209 
210  Redistributions in binary form must reproduce the above copyright
211  notice, this list of conditions and the following disclaimer in the
212  documentation and/or other materials provided with the distribution.
213 
214  Neither the name of the author nor the names of its contributors may
215  be used to endorse or promote products derived from this software
216  without specific prior written permission.
217 
218  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
219  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
220  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
221  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
222  COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
223  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
224  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
225  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
226  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
227  STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
228  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
229  OF THE POSSIBILITY OF SUCH DAMAGE.
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