how to manually slow down asynchronous javascript requests to parse.com in order to stay below 30 requests per second?

Question

how to manually slow down asynchronous javascript requests to parse.com in order to stay below 30 requests per second?

I'm fetching a collection called logCollection from parse.com in a node JS script on my machine. It has 200 elements. Each log has a link to another table (a pointer) called start. I need to fetch this one too.

Here is my code

Parse.User.logIn("user", "pass").then(function(user) {
  // Do stuff after successful login.
  console.log('succesfully logged in');
  return logCollection.fetch();
}).then(function(content) {
  console.log('done fetching logs: ' + logCollection.length);
  var promises = [];
  _.each(logCollection.models, function(thisLog) {

    promises.push(thisLog.attributes.start.fetch());

  });
  // Return a new promise that is resolved when all of the deletes are finished.
  return Parse.Promise.when(promises);
});

The thing is, it will fire at least 200 (start) fetch per second, and it will cause problems with the 30 requests per second limit at parse.com.

Is there a better way to do this? How can I slow down the way js fires the requests?

thanks

javascript
node.js
backbone.js
request
parse.com

Answer 1

In a Parse Query, you can get the fully-fetched objects which are pointed to by that object, by using the include method on the query:

var query = new Parse.Query("SomeClass");
query.include('columnName');
query.find().then(function(results) {
  // each result will have 'columnName' as a fully fetched parse object.
});

This also works with sub-sub objects:

query.include('columnName.nestedColumnName');

or as an array:

query.include(['columnName', 'anotherPointerColumn']);

Answer 2

I came out with this solution that works very good. It was all this time on the parse documentation.

https://www.parse.com/docs/js_guide#promises-series

The following code will fire one request only after the last one has been finished. Doing so, I can fire many requests without worrying about getting to the limit.

var query = new Parse.Query("Comments");
query.equalTo("post", 123);

query.find().then(function(results) {
  // Create a trivial resolved promise as a base case.
  var promise = Parse.Promise.as();
  _.each(results, function(result) {
    // For each item, extend the promise with a function to delete it.
    promise = promise.then(function() {
      // Return a promise that will be resolved when the delete is finished.
      return result.destroy();
    });
  });
  return promise;

}).then(function() {
  // Every comment was deleted.
});