Chicago Boss CSRF and variable passing to template files - erlang

Question

I've two problems with my simple application.
I've read the documents twice, but had no luck to using boss_csrf_filter and passing variables to templates.
First I've done the configuration for using CSRF filter in boss.config file as the following :
{controller_filter_config, [boss_csrf_filter]},
{session_adapter, mock},
{session_key, "_myapp_session"},
{session_exp_time, 525600},
{session_cookie_http_only, false},
{session_cookie_secure, false},
{session_domain, ".myappdomain.com"},
Then, I've add to variable in template (which is under src/view/world/hello.html)
<div class="row">
<div class="12u">
<textarea name="message" id="message" placeholder="placeholder" required></textarea>
{{ csrf_token }}
</div>
</div>
Everthing seems fine, but no any hidden input element appearing. Should I check/configure anything else?
The second problem is with my app is passing variables to templates. My is controller something like the following code :
-module(myapp_world_controller, [Req]).
-compile(export_all).
hello('GET', []) ->
{ok, [{world}]}.
postcontact('POST', []) ->
{redirect, "/",[{contactformsend, "ok"}]}.
The code is redirecting without any value. So, the following code is not working (the same template file with I've mentioned above) :
{% if contactformsend %}
<script>
alert("Hi there is!");
</script>
{% endif %}
What I am doing wrong? How can I fix the problems?

Answer 1

I would propose to split your question into two, because I have answer only for the second part. When you use redirect in controller, you don't pass the variables. In the docs you can read this:
{redirect, Location, Headers::proplist()}
So the third argument is list of headers, not variables passed to templates. It makes sense: the variables will be taken from the controller, that is responsible for rendering "/".