Add support for generic OAuth2 providers

Signed-off-by: Pedro Ferreira <pedro.ferreira@cern.ch>

lib/web/auth/oauth2/index.js

@@ -0,0 +1,106 @@
+'use strict'
+
+const Router = require('express').Router
+const passport = require('passport')
+const OAuth2Strategy = require('passport-oauth2').Strategy
+const config = require('../../../config')
+const {setReturnToFromReferer, passportGeneralCallback} = require('../utils')
+
+let oauth2Auth = module.exports = Router()
+
+class OAuth2CustomStrategy extends OAuth2Strategy {
+  constructor (options, verify) {
+    options.customHeaders = options.customHeaders || {}
+    super(options, verify)
+    this.name = 'oauth2'
+    this._userProfileURL = options.userProfileURL
+    this._oauth2.useAuthorizationHeaderforGET(true)
+  }
+
+  userProfile (accessToken, done) {
+    this._oauth2.get(this._userProfileURL, accessToken, function (err, body, res) {
+      var json
+
+      if (err) {
+        return done(new passport.InternalOAuthError('Failed to fetch user profile', err))
+      }
+
+      try {
+        json = JSON.parse(body)
+      } catch (ex) {
+        return done(new Error('Failed to parse user profile'))
+      }
+
+      let profile = parseProfile(json)
+      profile.provider = 'oauth2'
+
+      done(null, profile)
+    })
+  }
+}
+
+function extractProfileAttribute (data, path) {
+  // can handle stuff like `attrs[0].name`
+  path = path.split('.')
+  for (const segment of path) {
+    const m = segment.match(/([\d\w]+)\[(.*)\]/)
+    data = m ? data[m[1]][m[2]] : data[segment]
+  }
+  return data
+}
+
+function parseProfile (data) {
+  const username = extractProfileAttribute(data, config.oauth2.userProfileUsernameAttr)
+  const displayName = extractProfileAttribute(data, config.oauth2.userProfileDisplayNameAttr)
+  const email = extractProfileAttribute(data, config.oauth2.userProfileEmailAttr)
+
+  return {
+    id: username,
+    username: username,
+    displayName: displayName,
+    email: email
+  }
+}
+
+OAuth2CustomStrategy.prototype.userProfile = function (accessToken, done) {
+  this._oauth2.get(this._userProfileURL, accessToken, function (err, body, res) {
+    var json
+
+    if (err) {
+      return done(new passport.InternalOAuthError('Failed to fetch user profile', err))
+    }
+
+    try {
+      json = JSON.parse(body)
+    } catch (ex) {
+      return done(new Error('Failed to parse user profile'))
+    }
+
+    let profile = parseProfile(json)
+    profile.provider = 'oauth2'
+
+    done(null, profile)
+  })
+}
+
+passport.use(new OAuth2CustomStrategy({
+  authorizationURL: config.oauth2.authorizationURL,
+  tokenURL: config.oauth2.tokenURL,
+  clientID: config.oauth2.clientID,
+  clientSecret: config.oauth2.clientSecret,
+  callbackURL: config.serverURL + '/auth/oauth2/callback',
+  userProfileURL: config.oauth2.userProfileURL
+}, passportGeneralCallback))
+
+oauth2Auth.get('/auth/oauth2', function (req, res, next) {
+  setReturnToFromReferer(req)
+  passport.authenticate('oauth2')(req, res, next)
+})
+
+// github auth callback
+oauth2Auth.get('/auth/oauth2/callback',
+  passport.authenticate('oauth2', {
+    successReturnToOrRedirect: config.serverurl + '/',
+    failureRedirect: config.serverurl + '/'
+  })
+)