Wednesday, May 19, 2010

Novell IDM CSV Fanout Driver

In a traditional Novell IDM CSV driver, you have one event, which will create one output CSV file.  You can use the output transform to format the CSV files output so it does not necessarily have to be a true CSV file, but a text file of any format you wish.

I was recently presented with a unique challenge where I needed upwards of 120 or so CSV files for a single event.  The total number of files was dependent on a few factors, but they are irrelevant as that logic was programmed in policy.  The part that was pretty nifty was creating my own version of a CSV fanout driver.

Instead of using the traditional CSV driver, I used a Null Services driver.  I used typical policy to determine my outputs, but did so in a loop, so I could loop through each iteration of an output.  Each time I hit a valid output, I constructed my text file format and held it in a local variable.  It looked something like this:

<do-set-local-variable name="lv.outputString" scope="policy">
            Construct string here

I then added a ECMAScript object to my driver and added it to the driver configuration.  The ECMAScript was very simple:


function writeFile(fileName, contentString)
    try {
        var printFile = new;
        return "";
   } catch (e) {
        return e.toString();

All I needed to do at this point was use an XPATH expression to call my ECMAScript function.  I pass it the path to the file I want to create and the string I created.  The function will create the file with the contents I specified.

The only thing to note about this is you will need to use unique filenames.  The way I found to most easily do this is to use a timestamp.  The following file path uses a timestamp down to the millisecond, so it should always be unique.

   <do-set-local-variable name="lv.outputFile" scope="policy">
          <token-global-variable name="outputfilelocation"/>
          <token-text xml:space="preserve">\</token-text>
          <token-time format="yyyyMMddHHmmssSSS"/>
          <token-text xml:space="preserve">.csv</token-text>

Once we have the output file string, the contents string, and the ECMAScript object created and added to the driver, we just need to use our XPATH expression to call it and write out our files.

  <do-set-local-variable name="result" scope="policy">
          <token-xpath expression="es:writeFile($lv.outputFile,$lv.outputString)"/>

The local variable "result" is holding the return value, which should be blank.  If it is not blank, then there was a problem and the exception that was caught should be held in this value.  This can be used for simple error checking.

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