Returning JSON via node.js response.write has unexpected results

Question

Here is a snippet:

objects = [];
client.keys 'objects*', (err,keys) ->
for (i = 0; i < keys.length; i++){
  client.hgetall(keys[i], function(err, obj) {
    objects.push(obj);
    if (i === keys.length){
      response.writeHead(200, {'Content-Type': 'application/json'});
      console.log(JSON.stringify(objects));
      response.write(JSON.stringify(objects));
      response.end();
    }
  }
}

The var objects is an array of objects I populate by querying redis via node-redis, each with 6 properties. In the console, I get exactly what I would expect. In a client, however, I receive an array with only the last object. Wondering if it was the client's deseralizer, I captured it in Fiddler and it is still that array with a single object.

Here is what I get in the console via console.log:

[{"prop1":"11","prop2":"12","prop3":"13","prop4":"14","prop5":"15","prop6":"16"},  {"prop1":"21","prop2":"22","prop3":"23","prop4":"24","prop5":"25","prop6":"26"},{"prop1":"31","prop2":"32","prop3":"33","prop4":"34","prop5":"35","prop6":"36"},{"prop1":"41","prop2":"42","prop3":"43","prop4":"44","prop5":"45","prop6":"46"},{"prop1":"51","prop2":"52","prop3":"53","prop4":"54","prop5":"55","prop6":"56"},{"prop1":"61","prop2":"62","prop3":"63","prop4":"64","prop5":"65","prop6":"66"}]

I must be doing something wrong...

I edited my question to include more detail and hopefully address your comment. Also, I originally (incorrectly) stated I was only seeing the first object, when in fact I am only getting the last one. — CircusNinja
– CircusNinja, Commented Jan 12, 2012 at 17:07
Your async code is wrong. The line if (i === keys.length) will always return true because you are checking if client.hgetall has been called keys.length times and not if the calls have been completed. You should instead be checking (objects.length === keys.length) — fent
– fent, Commented Jan 13, 2012 at 16:54
Thanks @DeaDEnD. Changing this did work, so if you want to put it as an answer I will use it. This async stuff is kind of new to me, so my thinking wasn't in that lane. Thanks again! — CircusNinja
– CircusNinja, Commented Jan 16, 2012 at 17:24

Paul Sweatte · Accepted Answer · 2013-03-12 22:50:38Z

1

Your async code is wrong. The line if (i === keys.length) will always return true because you are checking if client.hgetall has been called keys.length times and not if the calls have been completed. You should instead be checking (objects.length === keys.length) – DeaDEnD

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