ZF2 how to localize date formats

[Ralf Eggert]

Hi,

when I use the dateFormat() view helper it expects to get a locale
passed as fourth parameter. Otherwise the default from the Locale class
is used. Since I don't want to pass the locale each time I use
dateFormat(), I want to set it somewhere.

In the module.config.php of the SkeletonApplication it is easy to change
the locale for the translator. But I did not finde anything for setting
the locale generally.

In the end I added this to module/Application/Module::onBootstrap()

  Locale::setDefault('de_DE');

This helps but seems a bit ugly. As well when I want to change the
locale depending on the routing this doesn't seem the right way.

So, what is the best way to set the locale in general and after routing?

Thanks and best regards,

Ralf

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[Jurian Sluiman-3]

2012/8/17 Ralf Eggert <[hidden email]>

In the module.config.php of the SkeletonApplication it is easy to change
the locale for the translator. But I did not finde anything for setting
the locale generally.

In the end I added this to module/Application/Module::onBootstrap()

  Locale::setDefault('de_DE');

This helps but seems a bit ugly. As well when I want to change the
locale depending on the routing this doesn't seem the right way.

So, what is the best way to set the locale in general and after routing?

I did some testing to set the route based on the HTTP Accept-Language header. It's a small snippet you can put in your onBootstrap(), for example inside your application module.

It supports a set of known locale and a default locale. The Accept-Language header must contain a known locale to be set, else the default one is used. I think you can use something similar if you look at the request path and grab the first segment of the path. Then the logic to check it against a known list or else a default will be set, is the same.

Read it here: http://juriansluiman.nl/en/article/118/auto-detect-user-locale-with-zend-http-request-headers-and-ext-intl

--
Jurian Sluiman

[Ralf Eggert]

Hi Jurian,

> Read it here:
> http://juriansluiman.nl/en/article/118/auto-detect-user-locale-with-zend-http-request-headers-and-ext-intl

That fits perfectly and I will be able to amend it to my needs. Though I
am also curious if this can somehow be separated and reuable class.

Thanks and best regards,

Ralf

[Jurian Sluiman-3]

2012/8/18 Ralf Eggert <[hidden email]>

Hi Jurian,

> Read it here:
> http://juriansluiman.nl/en/article/118/auto-detect-user-locale-with-zend-http-request-headers-and-ext-intl

That fits perfectly and I will be able to amend it to my needs. Though I
am also curious if this can somehow be separated and reuable class.

Thanks and best regards,

Ralf

These kind of questions pass by on IRC also more often. There is still a pet project for me to get started with a locale detection module, which would suit a variety of strategies:

1. Detect locale based on TLD (my-company.co,uk versus my-company.de)
2. Detect locale based on subdomain (nl.my-company.com versus fr.my-company.com)
3. Detect locale based on path (my-company.com/nl versus my-company.com/de)
4. Detect locale based on Accept-Language http header
5. Detect locale from cookie
6. Detect locale from user profile (ZfcUser)

A mixin of strategies would allow for example to say user profile > cookie > path > http header. Also a list of aliases ("nl" is "nl_NL") should be supported. Last, there can be a list of supported locales and a default locale when none is found. 

But I think it will take a while to find time to get started...

--
Jurian Sluiman

[Ralf Eggert]

Hi Jurian,

> These kind of questions pass by on IRC also more often. There is still a
> pet project for me to get started with a locale detection module, which
> would suit a variety of strategies:

Such an module sounds interesting. But I wonder if module with such a
limited scope don't blow up the module bootstrap process I dozens of
them in my application.

I would prefer to add this to my Application module which is already in
use. I could add in to the onBootstrap() method. But I wonder if there
is anything like the ressource plugins from ZF1 which can used in the
ZF2 Module.php classes.

Best regards,

Ralf

[Ralf Eggert]

Hi Jurian,

> Read it here:
> http://juriansluiman.nl/en/article/118/auto-detect-user-locale-with-zend-http-request-headers-and-ext-intl

Now I finally had some time to implement your solution, but I don't
manage to amend it to use the params from the routing. In ZF1 I would do
something like ->getRequest()->getParams() and there I would expect
module, controller and action. But this obviously does not work in ZF2.

So how can I access the params after the routing?

Is the onBootstrap() method really the right place or is the routing
processed after the bootstrapping?

I found Robs article here, but still I don't now how to solve this problem:

http://akrabat.com/zend-framework-2/a-list-of-zf2-events/

Thanks for your help.

Best regards,

Ralf

[Jurian Sluiman-3]

2012/8/20 Ralf Eggert <[hidden email]>

Such an module sounds interesting. But I wonder if module with such a

limited scope don't blow up the module bootstrap process I dozens of
them in my application.

I would prefer to add this to my Application module which is already in
use. I could add in to the onBootstrap() method. But I wonder if there
is anything like the ressource plugins from ZF1 which can used in the
ZF2 Module.php classes.

You have to ask Evan about the exact impact of a module, but modules in general are very lightweight. The cost of detecting a locale (or any other business logic you implement) is much higher than the cost of  instantiating a module. The benefit of self-contained modules are for me more than the benefit of micro optimizations.

