GraphQL Operations in React

This part builds upon the previous parts by demonstrating how to perform GraphQL operations with proper database permissions. You’ll learn how to design database tables, configure user permissions, and implement complete CRUD operations through GraphQL queries and mutations in a real todos application.

Note

This is Part 4 in the Full-Stack React Development with Nhost series. This part focuses on GraphQL operations, database management, and permission-based data access control in a production application.

Full-Stack React Development with Nhost

1. Create Project

Set up your Nhost project

2. Protected Routes

Route protection basics

3. User Authentication

Complete auth flow

4. GraphQL Operations

Current - CRUD operations with GraphQL

5. File Uploads

File upload and management

Prerequisites

• Complete the User Authentication part first
• The project from the previous part set up and running

What You’ll Build

By the end of this part, you’ll have:

• GraphQL queries and mutations for complete CRUD operations
• Database schema with proper relationships and constraints
• User permissions for secure data access control
• React components that interact with GraphQL endpoint

Step-by-Step Guide

Create the To-Dos Table

First, we’ll perform the database changes to set up the todos table with proper schema and relationships to users.

In your Nhost project dashboard:

1. Navigate to Database
2. Click on the SQL Editor

Enter the following SQL:

SQL

CREATE TABLE public.todos (
  id uuid DEFAULT gen_random_uuid() NOT NULL,
  created_at timestamptz DEFAULT now() NOT NULL,
  updated_at timestamptz DEFAULT now() NOT NULL,
  title text NOT NULL,
  details text,
  completed bool DEFAULT false NOT NULL,
  user_id uuid NOT NULL,
  PRIMARY KEY (id),
  FOREIGN KEY (user_id) REFERENCES auth.users (id) ON UPDATE CASCADE ON DELETE CASCADE
);


CREATE OR REPLACE FUNCTION update_updated_at_column()
RETURNS TRIGGER AS $$
BEGIN
  NEW.updated_at = now();
  RETURN NEW;
END;
$$ language 'plpgsql';


CREATE TRIGGER update_todos_updated_at
  BEFORE UPDATE ON public.todos
  FOR EACH ROW
  EXECUTE FUNCTION update_updated_at_column();

UI

Caution

Please make sure to enable Track this so that the new table todos is available through the auto-generated APIs

Set Up Permissions

It’s now time to set permission rules for the table you just created. With the table todos selected, click on …, followed by Edit Permissions. You will set permissions for the user role and actions insert, select, update, and delete.

Insert

When inserting permissions we are only allowing users to set the title, details, and completed columns as the rest of the columns are set automatically by the backend. The user_id column is configured as a preset to the currently authenticated user’s ID using the X-Hasura-User-Id session variable. This ensures that each todo is associated with the user who created it.

Select

For selecting (reading) todos, we are allowing to read all columns but only for rows where the user_id matches the authenticated user’s ID. This ensures that users can only see their own todos.

Update

When updating todos, we are allowing users to modify the title, details, and completed columns but only for rows where the user_id matches their own ID. This prevents users from modifying todos that do not belong to them.

Delete

For deleting todos, we are allowing users to delete rows only where the user_id matches their own ID. This ensures that users cannot delete todos that belong to other users.

Create the Todos Page Component

Now let’s implement the React component that uses the database we just configured.

import type { JSX } from "react";
import { useCallback, useEffect, useId, useState } from "react";
import { useAuth } from "../lib/nhost/AuthProvider";

// The interfaces below define the structure of our data
// They are not strictly necessary but help with type safety

// Represents a single todo item
interface Todo {
  id: string;
  title: string;
  details: string | null;
  completed: boolean;
  created_at: string;
  updated_at: string;
  user_id: string;
}

// This matches the GraphQL response structure for fetching todos
// Can be used as a generic type on the request method
interface GetTodos {
  todos: Todo[];
}

// This matches the GraphQL response structure for inserting a todo
// Can be used as a generic type on the request method
interface InsertTodo {
  insert_todos_one: Todo | null;
}

