Using Twig to generate JSON

问题:

I want to have a URL that returns a simple JSON object. I am trying to use Twig to generate the JSON object:

{
"urls": [
{% for child in page.root %}
    "{{ child.url }}"{% if not loop.last %},{% endif %}
{% endfor %}
]
}

The carriage returns will not remain in place though, and I keep getting a result that looks like this:

{'urls':['../ants/','../brick-report/','../the-pollution-intervention/','../barclay/','../broken-advertising/','../aldat-n-densom/','../thisisart/','../there-she-goes-again/']}

which Jquery will not parse with it's ajax or getJSON methods. It's totally ignoring this JSON. How might I convince Twig to put the right whitespace in place? I've looked at the manual and it only seems concerned with NOT inserting whitespace.

回答1:

That works for me (twig template):

var parsedJSON = JSON.parse('{{ ['one', 'two', 'three']|json_encode|e('js') }}');

And that:

console.log(parsedJSON);

will output:

 Array ["one", "two", "three"]

in FF console.

回答2:

Twig has a filter for this.

json_encode, it uses PHP json_encode function.

for your case:

{{ {'urls': page.root}|json_encode }}

will output

{"urls":["..\/ants\/","..\/brick-report\/","..\/the-pollution-intervention\/","..\/barclay\/","..\/broken-advertising\/","..\/aldat-n-densom\/","..\/thisisart\/","..\/there-she-goes-again\/"]}

the code is tested and works. For more information take a look at the Twig Documentation for json_encode.

回答3:

Don't use Twig to generate your json response.

In your controller, use:

return new Response(json_encode($var));

Sample:

public function sampleAction()
{
    $urls = array('../test', '../something', '../sample');
    return new Response(json_encode($var));
}

If URLs are generated from Symfony2 routes, you can use:

public function sampleAction()
{
    $urls = array(
             $this->generateUrl('my_test'),
             $this->generateUrl('my_something'),
             $this->generateUrl('my_sample'),
    );
    return new Response(json_encode($var));
}

回答4:

Thats easy if you extend twig.

First, create a class that will contain the extension:

<?php

namespace Acme\DemoBundle\Twig\Extension;

use Symfony\Component\DependencyInjection\ContainerInterface;  
use \Twig_Extension;

class VarsExtension extends Twig_Extension
{
    protected $container;

    public function __construct(ContainerInterface $container) 
    {
        $this->container = $container;
    }

    public function getName() 
    {
        return 'some.extension';
    }

    public function getFilters() {
        return array(
            'json_decode'   => new \Twig_Filter_Method($this, 'jsonDecode'),
        );
    }

    public function jsonDecode($str) {
        return json_decode($str);
    }
}

回答5:

Basically the $.getJson() method requires json but ther is a string so you can use $.get() to get the response and use the parser to parse the string to JSON

 $.get("ffff",function(data){
 // user parser
 JSON.parse();
 });