(Swift 3,4,5...) Refresh QuickBooks OAuth2 Access Token

Demonstrates how to refresh a QuickBooks OAuth2 access token.

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

func chilkatTest() {
    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // See Get QuickBooks OAuth2 Access Token 
    // for sample code showing how to obtain a QuickBooks access token for desktop apps.

    // This example assumes we previously obtained an OAuth2 access token for QuickBooks.

    let jsonToken = CkoJsonObject()!
    var success: Bool = jsonToken.loadFile("qa_data/tokens/qb-access-token.json")
    if success != true {
        print("Failed to load qb-access-token.json")
        return
    }

    // The access token JSON looks something like this:

    // {
    //   "expires_in": 3600,
    //   "x_refresh_token_expires_in": 8726400,
    //   "refresh_token": "L011546037639r ... 3vR2DrbOmg0Sdagw",
    //   "access_token": "eyJlbmMiOiJBMTI4Q0 ... oETJEMbeggg",
    //   "token_type": "bearer"
    // }

    let oauth2 = CkoOAuth2()!

    oauth2.tokenEndpoint = "https://oauth.platform.intuit.com/oauth2/v1/tokens/bearer"

    // Replace these with actual values.
    oauth2.clientId = "QUICKBOOKS-CLIENT-ID"
    oauth2.clientSecret = "QUICKBOOKS-CLIENT-SECRET"

    // Get the "refresh_token"
    oauth2.refreshToken = jsonToken.string(of: "refresh_token")

    // Send the HTTP POST to refresh the access token..
    success = oauth2.refreshAccessToken()
    if success != true {
        print("\(oauth2.lastErrorText!)")
        return
    }

    // The response contains a new access token, but we must keep
    // our existing refresh token for when we need to refresh again in the future.
    jsonToken.update("access_token", value: oauth2.accessToken)

    // Save the new JSON access token response to a file.
    // The access + refresh tokens contained in this JSON will be needed for the next refresh.
    let sbJson = CkoStringBuilder()!
    jsonToken.emitCompact = false

    jsonToken.emitSb(sbJson)
    sbJson.writeFile("qa_data/tokens/qb-access-token.json", charset: "utf-8", emitBom: false)

    print("OAuth2 token refreshed!")
    print("New Access Token = \(oauth2.accessToken!)")

}