Next.js 15 Fullstack (App Router + Server Actions) · Lezione

Creazione di un'app full stack

Sviluppi un progetto completo integrando tutti i concetti appresi in un'applicazione Next.js full stack.

Lezione 2 di 411 passaggi

Creazione di un'app full stack è una lezione Next.js 15 Fullstack (App Router + Server Actions) gratuita su CoddyKit. Questa è la lezione 2 di 4. Puoi leggere la lezione completa qui gratuitamente — poi esercitati direttamente nel browser con un editor di codice integrato e un tutor IA disponibile 24/7. Fa parte del percorso di apprendimento Next.js 15 Fullstack (App Router + Server Actions), e i tuoi progressi si sincronizzano tra il web e l'app CoddyKit. Il corso Next.js 15 Fullstack (App Router + Server Actions) include 4 lezioni in totale.

Parti di questa lezione non sono ancora state tradotte e vengono mostrate in inglese.

Fullstack App: Task Manager

Welcome to building a real-world fullstack application with Next.js 15! In this lesson, we'll integrate all the concepts you've learned to create a simple task manager.

Our app will allow users to:

  • Sign in securely.
  • View their personal tasks.
  • Add new tasks.
  • Mark tasks as complete.

This will demonstrate how Server Components, Client Components, Server Actions, data fetching, and authentication work together.

Project Init & Database Setup

First, let's set up our project and define the database schema using Prisma. We'll need models for users and tasks.

  • Initialize Next.js: npx create-next-app@latest my-fullstack-app
  • Install Prisma: npm install prisma @prisma/client
  • Initialize Prisma: npx prisma init --datasource-provider sqlite (or your preferred DB)

Here's a basic schema.prisma for our task manager:

// prisma/schema.prisma
generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider = "sqlite" // or "postgresql", "mysql"
  url      = env("DATABASE_URL")
}

model User {
  id        String    @id @default(cuid())
  email     String    @unique
  name      String?
  password  String // Hashed password
  tasks     Task[]
}

model Task {
  id        String    @id @default(cuid())
  title     String
  completed Boolean   @default(false)
  userId    String
  user      User      @relation(fields: [userId], references: [id])
  createdAt DateTime  @default(now())
  updatedAt DateTime  @updatedAt
}

Implementing NextAuth.js

Authentication is a core part of any fullstack application. We'll integrate NextAuth.js to handle user sign-in, sign-up, and session management. This involves creating an API route for NextAuth.

Our [...nextauth] route defines how users authenticate:

// app/api/auth/[...nextauth]/route.ts
import NextAuth from "next-auth";
import CredentialsProvider from "next-auth/providers/credentials";
import { PrismaAdapter } from "@auth/prisma-adapter";
import { PrismaClient } from "@prisma/client";
import bcrypt from "bcrypt";

const prisma = new PrismaClient();

const handler = NextAuth({
  adapter: PrismaAdapter(prisma),
  providers: [
    CredentialsProvider({
      name: "Credentials",
      credentials: {
        email: { label: "Email", type: "text" },
        password: { label: "Password", type: "password" }
      },
      async authorize(credentials) {
        if (!credentials?.email || !credentials?.password) return null;

        const user = await prisma.user.findUnique({
          where: { email: credentials.email }
        });

        if (!user || !(await bcrypt.compare(credentials.password, user.password))) {
          return null;
        }
        return { id: user.id, email: user.email, name: user.name };
      },
    }),
  ],
  session: { strategy: "jwt" },
  callbacks: {
    jwt: async ({ token, user }) => {
      if (user) {
        token.id = user.id;
        token.email = user.email;
      }
      return token;
    },
    session: async ({ session, token }) => {
      if (token) {
        session.user.id = token.id as string;
        session.user.email = token.email;
      }
      return session;
    },
  },
  pages: {
    signIn: "/auth/signin",
  },
});

export { handler as GET, handler as POST };

Displaying User Tasks (RSC)

Our main dashboard will display tasks specific to the logged-in user. We'll use a React Server Component (RSC) to fetch this data directly from the database, reducing client-side JavaScript.

This page.tsx fetches tasks and passes them to a Client Component for rendering:

// app/dashboard/page.tsx
import { getServerSession } from "next-auth";
import { authOptions } from "@/app/api/auth/[...nextauth]/route"; // Adjust path
import { PrismaClient } from "@prisma/client";
import TaskList from "./TaskList"; // This will be a Client Component

const prisma = new PrismaClient();

export default async function DashboardPage() {
  const session = await getServerSession(authOptions);

  if (!session || !session.user?.id) {
    return <p>Please sign in to view your tasks.</p>;
  }

  const tasks = await prisma.task.findMany({
    where: { userId: session.user.id },
    orderBy: { createdAt: "desc" },
  });

  return (
    <div>
      <h1>Welcome, {session.user.name || session.user.email}!</h1>
      <h2>Your Tasks</h2>
      <TaskList initialTasks={tasks} />
    </div>
  );
}

Adding Tasks with Server Actions

To add new tasks, we'll leverage Next.js Server Actions. This allows us to handle form submissions directly on the server, ensuring security and automatically revalidating data in our UI.

