Slack Slash Command Hello World in Rust using Rocket.

slash-command.rs

#![feature(proc_macro_hygiene, decl_macro)]
#[macro_use] extern crate rocket;

use rocket::request::Form;

#[derive(FromForm)]
pub struct Parameters {
    // Payload fields from "Preparing your app to receive Commands" section in documentation:
    // https://api.slack.com/interactivity/slash-commands#app_command_handling.
    pub token: String,
    pub team_id: String,
    pub team_domain: String,
    pub channel_id: String,
    pub channel_name: String,
    pub user_id: String,
    pub user_name: String,
    pub command: String,
    pub text: String,
    pub response_url: String,
    pub trigger_id: String,
    pub api_app_id: String,
}

#[post("/", data = "<input>")]
fn command(input: Form<Parameters>) -> String {
    // Unwrap inner object.
    let input_inner = input.into_inner();
    // Say hello to user.
    format!("Hello {}", input_inner.user_name)
}

#[catch(404)]
fn not_found() -> &'static str {
    // Catch all in case someone goes to the URL directly.
    "You are using this tool incorrectly. Please use it through the command line or Slack."
}

fn main() {
    // Initialize Rocket, mount root route and register 404 catcher.
    rocket::ignite().mount("/", routes![command]).register(catchers![not_found]).launch();
}