1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
|
<!doctype html public "-//W3C//DTD HTML 3.2 Final//EN">
<html>
<head>
<title>Ranges on the WN server</title>
<link rev="made" href="mailto:john@math.nwu.edu">
<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">
<meta http-equiv="last-modified" content="Fri, 09 Oct 1998 18:18:09 GMT">
<meta http-equiv="keywords" content="WN ranges">
</head>
<body bgcolor="#FFFFFF">
<p>
<a href="http://hopf.math.nwu.edu/"><img
src="images/powered.jpg"
border="0"
width="190"
height="41"
align="right"
alt="WN home page"
></a>
</p>
<strong>Version 2.0.3</strong>
<br>
<!-- pnuts --> <a href="filter.html">[Previous]</a> <a href="access.html">[Next]</a> <a href="manual.html">[Up]</a> <a href="manual.html">[Top]</a> <a href="dosearch.html">[Search]</a> <a href="docindex.html">[Index]</a>
<br clear="right">
<hr size="4">
<!-- #start -->
<h2 align="center">Ranges on the <em>WN</em> Server</h2>
<hr size="4">
<h3>9.1 <a name="parameters">URL Range Parameters</a></h3>
<p>
If the server receives a request like:
</p>
<blockquote>
http://host/dir/foo;lines=20-30
</blockquote>
<p>
and <code>foo</code> is any document with content-type
<code>text/*</code> it will return a <code>text/plain</code> document
consisting of lines <code>20</code> through <code>30</code> of file
<code>foo</code>. This is very useful for structured text files like
address lists or digests of mail and news. A <em>WN</em> utility called
<code><a href="utility.html#wn_mkdigest">wn_mkdigest</a></code> will
produce an <a href="http://www.w3c.org/MarkUp/">HTML</a> file with a list
of links to separate sections (line ranges) of the structured file. It
is described <a href="#wn_mkdigest">below</a>.
</p>
<p>
The option "<code>;lines=[first]-[last]</code>" can be appended to the
URL of any text file served by the <em>WN</em> server. It has the effect
of causing the server to return line <code>[first]</code> through line
<code>[last]</code> of the document to which it is attached. Line 1 is
the first line of a file. This parameter is ignored and an error is
logged if it is used with a binary file. When used with a text file the
content type of the returned document is set to <code>text/plain</code>
since, for example, a range of lines from an <a
href="http://www.w3c.org/MarkUp/">HTML</a> document is unlikely to be a
valid <a href="http://www.w3c.org/MarkUp/">HTML</a> document.
</p>
<p>
For any file, including binaries, but not <a
href="http://hoohoo.ncsa.uiuc.edu/cgi/">CGI/1.1</a> output or parsed or
filtered documents, the server will honor a byte range. A request for:
</p>
<blockquote>
<code>
http://host/dir/foo;bytes=256-1024
</code>
</blockquote>
<p>
will cause the server to return bytes <code>256</code> to
<code>1024</code> inclusive. The first byte is numbered 0 so a range of
0-100 represents the first 101 bytes. Note that while file lines are
numbered starting with 1, bytes are numbered starting with 0. The
content type of the returned document will be <code>text/plain</code> if
the document <code>foo</code> is a text document and
<code>application/octet-stream</code> otherwise.
</p>
<p>
A request for:
</p>
<blockquote>
<code>
http://host/dir/foo;bytes=256-
</code>
</blockquote>
<p>
will cause the server to return bytes <code>256</code> through the end of
the file, while:
</p>
<blockquote>
<code>
http://host/dir/foo;bytes=-1024
</code>
</blockquote>
<p>
requests the last <code>1024</code> bytes of the file.
</p>
<h3>9.2 <a name="header">The "<code>Range:</code>" Header</a></h3>
<p>
Requests for a specific range can also be made with the proposed <a
href="http://www.w3c.org/Protocols/">HTTP/1.1</a> header
"<code>Range:</code>". For example, if the server receives a request
with the header:
</p>
<blockquote>
<code>
Range: bytes=100-200
</code>
</blockquote>
<p>
it will send the 101 bytes starting with the 100th and ending with the
200th. The header "<code>Range: bytes=300-</code>" requests all
bytes starting with number 300 and continuing until the end of the file.
And "<code>Range: bytes=-300</code>" requests the last 300 bytes of
the file. This is normally done automatically by the client in
appropriate circumstances and is not under the control of the server
administrator.
</p>
<h3>9.3 <a name="wn_mkdigest">The <code>wn_mkdigest</code> Utility</a></h3>
<p>
The <a href="utility.html#wn_mkdigest"><code>wn_mkdigest</code></a>
utility is executed with two regular expressions: one to match the
section separator and the other to match the section title. For example,
for a mail digest named <code>foo</code>, the command:
</p>
<blockquote>
<code>
wn_mkdigest foo "^From" "^Subject:" foo
</code>
</blockquote>
<p>
will produce an <a href="http://www.w3c.org/MarkUp/">HTML</a> file called
<code>foo.index.html</code> which contains an unordered list of anchors.
Each has as a title the content of the Subject line of a mail message in
<code>foo</code> and <code>href</code> the range of lines in
<code>foo</code> containing that particular message. More detailed
information is available in the section "<a
href="utility.html#wn_mkdigest"><code>wn_mkdigest</code></a>" in this
guide.
</p>
<!-- #end -->
<hr size="4">
<address>
<em>WN</em> version 2.0.3
<br>
Copyright © 1998 <a href="mailto:john@math.nwu.edu">John Franks
<john@math.nwu.edu></a>
<br>
licensed under the <a href="http://www.opencontent.org/opl.html">
OpenContent Public License</a>
<br>
last-modified: Fri, 09 Oct 1998 18:18:09 GMT
</address>
<!-- pnuts --> <a href="filter.html">[Previous]</a> <a href="access.html">[Next]</a> <a href="manual.html">[Up]</a> <a href="manual.html">[Top]</a> <a href="dosearch.html">[Search]</a> <a href="docindex.html">[Index]</a>
</body>
</html>
|
