php service class example

stackoverflow.com › questions › 6524037 › designing-service-layer-classes-in-php

First, is user_service() an appropriate class name for my user() model or is there another standard?

That's acceptable. However, you should rather use one of the established PHP coding conventions, such as the PEAR or ZF conventions. In both cases, class names are UpperCamelCase and method names lowerCamelCase. Using this, the classes would be User and UserService

Since the methods in my service will only be doing one task, is it correct to think that these can always be a static function? A service class isn't representing data, but rather is a series a actions, so this seems appropriate.

No. It's a poor design choice to make methods static - and this applies to most code, not just services. One of the main reasons in case of a service would be that generally your service needs to interact with a data store or another class which represents the data layer (repository, data access object, whatever).

When your service has static methods, this means you would need to instanciate your dependencies in your methods. This in turn means that, amongst other things, the code becomes hard to test, as you can't easily replace the dependencies.

There's some good reading on this for example here (In fact nearly everything on that blog is good reading for software devs)

Should a service method only accept one argument, which would be an array?

This is dependent on what the method does. Assuming your example of processing a form's resultset, then yes this will probably work. In some other case it might be a poor choice.

I can add another field to my form and I won't have to update the controller, just the service. [ ... ]

If I didn't pass an array, I could setup functions with multiple arguments. [ ... ]

Yep, your argumentation for these two cases is pretty much spot on for this use-case in my opinion.

I could pass an object, but does that make sense? If I'm creating an object, it should the be the object it represents (the user in this case) right? But does it make sense that the controller instantiates the user object? Isn't that the whole point of the service layer in the first place?

This depends. For example, if you were using a framework which lets you represent forms as objects (such as the Zend Framework and Zend_Form), you could consider passing the form object straight to the service.

Maybe there is an argument for having some methods with multiple arguments (when there are just one to three) and some methods that accept an array (when there are lots of fields). This just seems like it could be a nightmare, as you would always have to reference the class to know what that particular method was asking for.

You should usually aim to make the parameters at least half-guessable based on the method's name. In something I work on, we have a model which has for example businesses and products, where a business can sponsor a product. In a ProductService, we have a method called sponsorProduct which takes a business and a product as parameters. You can pretty much guess it would take these two (if you were familiar with the codebase anyway)

IDE's generally help you with this too - they provide code-assist which displays what params functions take. This is one of the main reasons I think IDE's are very useful in larger projects where you can't always remember what exactly a certain function needs as parameters.

As for parameter count, I think usually you should try to have separate parameters. This allows anyone to easily see what parameters are required by just looking at the function's signature, and allows you to define typehints and default values quite easily.

However there is a point when you get so many parameters it's too much. This is maybe at +5 or so, depending a bit on what sort of method it is. In this case you can consider using an array, or something called a Parameter Object, which is essentially an object that contains all the parameters for the call. More on parameter objects here

Answer from Jani Hartikainen on Stack Overflow

Stack Overflow

stackoverflow.com › questions › 6524037 › designing-service-layer-classes-in-php

model view controller - Designing service layer classes in PHP - Stack Overflow

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First, is user_service() an appropriate class name for my user() model or is there another standard?

That's acceptable. However, you should rather use one of the established PHP coding conventions, such as the PEAR or ZF conventions. In both cases, class names are UpperCamelCase and method names lowerCamelCase. Using this, the classes would be User and UserService

Since the methods in my service will only be doing one task, is it correct to think that these can always be a static function? A service class isn't representing data, but rather is a series a actions, so this seems appropriate.

No. It's a poor design choice to make methods static - and this applies to most code, not just services. One of the main reasons in case of a service would be that generally your service needs to interact with a data store or another class which represents the data layer (repository, data access object, whatever).

When your service has static methods, this means you would need to instanciate your dependencies in your methods. This in turn means that, amongst other things, the code becomes hard to test, as you can't easily replace the dependencies.

There's some good reading on this for example here (In fact nearly everything on that blog is good reading for software devs)

Should a service method only accept one argument, which would be an array?

This is dependent on what the method does. Assuming your example of processing a form's resultset, then yes this will probably work. In some other case it might be a poor choice.

I can add another field to my form and I won't have to update the controller, just the service. [ ... ]

If I didn't pass an array, I could setup functions with multiple arguments. [ ... ]

Yep, your argumentation for these two cases is pretty much spot on for this use-case in my opinion.

I could pass an object, but does that make sense? If I'm creating an object, it should the be the object it represents (the user in this case) right? But does it make sense that the controller instantiates the user object? Isn't that the whole point of the service layer in the first place?

This depends. For example, if you were using a framework which lets you represent forms as objects (such as the Zend Framework and Zend_Form), you could consider passing the form object straight to the service.

Maybe there is an argument for having some methods with multiple arguments (when there are just one to three) and some methods that accept an array (when there are lots of fields). This just seems like it could be a nightmare, as you would always have to reference the class to know what that particular method was asking for.

You should usually aim to make the parameters at least half-guessable based on the method's name. In something I work on, we have a model which has for example businesses and products, where a business can sponsor a product. In a ProductService, we have a method called sponsorProduct which takes a business and a product as parameters. You can pretty much guess it would take these two (if you were familiar with the codebase anyway)

IDE's generally help you with this too - they provide code-assist which displays what params functions take. This is one of the main reasons I think IDE's are very useful in larger projects where you can't always remember what exactly a certain function needs as parameters.

As for parameter count, I think usually you should try to have separate parameters. This allows anyone to easily see what parameters are required by just looking at the function's signature, and allows you to define typehints and default values quite easily.

However there is a point when you get so many parameters it's too much. This is maybe at +5 or so, depending a bit on what sort of method it is. In this case you can consider using an array, or something called a Parameter Object, which is essentially an object that contains all the parameters for the call. More on parameter objects here

SymfonyCasts

symfonycasts.com › screencast › oo-ep2 › service-classes

Service Classes > OOP (Course 2): Services, Dependency Injection and Containers | SymfonyCasts

That's all you need to change: functions work the same inside or outside of a class: they have arguments, they return stuff. But we do need to change code where we call this function - in battle.php. So how can we call this? Well, when we want to call a method on Ship, we need to have a Ship object first.

Discussions

Opinion based discussion: Service class, how to use them?

Tbh this logic is so simple that I would avoid another layer of abstraction. Doesn't look like you need any logic there and it's not like you're doing API calls there. Just use the model directly. And you seem to be trying too much error handling yourself. I am not sure what errors are you expecting, but almost never need try/catch around things like this. FYI Car::where("id", $id)->first() is equivalent to Car::find($id) unless you've done some strange customization of the model. And maybe what you want to do is just Car::findOrFail($id) which throws an appropriate 404 response itself? The convention is that model names are singular, after all you're instantiating a new Car not a new Cars. So I used singular in my examples. More on reddit.com

r/laravel

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December 2, 2020

Injecting an object (from the IOC) using Laravel Blade Service Injection

This feels so wrong on so many levels.

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