(DataFlex) Microsoft Graph -- Renew Expiring Access Token (Azure AD v2.0 Endpoint)

Demonstrates how to renew an expiring access token using the refresh token. This example is for renewing an access token using the Azure AD v2.0 endpoint (not the Azure AD endpoint).

An app needs to watch for the expiration of these tokens and renew the expiring access token before the refresh token expires.

This example requires Chilkat v9.5.0.67 or greater.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Use ChilkatAx-win32.pkg

Procedure Test
    Handle hoJson
    Boolean iSuccess
    Handle hoDtExpire
    Variant vReq
    Handle hoReq
    Handle hoHttp
    Variant vResp
    Handle hoResp
    Handle hoFac
    String sTemp1
    Integer iTemp1
    Boolean bTemp1

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

    // We previously obtained an access token and saved the JSON to a file using this example:
    // Get Access Token using Azure AD v2.0 Endpoint

    // This example will examine the JSON and expiration date, and if near expiration will
    // refresh the access token.

    Get Create (RefClass(cComChilkatJsonObject)) To hoJson
    If (Not(IsComObjectCreated(hoJson))) Begin
        Send CreateComObject of hoJson
    End
    Get ComLoadFile Of hoJson "qa_data/tokens/microsoftGraph.json" To iSuccess
    If (iSuccess <> True) Begin
        Procedure_Return
    End

    // The contents of the JSON look like this:
    // {
    //   "token_type": "Bearer",
    //   "scope": "User.Read Mail.ReadWrite Mail.Send",
    //   "expires_in": 3600,
    //   "ext_expires_in": 0,
    //   "access_token": "EwBAA8l6B...",
    //   "refresh_token": "MCRMdbe6Cd...",
    //   "id_token": "eyJ0eXAiOiJ...",
    //   "expires_on": "1494112119"
    // }

    // The "expires_on" value is a Unix time.
    Get Create (RefClass(cComCkDateTime)) To hoDtExpire
    If (Not(IsComObjectCreated(hoDtExpire))) Begin
        Send CreateComObject of hoDtExpire
    End
    Get ComIntOf Of hoJson "expires_on" To iTemp1
    Get ComSetFromUnixTime Of hoDtExpire False iTemp1 To iSuccess

    // If this date/time expires within 10 minutes of the current system time, refresh the token.
    Get ComExpiresWithin Of hoDtExpire 10 "minutes" To bTemp1
    If (bTemp1 <> True) Begin
        Showln "No need to refresh, the access token won't expire within the next 10 minutes."
        Procedure_Return
    End

    // OK, we need to refresh the access token by sending a POST like this:
    // 

    // 	POST https://login.microsoftonline.com/common/oauth2/v2.0/token HTTP/1.1
    // 	Host: login.microsoftonline.com
    // 	Content-Type: application/x-www-form-urlencoded
    // 	Content-Length: ***
    // 
    // 	grant_type=refresh_token
    // 	&redirect_uri=http%3A%2F%2Flocalhost%3A3017%2F
    // 	&client_id=8b8539cd-7b75-427f-bef1-4a6264fd4940
    // 	&client_secret=PJW3dznGfyNSm3rM9aHeXWGKsTMepKXT1Eqy45XXdU4%3D
    // 	&refresh_token=AAABAAAAvPM1KaPlrEqdFSBzjqfTGM74--...

    Get Create (RefClass(cComChilkatHttpRequest)) To hoReq
    If (Not(IsComObjectCreated(hoReq))) Begin
        Send CreateComObject of hoReq
    End
    Send ComAddParam To hoReq "grant_type" "refresh_token"
    Send ComAddParam To hoReq "redirect_uri" "http://localhost:3017/"
    Send ComAddParam To hoReq "client_id" "MICROSOFT-GRAPH-CLIENT-ID"
    Send ComAddParam To hoReq "client_secret" "MICROSOFT-GRAPH-CLIENT-SECRET"
    Get ComStringOf Of hoJson "refresh_token" To sTemp1
    Send ComAddParam To hoReq "refresh_token" sTemp1

    Get Create (RefClass(cComChilkatHttp)) To hoHttp
    If (Not(IsComObjectCreated(hoHttp))) Begin
        Send CreateComObject of hoHttp
    End

    Get pvComObject of hoReq to vReq
    Get ComPostUrlEncoded Of hoHttp "https://login.microsoftonline.com/common/oauth2/v2.0/token" vReq To vResp
    If (IsComObject(vResp)) Begin
        Get Create (RefClass(cComChilkatHttpResponse)) To hoResp
        Set pvComObject Of hoResp To vResp
    End
    Get ComLastMethodSuccess Of hoHttp To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoHttp To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Load the JSON response.
    Get ComBodyStr Of hoResp To sTemp1
    Get ComLoad Of hoJson sTemp1 To iSuccess
    Set ComEmitCompact Of hoJson To False

    // Show the JSON response.
    Get ComEmit Of hoJson To sTemp1
    Showln sTemp1

    Get ComStatusCode Of hoResp To iTemp1
    Showln "Response status code: " iTemp1

    // If the response status code is not 200, then it's an error.
    Get ComStatusCode Of hoResp To iTemp1
    If (iTemp1 <> 200) Begin
        Procedure_Return
    End

    Send Destroy of hoResp

    // If an "expires_on" member does not exist, then add the JSON member by
    // getting the current system date/time and adding the "expires_in" seconds.
    // This way we'll know when the token expires.
    Get ComHasMember Of hoJson "expires_on" To bTemp1
    If (bTemp1 <> True) Begin
        Get ComSetFromCurrentSystemTime Of hoDtExpire To iSuccess
        Get ComIntOf Of hoJson "expires_in" To iTemp1
        Get ComAddSeconds Of hoDtExpire iTemp1 To iSuccess
        Get ComGetAsUnixTimeStr Of hoDtExpire False To sTemp1
        Get ComAppendString Of hoJson "expires_on" sTemp1 To iSuccess
    End

    // Save the refreshed access token JSON to a file for future requests.
    Get Create (RefClass(cComCkFileAccess)) To hoFac
    If (Not(IsComObjectCreated(hoFac))) Begin
        Send CreateComObject of hoFac
    End
    Get ComEmit Of hoJson To sTemp1
    Get ComWriteEntireTextFile Of hoFac "qa_data/tokens/microsoftGraph.json" sTemp1 "utf-8" False To iSuccess


End_Procedure