Last modified on 27 February 2011, at 02:41

XRX/Dictionary Editor

MotivationEdit

You want a simple application that saves one XML file per form. You want multiple users to each be editing individual records without conflict.

DesignEdit

We will put each term in a separate XML file, and the files will be numbered sequentially - 1.xml, 2.xml, and so on. Each file defines a single term, its acronym, and its definition.

MethodEdit

  1. Create a new eXist collection (aka Folder if you are using a WebDAV tool) called "dictionary"
  2. Create three collections called "data", "edit", and "views" within the "dictionary" collection.

data/1.xmlEdit

<Term>
   <id>1</id>
   <TermName>Hello</TermName>
   <TermDefinition>An informal greeting.</TermDefinition>
</Term>

data/2.xmlEdit

<Term>
   <id>2</id>
   <TermName>Howdy</TermName>
   <TermDefinition>An informal greeting used by cowboys.</TermDefinition>
</Term>

Your XForms application loads the data into an instance:

<xf:instance src="1.xml"/>

You pass the ID number to an XQuery "edit.xq" as a parameter in the URI, "id". "edit.xq" uses the ID parameter as a variable, "$id", to build the form.

Contents of edit/edit.xqEdit


calling format: edit.xq?id=1


xquery version "1.0";
let $id := request:get-paramter(id, '')
return
 
<html>
...
<xf:instance src="{$id}.xml"/>
<xf:submission method="post" action="save.xq"/>
...
</html>

Contents of new-instance.xmlEdit

<Term>
   <id/>
   <TermName/>
   <TermDefinition/>
</Term>

Contents of save.xqEdit

xquery version "1.0";
declare namespace xmldb="http://exist-db.org/xquery/xmldb";
 
(: this is the collection where we store all the terms, one file per term :)
let $collection := '/db/dictionary/data'
 
(: this is where the form "POSTS" documents to this XQuery using the POST method of a submission :)
let $term := request:get-data()
 
(: this logs you into the collection :)
let $collection := xmldb:collection('/db/dictionary/data', 'mylogin', 'mypassword')
 
(: get the next ID :)
let $next-id := doc(concat($collection, 'edit/next-id.xml'))/next-id/text()
let $file := concat($next-id, 'xml')
 
(: this creates a new file using the next-id and saves the term into the file :)
let $store := store($collection, $file, $term)
 
(: now that the save has been done we can increment the next-id :)
let $update := update insert doc("/db/dictionary/edit/next-id.xml")/data/next-id/text() ($next-id + 1)
 
(: now put in the id in the file we just created :)
let $update := update insert doc( concat($collection, '/', $file) )/Term/id/text() $next-id
 
<results>
    <message>{$term/TermName/text(), $term/id/text()} has been saved.</message>
</results>

Contents of edit/next-id.xmlEdit

<data>
   <next-id>3</next-id>
</data>

Contents of views/list-terms.xqEdit

As you save more and more terms, you will want to create a list of them. You can create an XQuery that list all terms. For each term you can include a link to view and edit each term.

xquery version "1.0";
 
let $collection := '/db/dictionary/data'
return
<html>
   <head>
      <title>Listing of Dictionary Terms</title>
   </head>
   <body>
   <h1>Dictionary Terms</h1>
   <ol>{for $term in collection($collection)/Term
      let $id := $term/id/text() 
      return
         <li>{$term/TermName/text()} : {$term/Defintion/text()}
             <a href="view-term.xq?id={$id}">View</a>
             <a href="../edit/edit.xq?id={$id}">Edit</a>
         </li>
   }</ol>
   </body>
</html>

Contents of edit/update.xqEdit

xquery version "1.0";
declare namespace xmldb="http://exist-db.org/xquery/xmldb";
 
(: update.xq :)
 
let $collection := '/db/dictionary/data'
 
(: this is where the form "POSTS" documents to this XQuery using the POST method of a submission :)
let $term := request:get-data()
 
(: this logs you into the collection :)
let $collection := xmldb:collection('/db/dictionary/data', 'mylogin', 'mypassword')
 
(: get the id out of the posted document :)
let $id := $term/id/text()
let $file := concat($id, '.xml')
 
(: this saves the new file and overwrites the old one :)
let $store := store($collection, $file, $term)
 
<results>
    <message>{$term/TermName/text(), $term/id/text()} has been updated.</message>
</results>

edit.xq HeaderEdit

The edit.xq takes parameters from the URI (i.e. in the form "edit.xq?id=2") and either puts a new element in the instance or it puts an existing element in the instance.

xquery version "1.0";
declare option exist:serialize "method=html media-type=text/html indent=yes";
 
let $new := request:get-parameter('new', '')
let $id := request:get-parameter('id', '')
 
return
(: check for required parameters :)
if (not($new or $id))
   then 
      <error>
           <message>Parameter "new" and "id" are both missing.  One of these two arguments is required for this web service.</message>
      </error>
   else
      let $server-port := substring-before(request:get-url(), '/exist/rest/db/') 
      let $collection := '/db/dictionary/data'
 
      (: put in the appropriate file name :)
      let $file := if ($new)
         then ('new-instance.xml')
         else ( concat( $server-port, '/exist/rest', $collection, '/', $id, '.xml'))
      return
 
<html xmlns="http://www.w3.org/1999/xhtml"
    xmlns:xf="http://www.w3.org/2002/xforms" 
    xmlns:xs="http://www.w3.org/2001/XMLSchema" 
    xmlns:ev="http://www.w3.org/2001/xml-events" >
    <head>
       <title>Edit Term</title>
       <xf:model>
           <!-- this line loads either the new instance or the current data file into the form model -->
           <xf:instance xmlns="" src="{$file}"/>
       </xf:model>
    </head>
    <body>
       <xf:output ref="id">
           <xf:label>ID:</xf:label>
       </xf:output >
       <xf:input ref="TermName" class="TermName">
           <xf:label>Term:</xf:label>
       </xf:input>
       <xf:textarea ref="TermDefinition" class="TermDefinition">
           <xf:label>TermDefinition:</xf:label>
       </xf:textarea >
    </body>
</html>

xforms.cssEdit

The following file can be linked into the form for formatting. [And which file might that be?]

 

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