Here's a simplified Server Action to create a new task:

// app/actions/task-actions.ts
"use server";

import { revalidatePath } from "next/cache";
import { getServerSession } from "next-auth";
import { authOptions } from "@/app/api/auth/[...nextauth]/route";
import { PrismaClient } from "@prisma/client";

const prisma = new PrismaClient();

export async function addTask(formData: FormData) {
  const session = await getServerSession(authOptions);

  if (!session || !session.user?.id) {
    throw new Error("Unauthorized");
  }

  const title = formData.get("title") as string;
  if (!title || title.trim() === "") {
    throw new Error("Task title cannot be empty.");
  }

  await prisma.task.create({
    data: {
      title,
      userId: session.user.id,
    },
  });

  revalidatePath("/dashboard"); // Revalidate dashboard to show new task
}

Interactive Task Management (RCC)

While Server Components handle initial data, Client Components (RCC) are essential for interactivity. We can use them to update the UI instantly, like marking a task complete, often with optimistic updates.

This TaskList component uses client-side state and a Server Action:

// app/dashboard/TaskList.tsx (Client Component)
"use client";

import { useState } from "react";
// Assume toggleTaskCompletion is another server action
import { toggleTaskCompletion } from "@/app/actions/task-actions"; 

export default function TaskList({ initialTasks }) {
  const [tasks, setTasks] = useState(initialTasks);

  const handleToggle = async (taskId: string, currentStatus: boolean) => {
    // Optimistic UI update
    setTasks(tasks.map(task =>
      task.id === taskId ? { ...task, completed: !currentStatus } : task
    ));
    try {
      await toggleTaskCompletion(taskId, !currentStatus);
    } catch (error) {
      console.error("Failed to toggle task:", error);
      // Revert if error
      setTasks(initialTasks); // Revert to initial state on error
    }
  };

  return (
    <ul>
      {tasks.map(task => (
        <li key={task.id}>
          <input
            type="checkbox"
            checked={task.completed}
            onChange={() => handleToggle(task.id, task.completed)}
          />
          <span style={{ textDecoration: task.completed ? "line-through" : "none" }}>
            {task.title}
          </span>
        </li>
      ))}
    </ul>
  );
}

Protecting Routes with Middleware

To secure our application, we must protect routes that require authentication. Next.js Middleware is ideal for this, allowing us to redirect unauthenticated users before they even reach a page.

Our middleware.ts can enforce authentication for specific paths:

// middleware.ts
import { withAuth } from "next-auth/middleware";
import { NextResponse } from "next/server";

export default withAuth(
  // `withAuth` augments the Next.js request with the user's token.
  function middleware(req) {
    const { pathname } = req.nextUrl;
    // Example: Only allow authenticated users to access /dashboard
    if (pathname.startsWith("/dashboard") && !req.nextauth.token) {
      return NextResponse.redirect(new URL("/auth/signin", req.url));
    }
    // Allow access to public pages or authenticated pages
    return NextResponse.next();
  },
  {
    callbacks: {
      authorized: ({ token }) => !!token, // Only allow if token exists
    },
    pages: {
      signIn: "/auth/signin",
    },
  }
);

export const config = {
  matcher: ["/dashboard/:path*", "/api/protected/:path*"], // Apply middleware to these paths
};

Loading & Error States

A robust fullstack app provides clear feedback. Next.js App Router helps with dedicated files for loading and error states:

  • loading.js: Automatically displays a loading UI for a route segment while its content is being fetched on the server.
  • error.js: Creates UI boundaries to catch and display errors gracefully for a route segment, preventing the whole app from crashing.

For Server Actions, you can also use client-side states like isPending from useFormStatus to show loading indicators.

The Fullstack Integration Flow

Let's visualize how these components work together in our task manager:

  • A user tries to access /dashboard.
  • middleware.ts checks their authentication status via NextAuth.js.
  • If authenticated, dashboard/page.tsx (an RSC) fetches user-specific tasks from Prisma.
  • TaskList.tsx (an RCC) renders these tasks and allows interactive toggling of completion status via a Server Action.
  • A separate form (RCC) uses another Server Action to add new tasks, which then revalidates the /dashboard path.

This seamless interaction creates a powerful and efficient user experience.

Fullstack Integration Check

Consider a Next.js fullstack application. Which of the following statements correctly describe the typical use of Server Components, Client Components, Server Actions, or Middleware?

Fullstack App Recap

You've just walked through the process of building a comprehensive fullstack Next.js application! We integrated several key features:

  • Prisma ORM for database interaction.
  • NextAuth.js for secure authentication.
  • React Server Components for efficient server-side data fetching.
  • Next.js Server Actions for secure data mutations and revalidation.
  • React Client Components for adding rich client-side interactivity.
  • Next.js Middleware for protecting routes.

This lesson ties together many foundational concepts, providing you with a robust understanding of how to build complex, production-ready Next.js applications.

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Domande Frequenti

La lezione «Creazione di un'app full stack» è gratuita?

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Cosa imparerò in «Creazione di un'app full stack»?

Sviluppi un progetto completo integrando tutti i concetti appresi in un'applicazione Next.js full stack. Eserciti Next.js 15 Fullstack (App Router + Server Actions) con codice pratico che esegui direttamente nel browser, e un tutor IA 24/7 risponde alle tue domande mentre lavori sulla lezione.

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Tutte le lezioni di questo corso

  1. Deployment su Vercel
  2. Creazione di un'app full stack
  3. Revisione del progetto e best practice
  4. Monitoraggio e tracciamento degli errori in produzione
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