// This matches the GraphQL response structure for updating a todo
// Can be used as a generic type on the request method
interface UpdateTodo {
  update_todos_by_pk: Todo | null;
}

export default function Todos(): JSX.Element {
  const { nhost, session } = useAuth();
  const [todos, setTodos] = useState<Todo[]>([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const [newTodoTitle, setNewTodoTitle] = useState("");
  const [newTodoDetails, setNewTodoDetails] = useState("");
  const [editingTodo, setEditingTodo] = useState<Todo | null>(null);
  const [showAddForm, setShowAddForm] = useState(false);
  const [expandedTodos, setExpandedTodos] = useState<Set<string>>(new Set());

  const titleId = useId();
  const detailsId = useId();

  const fetchTodos = useCallback(async () => {
    try {
      setLoading(true);
      // Make GraphQL request to fetch todos using Nhost client
      // The query automatically filters by user_id due to Hasura permissions
      const response = await nhost.graphql.request<GetTodos>({
        query: `
          query GetTodos {
            todos(order_by: { created_at: desc }) {
              id
              title
              details
              completed
              created_at
              updated_at
              user_id
            }
          }
        `,
      });

      // Check for GraphQL errors in the response body
      if (response.body.errors) {
        throw new Error(
          response.body.errors[0]?.message || "Failed to fetch todos",
        );
      }

      // Extract todos from the GraphQL response data
      setTodos(response.body?.data?.todos || []);
      setError(null);
    } catch (err) {
      setError(err instanceof Error ? err.message : "Failed to fetch todos");
    } finally {
      setLoading(false);
    }
  }, [nhost.graphql]);

  const addTodo = async (e: React.FormEvent) => {
    e.preventDefault();
    if (!newTodoTitle.trim()) return;

    try {
      // Execute GraphQL mutation to insert a new todo
      // user_id is automatically set by Hasura based on JWT token
      const response = await nhost.graphql.request<InsertTodo>({
        query: `
          mutation InsertTodo($title: String!, $details: String) {
            insert_todos_one(object: { title: $title, details: $details }) {
              id
              title
              details
              completed
              created_at
              updated_at
              user_id
            }
          }
        `,
        variables: {
          title: newTodoTitle.trim(),
          details: newTodoDetails.trim() || null,
        },
      });

      if (response.body.errors) {
        throw new Error(
          response.body.errors[0]?.message || "Failed to add todo",
        );
      }

      if (!response.body?.data?.insert_todos_one) {
        throw new Error("Failed to add todo");
      }
      setTodos([response.body?.data?.insert_todos_one, ...todos]);
      setNewTodoTitle("");
      setNewTodoDetails("");
      setShowAddForm(false);
      setError(null);
    } catch (err) {
      setError(err instanceof Error ? err.message : "Failed to add todo");
    }
  };

  const updateTodo = async (
    id: string,
    updates: Partial<Pick<Todo, "title" | "details" | "completed">>,
  ) => {
    try {
      // Execute GraphQL mutation to update an existing todo by primary key
      // Hasura permissions ensure users can only update their own todos
      const response = await nhost.graphql.request<UpdateTodo>({
        query: `
          mutation UpdateTodo($id: uuid!, $updates: todos_set_input!) {
            update_todos_by_pk(pk_columns: { id: $id }, _set: $updates) {
              id
              title
              details
              completed
              created_at
              updated_at
              user_id
            }
          }
        `,
        variables: {
          id,
          updates,
        },
      });

      if (response.body.errors) {
        throw new Error(
          response.body.errors[0]?.message || "Failed to update todo",
        );
      }

      if (!response.body?.data?.update_todos_by_pk) {
        throw new Error("Failed to update todo");
      }

      const updatedTodo = response.body?.data?.update_todos_by_pk;
      if (updatedTodo) {
        setTodos(todos.map((todo) => (todo.id === id ? updatedTodo : todo)));
      }
      setEditingTodo(null);
      setError(null);
    } catch (err) {
      setError(err instanceof Error ? err.message : "Failed to update todo");
    }
  };

