# Middleware in the Application

Middleware in this application provides a way to intercept and process HTTP requests before they reach the final handler. Each middleware serves a specific purpose, such as authentication, session management, or request modification.

# Types of Middleware

# 1. Preview Middleware

File: /internal/middlewares/preview_middleware.go

Purpose:
The Preview Middleware enables temporary preview functionality for administrators and developers, allowing them to render game content without affecting the live game.

Key Features:

• Detects HTMX preview requests from admin or template pages
• Creates a temporary team instance with a preview context
• Sets a short-lived game instance (1 hour duration), overriding the active instance

Usage Example:

middleware := PreviewMiddleware(teamService, nextHandler)

# 2. Team Middleware

File: /internal/middlewares/team_middleware.go

Purpose:
The Team Middleware extracts team information from the session and loads the associated game instance.

Key Features:

• Retrieves team code from the session
• Loads team and instance relationships
• Adds team context to the request

Usage Example:

middleware := TeamMiddleware(teamService, nextHandler)

# 3. Lobby Middleware

File: /internal/middlewares/lobby_middleware.go

Purpose:
The Lobby Middleware manages team access based on the game instance status, redirecting users to the lobby when necessary.

Key Features:

• Checks game instance status
• Redirects to lobby for inactive game instances
• Adds team context to the request

Usage Example:

middleware := LobbyMiddleware(teamService, nextHandler)

# 4. Admin Authentication Middleware

File: admin.go

Purpose:
Manages authentication and authorization for administrative routes.

Key Features:

• Verifies user authentication
• Checks email verification status
• Ensures users have selected an instance for admin actions

Usage Example:

middleware := AdminAuthMiddleware(authService, nextHandler)
middleware := AdminCheckInstanceMiddleware(nextHandler)

# 5. Text HTML Middleware

File: /internal/middlewares/middleware.go

Purpose:
A simple middleware to set the content type for responses.

Key Features:

• Sets Content-Type header to text/html

Usage Example:

middleware := TextHTMLMiddleware(nextHandler)

# Best Practices

1. Chaining Middleware: Use multiple middlewares in a chain to modularise request processing.
   • Preview Middleware must be the first middleware in the chain when used.
2. Context Management: Utilise request context to pass additional information between middlewares.
   • Use the internal contextkeys package for context keys.
3. Performance: Keep middleware logic lightweight and efficient.

# Common Patterns

# Adding Team to Context

ctx := context.WithValue(r.Context(), contextkeys.TeamKey, team)
next.ServeHTTP(w, r.WithContext(ctx))

# Passing Through Non-Matching Requests

if !matchingCondition {
    next.ServeHTTP(w, r)
    return
}

# Extending Middleware

To create a new middleware:

1. Define a function that takes a next http.Handler
2. Return a new http.Handler
3. Implement request interception logic
4. Call next.ServeHTTP() to continue the request chain

# Testing

Middleware can be tested by:

• Mocking services
• Creating test requests
• Verifying context modifications
• Checking response behaviours

Refer to internal/middlewares/preview_middleware_test.go for example tests.