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Revision 881

Added by berkley over 22 years ago

updated documentation. removed a lot of typos and updated all of the new stuff for the new release

View differences:

metacatread.html
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  wants to specify the requested document.  </p>
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  <P> <img alt="architecture diagram of the Metacat read process"
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           src="metadataread.gif">  </p>
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  <p>The documents are requested by <b>docid</b> servlet parameter:
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  <ul>
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     <li> By docid alone as: <br>
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       <i>docid=NCEAS.54</i></li>
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     <li> By Metacat URL as: <br>
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       <i>docid=metacat://server.domain.com/metacat?docid=NCEAS.54</i></li>
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     <li> By HTTP URL: <br>
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       <i>docid=http://otherserver.domain.com/filename</i></li>
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  </ul>
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  <p>The documents are requested by the <b>docid</b> servlet parameter by specifying
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  the document id that you wish to read.<br>
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  </p>
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  <p>There are two different output formats that a client can request from
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  Metacat: HTML or XML.  This is specified by the <b>qformat</b> parameter. <br>
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  If more than one document is requested, the qformat does not matter,
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  instead the documents are zipped together and retrieved to the client. <br>
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  When <b>abstractpath</b> parameter along with docid parameter is
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  specified as a XPath expression of the location of abstract data within
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  XML document, the abstract data only are read and retrieved in XML format.
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  <p>
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    Metacat allows the dynamic transformation of read documents through the use
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    of style-sets.  A style-set is an xsl stylesheet or a group of stylesheets
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    that are specified in a config file.  The following is an example of a style-set
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    config file:
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  </p>
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  <pre>
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    &lt;?xml version="1.0"?&gt;
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    &lt;style-set name="knb"&gt;
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      &lt;default-style&gt;http://http://server.domain.com/metacat/style/ascii-treeview.xsl&lt;/default-style&gt;
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      &lt;doctype publicid="-//NCEAS//resultset//EN"&gt;
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        &lt;target publicid="-//W3C//HTML//EN"&gt;http://http://server.domain.com/metacat/style/resultset.xsl&lt;/target&gt;
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      &lt;/doctype&gt;
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      &lt;doctype publicid="-//NCEAS//login//EN"&gt;
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        &lt;target publicid="-//W3C//HTML//EN"&gt;http://http://server.domain.com/metacat/style/login.xsl&lt;/target&gt;
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      &lt;/doctype&gt;
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      &lt;doctype publicid="-//NCEAS//eml-dataset-2.0//EN"&gt;
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        &lt;target publicid="-//W3C//HTML//EN"&gt;http://http://server.domain.com/metacat/style/eml-dataset-display.xsl&lt;/target&gt;
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      &lt;/doctype&gt;
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      &lt;doctype publicid="-//NCEAS//eml-dataset//EN"&gt;
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        &lt;target publicid="-//W3C//HTML//EN"&gt;http://http://server.domain.com/metacat/style/eml-dataset-display.xsl&lt;/target&gt;
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      &lt;/doctype&gt;
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      &lt;doctype publicid="-//NCEAS//eml-resource//EN"&gt;
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        &lt;target publicid="-//W3C//HTML//EN"&gt;http://http://server.domain.com/metacat/style/eml-dataset-display.xsl&lt;/target&gt;
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      &lt;/doctype&gt;
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      &lt;doctype publicid="-//ecoinformatics.org//eml-dataset-2.0.0beta4//EN"&gt;
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        &lt;target publicid="-//W3C//HTML//EN"&gt;http://http://server.domain.com/metacat/style/eml-dataset-display.xsl&lt;/target&gt;
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      &lt;/doctype&gt;
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    &lt;/style-set&gt;
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  </pre>
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  <p>For example, if a user wanted to request document NCEAS.54 and have it


  		




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     returned as HTML, the servlet call would look like this: <br>


  		




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     <i>http://server.domain.com/knb/servlet/metacat?action=read&amp;qformat=html&amp;docid=NCEAS.54</i>


  		




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     <br>


  		




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     Another way to request a document is by Metacat URL.  the URL would look like: <br>


  		




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     <i>http://server.domain.com/knb/servlet/metacat?


  		




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       action=read&qformat=xml&amp;docid=metacat://server.domain.com/metacat?docid=NCEAS.54</i>


  		




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     <br>


  		




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     Note that this url requests that the document be delivered in xml instead of html.


  		




  
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  <p>


  		




  
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    Whenever a read action is requested from Metacat, you can also provide a qformat parameter.


  		




  
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    This qformat parameter should be the name of the style-set that you wish to use


  		




  
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    to transform the document you are requesting.  Note that the value that you set


  		




  
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    qformat to must equal the &lt;style-set&gt; name parameter.


  		




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  </p>


  		




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  <p>


  		




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    Metacat URLs as in the second example become useful when more than one Metacat


  		




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    server is being run at one site or a bunch of sites are replicating between each


  		




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    other and you want to specify a document at a precise location.


  		




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    <!--  <a href="./packages.html">Package</a>


  		




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    files exclusively use Metacat URLs for document identification. -->


  		




  
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    A default style-set can be set in the metacat.properties file.  If qformat


  		




  
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    is set to 'html', Metacat will use the default.  If qformat is set to 'xml',


  		




  
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    Metacat will return the XML document untransformed.


  		




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  </p>


  		




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  <br>


  		




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