identity/lib/app_communication.js

Identity client

var restify = require('restify');
var URL = require('url');
var http = require('http');


module.exports = function(api, config){
  
  //restify config
  var identity_server = restify.createJsonClient({
    url: config.site,
    userAgent: api.config.general.serverName
  });
  
  //helper function
  var startRequest = function(application, path, method, options, callback){
    path = '/api/' + path;
    
    //add the access_token
    if(path.indexOf('?') !== -1){
      path += '&access_token=' + application.access_token;
    }else{
      path += '?access_token=' + application.access_token;
    }
    
    var headers;
    
    if(method === 'del'){
      headers = {
        'content-length': 0
      };
    }
    
    //create restify instance            
    var app = restify.createJsonClient({
      url: application.url,
      userAgent: api.config.general.serverName,
      headers: headers
    });
    
    api.logger.info('Request "' + path + '" of application "' + application.name + '" (' + application.url + ')');

    //replace callback with a simpler version
    if(typeof callback === 'function'){
      var original = callback;
      callback = function(err, req, res, resp){
        original(err, resp, req, res);
      }
    }
  
    //start request
    if(options === null){
      app[method](path, callback);
    }else{
      app[method](path, options, callback);
    }
    
  };
  
  
  
  return function application(name, access_token){    
    var key = '__identity_application_' + name + (access_token || '');

    return {
      action: function(path, method, options, callback){
        
        //get the current access_token for the application
        this.getAccessToken(function(application){
          if(application){
            
            if(access_token && name === 'identity'){
              //if there is a given access_token - use it inseatd
              application.access_token = access_token;
            }
            
            startRequest(application, path, method, options, callback);
          }else{
            api.logger.error('did not get an access_token for application ' + name);
            callback('did not get an access_token for application ' + name);
          }
        
        });
        
      },
      
      
      get: function(path, options, callback){
        //put params into the url... restify wont do it for us :(
        path = URL.format({pathname: path, query:options});
        this.action(path, 'get', null, callback);
      },
      
      post: function(path, options, callback){
        this.action(path, 'post', options, callback);
      },
      
      put: function(path, options, callback){
        this.action(path, 'put', options, callback);        
      },
      
      del: function(path, callback){
        this.action(path, 'del', null, callback);        
      },
      
      
      proxy: function(path, connection, next){
        var req = connection.rawConnection.req;
        var res = connection.rawConnection.res;
        
        this.getAccessToken(function(application){
          
          if(access_token && name === 'identity'){
            //if there is a given access_token - use it inseatd
            application.access_token = access_token;
          }          
          
          path = '/api/' + path;
    
          //add the access_token
          if(path.indexOf('?') !== -1){
            path += '&access_token=' + application.access_token;
          }else{
            path += '?access_token=' + application.access_token;
          }
    
          api.logger.info('Request "' + path + '" of application "' + application.name + '" (' + application.url + ')');
          
          var options = {};
          var uri = URL.parse(application.url);
          
          options.hostname = uri.hostname;
          options.path = path;
          options.port =  uri.port;
          options.method = req.method;
          
          var json = null;
          
          if(req.method === 'POST'){
            json = JSON.stringify(connection.rawConnection.params.body);
            var len = Buffer.byteLength(json, 'utf8');
            options.headers = {'content-type': req.headers['content-type'], 'content-length': len};
          }
   
          var newReq = http.request(options, function(newRes) {
            var headers = newRes.headers;            
            delete headers['set-cookie'];
            
            res.writeHead(newRes.statusCode, headers);
            
            newRes.pipe(res).on('finish', function(){
              next(connection, false);
            });
          }).on('error', function(err) {
            res.statusCode = 500;
            res.end();
          });

          if(json){
            newReq.write(json);
          }
          newReq.end();
          
        });
      },
      
      
      
      
      getAccessToken: function(callback){
        //load the current access_token from our cache
        api.cache.load(key, function(error, application){
          if(application && application.access_token && application.expires_at > new Date().getTime()){
            //return it
            callback(application)
          }else{
            var url = '/api/application/access_token';
            var params = {client_id: config.id, secret: config.secret, application_name: name};
            
            if(name !== 'identity' && access_token){
              url = '/api/user/access_token';
              params = {access_token: access_token, application_name: name};
            }
            
            //ask identity server for a new token
            identity_server.post(url, params , function(err, req, res, resp){
              if(err || resp === null){
                return callback(null);
              }

              var application = resp.application;
              
              if(application && application.access_token){
                var ttl = (application.ttl - 10) * 1000
                
                application.expires_at = new Date().getTime() + ttl;
                api.cache.save(key, application, ttl, function(error){
                  //TODO: error handling...
                  callback(application);
                });
              }else{
                callback(null);
              }
            });
          }          
        });
        
      }
    }
    
  }
  
  
};