Fullstack Workflow

Complete guide for building features from API to UI, combining GET API routes, data fetching, form handling, and server actions.

Overview

When building a new feature, follow this pattern:

1. GET API Route - For fetching data
2. Server Action - For mutations (create/update/delete)
3. Data Fetching - Using SWR on the client
4. Form Handling - Using React Hook Form with Zod validation

1. GET API Route

For fetching data. Always wrap with withAuth or withEmailAccount:

// apps/web/app/api/user/example/route.ts
import { NextResponse } from "next/server";
import prisma from "@/utils/prisma";
import { withEmailAccount } from "@/utils/middleware";

// Auto-generate response type for client use
export type GetExampleResponse = Awaited<ReturnType<typeof getData>>;

export const GET = withEmailAccount(async (request) => {
  const { emailAccountId } = request.auth;
  
  const result = await getData({ emailAccountId });
  return NextResponse.json(result);
});

// We make this its own function so we can infer the return type for a type-safe response on the client
async function getData({ emailAccountId }: { emailAccountId: string }) {
  const items = await prisma.example.findMany({
    where: { emailAccountId },
  });

  return { items };
}

2. Server Action

For mutations. Use next-safe-action with proper validation.

Action clients (defined in apps/web/utils/actions/safe-action.ts):

Always use .metadata({ name: "actionName" }) for Sentry instrumentation. Use SafeError for expected errors.

Validation Schema (apps/web/utils/actions/example.validation.ts):

import { z } from "zod";

export const createExampleBody = z.object({
  name: z.string().min(1, "Name is required"),
  email: z.string().email("Invalid email"),
  description: z.string().optional(),
});
export type CreateExampleBody = z.infer<typeof createExampleBody>;

export const updateExampleBody = z.object({
  id: z.string(),
  name: z.string().optional(),
  email: z.string().email().optional(),
  description: z.string().optional(),
});
export type UpdateExampleBody = z.infer<typeof updateExampleBody>;

Server Action (apps/web/utils/actions/example.ts):

"use server";

import { actionClient } from "@/utils/actions/safe-action";
import { createExampleBody, updateExampleBody } from "@/utils/actions/example.validation";
import prisma from "@/utils/prisma";

export const createExampleAction = actionClient
  .metadata({ name: "createExample" })
  .inputSchema(createExampleBody)
  .action(async ({ 
    ctx: { emailAccountId }, 
    parsedInput: { name, email, description } 
  }) => {
    const example = await prisma.example.create({
      data: {
        name,
        email,
        description,
        emailAccountId,
      },
    });
    
    return example;
  });

export const updateExampleAction = actionClient
  .metadata({ name: "updateExample" })
  .inputSchema(updateExampleBody)
  .action(async ({ 
    ctx: { emailAccountId }, 
    parsedInput: { id, name, email, description } 
  }) => {
    const example = await prisma.example.update({
      where: { id, emailAccountId },
      data: { name, email, description },
    });
    
    return example;
  });

3. Data Fetching

Use SWR for client-side data fetching:

import useSWR from "swr";
import { GetExampleResponse } from "@/app/api/user/example/route";

export function useExamples() {
  return useSWR<GetExampleResponse>("/api/user/example");
}

4. Form Handling

Use React Hook Form with useAction from next-safe-action/hooks:

import { useCallback } from "react";
import { useForm, type SubmitHandler } from "react-hook-form";
import { useAction } from "next-safe-action/hooks";
import { zodResolver } from "@hookform/resolvers/zod";
import { Input } from "@/components/Input";
import { Button } from "@/components/ui/button";
import { toastSuccess, toastError } from "@/components/Toast";
import { getActionErrorMessage } from "@/utils/error";
import { createExampleAction } from "@/utils/actions/example";
import { createExampleBody, type CreateExampleBody } from "@/utils/actions/example.validation";

export function ExampleForm({ onSuccess }: { onSuccess?: () => void }) {
  const {
    register,
    handleSubmit,
    formState: { errors },
    reset,
  } = useForm<CreateExampleBody>({
    resolver: zodResolver(createExampleBody),
  });

  const { execute, isExecuting } = useAction(createExampleAction, {
    onSuccess: () => {
      toastSuccess({ description: "Example created!" });
      reset();
      onSuccess?.();
    },
    onError: (error) => {
      toastError({
        description: getActionErrorMessage(error.error),
      });
    },
  });

  return (
    <form className="space-y-4" onSubmit={handleSubmit(execute)}>
      <Input
        type="text"
        name="name"
        label="Name"
        registerProps={register("name")}
        error={errors.name}
      />
      <Input
        type="email"
        name="email"
        label="Email"
        registerProps={register("email")}
        error={errors.email}
      />
      <Input
        type="text"
        name="description"
        label="Description"
        registerProps={register("description")}
        error={errors.description}
      />
      <Button type="submit" loading={isExecuting}>
        Create Example
      </Button>
    </form>
  );
}

5. Complete Data Fetching Component

'use client';

import { useExamples } from "@/hooks/useExamples";
import { Button } from "@/components/ui/button";
import { LoadingContent } from "@/components/LoadingContent";

export function Examples() {
  const { data, isLoading, error } = useExamples();

  return (
    <LoadingContent loading={isLoading} error={error}>
      <div className="grid gap-4">
        {data?.examples.map((example) => (
          <div key={example.id} className="border p-4 rounded">
            <h3 className="font-semibold">{example.name}</h3>
            <p className="text-gray-600">{example.email}</p>
            {example.description && (
              <p className="text-sm text-gray-500">{example.description}</p>
            )}
          </div>
        ))}
      </div>
    </LoadingContent>
  );
}

Key Guidelines

Authentication & Authorization

• Use withAuth for user-level operations
• Use withEmailAccount for email-account-level operations
• Server actions automatically get the right context

Mutations

• Use server actions for all mutations (create/update/delete operations)
• Do NOT use POST API routes for mutations - use server actions instead

Error Handling

• Use useAction hook with onSuccess and onError callbacks
• Use getActionErrorMessage(error.error) from @/utils/error to extract user-friendly messages
• For prefix + error pattern: getActionErrorMessage(error.error, { prefix: "Failed to save" })
• next-safe-action provides centralized error handling with flattened validation errors
• No need for try/catch in GET routes when using middleware

Type Safety

• Export response types from GET routes
• Use Zod schemas for validation on both client and server
• Leverage TypeScript inference for better DX

Loading and Error States

• Use LoadingContent component to handle loading and error states consistently
• Pass loading, error, and children props to LoadingContent
• This provides a standardized way to show loading spinners and error messages

Performance

• Use SWR for efficient data fetching and caching
• Call mutate() after successful mutations to refresh data

File Organization

apps/web/
├── app/api/user/example/route.ts          # GET API route
├── utils/actions/example.validation.ts    # Zod schemas
├── utils/actions/example.ts               # Server actions
├── hooks/useExamples.ts                   # SWR hook
└── components/ExampleForm.tsx              # Form component

Related Rules

• [GET API Route Guidelines](mdc:.cursor/rules/get-api-route.mdc)
• [Data Fetching with SWR](mdc:.cursor/rules/data-fetching.mdc)
• [Form Handling](mdc:.cursor/rules/form-handling.mdc)
• [Server Actions](mdc:.cursor/rules/server-actions.mdc)