How to append extra info (like session info ,data from async request) to the event?

[thenativeweb]

How to append extra info (like session info ,data from async request) to the event?

[adrai]

yes, you can pass extra infos via command.meta to the event

[vishant-dhandha]

Is there any other way to achieve this??
i mean inside domain.defineCommand() i want to use my custom method to append data to event.. here is my code structure..

module.exports = require('cqrs-domain').defineCommand({
    name: 'createNarration', 
    payload: 'payload'
}, function (data, aggregate) {
       require('/path/to/myfile.js').append(data, "createNarration", function(err, res){
        if(err){
           cosnole.log(err);
        }else{
           // Not working :Type Error is generated..
            aggregate.apply('narrationCreated', data);
        }
    });
})

If my code structure is like below, its working fine..

module.exports = require('cqrs-domain').defineCommand({
    name: 'createNarration', 
    payload: 'payload'
}, function (data, aggregate) {
    //Working fine but i want to append info to data..
    aggregate.apply('narrationCreated', data);   
})

But i am using my custom method to fill data before event created. Though data is filled with my custom info but,
The problem here i am facing is after appending data to events ,aggregate.apply can not apply data to event ..
Error is like

 aggregate.apply('narrationCreated', data);
           ^
TypeError: Object #<Object> has no method 'apply'
    at /home/vishant/Documents/cqrs-sample-vishant/domain/domainFiles/masters/narration/commands/createNarration.js:12:23
    at module.exports.append (/home/vishant/BizOs/bizosprojects/commonfeatures/eventdenormalizerservice/utility/commandappenderutil.js:155:13)
    at _asyncMap (/home/vishant/BizOs/bizosprojects/commonfeatures/node_modules/async/lib/async.js:254:17)
    at async.eachSeries.iterate (/home/vishant/BizOs/bizosprojects/commonfeatures/node_modules/async/lib/async.js:157:25)
    at _asyncMap (/home/vishant/BizOs/bizosprojects/commonfeatures/node_modules/async/lib/async.js:251:21)
    at async.series.results (/home/vishant/BizOs/bizosprojects/commonfeatures/node_modules/async/lib/async.js:615:34)
    at module.exports.append.async.series.data.error (/home/vishant/BizOs/bizosprojects/commonfeatures/eventdenormalizerservice/utility/commandappenderutil.js:150:17)
    at async.series.results (/home/vishant/BizOs/bizosprojects/commonfeatures/node_modules/async/lib/async.js:610:21)
    at _asyncMap (/home/vishant/BizOs/bizosprojects/commonfeatures/node_modules/async/lib/async.js:249:17)
    at async.eachSeries.iterate (/home/vishant/BizOs/bizosprojects/commonfeatures/node_modules/async/lib/async.js:149:13)

Process finished with exit code 8

_F.Y.I. aggregate object has all the attribute & methods except 1 that is apply method_

[vishant-dhandha]

This is what i was trying to say.. I have replicate the issue ..
I have added a custom function to your cqrs-sample project.. Below is my commit to your repo..

vishant-dhandha/cqrs-sample@20a0f24

Here i have added async http call to fetch some info & append to the 'data'..

At aggregate.apply('itemCreated', data); data contains my desired info but some how server stopped with TypeError: Object #Object has no method 'apply'

[adrai]

this is not possible... the whole apply part is completely sync...
can't you extend your command before it enters the domain.handle?

[vishant-dhandha]

I want to make a async call, if that async call successfully returned then and then only the event should be generated.
How could i make out this?

Saga is the solution for that???

[adrai]

asynccall(function (err, extenstion) {

  if (!err) {
    command.myExtension = extension;
    domain.handle(command);
  }

});

[adrai]

I have an idea:
Would it be ok for you, if you define a precondition for that command in which you make your async requests and save the resulting data in a sort of clipboard on the aggregate and afterwards in de command just get that saved data and extend your event?

[vishant-dhandha]

Yes , this (precondition) solved my problem..
thank you