Xbase++

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). Xbase++

LOCAL nSuccess
LOCAL oHttp
LOCAL oReq
LOCAL oResp
LOCAL oSbResponseBody
LOCAL oJResp
LOCAL nRespStatusCode
LOCAL cToken_type
LOCAL cAccess_token
LOCAL cExpires_in
LOCAL cScope

nSuccess := 0

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

oHttp := CreateObject("Chilkat.Http")

//  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.

oReq := CreateObject("Chilkat.HttpRequest")
oReq:AddParam("grant_type", "client_credentials")
//  Use your actual client ID and client secret...
oReq:AddParam("client_id", "d0394a9f-0607-40de-a978-2d3eb8375b04")
oReq:AddParam("client_secret", "6d62315e-d65a-4e41-9112-4195ea834edf")

oReq:AddHeader("posserial", "1234567899")
oReq:AddHeader("pososversion", "os")
oReq:AddHeader("posmodelframework", "1")
oReq:AddHeader("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"
oReq:HttpVerb := "POST"
oReq:ContentType := "application/x-www-form-urlencoded"

oResp := CreateObject("Chilkat.HttpResponse")
nSuccess := oHttp:HttpReq("https://invoicing.eta.gov.eg/connect/token", oReq, oResp)
IF (nSuccess == 0)
    ? oHttp:LastErrorText
    oHttp:destroy()
    oReq:destroy()
    oResp:destroy()
    RETURN
ENDIF

oSbResponseBody := CreateObject("Chilkat.StringBuilder")
oResp:GetBodySb(oSbResponseBody)

oJResp := CreateObject("Chilkat.JsonObject")
oJResp:LoadSb(oSbResponseBody)
oJResp:EmitCompact := 0

? "Response Body:"
? oJResp:Emit()

nRespStatusCode := oResp:StatusCode
? "Response Status Code = " + Str(nRespStatusCode)
IF (nRespStatusCode >= 400)
    ? "Response Header:"
    ? oResp:Header
    ? "Failed."
    oHttp:destroy()
    oReq:destroy()
    oResp:destroy()
    oSbResponseBody:destroy()
    oJResp:destroy()
    RETURN
ENDIF

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

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

cToken_type := oJResp:StringOf("token_type")
cAccess_token := oJResp:StringOf("access_token")
cExpires_in := oJResp:StringOf("expires_in")
cScope := oJResp:StringOf("scope")

oHttp:destroy()
oReq:destroy()
oResp:destroy()
oSbResponseBody:destroy()
oJResp:destroy()