qewd/up/ms_handlers.js

/*

 ----------------------------------------------------------------------------
 | qewd-up: Rapid QEWD API Development                                      |
 |                                                                          |
 | Copyright (c) 2018-19 M/Gateway Developments Ltd,                        |
 | Redhill, Surrey UK.                                                      |
 | All rights reserved.                                                     |
 |                                                                          |
 | http://www.mgateway.com                                                  |
 | Email: rtweed@mgateway.com                                               |
 |                                                                          |
 |                                                                          |
 | Licensed under the Apache License, Version 2.0 (the "License");          |
 | you may not use this file except in compliance with the License.         |
 | You may obtain a copy of the License at                                  |
 |                                                                          |
 |     http://www.apache.org/licenses/LICENSE-2.0                           |
 |                                                                          |
 | Unless required by applicable law or agreed to in writing, software      |
 | distributed under the License is distributed on an "AS IS" BASIS,        |
 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
 | See the License for the specific language governing permissions and      |
 |  limitations under the License.                                          |
 ----------------------------------------------------------------------------

  4 July 2019

*/

var router = require('qewd-router');
var createDocStoreEvents = require('./createDocStoreEvents');
var handleDocStoreEvents = require('./handleDocStoreEvents');

var ignore_jwt = {};
var workerResponseHandler = {};
var onWorkerLoad;
var beforeHandler;
var docStoreEvents;

function loadRoutes(onHandledOnly) {
  var fs = require('fs');
  var cwd = process.cwd() + '/mapped';
  var ms_name = process.env.microservice;
  var mode = process.env.mode;
  if (mode && ms_name) {
    cwd = process.cwd() + '/' + ms_name;
  }

  var routes_data = require(cwd + '/configuration/routes.json');
  var config_data = require(cwd + '/configuration/config.json');
  var ms_path;

  if (mode === 'microservice') {
    ms_name = config_data.ms_name;
    ms_path = cwd + '/';
  }
  else {
    ms_path = cwd + '/' + ms_name + '/';
  }

  var routes = {};

  //console.log('loading up/ms_handlers in process ' + process.pid);
  //console.log('ms_name = ' + ms_name);
  //console.log('routes_data = ' + JSON.stringify(routes_data, null, 2));

  // check for any grouped destinations that include this microservice name

  var group_matches = {};
  if (!mode) {
    config_data.microservices.forEach(function(microservice) {
      if (microservice.members) {
        microservice.members.forEach(function(member_name) {
          if (member_name === ms_name) {
            group_matches[microservice.name] = true;
          }
        });
      }
    });
  }

  routes_data.forEach(function(route) {
    if (mode === 'microservice') {
      route.on_microservice = ms_name;
    }
    //console.log('route: ' + JSON.stringify(route, null, 2));
    var handler;
    var ms_match = false;
    var ms_source = ms_name;
    var i;

    if (route.on_microservice) {
      if (route.on_microservice === ms_name) {
        // direct match
        ms_match = true;
      }
      if (group_matches[route.on_microservice]) {
        // group destination match
        ms_match = true;
        if (route.handler_source) {
          ms_source = route.handler_source;
        }
      }
    }
    if (!ms_match && route.on_microservices) {
      route.on_microservices.forEach(function(on_ms_name) {
        if (on_ms_name === ms_name) ms_match = true;
        if (route.handler_source) {
          ms_source = route.handler_source;
        }
      });
    }

    if (ms_match) {
      if (onHandledOnly) {
        var onMSResponsePaths = [
          ms_path + route.handler + '/onMSResponse.js',
          ms_path + 'apis/' + route.handler + '/onMSResponse.js',
        ];
        for (i = 0; i < onMSResponsePaths.length; i++) {
          if (fs.existsSync(onMSResponsePaths[i])) {
            try {
              workerResponseHandler[route.uri] = require(onMSResponsePaths[i]);
              console.log('onMSResponse handler loaded from ' + onMSResponsePaths[i]);
            }
            catch(err) {
              console.log('** Warning: onMSResponse handler could not be loaded from ' + onMSResponsePaths[i]);
            }
            break;
          }
        }
      }
      else {
        if (!routes[route.uri]) routes[route.uri] = {};
        //console.log('route.uri = ' + route.uri);
        var path = cwd + '/' + ms_source + '/';
        var handlerPaths = [
          path + route.handler + '.js',
          path + route.handler + '/handler.js',
          path + route.handler + '/index.js',
          path + 'apis/' + route.handler + '/index.js'
        ];
        if (mode === 'microservice') {
          handlerPaths.push(cwd + '/apis/' + route.handler + '/index.js');
          handlerPaths.push(cwd + '/apis/' + route.handler + '/handler.js');
        }
        var handlerFound = false;
        for (i = 0; i < handlerPaths.length; i++) {
          console.log('** trying to load from ' + handlerPaths[i]);
          if (fs.existsSync(handlerPaths[i])) {
            try {
              handler = require(handlerPaths[i]);
              console.log('loaded handler from ' + handlerPaths[i]);
            }
            catch(err) {
              console.log('*** Warning - handler for ' + route.handler + ' found but could not be loaded from ' + handlerPaths[i]);
              console.log(err);
            }
            handlerFound = true;
            break;
          }
        }
        if (!handlerFound) {
          console.log('*** Warning - handler for ' + route.handler + ' not found');
        }

