Serve static files and modify headers

server.py

from twisted.web.server import Site
from twisted.web.static import File
from twisted.internet import reactor


static_path = '/path/to/folder'

class ResponseFile(File):

    def render(self, request):        
        request.setHeader('Access-Control-Allow-Origin','*')
        request.setHeader('Access-Control-Allow-Methods','POST, GET, OPTIONS')
        request.setHeader('Access-Control-Allow-Credentials','true')
        request.setHeader('Access-Control-Allow-Headers','origin, x-requested-with, accept, content-type')
        
        return File.render(self, request)
      
    
    def render_OPTIONS(self, request):        
        return self.render_GET(request)


if __name__ == "__main__":

    root = ResponseFile(static_path)    
    reactor.listenTCP(8000, Site(root))
    reactor.run()