  const deleteTodo = async (id: string) => {
    if (!confirm("Are you sure you want to delete this todo?")) return;

    try {
      // Execute GraphQL mutation to delete a todo by primary key
      // Hasura permissions ensure users can only delete their own todos
      const response = await nhost.graphql.request({
        query: `
          mutation DeleteTodo($id: uuid!) {
            delete_todos_by_pk(id: $id) {
              id
            }
          }
        `,
        variables: {
          id,
        },
      });

      if (response.body.errors) {
        throw new Error(
          response.body.errors[0]?.message || "Failed to delete todo",
        );
      }

      setTodos(todos.filter((todo) => todo.id !== id));
      setError(null);
    } catch (err) {
      setError(err instanceof Error ? err.message : "Failed to delete todo");
    }
  };

  const toggleComplete = async (todo: Todo) => {
    await updateTodo(todo.id, { completed: !todo.completed });
  };

  const saveEdit = async () => {
    if (!editingTodo) return;
    await updateTodo(editingTodo.id, {
      title: editingTodo.title,
      details: editingTodo.details,
    });
  };

  const toggleTodoExpansion = (todoId: string) => {
    const newExpanded = new Set(expandedTodos);
    if (newExpanded.has(todoId)) {
      newExpanded.delete(todoId);
    } else {
      newExpanded.add(todoId);
    }
    setExpandedTodos(newExpanded);
  };

  // Fetch todos when user session is available
  // The session contains the JWT token needed for GraphQL authentication
  useEffect(() => {
    if (session) {
      fetchTodos();
    }
  }, [session, fetchTodos]);

  if (!session) {
    return (
      <div className="auth-message">
        <p>Please sign in to view your todos.</p>
      </div>
    );
  }

  return (
    <div className="container">
      <header className="page-header">
        <h1 className="page-title">
          My Todos
          {!showAddForm && (
            <button
              type="button"
              onClick={() => setShowAddForm(true)}
              className="add-todo-btn"
              title="Add a new todo"
            >
              +
            </button>
          )}
        </h1>
      </header>

      {error && (
        <div className="error-message">
          <strong>Error:</strong> {error}
        </div>
      )}

      {showAddForm && (
        <div className="todo-form-card">
          <form onSubmit={addTodo} className="todo-form">
            <h2 className="form-title">Add New Todo</h2>
            <div className="form-fields">
              <div className="field-group">
                <label htmlFor={titleId}>Title *</label>
                <input
                  id={titleId}
                  type="text"
                  value={newTodoTitle}
                  onChange={(e) => setNewTodoTitle(e.target.value)}
                  placeholder="What needs to be done?"
                  required
                />
              </div>
              <div className="field-group">
                <label htmlFor={detailsId}>Details</label>
                <textarea
                  id={detailsId}
                  value={newTodoDetails}
                  onChange={(e) => setNewTodoDetails(e.target.value)}
                  placeholder="Add some details (optional)..."
                  rows={3}
                />
              </div>
              <div className="form-actions">
                <button type="submit" className="btn btn-primary">
                  Add Todo
                </button>
                <button
                  type="button"
                  onClick={() => {
                    setShowAddForm(false);
                    setNewTodoTitle("");
                    setNewTodoDetails("");
                  }}
                  className="btn btn-secondary"
                >
                  Cancel
                </button>
              </div>
            </div>
          </form>
        </div>
      )}

