class BaseHandler(webapp2.RequestHandler):

    def jinja2(self):
        return jinja2.get_jinja2(app=self.app)

def render_template(self, template, **context):
    self.response.write(self.jinja2.render_template(template, **context))

def get(self, **params):
    context = {}
context['a'] = webapp2.request.get('a')
context['b'] = webapp2.request.get('b')
context['c'] = webapp2.request.get('c')
self.render_template([template], **context)
Getting a request parameter in Jinja2