Redis Pop in Series

Redis-pop-series

  /**                                                                                                                                                                                                                
   * Query Redis for emails still needing to be parsed                                                                                                                                                               
   * Should return error if no items exist                                                                                                                                                                           
   * @param user_name                                                                                                                                                                                                
   * @param cb - Callback(err,                                                                                                                                                                                       
   *    [ {uid: }, {msgid: } ],...                                                                                                                                                                                   
   * Note: Will return NO_EMAILS_TO_PARSE error when                                                                                                                                                                 
   * no emails to parse                                                                                                                                                                                              
   */                                                                                                                                                                                                                
  var getUIDAttachList = function(user_name, cb) {                                                                                                                                                                   
    var attachList = [];                                                                                                                                                                                             
                                                                                                                                                                                                                     
    //Pops in Series                                                                                                                                                                                                 
    var popAll = function(done_cb) {                                                                                                                                                                                 
      redisClient.lpop(user_name, function(err, msg_id) {                                                                                                                                                            
        if(err) {                                                                                                                                                                                                    
          logger.error("Error popping msg_id from " + user_name + ": "+ err);                                                                                                                                        
        } else {                                                                                                                                                                                                     
          if(!msg_id) {                                                                                                                                                                                              
            done_cb();                                                                                                                                                                                               
          } else {                                                                                                                                                                                                   
            redisClient.hgetall(msg_id, function(err, email) {                                                                                                                                                       
              if(err) {                                                                                                                                                                                              
                logger.error("Error getting hash for " + msg_id + ": " + err);                                                                                                                                       
              } else {                                                                                                                                                                                               
                attachList.push(email);                                                                                                                                                                              
              }                                                                                                                                                                                                      
              popAll(done_cb);                                                                                                                                                                                       
            });                                                                                                                                                                                                      
          }                                                                                                                                                                                                          
        }                                                                                                                                                                                                            
      });                                                                                                                                                                                                            
    };                                                                                                                                                                                                               
                                                                                                                                                                                                                     
    popAll(function() {                                                                                                                                                                                              
      if(attachList.length === 0) {                                                                                                                                                                                  
        cb(NO_EMAILS_TO_PARSE);                                                                                                                                                                                      
      } else {                                                                                                                                                                                                       
        cb(null, attachList);                                                                                                                                                                                        
      }                                                                                                                                                                                                              
    });                                                                                                                                                                                                              
  };