      {!showAddForm &&
        (loading ? (
          <div className="loading-container">
            <div className="loading-content">
              <div className="spinner"></div>
              <span className="loading-text">Loading todos...</span>
            </div>
          </div>
        ) : (
          <div className="todos-list">
            {todos.length === 0 ? (
              <div className="empty-state">
                <svg
                  className="empty-icon"
                  fill="none"
                  stroke="currentColor"
                  viewBox="0 0 24 24"
                  aria-hidden="true"
                >
                  <path
                    strokeLinecap="round"
                    strokeLinejoin="round"
                    strokeWidth={1.5}
                    d="M9 5H7a2 2 0 00-2 2v10a2 2 0 002 2h8a2 2 0 002-2V7a2 2 0 00-2-2h-2M9 5a2 2 0 002 2h2a2 2 0 002-2M9 5a2 2 0 012-2h2a2 2 0 012 2"
                  />
                </svg>
                <h3 className="empty-title">No todos yet</h3>
                <p className="empty-description">
                  Create your first todo to get started!
                </p>
              </div>
            ) : (
              todos.map((todo) => (
                <div
                  key={todo.id}
                  className={`todo-card ${todo.completed ? "completed" : ""}`}
                >
                  {editingTodo?.id === todo.id ? (
                    <div className="todo-edit">
                      <div className="edit-fields">
                        <div className="field-group">
                          <label htmlFor={`${titleId}-edit`}>Title</label>
                          <input
                            id={`${titleId}-edit`}
                            type="text"
                            value={editingTodo.title}
                            onChange={(e) =>
                              setEditingTodo({
                                ...editingTodo,
                                title: e.target.value,
                              })
                            }
                          />
                        </div>
                        <div className="field-group">
                          <label htmlFor={`${detailsId}-edit`}>Details</label>
                          <textarea
                            id={`${detailsId}-edit`}
                            value={editingTodo.details || ""}
                            onChange={(e) =>
                              setEditingTodo({
                                ...editingTodo,
                                details: e.target.value,
                              })
                            }
                            rows={3}
                          />
                        </div>
                        <div className="edit-actions">
                          <button
                            type="button"
                            onClick={saveEdit}
                            className="btn btn-primary"
                          >
                            ✓ Save Changes
                          </button>
                          <button
                            type="button"
                            onClick={() => setEditingTodo(null)}
                            className="btn btn-cancel"
                          >
                            ✕ Cancel
                          </button>
                        </div>
                      </div>
                    </div>
                  ) : (
                    <div className="todo-content">
                      <div className="todo-header">
                        <button
                          type="button"
                          className={`todo-title-btn ${todo.completed ? "completed" : ""}`}
                          onClick={() => toggleTodoExpansion(todo.id)}
                        >
                          {todo.title}
                        </button>
                        <div className="todo-actions">
                          <button
                            type="button"
                            onClick={() => toggleComplete(todo)}
                            className="action-btn action-btn-complete"
                            title={
                              todo.completed
                                ? "Mark as incomplete"
                                : "Mark as complete"
                            }
                          >
                            {todo.completed ? "↶" : "✓"}
                          </button>
                          <button
                            type="button"
                            onClick={() => setEditingTodo(todo)}
                            className="action-btn action-btn-edit"
                            title="Edit todo"
                          >
                            ✏️
                          </button>
                          <button
                            type="button"
                            onClick={() => deleteTodo(todo.id)}
                            className="action-btn action-btn-delete"
                            title="Delete todo"
                          >
                            🗑️
                          </button>
                        </div>
                      </div>

                      {expandedTodos.has(todo.id) && (
                        <div className="todo-details">
                          {todo.details && (
                            <div
                              className={`todo-description ${todo.completed ? "completed" : ""}`}
                            >
                              <p>{todo.details}</p>
                            </div>
                          )}

                          <div className="todo-meta">
                            <div className="meta-dates">
                              <span className="meta-item">
                                Created:{" "}
                                {new Date(todo.created_at).toLocaleString()}
                              </span>
                              <span className="meta-item">
                                Updated:{" "}
                                {new Date(todo.updated_at).toLocaleString()}
                              </span>
                            </div>
                            {todo.completed && (
                              <div className="completion-badge">
                                <svg
                                  className="completion-icon"
                                  fill="none"
                                  stroke="currentColor"
                                  viewBox="0 0 24 24"
                                  aria-hidden="true"
                                >
                                  <path
                                    strokeLinecap="round"
                                    strokeLinejoin="round"
                                    strokeWidth={2}
                                    d="M9 12l2 2 4-4m6 2a9 9 0 11-18 0 9 9 0 0118 0z"
                                  />
                                </svg>
                                <span>Completed</span>
                              </div>
                            )}
                          </div>
                        </div>
                      )}
                    </div>
                  )}
                </div>
              ))
            )}
          </div>
        ))}
    </div>
  );
}

