snippetbox

Description

This application lets people paste and share snippets of text, a bit like Pastebin or Github's Gists. I have built it while reading the Alex Edwards book "Let's Go".

Prerequisites

• Go (v1.20)
• MySQLDB

Deployment

Database

Create a new snippetbox database:

-- Create a new UTF-8 `snippetbox` database.
CREATE DATABASE snippetbox CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

-- Switch to using the `snippetbox` database.
USE snippetbox;

Create a new snippets table to hold the text snippets for our application:

-- Create a `snippets` table.
CREATE TABLE snippets (
    id INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
    title VARCHAR(100) NOT NULL,
    content TEXT NOT NULL,
    created DATETIME NOT NULL,
    expires DATETIME NOT NULL
);

-- Add an index on the created column.
CREATE INDEX idx_snippets_created ON snippets(created);

Create a new user:

CREATE USER 'web'@'localhost';
GRANT SELECT, INSERT, UPDATE, DELETE ON snippetbox.* TO 'web'@'localhost';
-- Important: Make sure to swap 'pass' with a password of your own choosing.
ALTER USER 'web'@'localhost' IDENTIFIED BY 'pass';

Create a sessions table in our MySQL database to hold the session data for our users:

USE snippetbox;

CREATE TABLE sessions (
    token CHAR(43) PRIMARY KEY,
    data BLOB NOT NULL,
    expiry TIMESTAMP(6) NOT NULL
);

CREATE INDEX sessions_expiry_idx ON sessions (expiry);

Create the test version of our MySQL database and test_web user:

CREATE DATABASE test_snippetbox CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

CREATE USER 'test_web'@'localhost';
GRANT CREATE, DROP, ALTER, INDEX, SELECT, INSERT, UPDATE, DELETE ON test_snippetbox.* TO 'test_web'@'localhost';
ALTER USER 'test_web'@'localhost' IDENTIFIED BY 'pass';

Certificate

For development purposes we can generate a self-signed certificate:

$ go run /usr/local/go/src/crypto/tls/generate_cert.go --rsa-bits=2048 --host=localhost

Run

$ go run cmd/web/!(*_test).go

Debug Mode

$ go run ./cmd/web/ -debug

Testing

$ go test -v ./cmd/web

Features

API Routes

Method	Pattern	Handler	Action
ANY	/	home	Display the home page
GET	/about	about	Display the about page
GET	/snippet/view/:id	snippetView	Display a specific snippet
GET	/snippet/create	snippetCreate	Display the snippet creation form
POST	/snippet/create	snippetCreatePost	Create a new snippet
GET	/account/view	accountView	Display the user profile
GET	/user/signup	userSignup	Display the sign up
POST	/user/signup	userSignupPost	Create a new user
GET	/user/login	userLogin	Display the login form
POST	/user/login	userLoginPost	User authentication
POST	/user/logout	userLogoutPost	User logout
GET	/account/password/update	accountPasswordUpdatePost	Display the password update page
POST	/account/password/update	accountPasswordUpdatePost	Change the user password
GET	/static/	http.FileServer	Serve a specific static file

General

• Command-line flags
• Dependency injection

Testing

• Unit Testing & sub-tests
• Table-driven tests
• End-to-end testing
• Mocking dependencies
• Testing HTML forms
• Integration testing
• Debug mode

UI

• User interface using HTML template composition
• Dynamic HTML templates
• Caching templates
• Processing forms
• Automatic form parsing
• Contents changes depending on whether a user is authenticated or not
• About page
• Account page

HTTP

• HTTP status codes
• Serving static files
• Directory listing disabled
• Chaining HTTP handlers
• Stateful HTTP
• Session manager
• HTTPS connection
• HTTP/2 connections

API

• REST API
• Isolated application routes
• Use of middleware
• Composable middleware chains
• Advanced routing

Logging & Errors

• Centralized error handling
• Leveled logging
• Request logging
• Panic recovery
• Custom error handlers

Database

• Database connection with MariaDB
• Use of transactions to execute multiple SQL statements in one atomic action
• Database connection pools
• Use of prepared statements

Security

• Secure HTTP headers
• Security headers
• Validating form data
• TLS versions restricted
• Cipher suites restricted
• Connection timeouts
• SQL injection prevention
• Sign up
• Authentication
• Authorization
• Logout
• CSRF protection
• Change password feature