Replaced generic struct based AWSAppSyncClientError by a typed enum…

[MarioBajr]

The struct based AWSAppSyncClientError doesn't provide enough informations about the error. Requiring the user to do string matching with additionalInfo to figure out what exactly went wrong.

Description of changes:

• Replaced the struct based AWSAppSyncClientError by a typed enum based, providing better description for each type of error, including inner errors when applied.
• Moved common request code into a single method in AWSAppSyncHTTPNetworkTransport.

Considerations:

• Good to have in mind that this PR changes the public interface. Being non backward compatible with written code.

[rohandubal]

Hello @MarioBajr

Thanks for the PR!

As you have noted, this would be a breaking change, I was wondering if we could make the struct a property of AWSAppSyncClientError instead of completely replacing the type. Any particular reason you think we need to completely replace this?

Thanks,
Rohan

[MarioBajr]

Sure thing, gonna replace tomorrow to the enum be a property of AWSAppSyncClientError.
Cheers

[rohandubal]

Awesome! thanks @MarioBajr will wait for the update!

[MarioBajr]

Hi @rohandubal. How do you feel about the additions of the redundant parameters with deprecated flag as an effort not to break the backward compatibility, but keeping the interface clean in the long run?

@available(*, deprecated, message: "use the enum pattern matching instead")
public var body: Data? {
    switch self {
    case .parseError(let data, _, _):
        return data
    case .requestFailed(let data, _, _):
        return data
    case .noData:
        return nil
    }
}

@available(*, deprecated, message: "use the enum pattern matching instead")
public var response: HTTPURLResponse? {
    switch self {
    case .parseError(_, let response, _):
        return response as? HTTPURLResponse
    case .requestFailed(_, let response, _):
        return response as? HTTPURLResponse
    case .noData:
        return nil
    }
}

@available(*, deprecated)
var isInternalError: Bool {
    return false
}

@available(*, deprecated)
var additionalInfo: String? {
    switch self {
    case .parseError(_, _, _):
        return "Could not parse response data."
    case .requestFailed(_, _, _):
        return "Did not receive a successful HTTP code."
    case .noData:
        return "No Data received in response."
    }
}

[rohandubal]

I think that is a fair approach. I will discuss it with the team and get back to you if we are all clear for this approach. Thanks again!

[rohandubal]

Reviewing the latest changes.

[rohandubal]

Hello @MarioBajr

The changes look great! However, I am unable to merge due to conflicts. Is it possible for you to rebase onto master? I will release them as soon as they are rebased.

Thanks,
Rohan

[MarioBajr]

Done 👍

[rohandubal]

Awesome, thanks @MarioBajr Will merge it soon 😄