ng-server/lib/middlewares.js

A NodeJs server for Angular 2 applications

/*eslint-env node */
var Cache = require('./cache');
var Helper = require('./helper');
var MimeType = require('./mime-types');

module.exports = function (context) {
  
  // ========================= MIDDLEWARES ========================= 
  
  this.cacheResponse = function (req, res, next) {
      var cached = context.$cache.get(req.url);
      
      if (!cached) {
          next();
          return;
      }
      
      context.$logger.success('File (cached): ' + req.url + ' sent.');
      
      for (var reader in cached.headers)
          res.setHeader(reader, cached.headers[reader]);
        
      res.status(200);
      res.send(cached.data);
      
  };
  
  // add the path config to request object
  this.putPathData = function (req, res, next) {
      context.$logger.info ('Request: ' + req.url);
      
      // looking for the path context
      for (var path in context) {
          if (req.url.startsWith(path)) {
            req.$path = path;
            req.$pathContext = context[path];
            break;
          }
      }
      
      // If path not exists
      if (!req.$pathContext) {
          Helper.sendErr404(res);
          return;
      }
      
      next();
  };
  
  // verify the cors
  this.corsFilter = function (req, res, next) {
      var cors = context[req.$path].cors;
      
      if (cors.indexOf('*') > -1) {
          next();
          return;
      }

      if (cors.indexOf(req.host) === -1) Helper.sendErr403(res);
      
      next();
  };
  
  // serve static files
  this.serveStatics = function (req, res, next) {
      var resources = req.$pathContext.resources;
      var goNext = true;
      var srcUrl = '';
      
      for (var src in resources) {
          src = resources[src];
          srcUrl = req.$path === '/'? src.url: req.$path + src.url;
          
          if (req.url.startsWith(srcUrl)) {
              srcUrl = src.path + req.url.substring(srcUrl.length);
              
              Helper.readFile(res, srcUrl, function (data) {
                  context.$logger.success('File: ' + srcUrl + ' sent.');
                  
                  var readers = {
                    'Content-Type': MimeType.get(srcUrl),
                    'Access-Control-Allow-Origin': context[req.$path].cors,
                  };
            
                  var item =context.$cache.add (req.url, srcUrl, readers, data);
                  
                  for (var reader in item.headers)
                    res.setHeader(reader, item.headers[reader]);
        
                  res.status(200);
                  res.send(item.data);
              });
              
              goNext = false;
          }
      }

      if (goNext) next();
  };
  
  // SEND NOT STATIC FILES
  this.sendFiles = function (req, res, next) {
      var srcUrl = context[req.$path].path + (req.url === '/'? '/' + context[req.$path].entry_point: req.url);
      
      Helper.readFileOrMoveNext(res, next, srcUrl, function (data) {
          
        Helper.compressFile(data, function (err, ziped) {
            
            if (err) {
                Helper.sendErr500(res, "Can't gzip response data");
                return;
            }
            
            context.$logger.success('File (gziped): ' + srcUrl + ' sent.');
            
            var readers = {
                'Content-Type': MimeType.get(srcUrl),
                'Access-Control-Allow-Origin': context[req.$path].cors,
                'Content-Encoding': 'gzip'
            };
            
            var item =context.$cache.add (req.url, srcUrl, readers, ziped);
            
            for (var reader in item.headers)
                res.setHeader(reader, item.headers[reader]);

        
            res.status(200);
            res.send(item.data);
            
        });
        
      });
      
  };
  
  // USE ENTRY POINT AS RESPONSE
  this.angularRouteResponse = function (req, res, next) {
      var srcUrl = context[req.$path].path + '/' + context[req.$path].entry_point;
      
      Helper.readFile(res, srcUrl, function (data) {
        
        Helper.compressFile(data, function (err, ziped) {
            
            if (err) {
                Helper.sendErr500(res, "Can't gzip response data");
                return;
            }
            
            context.$logger.success('File (gziped): ' + srcUrl + ' sent.');
            
            var readers = {
                'Content-Type': MimeType.get(srcUrl),
                'Access-Control-Allow-Origin': context[req.$path].cors,
                'Content-Encoding': 'gzip'
            };
            
            var item = context.$cache.add (req.url, srcUrl, readers, ziped);
            
            for (var reader in item.headers) 
                res.setHeader(reader, item.headers[reader]);
        
            res.status(200);
            res.send(item.data);
            
        });
        
        
      });
  };
  
  this.send = function(res, item) {
      for (var reader in item.headers)
        res.setHeader(reader[0], reader[1]);
        
      res.status(200);
      res.send(item.data);
  };
  
  this.cacheAndSend = function (res, url, dir, headers, data) {
      var item =context.$cache.add (url, dir, headers, data);
      this.send(res, item);
  };
  
  // setting
  this.init = function () {
    
    context.$cache = new Cache();
    
    context.$server.use(this.cacheResponse);
    context.$server.use(this.putPathData);
    context.$server.use(this.corsFilter);
    context.$server.use(this.serveStatics);
    context.$server.use(this.sendFiles);
    context.$server.use(this.angularRouteResponse);
  };
  
};