Fix crash when request download with fileURL

[devtak]

Issue Link 🔗

#3293

Goals ⚽

Crash occurs when request download with fileURL (AF.download)

• modified to throw an error without causing a crash.

Implementation Details 🚧

If URL is fileURL, throw AFError.invalidURL

switch request {
    case is DownloadRequest:
        if let url = initialRequest.url, url.isFileURL {
            throw AFError.invalidURL(url: url)
        }
    default:
        break
}

Testing Details 🔍

add downloadTestCase (testDownloadRequestWithLocalFileURLStringThrowsAnError)

[jshier]

Thanks for the PR. However, can you be more specific about the crash you're seeing? Additionally, if a file URL doesn't work for DownloadRequest, is it also broken for DataRequest and the others as well? If that's the case we probably want this logic in a more general location, like our URLRequest validation.

[jshier]

Investigating this error more, this definitely seems like something that should just be general check in our validate() method on URLRequest. This lives in our Alamofire+URLRequest.swift file. You could add this to the top of the validate function:

if let url = url, url.isFileURL {
    // This should become another urlRequestValidationFailed error in Alamofire 6.
    throw AFError.invalidURL(url: url)
}

Additional tests for DataRequest and DataStreamRequest would also be needed.

[devtak]

@jshier i updated it. thanks for the review

[jshier]

👍 Nice catch, thanks!