Polling a resource in Angular

[Ruiwen Chua]

Hi all,

I'm new to Angular so I've been going through the documentation trying
to familiarise myself with it.

Was just wondering, is there a way to create a polling function using
Angular, ie. one that checks a resource periodically and updates the
view if necessary?


Cheers
Ruiwen

[Misko Hevery]

Hi Ruiwen,

Yes, there is. In general you can do evrything you need with normal JavaScript, but when you go outside of angular, such as when you call setTimeout, you may have to call scope.$root.$eval() manually. Here is an example

function MyAppCntroller(){

  var self = this;

  this.startPolling = function(){

    function poll(){

      // do something.

      self.$root.$eval();

      window.setTimeout(poll, 1000);

    };

    poll();

  };

};

we are about to release a new wersion of angular 0.9.9 http://code.angularjs.org and then you will be able to write this

function MyAppCntroller($defer){

  var self = this;

  this.startPolling = function(){

    function poll(){

      // do something.

      // self.$root.$eval(); // not needed as $defer does this for you

      $defer(poll, 1000);

    };

    poll();

  };

};

MyAppController.$inject=['$defer'];

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[Ruiwen Chua]

Thanks for the top Misko!

Have managed to get polling to work now. 

Next question, how do I get polling to stop? =P

Cheers

Ruiwen

[Igor Minar]

you jus don't schedule the next $defer execution

function MyAppCntroller($defer){

  var self = this;

  this.startPolling = function(){

    function poll(){

      // do something.

      // self.$root.$eval(); // not needed as $defer does this for you

      if (keepOnGoing) {

        $defer(poll, 1000);

      }

    };

    poll();

  };

};

MyAppController.$inject=['$defer'];

Cheers

Ruiwen

--

[Ruiwen Chua]

Ah, thought as much =)

Thanks Igor!

[mineralf]

Hi Misko, Igor and anybody out there having trouble with $defer,

I wrote a little full functional code for counting up a number with a
start and stop button.
I pulled out the inner function as I personally didn't want it to be a
inner function for testability reasons...

Anybody interested:
http://jsfiddle.net/zh2GU/

Would be really great to have such an example on the angular docs
http://docs.angularjs.org/#!angular.service.$defer as I needed much
too long (several hours) to figure out how $defer works and how to
avoid the scope problem etc. (self = this)...

Thx for a great framework - keep on like this!!
Ralf

[mineralf]

Hi all,
my message did somehow not show up? Or is it revised manually?
Whatever...

Took me far too long to get $defer work as I wanted it. (self=this
trick etc.) Thx god I found this thread here. I've build a small
example without inner functions for testability reasons...

Here's the example code: http://jsfiddle.net/zh2GU/
And please include sth. similar to the docs: http://docs.angularjs.org/#!angular.service.$defer

Thx for the great work on angular! Love it!
Ralf

[Igor Minar]

On Wed, Mar 23, 2011 at 11:29 AM, mineralf <mine...@gmail.com> wrote:
> Hi all,
> my message did somehow not show up? Or is it revised manually?

yes, the *first* time someone post to the mailing list we have to
approve it to weed out all the spammers.

> Whatever...
>
> Took me far too long to get $defer work as I wanted it. (self=this
> trick etc.) Thx god I found this thread here. I've build a small
> example without inner functions for testability reasons...
>
> Here's the example code: http://jsfiddle.net/zh2GU/
> And please include sth. similar to the docs: http://docs.angularjs.org/#!angular.service.$defer

good idea, we do need an example there. however, I think that running
a task at scheduled intervals is too common of a use case not to have
a api to do just that. you can use $defer to achieve the same thing,
but that's not what $defer was primarily designed for, so the code is
longer than what it needs to be.

$schedule anyone? :)

/i

> Thx for the great work on angular! Love it!
> Ralf
>

[mineralf]

On 24 Mrz., 00:01, Igor Minar <iimi...@gmail.com> wrote:
> good idea, we do need an example there. however, I think that running
> a task at scheduled intervals is too common of a use case not to have
> a api to do just that. you can use $defer to achieve the same thing,
> but that's not what $defer was primarily designed for, so the code is
> longer than what it needs to be.
>
> $schedule anyone? :)

Your right. Sounds like a own service would be what we need... Maybe
I'll give it a try if I find some free time the next days/weeks.
But following all steps described at http://docs.angularjs.org/#!contribute
will cost me forever. (Never did any open source contribution so far)

The example code from before without Syntax Errors and JS seperated
from HTML: http://jsfiddle.net/zh2GU/3/

Cheers,
Ralf

[Igor Minar]

On Thu, Mar 24, 2011 at 5:25 AM, mineralf <mine...@gmail.com> wrote:
> On 24 Mrz., 00:01, Igor Minar <iimi...@gmail.com> wrote:
>> $schedule anyone? :)
>
> Your right. Sounds like a own service would be what we need... Maybe
> I'll give it a try if I find some free time the next days/weeks.

cool :)

> But following all steps described at http://docs.angularjs.org/#!contribute
> will cost me forever. (Never did any open source contribution so far)

That doc is more of a guide on how to work with our git repo, build
angular, run tests, etc.

The requirements really are just three:
- send us a git pull request
- include tests
- follow the handful of style rules we have

We can delete the rest of the doc, but then you'll need to figure out
how we write, test and build our code on your own.

> The example code from before without Syntax Errors and JS seperated
> from HTML: http://jsfiddle.net/zh2GU/3/

This looks much better!

/i

>
> Cheers,

[Pepper Lebeck-Jobe]

Suppose I want to start polling as soon as the page is fully loaded and the controller is initialized.  What hooks does the angular life-cycle management provide for this?

Thanks,

Pepper

[Miško Hevery]

If you are using 10.6 then you can put that code in the module run method, which gets called as soon as the app gets bootstraped