(DataFlex) Egyptian eReceipt OAuth2 Client Credentials

See more Egypt eReceipt Examples

Get an OAuth2 access token for the Egyptian eReceipt REST API using client credentials (no interactivity with a web browser required).

For more information, see https://sdk.invoicing.eta.gov.eg/ereceiptapi/01-authenticate-pos/

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

Use ChilkatAx-win32.pkg

Procedure Test
    Handle hoHttp
    Boolean iSuccess
    Variant vReq
    Handle hoReq
    Variant vResp
    Handle hoResp
    Variant vSbResponseBody
    Handle hoSbResponseBody
    Handle hoJResp
    Integer iRespStatusCode
    String sToken_type
    String sAccess_token
    String sExpires_in
    String sScope
    String sTemp1
    Boolean bTemp1

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

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

    // Note: Any provider of a REST API, such as the Egyptian government in this case, can make life 
    // much easier for developers by providing one or more of the following in the API documentation:
    // 
    // 1) A sample CURL statement for each API call.
    // 2) A Postman collection, or Swagger/OpenAPI specification file.
    // 3) A sample of a raw HTTP request and response for each API call.
    // 
    // The sample CURL statements or raw HTTP request/responses do not need to comprehensively show all 
    // possible options.  Providing a sample allows one to quickly make a successful API call.
    // It also allows for code generation directly from the CURL, Postman collection, or raw request/response,
    // and it tends to answer all questions about the format/structure of a request that, suprisingly,
    // remain ambiguous or not obvious in other forms of documentation.

    Get Create (RefClass(cComChilkatHttpRequest)) To hoReq
    If (Not(IsComObjectCreated(hoReq))) Begin
        Send CreateComObject of hoReq
    End
    Send ComAddParam To hoReq "grant_type" "client_credentials"
    // Use your actual client ID and client secret...
    Send ComAddParam To hoReq "client_id" "d0394a9f-0607-40de-a978-2d3eb8375b04"
    Send ComAddParam To hoReq "client_secret" "6d62315e-d65a-4e41-9112-4195ea834edf"

    Send ComAddHeader To hoReq "posserial" "1234567899"
    Send ComAddHeader To hoReq "pososversion" "os"
    Send ComAddHeader To hoReq "posmodelframework" "1"
    Send ComAddHeader To hoReq "presharedkey" "03ac674216f3e1..."

    // When writing this example, the documentation at https://sdk.invoicing.eta.gov.eg/ereceiptapi/01-authenticate-pos/
    // shows us the HTTP verb and path (POST /connect/token), however,
    // we don't see the actual domain where the request is to be sent.
    // What are the endpoints???
    // It took some searching, but we found some endpoints here:  https://sdk.invoicing.eta.gov.eg/faq/
    // It's not immediately apparent which endpoint is to be used with a given API call.
    // Why not just include the endpoint in the documentation for each REST API call?
    // Endpoints are literally the #1 thing that needs to be known.
    // They can't just be buried in a FAQ.  They should be up-front and obvious.
    // 
    // So.. we're guessing the endpoint is likely "https://invoicing.eta.gov.eg/connect/token"
    Get pvComObject of hoReq to vReq
    Get ComPostUrlEncoded Of hoHttp "https://invoicing.eta.gov.eg/connect/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 = False) Begin
        Get ComLastErrorText Of hoHttp To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get Create (RefClass(cComChilkatStringBuilder)) To hoSbResponseBody
    If (Not(IsComObjectCreated(hoSbResponseBody))) Begin
        Send CreateComObject of hoSbResponseBody
    End
    Get pvComObject of hoSbResponseBody to vSbResponseBody
    Get ComGetBodySb Of hoResp vSbResponseBody To iSuccess

    Get Create (RefClass(cComChilkatJsonObject)) To hoJResp
    If (Not(IsComObjectCreated(hoJResp))) Begin
        Send CreateComObject of hoJResp
    End
    Get pvComObject of hoSbResponseBody to vSbResponseBody
    Get ComLoadSb Of hoJResp vSbResponseBody To iSuccess
    Set ComEmitCompact Of hoJResp To False

    Showln "Response Body:"
    Get ComEmit Of hoJResp To sTemp1
    Showln sTemp1

    Get ComStatusCode Of hoResp To iRespStatusCode
    Showln "Response Status Code = " iRespStatusCode
    If (iRespStatusCode >= 400) Begin
        Showln "Response Header:"
        Get ComHeader Of hoResp To sTemp1
        Showln sTemp1
        Showln "Failed."
        Send Destroy of hoResp
        Procedure_Return
    End

    Send Destroy of hoResp

    // If successful, the OAuth2 access token JSON looks like this:

    // {
    //   "token_type": "Bearer",
    //   "access_token": "eyJraW......R2sbqrY",
    //   "expires_in": "3600",
    //   "scope": "..."
    // }

    Get ComStringOf Of hoJResp "token_type" To sToken_type
    Get ComStringOf Of hoJResp "access_token" To sAccess_token
    Get ComStringOf Of hoJResp "expires_in" To sExpires_in
    Get ComStringOf Of hoJResp "scope" To sScope


End_Procedure