(Swift 3,4,5...) PayPal -- Get an OAuth 2.0 Access Token

Demonstrates how to send a request to get a PayPal OAuth2 access token. Sends an HTTP request equivalent to the following:

curl https://api.sandbox.paypal.com/v1/oauth2/token \
  -H "Accept: application/json" \
  -H "Accept-Language: en_US" \
  -u "Client-Id:Secret" \
  -d "grant_type=client_credentials"

Chilkat Downloads for the Swift Programming Language MAC OS X (Cocoa) Objective-C/Swift Libs iOS Objective-C/Swift Libs

func chilkatTest() {
    // Note: Requires Chilkat v9.5.0.64 or greater.

    // This requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    let rest = CkoRest()!

    // Make the initial connection.
    // A single REST object, once connected, can be used for many PayPal REST API calls.
    // The auto-reconnect indicates that if the already-established HTTPS connection is closed,
    // then it will be automatically re-established as needed.
    var bAutoReconnect: Bool = true
    var success: Bool = rest.connect("api.sandbox.paypal.com", port: 443, tls: true, autoReconnect: bAutoReconnect)
    if success != true {
        print("\(rest.lastErrorText!)")
        return
    }

    // Duplicate this request:

    // 	curl https://api.sandbox.paypal.com/v1/oauth2/token \
    // 	  -H "Accept: application/json" \
    // 	  -H "Accept-Language: en_US" \
    // 	  -u "Client-Id:Secret" \
    // 	  -d "grant_type=client_credentials"

    rest.addHeader("Accept", value: "application/json")
    rest.addHeader("Accept-Language", value: "en_US")

    // For additional help on where to find  your client ID and API secret, see PayPal Client_ID and API_Secret
    rest.setAuthBasic("PAYPAL_REST_API_CLIENT_ID", password: "PAYPAL_REST_API_SECRET")

    rest.addQueryParam("grant_type", value: "client_credentials")

    var responseStr: String? = rest.fullRequestFormUrlEncoded("POST", uriPath: "/v1/oauth2/token")
    if rest.lastMethodSuccess != true {
        print("\(rest.lastErrorText!)")
        return
    }

    print("\(rest.lastRequestHeader!)")

    // A sample response:

    // 	{
    // 	  "scope": "https://api.paypal.com/v1/payments/.* https://api.paypal.com/v1/vault/credit-card https://api.paypal.com/v1/vault/credit-card/.*",
    // 	  "access_token": "EEwJ6tF9x5WCIZDYzyZGaz6Khbw7raYRIBV_WxVvgmsG",
    // 	  "token_type": "Bearer",
    // 	  "app_id": "APP-6XR95014BA15863X",
    // 	  "expires_in": 28800
    // 	}

    let json = CkoJsonObject()!
    json.load(responseStr)
    json.emitCompact = false

    // Check the response status code.  A 200 indicates success..
    if rest.responseStatusCode.intValue != 200 {
        print("\(json.emit()!)")
        print("Failed.")
        return
    }

    // Given that the access token expires in approx 8 hours,
    // let's record the date/time this token was created.
    // This will allow us to know beforehand if the token
    // is expired (and we can then fetch a new token).
    let dateTime = CkoDateTime()!
    var bLocalTime: Bool = false
    var dtNow: Int = dateTime.getAsUnixTime(bLocalTime)
    json.appendInt("tokenCreateTimeUtc", value: dtNow)

    // Examine the access token and save to a file.
    print("Access Token: \(json.string(of: "access_token")!)")
    print("Full JSON Response:")
    print("\(json.emit()!)")

    let sbResponse = CkoStringBuilder()!
    sbResponse.append(json.emit())
    var bEmitBom: Bool = false
    sbResponse.writeFile("qa_data/tokens/paypal.json", charset: "utf-8", emitBom: bEmitBom)

}