Create Tera filters

examples/rocket/create-tera-filter/Cargo.toml

[package]
name = "tera-filter"
version = "0.1.0"
edition = "2021"

[dependencies]
rocket = "0.5"
rocket_dyn_templates = { version = "0.2.0", features = ["tera"] }
serde_json = "1.0.128"
tera = "1.20.0"

examples/rocket/create-tera-filter/Rocket.toml

[default]
port = 8001

examples/rocket/create-tera-filter/src/main.rs

#[macro_use]
extern crate rocket;

mod mytera;

#[cfg(test)]
mod tests;

use rocket::response::content::RawHtml;
use rocket_dyn_templates::{context, Template};

#[get("/")]
fn index() -> RawHtml<&'static str> {
    RawHtml(r#"See <a href="/hello/Foo Bar">Foo Bar</a>."#)
}

#[get("/hello/<name>")]
pub fn hello(name: &str) -> Template {
    Template::render(
        "index",
        context! {
            title: "Hello",
            name: Some(name),
        },
    )
}

#[launch]
fn rocket() -> _ {
    rocket::build()
        .mount("/", routes![index, hello])
        .attach(Template::custom(|engines| {
            mytera::customize(&mut engines.tera);
        }))
}

examples/rocket/create-tera-filter/src/mytera.rs

use std::collections::HashMap;

use rocket_dyn_templates::tera::Tera;
use tera::{to_value, Result, Value};

fn my_len(val: &Value, _map: &HashMap<String, Value>) -> Result<Value> {
    let s = val.as_str().unwrap();
    Ok(to_value(s.len()).unwrap())
}

pub fn customize(tera: &mut Tera) {
    tera.register_filter("my_len", my_len);
}

examples/rocket/create-tera-filter/src/tests.rs

use super::rocket;

use rocket::http::Status;
use rocket::local::blocking::Client;

#[test]
fn test_name() {
    let client = Client::tracked(rocket()).unwrap();
    let response = client.get("/hello/Tera%20Rocket").dispatch();
    assert_eq!(response.status(), Status::Ok);
    let html = response.into_string().unwrap();
    assert!(html.contains("Hi Tera Rocket!"));
    assert!(html.contains("The name is 11 characters long."));
    assert!(html.contains("My number is 11."));
}

#[test]
fn test_index() {
    let client = Client::tracked(rocket()).unwrap();
    let response = client.get("/").dispatch().into_string().unwrap();
    assert!(response.contains(r#"See <a href="/hello/Foo Bar">Foo Bar</a>."#));
}

examples/rocket/create-tera-filter/templates/index.html.tera

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8" />
    <title>Tera Demo - {{ title }}</title>
  </head>
  <body>

<a href="/">Home</a> | <a href="/hello/Unknown">Hello</a>
    <h1>Hi {{ name }}!</h1>
    <div>The name is {{ name | length }} characters long.</div>
    <div>My number is {{ name | my_len }}.</div>
    <p>Try going to <a href="/hello/Your%20Name">/hello/Your Name</a></p>
  </body>
</html>