variable substitution in python twisted static file
Question
How can you substitute a twisted server variable into the file resource that is served out.
For example, the following code serves up a webpage where i can go and load up ./templates/index.html :
if __name__ == '__main__':
var = 'my variable'
from twisted.web.static import File
webdir = File("{0}/templates/".format(os.path.dirname(os.path.realpath(__file__))))
web = Site(webdir)
reactor.listenTCP(int(os.environ.get('SR_LISTEN_PORT')), web)
reactor.run()
I want the variable 'var' to be substituted for {{variable}} in a basic index.html page
so the page would render 'my variable' instead of hello world for instance.
How can I accomplish this?
1 answers
solution1
0 2017-01-13 08:43:46
It looks like you need a template engine for serving files, you can use jinja2 for it. In your case static.File should be used to render template directory and resource.Resource — to serve files in it rendered via jinja2:
import os
import jinja2
from twisted.internet import reactor
from twisted.web.resource import Resource
from twisted.web.static import File
from twisted.web.server import Site
template_dir = '{}/templates/'.format(os.path.dirname(os.path.realpath(__file__)))
def render(template_file, context):
env = jinja2.Environment(loader=jinja2.FileSystemLoader(template_dir))
return env.get_template(template_file).render(context).encode('utf-8')
class RDirectory(File):
def getChild(self, name, request):
if name == '':
return super(RDirectory, self).getChild(name, request)
return RFile()
class RFile(Resource):
isLeaf = True
def render_GET(self, request):
data = {'var': 'my variable'}
return render(request.uri, data)
if __name__ == '__main__':
web = Site(RDirectory(template_dir))
reactor.listenTCP(int(os.environ.get('SR_LISTEN_PORT')), web)
reactor.run()
File can be something like this:
<html>
<head><title>Test</title></head>
<body>{{ var }}</body>
</html>
Note that jinja2 rendering is a synchronous operation and it will block twisted reactor. To avoid it you can launch rendering in a thread or try to use built-in twisted templates but they do not provide many possibilities.
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