目錄
簡介
初始項目設定
設定 PostgreSQL
設定 Prisma
定義資料模型
將 Prisma 與 Express 整合
使用 TypeScript 實作型別安全性
測試 API
部署注意事項
結論
在現代 Web 開發中，建立健壯、可擴展且類型安全的 API 至關重要。結合 Prisma 作為 ORM、Express 用於伺服器端邏輯、TypeScript 用於靜態類型以及 PostgreSQL 作為可靠的資料庫解決方案的強大功能，我們可以創建強大的 RESTful API。
Prisma 透過提供支援類型安全性查詢、遷移和無縫資料庫模式管理的現代 ORM 來簡化資料庫管理。 Express 是一個最小且靈活的 Node.js Web 應用程式框架，為 Web 和行動應用程式提供了一組強大的功能。 TypeScript 為 JavaScript 添加了靜態類型定義，有助於在開發過程的早期捕獲錯誤。 PostgreSQL 是一個功能強大的開源關係型資料庫系統，以其可靠性和功能集而聞名。
Prisma 與 Sequelize 和 TypeORM 等傳統 ORM 相比具有多種優點：
在我們深入研究程式碼之前，請確保您的電腦上安裝了以下工具：
安裝這些工具後，我們就可以開始建立我們的 API。
mkdir prisma-express-api cd prisma-express-api
npm init -y
這將在您的專案目錄中建立一個 package.json 檔案。
npm install typescript @types/node --save-dev
npx tsc --init
此指令建立一個 tsconfig.json 文件，它是 TypeScript 的設定檔。根據您的項目需要對其進行修改。這是基本設定：
{
"compilerOptions": {
"target": "ES2020",
"module": "commonjs",
"strict": true,
"esModuleInterop": true,
"skipLibCheck": true,
"forceConsistentCasingInFileNames": true,
"outDir": "./dist"
},
"include": ["src/**/*"]
}
mkdir src touch src/index.ts
要開始使用 Express 和 Prisma，您需要安裝一些必要的軟體包：
npm install express prisma @prisma/client npm install --save-dev ts-node nodemon @types/express
PostgreSQL can be installed via your operating system’s package manager or directly from the official website. For example, on macOS, you can use Homebrew:
brew install postgresql brew services start postgresql
Once PostgreSQL is installed and running, you can create a new database for your project:
psql postgres CREATE DATABASE prisma_express;
Replace prisma_express with your preferred database name.
To connect to the PostgreSQL database, create a .env file in your project’s root directory and add the following environment variables:
DATABASE_URL="postgresql://<user>:<password>@localhost:5432/prisma_express"
Replace
Prisma is already installed in the previous step, so the next step is to initialize it within the project:
npx prisma init
This command will create a prisma directory containing a schema.prisma file and a .env file. The .env file should already contain the DATABASE_URL you specified earlier.
The schema.prisma file is where you'll define your data models, which will be used to generate database tables.
Here’s a basic example schema:
generator client {
provider = "prisma-client-js"
}
datasource db {
provider = "postgresql"
url = env("DATABASE_URL")
}
model User {
id Int @id @default(autoincrement())
name String
email String @unique
createdAt DateTime @default(now())
posts Post[]
}
model Post {
id Int @id @default(autoincrement())
title String
content String?
published Boolean @default(false)
authorId Int
author User @relation(fields: [authorId], references: [id])
}
In this schema, we have two models: User and Post. Each model corresponds to a database table. Prisma uses these models to generate type-safe queries for our database.
Prisma Schema Language (PSL) is used to define your database schema. It's intuitive and easy to read, with a focus on simplicity. Each model in the schema represents a table in your database, and each field corresponds to a column.
In the schema defined earlier, we created two models:
To apply your schema changes to the database, you’ll need to run a migration:
npx prisma migrate dev --name init
This command will create a new migration file and apply it to your database, creating the necessary tables.
