cgit.sxemacs.org Git - packages/blob - xemacs-packages/w3/tests/url-expansion.html

   1 <HTML><HEAD>
   2 <TITLE>Examples of Resolving Relative URLs</TITLE>
   3 <BASE href="http://a/b/c/d;p?q">
   4 </HEAD><BODY>
   5 <H1>Examples of Resolving Relative URLs</H1>
   6
   7 This document has an embedded base URL of
   8 <PRE>
   9    Content-Base: http://a/b/c/d;p?q
  10 </PRE>
  11 the relative URLs should be resolved as shown below.
  12 <P>
  13 I will need your help testing the examples on multiple browsers.
  14 What you need to do is point to the example anchor and compare it to the
  15 resolved URL in your browser (most browsers have a feature by which you
  16 can see the resolved URL at the bottom of the window/screen when the anchor
  17 is active).
  18
  19 <H2>Tested Clients and Client Libraries</H2>
  20
  21 <DL COMPACT>
  22 <DT>[R]
  23 <DD>RFC 2396 (the right way to parse)
  24 <DT>[X]
  25 <DD>RFC 1808
  26 <DT>[1]
  27 <DD>Mozilla/4.03 [en] (X11; U; SunOS 5.5 sun4u; Nav)
  28 <DT>[2]
  29 <DD>Lynx/2.7.1 libwww-FM/2.14
  30 <DT>[3]
  31 <DD>MSIE 3.01; Windows 95
  32 <DT>[4]
  33 <DD>NCSA_Mosaic/2.6 (X11;SunOS 4.1.2 sun4m) libwww/2.12
  34 <DT>[5]
  35 <DD>libwww-perl/5.14 [Martijn Koster]
  36 </DL>
  37
  38 <H2>Normal Examples</H2>
  39 <PRE>
  40               RESULTS                     from
  41
  42 <a href="g:h">g:h</a>        =  g:h                         [R,X,2,3,4,5]
  43               http://a/b/c/g:h            [1]
  44
  45 <a href="g">g</a>          =  http://a/b/c/g              [R,X,1,2,3,4,5]
  46
  47 <a href="./g">./g</a>        =  http://a/b/c/g              [R,X,1,2,3,4,5]
  48
  49 <a href="g/">g/</a>         =  http://a/b/c/g/             [R,X,1,2,3,4,5]
  50
  51 <a href="/g">/g</a>         =  http://a/g                  [R,X,1,2,3,4,5]
  52
  53 <a href="//g">//g</a>        =  http://g                    [R,X,1,2,3,4,5]
  54
  55 <a href="?y">?y</a>         =  http://a/b/c/?y             [R,1,2,3,4]
  56               http://a/b/c/d;p?y          [X,5]
  57
  58 <a href="g?y">g?y</a>        =  http://a/b/c/g?y            [R,X,1,2,3,4,5]
  59
  60 <a name="s" href="#s">#s</a>         =  (current document)#s        [R,2,4]
  61               http://a/b/c/d;p?q#s        [X,1,3,5]
  62
  63 <a href="g#s">g#s</a>        =  http://a/b/c/g#s            [R,X,1,2,3,4,5]
  64
  65 <a href="g?y#s">g?y#s</a>      =  http://a/b/c/g?y#s          [R,X,1,2,3,4,5]
  66
  67 <a href=";x">;x</a>         =  http://a/b/c/;x             [R,1,2,3,4]
  68               http://a/b/c/d;x            [X,5]
  69
  70 <a href="g;x">g;x</a>        =  http://a/b/c/g;x            [R,X,1,2,3,4,5]
  71
  72 <a href="g;x?y#s">g;x?y#s</a>    =  http://a/b/c/g;x?y#s        [R,X,1,2,3,4,5]
  73
  74 <a href=".">.</a>          =  http://a/b/c/               [R,X,2,5]
  75               http://a/b/c/.              [1]
  76               http://a/b/c                [3,4]
  77
  78 <a href="./">./</a>         =  http://a/b/c/               [R,X,1,2,3,4,5]
  79
  80 <a href="..">..</a>         =  http://a/b/                 [R,X,2,5]
  81               http://a/b                  [1,3,4]
  82
  83 <a href="../">../</a>        =  http://a/b/                 [R,X,1,2,3,4,5]
  84
  85 <a href="../g">../g</a>       =  http://a/b/g                [R,X,1,2,3,4,5]
  86
  87 <a href="../..">../..</a>      =  http://a/                   [R,X,2,5]
  88               http://a                    [1,3,4]
  89
  90 <a href="../../">../../</a>     =  http://a/                   [R,X,1,2,3,4,5]
  91
  92 <a href="../../g">../../g</a>    =  http://a/g                  [R,X,1,2,3,4,5]
  93 </PRE>
  94
  95 <H2>Abnormal Examples</H2>
  96
  97 Although the following abnormal examples are unlikely to occur in
  98 normal practice, all URL parsers should be capable of resolving them
  99 consistently.  Each example uses the same base as above.<P>
 100
 101 An empty reference refers to the start of the current document.
 102 <PRE>
 103 <a href="">&lt;&gt;</a>         =  (current document)          [R,2,4]
 104               http://a/b/c/d;p?q          [X,3,5]
 105               http://a/b/c/               [1]
 106 </PRE>
 107 Parsers must be careful in handling the case where there are more
 108 relative path ".." segments than there are hierarchical levels in the
 109 base URL's path.  Note that the ".." syntax cannot be used to change
 110 the site component of a URL.
