SwiftyRequest 2.2.1

SwiftyRequest 2.2.1

Maintained by Danny Sung, Andrew Lees, Swift-at-IBM, Matt Kilner, David Jones, Mathieu Barnachon.

Depends on:
LoggerAPI~> 1.7
IBMSwiftCircuitBreaker~> 5.0

  • By
  • IBM


APIDoc Build Status - Master macOS Linux Apache 2 Slack Status


SwiftyRequest is an HTTP networking library built for Swift.

SwiftyRequest uses URLSession for the underlying transport. URLSession on Linux is not yet completely implemented so you may find that this library is less reliable on Linux than Darwin (reference issues #24 and #25, the second of these references a Foundation PR).



  • Several response methods (e.g. Data, Object, Array, String, etc.) to eliminate boilerplate code in your application.
  • JSON encoding and decoding.
  • Integration with the CircuitBreaker library.
  • Authentication tokens.
  • Multipart form data.

Swift version

This repository supports Swift 4.0.3 and later.


To leverage the SwiftyRequest package in your Swift application, you should specify a dependency for it in your Package.swift file:

Add dependencies

Add SwiftyRequest to the dependencies within your application's Package.swift file. Substitute "x.x.x" with the latest SwiftyRequest release.

.package(url: "https://github.com/IBM-Swift/SwiftyRequest.git", from: "x.x.x")

Add SwiftyRequest to your target's dependencies:

.target(name: "example", dependencies: ["SwiftyRequest"]),


Make Requests

To make outbound HTTP calls using SwiftyRequest, create a RestRequest instance. The method parameter is optional (it defaults to GET), the url parameter is required.

Example usage of RestRequest:

import SwiftyRequest

let request = RestRequest(method: .get, url: "http://myApiCall/hello")
request.credentials = .apiKey

You can customize the following parameters in the HTTP request:

  • headerParameters : The HTTP header fields which form the header section of the request message.
  • credentials : The HTTP authentication credentials for the request.
  • acceptType : The HTTP Accept header, defaults to application/json.
  • messageBody : The HTTP message body of the request.
  • productInfo : The HTTP User-Agent header.
  • circuitParameters : A CircuitParameters object which includes a reference to a fallback function that will be invoked when the circuit is failing fast (see CircuitBreaker Integration).
  • contentType : The HTTP Content-Type header, defaults to application/json.
  • method : The HTTP method specified in the request, defaults to .get.

Invoke Response

In this example, responseToError is simply an error handling function. The response object we get back is of type RestResponse<String> so we can perform a switch on the response.result to determine if the network call was successful.

request.responseString(responseToError: responseToError) { response in
    switch response.result {
    case .success(let result):
    case .failure(let error):

Invoke Response with Template Parameters

In this example, we invoke a response method with two template parameters to be used to replace the {state} and {city} values in the url. This allows us to create multiple response invocations with the same RestRequest object, but possibly using different url values.

let request = RestRequest(url: "http://api.weather.com/api/123456/conditions/q/{state}/{city}.json")
request.credentials = .apiKey

request.responseData(templateParams: ["state": "TX", "city": "Austin"]) { response in
	// Handle response

Invoke Response with Query Parameters

In this example, we invoke a response method with a query parameter to be appended onto the url behind the scenes so that the RestRequest gets executed with the following url: http://api.weather.com/api/123456/conditions/q/CA/San_Francisco.json?hour=9. If there are query items already specified in the request URL they will be replaced.

let request = RestRequest(url: "http://api.weather.com/api/123456/conditions/q/CA/San_Francisco.json")
request.credentials = .apiKey

request.responseData(queryItems: [URLQueryItem(name: "hour", value: "9")]) { response in
	// Handle response

CircuitBreaker Integration

SwiftyRequest now has additional built-in functionality for leveraging the CircuitBreaker library to increase your application's stability. To make use of this functionality, you just need to provide a CircuitParameters object to the RestRequest initializer. A CircuitParameters object will include a reference to a fallback function that will be invoked when the circuit is failing fast.


Here is an example of a fallback closure:

let fallback = { (error: BreakerError, msg: String) in
    print("Fallback closure invoked... circuit must be open.")


We initialize the CircuitParameters object and create a RestRequest instance. The only required value you need to set for CircuitParameters is the fallback (everything else has default values).

let circuitParameters = CircuitParameters(timeout: 2000,
                                          maxFailures: 2,
                                          fallback: breakFallback)

let request = RestRequest(method: .get, url: "http://myApiCall/hello")
request.credentials = .apiKey,
request.circuitParameters = circuitParameters

At this point, you can use any of the response methods mentioned in the section below.

Response Methods

There are various response methods you can use based on the result type you want, here they are:

  • responseData returns a Data object.
  • responseObject<T: Codable> returns a Codable object of type T.
  • responseObject<T: JSONDecodable> returns an object of type T.
  • responseArray<T: JSONDecodable> returns an array of type T.
  • responseString returns a String.
  • responseVoid returns Void.

API documentation

For more information visit our API reference.


We love to talk server-side Swift, and Kitura. Join our Slack to meet the team!


This library is licensed under Apache 2.0. Full license text is available in LICENSE.