In your src/index.ts, set up the basic Express server:
import express, { Request, Response } from 'express';
import { PrismaClient } from '@prisma/client';
const app = express();
const prisma = new PrismaClient();
app.use(express.json());
app.get('/', (req: Request, res: Response) => {
res.send('Hello, Prisma with Express!');
});
const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
console.log(`Server is running on port ${PORT}`);
});
This code sets up a simple Express server and initializes the Prisma client.
Next, let’s create some CRUD (Create, Read, Update, Delete) routes for our User model.
Create a new user:
app.post('/user', async (req: Request, res: Response) => {
const { name, email } = req.body;
const user = await prisma.user.create({
data: { name, email },
});
res.json(user);
});
Read all users:
app.get('/users', async (req: Request, res: Response) => {
const users = await prisma.user.findMany();
res.json(users);
});
Update a user:
app.put('/user/:id', async (req: Request, res: Response) => {
const { id } = req.params;
const { name, email } = req.body;
const user = await prisma.user.update({
where: { id: Number(id) },
data: { name, email },
});
res.json(user);
});
Delete a user:
app.delete('/user/:id', async (req: Request, res: Response) => {
const { id } = req.params;
const user = await prisma.user.delete({
where: { id: Number(id) },
});
res.json(user);
});
To enhance the robustness of your API, consider adding error handling and validation:
app.post('/user', async (req: Request, res: Response) => {
try {
const { name, email } = req.body;
if (!name || !email) {
return res.status(400).json({ error: 'Name and email are required' });
}
const user = await prisma.user.create({
data: { name, email },
});
res.json(user);
} catch (error) {
res.status(500).json({ error: 'Internal Server Error' });
}
});
Prisma automatically generates TypeScript types for your models based on your schema. This ensures that your database queries are type-safe.
For example, when creating a new user, TypeScript will enforce the shape of the data being passed:
const user = await prisma.user.create({
data: { name, email }, // TypeScript ensures 'name' and 'email' are strings.
});
With TypeScript, you get autocomplete and type-checking for all Prisma queries, reducing the chance of runtime errors:
const users: User[] = await prisma.user.findMany();
Using TypeScript throughout your API development helps catch potential bugs early, improves code readability, and enhances overall development experience.
Testing is an essential part of any application development. You can write unit tests for your Prisma models using a testing framework like Jest:
npm install jest ts-jest @types/jest --save-dev
Create a jest.config.js file:
module.exports = {
preset: 'ts-jest',
testEnvironment: 'node',
};
Example test for creating a user:
import { PrismaClient } from '@prisma/client';
const prisma = new PrismaClient();
test('should create a new user', async () => {
const user = await prisma.user.create({
data: {
name: 'John Doe',
email: 'john.doe@example.com',
},
});
expect(user).toHaveProperty('id');
expect(user.name).toBe('John Doe');
});
You can also write integration tests using Supertest:
npm install supertest --save-dev
Example integration test:
import request from 'supertest';
import app from './app'; // Your Express app
test('GET /users should return a list of users', async () => {
const response = await request(app).get('/users');
expect(response.status).toBe(200);
expect(response.body).toBeInstanceOf(Array);
});
For testing purposes, you might want to mock the Prisma client. You can do this using tools like jest.mock() or by creating a mock instance of the Prisma client.
Before deploying your API, ensure you:
You can deploy PostgreSQL using cloud services like AWS RDS, Heroku, or DigitalOcean. Make sure to secure your database with proper authentication and network settings.
For deploying the Node.js application, consider using services like:
Using Prisma as an ORM with Express and TypeScript provides a powerful combination for building scalable, type-safe, and efficient RESTful APIs. With Prisma, you get automated migrations, type-safe queries, and an intuitive schema language, making database management straightforward and reliable.
Congratulations!! You've now built a robust RESTful API using Prisma, Express, TypeScript, and PostgreSQL. From setting up the environment to deploying the application, this guide covered the essential steps to get you started. As next steps, consider exploring advanced Prisma features like nested queries, transactions, and more complex data models.
Happy coding!
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