 111 <PRE>
 112 <a href="../../../g">../../../g</a>    =  http://a/../g            [R,X,2,4,5]
 113                  http://a/g               [R,1,3]
 114
 115 <a href="../../../../g">../../../../g</a> =  http://a/../../g         [R,X,2,4,5]
 116                  http://a/g               [R,1,3]
 117 </PRE>
 118 In practice, some implementations strip leading relative symbolic
 119 elements (".", "..") after applying a relative URL calculation, based
 120 on the theory that compensating for obvious author errors is better
 121 than allowing the request to fail.  Thus, the above two references
 122 will be interpreted as "http://a/g" by some implementations.
 123 <P>
 124 Similarly, parsers must avoid treating "." and ".." as special when
 125 they are not complete components of a relative path.
 126 <PRE>
 127 <a href="/./g">/./g</a>      =  http://a/./g                 [R,X,2,3,4,5]
 128              http://a/g                   [1]
 129
 130 <a href="/../g">/../g</a>     =  http://a/../g                [R,X,2,3,4,5]
 131              http://a/g                   [1]
 132
 133 <a href="g.">g.</a>        =  http://a/b/c/g.              [R,X,1,2,3,4,5]
 134
 135 <a href=".g">.g</a>        =  http://a/b/c/.g              [R,X,1,2,3,4,5]
 136
 137 <a href="g..">g..</a>       =  http://a/b/c/g..             [R,X,1,2,3,4,5]
 138
 139 <a href="..g">..g</a>       =  http://a/b/c/..g             [R,X,1,2,3,4,5]
 140 </PRE>
 141 Less likely are cases where the relative URL uses unnecessary or
 142 nonsensical forms of the "." and ".." complete path segments.
 143 <PRE>
 144 <a href="./../g">./../g</a>     =  http://a/b/g                [R,X,1,2,5]
 145               http://a/b/c/../g           [3,4]
 146
 147 <a href="./g/.">./g/.</a>      =  http://a/b/c/g/             [R,X,2,5]
 148               http://a/b/c/g/.            [1]
 149               http://a/b/c/g              [3,4]
 150
 151 <a href="g/./h">g/./h</a>      =  http://a/b/c/g/h            [R,X,1,2,3,4,5]
 152
 153 <a href="g/../h">g/../h</a>     =  http://a/b/c/h              [R,X,1,2,3,4,5]
 154
 155 <a href="g;x=1/./y">g;x=1/./y</a>  =  http://a/b/c/g;x=1/y        [R,1,2,3,4]
 156               http://a/b/c/g;x=1/./y      [X,5]
 157
 158 <a href="g;x=1/../y">g;x=1/../y</a> =  http://a/b/c/y              [R,1,2,3,4]
 159               http://a/b/c/g;x=1/../y     [X,5]
 160
 161 </PRE>
 162 All client applications remove the query component from the base URL
 163 before resolving relative URLs.  However, some applications fail to
 164 separate the reference's query and/or fragment components from a
 165 relative path before merging it with the base path.  This error is
 166 rarely noticed, since typical usage of a fragment never includes the
 167 hierarchy ("/") character, and the query component is not normally
 168 used within relative references.
 169 <PRE>
 170 <a href="g?y/./x">g?y/./x</a>    =  http://a/b/c/g?y/./x        [R,X,5]
 171               http://a/b/c/g?y/x          [1,2,3,4]
 172
 173 <a href="g?y/../x">g?y/../x</a>   =  http://a/b/c/g?y/../x       [R,X,5]
 174               http://a/b/c/x              [1,2,3,4]
 175
 176 <a href="g#s/./x">g#s/./x</a>    =  http://a/b/c/g#s/./x        [R,X,2,3,4,5]
 177               http://a/b/c/g#s/x          [1]
 178
 179 <a href="g#s/../x">g#s/../x</a>   =  http://a/b/c/g#s/../x       [R,X,2,3,4,5]
 180               http://a/b/c/x              [1]
 181 </PRE>
 182    Some parsers allow the scheme name to be present in a relative URI if
 183    it is the same as the base URI scheme.  This is considered to be a
 184    loophole in prior specifications of partial URI [RFC1630]. Its use
 185    should be avoided.
 186 <PRE>
 187 <a href="http:g">http:g</a>    =  http:g                       [R,X,5]
 188           |  http://a/b/c/g               [1,2,3,4]  (ok for compat.)
 189
 190 <a href="http:">http:</a>     =  http:                        [R,X,5]
 191              http://a/b/c/                [1]
 192              http://a/b/c/d;p?q           [2,3,4]
 193 </PRE>
 194 </BODY></HTML>