XSLT - Editing XML

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# XSLT - Editing XML

Data stored in XML files can be edited from an Internet browser.

## Open, Edit and Save XML

Now, we will show how to open, edit, and save an XML file that is stored on the server.

We will use XSL to transform the XML document into an HTML form. The values of the XML elements will be written to HTML input fields in an HTML form. The HTML form is editable. After editing the data, the data is going to be submitted back to the server and the XML file will be updated (this part is done with ASP).

## The XML File and the XSL File

First, look at the XML document that will be used ("tool.xml"):

    <?xml version="1.0" encoding="ISO-8859-1"?>
    <tool>
      <field id="prodName">
        <value>HAMMER HG2606</value>
      </field>
      <field id="prodNo">
        <value>32456240</value>
      </field>
      <field id="price">
        <value>$30.00</value>
      </field>
    </tool>

View the XML file.

Then, take a look at the following style sheet ("tool.xsl"):

    <?xml version="1.0" encoding="ISO-8859-1"?>
    <xsl:stylesheet version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

    <xsl:template match="/">
    <html>
    <body>
    <form method="post" action="edittool.asp">
    <h2>Tool Information (edit):</h2>
    <table border="0">
    <xsl:for-each select="tool/field">
    <tr>
    <td>
    <xsl:value-of select="@id"/>
    </td>
    <td>
    <input type="text">
    <xsl:attribute name="id">
      <xsl:value-of select="@id" />
    </xsl:attribute>
    <xsl:attribute name="name">
      <xsl:value-of select="@id" />
    </xsl:attribute>
    <xsl:attribute name="value">
      <xsl:value-of select="value" />
    </xsl:attribute>
    </input>
    </td>
    </tr>
    </xsl:for-each>
    </table>
    <br />
    <input type="submit" id="btn_sub" name="btn_sub" value="Submit" />
    <input type="reset" id="btn_res" name="btn_res" value="Reset" />
    </form>
    </body>
    </html>
    </xsl:template>
    </xsl:stylesheet>

View the XSL file.

The XSL file above loops through the elements in the XML file and creates one input field for each XML "field" element. The value of the XML "field" element's "id" attribute is added to both the "id" and "name" attributes of each HTML input field. The value of each XML "value" element is added to the "value" attribute of each HTML input field. The result is an editable HTML form that contains the values from the XML file.

Then, we have a second style sheet: "tool_updated.xsl". This is the XSL file that will be used to display the updated XML data. This style sheet will not result in an editable HTML form, but a static HTML table:

    <?xml version="1.0" encoding="ISO-8859-1"?>
    <xsl:stylesheet version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

    <xsl:template match="/">
    <html>
    <body>
    <h2>Updated Tool Information:</h2>
    <table border="1">
    <xsl:for-each select="tool/field">
    <tr>
    <td><xsl:value-of select="@id" /></td>
    <td><xsl:value-of select="value" /></td>
    </tr>
    </xsl:for-each>
    </table>
    </body>
    </html>
    </xsl:template>

    </xsl:stylesheet>

View the XSL file.

## The ASP File

The HTML form in the "tool.xsl" file above has an action attribute with a value of "edittool.asp".

The "edittool.asp" page contains two functions: The loadFile() function loads and transforms the XML file for display and the updateFile() function applies the changes to the XML file:

    <%
    function loadFile(xmlfile,xslfile)
    Dim xmlDoc,xslDoc

    'Load XML file
    set xmlDoc = Server.CreateObject("Microsoft.XMLDOM")
    xmlDoc.async = false
    xmlDoc.load(xmlfile)

    'Load XSL file
    set xslDoc = Server.CreateObject("Microsoft.XMLDOM")
    xslDoc.async = false
    xslDoc.load(xslfile)

    'Transform file
    Response.Write(xmlDoc.transformNode(xslDoc))
    end function

    function updateFile(xmlfile)
    Dim xmlDoc,rootEl,f
    Dim i

    'Load XML file
    set xmlDoc = Server.CreateObject("Microsoft.XMLDOM")
    xmlDoc.async = false
    xmlDoc.load(xmlfile)

    'Set the rootEl variable equal to the root element
    Set rootEl = xmlDoc.documentElement

    'Loop through the form collection
    for i = 1 To Request.Form.Count
      'Eliminate button elements in the form
      if instr(1,Request.Form.Key(i),"btn_")=0 then
        'The selectSingleNode method queries the XML file for a
        'single node that matches a query. This query requests
        'the value element that is the child of a field element
        'that has an id attribute which matches the current key
        'value in the Form Collection. When there is a match -
        'set the text property equal to the value of the current
        'field in the Form Collection.
        set f = rootEl.selectSingleNode("field[@id='" & _
        Request.Form.Key(i) & "']/value")
        f.Text = Request.Form(i)
      end if
    next

    'Save the modified XML file
    xmlDoc.save xmlfile

    'Release all object references
    set xmlDoc=nothing
    set rootEl=nothing
    set f=nothing

    'Load the modified XML file with a style sheet that
    'allows the client to see the edited information
    loadFile xmlfile,server.MapPath("tool_updated.xsl")
    end function

    'If the form has been submitted update the
    'XML file and display result - if not,
    'transform the XML file for editing
    if Request.Form("btn_sub")="" then
    loadFile server.MapPath("tool.xml"),server.MapPath("tool.xsl")
    else
    updateFile server.MapPath("tool.xml")
    end if
    %>

Tip: If you don't know how to write ASP, you can study our ASP tutorial.

Note: We are doing the transformation and applying the changes to the XML file on the server. This is a cross-browser solution. The client will only get HTML back from the server - which will work in any browser.

From http://www.w3schools.com (Copyright Refsnes Data)