Comparison of Object Binding Methods in Laravel Service Container
| Method | bind() |
singleton() |
scoped() |
instance() |
|---|---|---|---|---|
| Description | Creates a new instance every time it is resolved. | Creates only one instance and returns the same instance in subsequent requests. | Creates only one instance within each request/job lifecycle; it is cleared after the request ends. | Binds an existing instance to the container and returns that instance every time it is resolved. |
| Pros | - A fresh instance for every request, no state sharing issues - Clean memory usage - Suitable for logic requiring independent state - Can provide unique configuration for each request |
- Saves system resources by creating an instance only once - Ensures state consistency - Suitable for shared configuration and resources - Better performance under high concurrency |
- Balances memory usage and state sharing - Shares state within a request but isolated between requests - Suitable for Web request scenarios |
- Full control over instance creation timing - Can pre-configure instance state - Suitable for services requiring specific configuration |
| Cons | - Requires more system resources to repeatedly create instances - May affect performance under high concurrency - Not suitable for scenarios requiring shared state - May cause performance issues because a new instance is created every time. |
- Shared state may lead to hard-to-trace bugs - Not suitable for scenarios requiring independent state - Memory usage persists until the program ends - Testing requires special attention to state reset - If the instance holds state, it may cause unexpected behavior. |
- May cause issues in long-running tasks - Requires understanding of request lifecycle - Not suitable for CLI commands |
- Less flexible - Cannot dynamically adjust instance configuration - May occupy memory at startup - Not suitable for cases requiring lazy loading or multiple instances. |
| Use Case | For short-lived services or classes requiring independent state. | For globally shared services, such as loggers or configuration managers. | For services that need to maintain state within a request but not across requests, such as database connections. | When you already have an instance and want to reuse it, such as a shared configuration object. |
| Example | When you have a Product class and want to create a new Product instance every time different product data is requested. |
When you have a Logger class and want all log write operations to use the same instance to maintain consistency. |
When you have a ShoppingCart class and need to share the shopping cart state within the same request. |
When you have a DatabaseConfig class and need to set connection parameters when the application starts. |
Examples
Using bind()
$this->app->bind('Product', function () {
return new Product();
});
Every time app('Product') is called, it returns a new Product instance.
Using singleton()
$this->app->singleton('Logger', function () {
return new Logger();
});
Every time app('Logger') is called, it returns the same Logger instance.
Using scoped()
$this->app->scoped(Transistor::class, function (Application $app) {
return new Transistor($app->make(PodcastParser::class));
});
Shares the same instance within the same request lifecycle; different requests will create new instances.
Using instance()
$service = new Transistor(new PodcastParser);
$this->app->instance(Transistor::class, $service);
Directly binds an existing instance to the container.
Summary
Laravel can currently be applied in many different types of scenarios, such as Web Requests, CLI Commands, Queue Jobs, Console Commands, etc.
So, when choosing which binding method to use, you need to consider the needs of the service in different scenarios, and whether you need to share state or configuration.