Getting the output file names from processing algorithms

Sometimes, you need to know the variable name a QGIS processing algorithm uses to hold the location of temporary output files. Of course you can set the output file name for most algorithms, but if you are chaining several processes together, you can take advantage of the automatic cleanup for temporary files provided by QGIS when it exits if you use the temporary file. While the processing framework is mostly very consistent, the names of output variables vary. In this recipe, we'll use PyQGIS to programmatically get the output variable name.

Getting ready

Open the QGIS Python Console by going to the Plugins menu and selecting Python Console.

How to do it...

We'll import the processing module and create a function to access algorithm output names. Then, we'll test out a couple of algorithms to see if the function works as expected:

1. First, we import the processing module:

           import processing 
   

2. Next, we'll create...