Connecting an InfoPath 2013 form to a REST webservice (for example a Dynamics CRM service) is quite easy. Unfortunately, it returns only the last 50 elements by default. So let’s filter the result by a adding a dynamic parameter containing a value from a textfield.
Step 1: Add a rule to the textfield, the condition should be “is not blank”, this means the following rules will run after you enter some text.
Step 2: The first rule has to be a “Change REST URL” rule. Edit the rule and click the formula field (“fx”). Now add the parameter by using the concat function:
concat("https://yoururl.com/CRM/XRMServices/2011/OrganizationData.svc/ProjectSet?$filter=Projectnumber%20eq%20'"; .; "'")
Step 3: Query the data connection and do your stuff.