Swift Byte #8: How to Use Alamofire 5 Event Monitor to log request & responses

A cleaner approach to log Alamofire 5 requests and responses

While I was working on refactoring the networking layer and upgrading Alamofire from 4 to 5, I learn about the existence of EventMonitor.

What is EventMonitor?

Essentially, EventMonitor is a protocol that allows me to "monitor” the session’s network requests and response.

Implementing EventMonitor is a matter of creating a class that conforms to the EventMonitor protocol.

For example, in my case I want to log every request and response that’s happening to Xcode console log to make debugging easier.

/// Monitor Alamofire request and response and print it to Xcode console
/// for debugging purpose.

class ConsoleLogEventMonitor: EventMonitor {
    func requestDidResume(_ request: Request) {
        print("""
            [REQ]: \(request.request?.url?.absoluteString ?? "")
            \(request.cURLDescription())
        """)
    }

    func request<Value>(_ request: DataRequest, didParseResponse response: DataResponse<Value, AFError>) {
        print("""
            [RESP]: \(request.request?.url?.absoluteString ?? "")
            \(response.debugDescription)
        """)
    }
}

To use it, I just have to add ConsoleLogEventMonitor to the Alamofire’s Session like so:

let session = Session(eventMonitors: [ConsoleLogEventMonitor()])
session.request(urlComponents)

With this, each of my session requests will be printed out in the Xcode console.

Session can accept multiple event monitors too. In a way, I can create multiple event monitors based on functionalities like DataDog analytics, logging or even custom behaviours.

That’s all for from me today. Thanks for reading!

References:

1. Official docs on how to use Event Monitors

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