Hi
I would like to understand what the proper way is to return status and status information within the application. For example when a controller calls a component or a command calls a service. I would like to get a status and status information returned so I can handle the response respectively.
The Response class is for handling HTTP responses, not return values from functions. It might make sense in some cases to return that from a function, but that’s not a general purpose use case.
Your service classes can of course return whatever you want them to, or throw exceptions.
If you need to send structured data back from a service to let the caller know a number of things about it (e.g. perhaps not just a success/failure, but a list of record IDs that the function updates), you might think about creating your own data transfer object (DTO) class, and return an instance of that.
If it’s more about notifying the caller about failures, then throwing an exception is the most common way. Again, you can define your own exception classes, which can store whatever you want in them (so, they are in that respect a special case of DTO). The caller can catch those exceptions by type, so you can even have multiple different possible exception classes for different scenarios or different bits of data you want to return.
If you just want to return a message and an HTTP status code, Cake already comes with a number of exception classes that map to all the common status codes, for example throw new Cake\Http\Exception\NotFoundException('Not found.') will throw an exception that will default to a 404 error code with the provided message. Depending on your use case, that might be all you need to do to get the desired error page (the error handler middleware will deal with many of these things for you). If you’re calling the service from a command line task and want to do something different with that error (log it, send somebody an email or whatever), you might catch that exception (or more generically by the base class Cake\Http\Exception\HttpException) and do something with the message and status code available through it.
Wow, many thanks @Zuluru for your detailed and very valuable answer! You have provided me with helpful options. It looks like I need to do further thinking about how I want to use it. Based on your input I have read about DTOs and I see also other valuable use cases like API responses (source: DTOs in CakePHP – DerEuroMark). So thank you for taking the time understanding my problem and sharing your knowledge!