Building a To-Do API with Rocket and Diesel

Prerequisites

To follow this tutorial, you should have:

• Familiarity with the Rust programming language and Cargo build system
• Basic understanding of database connections
• Ability to start a development project in your preferred environment

Setting Up the Project

Create a new project using Cargo:

cargo new todo_api

Add dependencies to Cargo.toml:

[dependencies]
rocket = "0.5.0-rc.1"
diesel = { version = "1.4.7", features = ["sqlite"] }

Install Diesel CLI:

cargo install diesel_cli --no-default-features --features sqlite

Creating Migrations with Diesel

Run diesel setup to create a migrations directory:

diesel setup

Create a new migration:

diesel migration generate create_tasks

Write SQL statements for creating and dropping tasks table in up.sql and down.sql files:

-- up.sql
CREATE TABLE tasks (
    id SERIAL PRIMARY KEY,
    title VARCHAR(255) NOT NULL,
    completed BOOLEAN NOT NULL DEFAULT FALSE
);

-- down.sql
DROP TABLE tasks;

Apply migration:

diesel migration run

Writing API Logic in Rust

Create a new module: database.rs

// database.rs
use diesel::prelude::*;
use diesel::sqlite::SqliteConnection;

pub struct Database {
    conn: SqliteConnection,
}

impl Database {
    pub fn new() -> Self {
        // Initialize database connection
    }

    pub fn create_task(&self, title: &str) {
        // Create a new task
    }

    pub fn get_tasks(&self) -> Vec<Task> {
        // Get all tasks
    }
}

Routing API with Rocket

Import Rocket and define routes:

// main.rs
#[macro_use] extern crate rocket;

use rocket::Request;
use rocket::response::content;

mod database;

#[get("/tasks")]
fn get_tasks(db: database::Database) -> Vec<Task> {
    db.get_tasks()
}

#[post("/tasks", data = "<r>")]
fn create_task(db: database::Database, title: &str) -> String {
    db.create_task(title);
    "Task created successfully!".to_string()
}

fn main() {
    rocket::ignite().mount("/", routes![get_tasks, create_task]).launch();
}

Note: I’ve added some code snippets to illustrate the steps, but you may need to complete the implementation details.