[WIP] New powerfull feature zlink

[sam2x]

Hello,

Since now 15days, i'm using Nohm as a Model Abstraction to redis.
After some practise and several tests cases, i decided to keep it
as a main Redis interaction for my project.

Here the benefits i can highlight :

• NodeJS-oriented, easy to deploy
• Maintain code more easily than the raw Redis Node API.
• Model definition is complete & powerfull:
  • Type & Validation are elegants manner to ensure user-input data.
  • A set of essential options are available for properties (index, unique; defaultvalue, etc.)

I also fall in some unpleasant issue that should be imho redesigned :

• Not using Redis Sorted Set feature at all on main Nohm feature (except Sort)
• Ambiguous context of documentation, i needed to create several code test
  • Model context during loading (this)
  • Difference about nohm.factory, nohm.models, etc, and suited-use explication

As Sorted Set is one of the best benefit of Redis, i decided to integrate it in the relation model feature.
My pull request allow to specify a score in the zlink function :
User.zlink(Action, { score : date })

Remaining things to do :

• Since i use the proxied function Link, a warning should be raised when score is used with 'link' and not 'zlink'. (else the score will be inserted as item in the classical SET).
• zunlink / zunlinkByScore
• relGetRangeByScore (relName, options { min(0), max, withscores_, limit_, offset_, count_}
• relGetRevRangeByScore
• others relevant redis function of sorted set (http://redis.io/commands#sorted_set)

What is the benefit ?

• Powerfull Redis Type for fast retrieve
• Native Redis API SSET function based on the score (ZRANGEBYSCORE)
  • Limit feature
  • Score fast search

Now in ONE call, we give relation powerfull search :
get object id of Y linked to object X, which have [min/max] score S [limit the result to L] [DESC/ASC]

What do you think ?

Well, this is a small contribution. I think there is other improvement to bring about some Redis feature(eg: sscan/zscan).
Anyway thank you for your project, it is truely helping. Please don't let it go ;)
I hope to have time to help you again in the near future.

Regards,
S

[sam2x]

The dbVals code added is misplaced, he should placed during multi (since the number of parameter differs between zadd and sadd) :

        async.forEach(dbVals, 
          function (val, next) {
            var multi = client.multi();
            if (type === 'zadd' || type === 'zrem')
            {
              val.score = options.score
              multi[type](Nohm.prefix.relationKeys+val.keyStore, val.score, val.key);
              multi[type](val.key, val.score, val.id);
            }
            else {
              multi[type](Nohm.prefix.relationKeys+val.keyStore, val.key);
              multi[type](val.key, val.id);
            }
            multi.exec(next);

Also, as you likely noticed, my code related to the fireevent is incorrect.
About GetByScore :

    /**
   * Retrieves all sorted set relations to another model  .
   */
  exports.getByScore = function getByScore(objName, options, name) {
    var callback = h.getCallback(arguments),
    self = this;
    name = name && typeof name !== 'function' ? name : 'default';
    if (!this.id) {
      Nohm.logError('Calling getAll() even though this '+this.modelName+' has no id. Please load or save it first.');
    }
    args = []
    args.push(this.relationKey(objName, name))
    if(options.rev)
    {
      // ZREVRANGEBYSCORE key max min [WITHSCORES] [LIMIT offset count] 
      options.max !== undefined ? args.push(options.max) : args.push('+inf')
      options.min !== undefined ? args.push(options.min) : args.push('-inf')
      options.withScore ? args.push("WITHSCORES") : 0
      options.offset !== undefined && options.count !== undefined ? args.push("LIMIT", options.offset, options.count) : 0

      this.getClient().zrevrangebyscore(args, function(err, value){
        callback.call(self, err, value);
      })
    }
    else{
      // ZRANGEBYSCORE key min max [WITHSCORES] [LIMIT offset count] 
      options.min !== undefined ? args.push(options.min) : args.push('-inf')
      options.max !== undefined ? args.push(options.max) : args.push('+inf')
      options.withScore ? args.push("WITHSCORES") : 0
      options.offset !== undefined && options.count !== undefined ? args.push("LIMIT", options.offset, options.count) : 0

      this.getClient().zrangebyscore(args, function(err, value){
        callback.call(self, err, value);
      })   
    }
  }

[sam2x]

Patch incomplete, i added a scan/zscan feature with zlink that i didnt push (important for search stuff, etc.). I need to clean up my code and push my change.

[maritz]

Same problem as #104 I think this should be converted into a new feature for v2.x (probably 2.2 or 2.3), instead of attempting to put it into v0.9 and then porting it.