Update App Routes

Add the todos page to your application routing.

import {
  createBrowserRouter,
  createRoutesFromElements,
  Navigate,
  Outlet,
  Route,
  RouterProvider,
} from "react-router-dom";
import Navigation from "./components/Navigation";
import ProtectedRoute from "./components/ProtectedRoute";
import { AuthProvider } from "./lib/nhost/AuthProvider";
import Home from "./pages/Home";
import Profile from "./pages/Profile";
import SignIn from "./pages/SignIn";
import SignUp from "./pages/SignUp";
import Todos from "./pages/Todos";
import Verify from "./pages/Verify";

// Root layout component to wrap all routes
const RootLayout = () => {
  return (
    <>
      <Navigation />
      <div className="app-content">
        <Outlet />
      </div>
    </>
  );
};

// Create router with routes
const router = createBrowserRouter(
  createRoutesFromElements(
    <Route element={<RootLayout />}>
      <Route index element={<Home />} />
      <Route path="signin" element={<SignIn />} />
      <Route path="signup" element={<SignUp />} />
      <Route path="verify" element={<Verify />} />
      <Route element={<ProtectedRoute />}>
        <Route path="profile" element={<Profile />} />
        <Route path="todos" element={<Todos />} />
      </Route>
      <Route path="*" element={<Navigate to="/" />} />
    </Route>,
  ),
);

function App() {
  return (
    <AuthProvider>
      <RouterProvider router={router} />
    </AuthProvider>
  );
}

export default App;

Update Navigation Links

Add a link to the todos page in the navigation bar.

import { Link, useNavigate } from "react-router-dom";
import { useAuth } from "../lib/nhost/AuthProvider";

export default function Navigation() {
  const { isAuthenticated, session, nhost } = useAuth();
  const navigate = useNavigate();

  const handleSignOut = async () => {
    try {
      if (session) {
        await nhost.auth.signOut({
          refreshToken: session.refreshToken,
        });
      }
      navigate("/");
    } catch (err: unknown) {
      const message = err instanceof Error ? err.message : String(err);
      console.error("Error signing out:", message);
    }
  };

  return (
    <nav className="navigation">
      <div className="nav-container">
        <Link to="/" className="nav-logo">
          Nhost React Demo
        </Link>

        <div className="nav-links">
          <Link to="/" className="nav-link">
            Home
          </Link>

          {isAuthenticated ? (
            <>
              <Link to="/todos" className="nav-link">
                Todos
              </Link>
              <Link to="/profile" className="nav-link">
                Profile
              </Link>
              <button
                type="button"
                onClick={handleSignOut}
                className="nav-link nav-button"
              >
                Sign Out
              </button>
            </>
          ) : (
            <>
              <Link to="/signin" className="nav-link">
                Sign In
              </Link>
              <Link to="/signup" className="nav-link">
                Sign Up
              </Link>
            </>
          )}
        </div>
      </div>
    </nav>
  );
}

Test Your Complete Application

Run your application and test all the functionality:

npm run dev

Things to try out:

1. Try signing in and out and see how the Todos page is only available when authenticated
2. Create, view, edit, complete, and delete todos. See how the UI updates accordingly
3. Open the application in another browser or incognito window, sign in with a different account and verify that you cannot see or modify todos from the first account

Key Features Implemented

Database Schema

Properly designed todos table with constraints, indexes, and automatic timestamp updates for optimal performance.

GraphQL API

Auto-generated GraphQL API with queries and mutations for full CRUD operations on todos.

Row-Level Security

Comprehensive permissions ensuring users can only access their own todos through all GraphQL operations.

CRUD Operations

Complete Create, Read, Update, Delete functionality with proper error handling and user feedback.

Rich Interface

Expandable todo items, inline editing, completion status, and detailed timestamps.