Project

General

Profile

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&amp;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&amp;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>
(10-10/66)