QGIS 2 (python2) project file parser writing layer properties to JSON file

parseQGS2.py

# If you are not inside a QGIS console you first need to import
# qgis and PyQt5 classes you will use in this script as shown below:
from qgis.core import *
from PyQt4.QtCore import QFileInfo
import json

# create a reference to the QgsApplication, setting the
# second argument to False disables the GUI
qgs = QgsApplication([], False)

# supply path to qgis install location
qgs.setPrefixPath("/usr", True)

# load providers
qgs.initQgis()

# Get the project instance
project = QgsProject.instance()
# Load qgis project
project.read(QFileInfo('/home/gerald/Documents/poum.qgs'))
print "Project file:"+project.fileName()
print "Project title: "+project.title()

def layertree(node):
	obj = {}
	if isinstance(node, QgsLayerTreeLayer):
		obj['name'] = node.layerName()
		obj['id'] = node.layerId()
		obj['type'] = "layer"
		obj['indentifiable'] = node.layerId() not in nonidentify
		obj['fields'] = []
		obj['actions'] = []
		#print "- layer: ", node.layerName()
		
		layer = QgsMapLayerRegistry.instance().mapLayer(node.layerId())
		conf = layer.editFormConfig()
		for field in layer.fields():
			if conf.widgetType(field.name()) != 'Hidden':
				f = {}
				f['name'] = field.name()
				f['alias'] = field.alias()
				f['type'] = field.typeName()
				obj['fields'].append(f)

		for action in layer.actions().listActions():
			a = {}
			a['name'] = action.name()
			a['action'] = action.action()
			obj['actions'].append(a)
		
		return obj

	elif isinstance(node, QgsLayerTreeGroup):
		obj['name'] = node.name()
		obj['type'] = "group"
		obj['children'] = []
		#print "- group: " ,node.name()
        for child in node.children():
			obj['children'].append(layertree(child))

	return obj

info=[]
print "Project tree:"
nonidentify = project.nonIdentifiableLayers()
root = project.layerTreeRoot()
for group in root.children():
	obj = layertree(group)
	info.append(obj)

# identifiable <Identify>
#print project.readEntry("qgis", "Identify")

# write to json file
f=open('info.json', 'w+')
f.write(json.dumps(info))
f.close()

# When your script is complete, call exitQgis() to remove the
# provider and layer registries from memory
qgs.exitQgis()