"done" in the command chain

[rchipka]

"done" in the command chain

[rchipka]

Yes, done should be called after all callbacks and commands have called "next(context, data)".

The problem here is that then should come before the data command. The order of the console.log messages will then be: then, done, then data.

The reason data will still appear to happen last is because it's printing after an async function (fs.readdir) has been called. Unlike .then, .data doesn't expect a next(context, data) call. This means that Osmosis has no way of knowing when the .data callback finishes.

So done is the last thing being called, which means Osmosis is done doing everything it needs to and now your callback code is doing what it needs to.

If you merge your .data callback code with your .then callback code you can use next to tell Osmosis when your code is done. This will cause your console.log's to happen in the order you expect.

To verify the order:

var fs = require('fs');
var osmosis = require('osmosis');

osmosis
.get('www.craigslist.org/about/sites')
.data(function(data) {
    console.log('data');
})
.then(function(context, data, next) {
  console.log('then');
  next(context, data);
})
.done(function(){
  console.log('done');
})

[anasqadrei]

My real problem is something like this

osmosis
.get('www.craigslist.org/about/sites')
.then(function(context, data, next) {
  database.query(query, function(err, queryResults){
    //working on queryResults
    next(context, data);
  });
})
.done(function(){
  database.disconnect();
})

The problem is that it disconnects from the database before finishing the query which causes a database connection error in "then".

[rchipka]

In that case, done shouldn't be called until then has called next. Obviously this must not be the case if you are still having an issue. Is your "working on queryResults" code asynchronous? this would cause next to be called before it finished working on the query.

[anasqadrei]

Yes done shouldn't be called until then has called next. But that is not the case.

This is another illustration that proves that done is not waiting for next. I'm setting a timeout of 5 seconds and then call next.

var osmosis = require('osmosis');

osmosis
.get('www.google.com')
.then(function(context, data, next) {
    //call next after 5 secs
    setTimeout(function(){
      console.log('then');
      next(context, data);
    },5000);
})
.done(function(){
  console.log('done');
})

In that case, the output is done and 5 seconds later it writes then. Shouldn't done also wait 5 seconds for next to be called?

[rchipka]

There seems to be an issue when using then immediately before done. If you place a command between then and done then the code works as expected. This should be fixed in the next release.

In my test code I used the doc command in between:

var osmosis = require('/root/node-osmosis');

osmosis
.get('www.google.com')
.then(function(context, data, next) {
    //call next after 5 secs
    setTimeout(function(){
      console.log('then');
      next(context, data);
    },5000);
})
.doc()
.done(function(){
  console.log('done');
})

[rchipka]

As of Osmosis version 0.0.9 significant stack counting changes were made and these issues should be resolved.