1
|
<!--
|
2
|
* datafiles.html
|
3
|
*
|
4
|
* Authors: Chad Berkley
|
5
|
* Copyright: 2000 Regents of the University of California and the
|
6
|
* National Center for Ecological Analysis and Synthesis
|
7
|
* For Details: http://www.nceas.ucsb.edu/
|
8
|
* Created: 2001 January 23
|
9
|
* Version:
|
10
|
* File Info: '$ '
|
11
|
*
|
12
|
*
|
13
|
-->
|
14
|
<HTML>
|
15
|
<HEAD>
|
16
|
<TITLE>Metacat</TITLE>
|
17
|
<link rel="stylesheet" type="text/css" href="./default.css">
|
18
|
</HEAD>
|
19
|
<BODY>
|
20
|
<table width="100%">
|
21
|
<tr>
|
22
|
<td class="tablehead" colspan="2"><p class="label">Non-XML Data Files</p></td>
|
23
|
<td class="tablehead" colspan="2" align="right">
|
24
|
<a href="./replication.html">Back</a> | <a href="./metacattour.html">Home</a> |
|
25
|
<a href="./properties.html">Next</a>
|
26
|
</td>
|
27
|
</tr>
|
28
|
</table>
|
29
|
|
30
|
<p>Metacat has the capability of proxying a connection to a data file
|
31
|
server. This capability is provided through an abstract class called
|
32
|
DataFileUploadInterface. Currently, there is a data file server implemented
|
33
|
for this interface that can store non-XML data files on the local UNIX
|
34
|
file system. Theoretically, any file storage system could be proxied
|
35
|
through this interface.</p>
|
36
|
<P> <img alt="architecture diagram of the Metacat Data File Upload process"
|
37
|
src="dataload.gif"> </p>
|
38
|
|
39
|
<b>Reasoning</b>
|
40
|
<p>Since Metacat has been designed as a metadata storage system for
|
41
|
ecological data, there was a concern that data and metadata files were being
|
42
|
stored seperately and that users would find it impractical to have to use
|
43
|
two different systems to get their data and metadata. This system also allows
|
44
|
users to specify <a href="./acontrol.html">access control</a> restraints on their
|
45
|
data files the same way that they are specified on the xml metadata files.</p>
|
46
|
|
47
|
<b>Data Download (GET)</b>
|
48
|
<p>Metacat Server can retrieve data files that are stored on Metacat
|
49
|
file system or in any other file system on Internet. <br>
|
50
|
Metacat stores data files in a directory under the servlet context.
|
51
|
It writes information about these data files in xml_documents just like
|
52
|
about any XML file. <br>
|
53
|
An example of HTTP request for download of data file on Metacat is shown below: </p>
|
54
|
<pre><i>http://server.domain.com/metacat?action=read&docid=nceas.55</i></pre>
|
55
|
<p>An example of HTTP request for download of data file on Internet is shown below:</p>
|
56
|
<pre><i>http://server.domain.com/metacat?action=read&docid=http://otherserver.domain.com/filename</i></pre>
|
57
|
<p>Note in <i>docid=http://otherserver.domain.com/filename</i> HTTP protocol is used,
|
58
|
i.e. currently for file download HTTP protocol is only supported.</p>
|
59
|
|
60
|
<p><b>Data Upload (PUT)</b></p>
|
61
|
<p>
|
62
|
The insertion and update process for a data file is the same as the
|
63
|
insertion process for an <a href="metacatload.html">XML file</a>.
|
64
|
</p>
|
65
|
|
66
|
<br>
|
67
|
<a href="./replication.html">Back</a> | <a href="./metacattour.html">Home</a> |
|
68
|
<a href="./properties.html">Next</a>
|
69
|
</BODY>
|
70
|
</HTML>
|