Ah, those pesky customers of ours, always looking for some niche functionality that is impossible to include in a generic product. However, using the Workflow Power Pack for SharePoint we can achieve almost anything we can think of…..almost.
A quick introduction for those not familiar with the product: The Muhimbi Workflow Power Pack for SharePoint allows custom C# or VB.NET code to be embedded in SharePoint Designer Workflows without the need to resort to complex Visual Studio based workflows, the development of bespoke Workflow Activities or long development cycles.
As the code is well documented it is easy to make further changes and customisations, e.g. change the formatting of the date or position of the label. Note that this has only been tested with a recent version of Adobe Acrobat reader. If you use a different PDF viewer your mileage may vary.
Create the workflow as follows:
We need to be able to access functionality in the Muhimbi.SharePoint.DocumentConverter.PDF and System.Drawing assemblies. Add these references to the relevant Web Application using the Workflow Power Pack Central Administration screens as described in the Administration Guide. Make sure to place each reference on a new line.
Make sure you have the appropriate privileges to create workflows on a site collection.
Create a new workflow using SharePoint Designer.
On the Workflow definition screen associate the workflow with the Shared Documents library, tick the boxes next to both ‘ Automatically start….’ options and proceed to the next screen.
We only want to act on files of type PDF. Although we could have put this validation in the code, in this example we use a workflow condition for it so add a Compare Any Data Source condition and:
a. Click on the first value followed by the display data binding (fx) button.
b. Select Current Item as the Source and select File Type in the Field. Click the OK button to continue.
d. Click on the second value and enter pdf. (Use lower case as the compare option is case sensitive).
Click the Actions button and insert the Execute Custom Code action .
Optionally click parameter 1 and enter a relative or absolute destination path. Leave the parameter empty to save the modified file on top of the existing PDF file. For details about how paths are handled, see this post and search for the words ‘this url’.
Insert the C# based code embedded in step #3’s download (also listed below) by clicking this code.
Click the Actions button, select Log to History List, click this message and enter File watermarked.
Close the Workflow Designer.