        routes[route.uri][route.method] =  handler;
        //console.log(route.uri + ': authenticate = ' + route.authenticate);
        if (route.authenticate === false) {
          ignore_jwt[route.uri] = true;
        }
      }
    }
  });

  if (onHandledOnly) return;

  var onWorkerLoadPath = ms_path + 'onWorkerLoad.js';
  if (fs.existsSync(onWorkerLoadPath)) {
    try {
      onWorkerLoad = require(onWorkerLoadPath);
      console.log('Loaded onWorkerLoad module from ' + onWorkerLoadPath);
    }
    catch(err) {
      console.log('** Warning - unable to load onWorkerLoad module from ' + onWorkerLoadPath);
    }
  }

  var beforeHandlerPath = ms_path + 'beforeHandler.js';
  if (fs.existsSync(beforeHandlerPath)) {
    try {
      beforeHandler = require(beforeHandlerPath);
      console.log('Loaded beforeHandler module from ' + beforeHandlerPath);
    }
    catch(err) {
      console.log('** Warning - unable to load ' + beforeHandlerPath);
    }
  }
  else {
    beforeHandlerPath = ms_path + 'apis/beforeHandler.js';
    if (fs.existsSync(beforeHandlerPath)) {
      try {
        beforeHandler = require(beforeHandlerPath);
        console.log('Loaded beforeHandler module from ' + beforeHandlerPath);
      }
      catch(err) {
        console.log('** Warning - unable to load ' + beforeHandlerPath);
      }
    }
  }

  var docStoreEventsPath = ms_path + 'docStoreEvents/events.json';
  if (fs.existsSync(docStoreEventsPath)) {
    docStoreEvents = createDocStoreEvents(docStoreEventsPath, ms_path);
    //console.log('** docStoreEvents: ' + JSON.stringify(docStoreEvents, null, 2));
  }

  //console.log('routes: ' + JSON.stringify(routes, null, 2));
  return routes;
}

loadRoutes(true); // when called by master process for workerResponseHandlers
                  // to prevent unnecessary loading of route handlers
 

module.exports = {
  init: function() {
    var routes = loadRoutes();
    if (onWorkerLoad) {
      onWorkerLoad.call(this);
    }

    if (docStoreEvents) {
      handleDocStoreEvents.call(this, docStoreEvents);
    }

    router.addMicroServiceHandler(routes, module.exports);
  },
  beforeMicroServiceHandler: function(req, finished) {
    console.log('beforeMicroServiceHandler for ' + req.pathTemplate);
    //console.log('ignore_jwt = ' + JSON.stringify(ignore_jwt, null, 2));
    if (ignore_jwt[req.pathTemplate]) return;
    var authorised = this.jwt.handlers.validateRestRequest.call(this, req, finished);
    if (authorised && beforeHandler) {
      return beforeHandler.call(this, req, finished);
    }
    return authorised;
  },
  workerResponseHandlers: {
    restRequest: function(message, send) {
      if (workerResponseHandler[message.path]) {
        var _this = this;
        function forward(message, jwt, callback) {
          message.headers = {
            authorization: 'Bearer ' + jwt
          };
          return _this.microServiceRouter.call(_this, message, callback);
        }
        var jwt = message.token;
        var status = workerResponseHandler[message.path].call(this, message, jwt, forward, send);
        if (typeof status === 'undefined') return true;
        if (status === false) return;
        return status;
      }
    }
  }
};