If later on you might think the amount of modules is a bottleneck for your application, you can always use the classes in the module and call those from your own existing module. So you do not turn on the module in your application.config.php, but you load the files and use them on your own.

--
Jurian Sluiman

[Jurian Sluiman-3]

2012/8/20 Ralf Eggert <[hidden email]>

Now I finally had some time to implement your solution, but I don't

manage to amend it to use the params from the routing. In ZF1 I would do
something like ->getRequest()->getParams() and there I would expect
module, controller and action. But this obviously does not work in ZF2.

So how can I access the params after the routing?

Is the onBootstrap() method really the right place or is the routing
processed after the bootstrapping?

I found Robs article here, but still I don't now how to solve this problem:

http://akrabat.com/zend-framework-2/a-list-of-zf2-events/

The bootstrap event is an early event. Prior to the "run" state of the application, all the code is initialized during bootstrap. Bootstrap is something that always happen and is independent of routing or dispatching.

If you need to wait after routing took place, you can create a listener which listens late to the routing event. The route took place at normal priority, so if you attach a listener at low priority, the routing has been done. The result of routing is a (potential) route match object (NB. No route match object means a page-not-found error). Then you are able to look at the route match parameters and then detect your locale.

You can create the late route listener during bootstrap. So in your onBootstrap method:

use Locale;

use Zend\Mvc\MvcEvent;

public function onBootstrap($event)
{

  $app = $event->getApplication();

  $em  = $app->getEventManager();

  $em->attach(MvcEvent::EVENT_ROUTE, function($e) {

    // Route has taken place now

    $routeMatch = $e->getRouteMatch();

    $locale = $routeMatch->getParam('locale', null);

    Locale::setDefault($locale);

  }, -100);

}

Now if you have a route /:locale/something/else and you request en_US/something/else your locale will be set to en_US.

--
Jurian Sluiman

[Ralf Eggert]

Hi Jurian,

thanks for your explanations. Makes sense to me now. I added the code
and it worked as expected. But I was not satiesfied since I still have
no "class" which does the job.

Then I stumpled upon the EventManager::attachAggregate() and thought
that that might be an even better solution. I ended up with my first
listener class:

------------------------------------------------------------------------
namespace Application\Listener;
use Zend\EventManager\EventManagerInterface;
use Zend\EventManager\ListenerAggregateInterface;
use Zend\EventManager\EventCollection;
use Zend\Mvc\MvcEvent;
use Locale;

class RouteListener implements ListenerAggregateInterface
{
    public function attach(EventManagerInterface $events)
    {
        $events->attach('route', array($this, 'language'), -100);
    }

    public function detach(EventManagerInterface $events)
    {
        $events->detach($this);
    }

    public function language($e)
    {
        $routeMatch = $e->getRouteMatch();
        $locale = $routeMatch->getParam('lang', null);
        Locale::setDefault($locale);
    }
}
------------------------------------------------------------------------

That works perfectly and with this listener class I got what I wanted.

One question I still have: a ListenerAggregateInterface::detach() method
is needed, but it does not seem to be called automatically. Could I just
leave it empty?

Best regards,

Ralf

[Jurian Sluiman-3]

Hello Ralph,

2012/8/20 Ralf Eggert <[hidden email]>

One question I still have: a ListenerAggregateInterface::detach() method
is needed, but it does not seem to be called automatically. Could I just
leave it empty?

Typically to save the callback handler which is registered as listener. When you want to detach the aggregate, you loop through all listeners and detach them again. An example how this can be done is found here: https://github.com/juriansluiman/SlmLocale/blob/master/src/SlmLocale/Strategy/AbstractStrategy.php#L55-81

This directly let's me say you might check out SlmLocale as well: https://github.com/juriansluiman/SlmLocale. It's a small module (for now) which handles the various strategies I wrote down in some posts earlier. At this moment I only have the HTTP Accept-Language header as working prototype, the others still need to be implemented. The only issue now for route match based locales is the moment where I start looking for a locale. I prefer to do this as early as possible, so at bootstrap for now. All listed strategies can be implemented on bootstrap, only the route match strategy not, since it requires routing first. However, you can use a UriPath strategy as well, leaving your original routes intact (and locale independent).

--
Jurian Sluiman

[Ralf Eggert]

Hi Jurian,

thanks again. After I sent my message yesterday I looked into the
ModuleRouteListener and found the same implementation for detach, which
I use myself now.

https://github.com/zendframework/zf2/blob/master/library/Zend/Mvc/ModuleRouteListener.php

I also updated the example at the bottom of this page and sent a pull
request for it, which is still waiting for acceptance.

http://zf2.readthedocs.org/en/latest/modules/zend.event-manager.event-manager.html

> This directly let's me say you might check out SlmLocale as well:
> https://github.com/juriansluiman/SlmLocale.

That looks really promising and I will definitely keep an eye on this.
For my current project the locale detection is only needed for the
route, so my RouteListener will do the job. But in future projects I
definetely will need a more flexible solution like yours.

Regards,

Ralf