QGIS script for Processing to export WKT geometry representation

export_wkt.py

##Geometry=group
##Export WKT to file=name
##Input_Layer=vector
##Output_File=output file

from qgis.core import *
from PyQt4.QtCore import *
import processing

v_in = processing.getObject(Input_Layer)

with open(Output_File,"w") as f_out:
    for f in v_in.getFeatures():
        out_str = "{0},{1}".format(f.id(),f.geometry().exportToWkt())
        f_out.write(out_str)