https://github.com/jbuck/express-persona

persona.coffee

app.post '/api/verify', (req, res) ->
  fail = ->
    res.json status: 'failure'
  if not req.body?
    fail()
  opts = {
    host: "https://verifier.login.persona.org"
    path: "/verify"
    method: 'POST'
    regectUnauthorized: true
  }
  vreq = https.request opts, (verifier) ->
    body = ""
    verifier.on 'error', fail
    verifier.on 'data', (chunk) -> body += chunk
    verifier.on 'end', ->
      try
        response = JSON.parse body
        valid = response? and response.valid
        email = response.email
      catch error
        fail()
      if response.status != 'okay' or not req.session?
        fail()
      req.session.email = response.email
      res.json status: 'okay'
  # SSL validation can fail
  vreq.on 'error', fail
  vreq.setHeader "Content-Type", "application/json"
  data = JSON.stringify
    assertion: req.body.assertion,
    audience: 'http://localhost:3000/'
  vreq.setHeader "Content-Length", data.length
  vreq.end data