(Xojo Plugin) 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 Xojo Plugin Download Xojo Plugin for Windows, Linux, Mac OS X, and ARM, ARM64

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

Dim http As New Chilkat.Http
Dim success As Boolean

// 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.

Dim req As New Chilkat.HttpRequest
req.AddParam "grant_type","client_credentials"
// Use your actual client ID and client secret...
req.AddParam "client_id","d0394a9f-0607-40de-a978-2d3eb8375b04"
req.AddParam "client_secret","6d62315e-d65a-4e41-9112-4195ea834edf"

req.AddHeader "posserial","1234567899"
req.AddHeader "pososversion","os"
req.AddHeader "posmodelframework","1"
req.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"
Dim resp As Chilkat.HttpResponse
resp = http.PostUrlEncoded("https://invoicing.eta.gov.eg/connect/token",req)
If (http.LastMethodSuccess = False) Then
    System.DebugLog(http.LastErrorText)
    Return
End If

Dim sbResponseBody As New Chilkat.StringBuilder
success = resp.GetBodySb(sbResponseBody)

Dim jResp As New Chilkat.JsonObject
success = jResp.LoadSb(sbResponseBody)
jResp.EmitCompact = False

System.DebugLog("Response Body:")
System.DebugLog(jResp.Emit())

Dim respStatusCode As Int32
respStatusCode = resp.StatusCode
System.DebugLog("Response Status Code = " + Str(respStatusCode))
If (respStatusCode >= 400) Then
    System.DebugLog("Response Header:")
    System.DebugLog(resp.Header)
    System.DebugLog("Failed.")

    Return
End If

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

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

Dim token_type As String
token_type = jResp.StringOf("token_type")
Dim access_token As String
access_token = jResp.StringOf("access_token")
Dim expires_in As String
expires_in = jResp.StringOf("expires_in")
Dim scope As String
scope = jResp.StringOf("scope")