Twig模板外部url img

I am trying to display image from facebook profile.

routing.yml

_graph_facebook:
path: graph.facebook.com/{fbId}/{var}
requirements:
    _scheme:  https

template.html.twig

What I get is htpps://mydomain.local/graph.facebook.com/facebookId/picture .

I was trying with assets but it works only if it's hardcoded.

{% image 'https://graph.facebook.com/'~app.user.facebookId~'/picture'%}
        <img src="{{ asset_url }}" alt="Example" />
{% endimage %}

This code doesn't work it says that: Unexpected token "operator" of value "~". I couldn't find answer probably it's vaery simply.Thanks for Your help

As said in the comments, the router only applies to the URLs of your website.

Anyway, you can simply display the image with the facebookId value:

<img src="https://graph.facebook.com/{{ app.user.facebookId }}/picture" alt="Example" />

You can't use routing for external URI management only internal.

If you want to encapsulate this "behavior" in a method/function accessible by twig i can suggest you to create a Twig_Method via an custom twig extension : http://symfony.com/doc/current/cookbook/templating/twig_extension.html

Concatenation operator's ~ arguments should be space-char separated.

'https://graph.facebook.com/' ~ app.user.facebookId ~ '/picture'

External urls should be escaped with html_attr filter:

<img src="{{ asset_url|e('html_attr') }}" alt="Example" />