(Mono C#) 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/

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

Chilkat.Http http = new Chilkat.Http();
bool success;

// 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.

Chilkat.HttpRequest req = 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"
Chilkat.HttpResponse resp = http.PostUrlEncoded("https://invoicing.eta.gov.eg/connect/token",req);
if (http.LastMethodSuccess == false) {
    Debug.WriteLine(http.LastErrorText);
    return;
}

Chilkat.StringBuilder sbResponseBody = new Chilkat.StringBuilder();
resp.GetBodySb(sbResponseBody);

Chilkat.JsonObject jResp = new Chilkat.JsonObject();
jResp.LoadSb(sbResponseBody);
jResp.EmitCompact = false;

Debug.WriteLine("Response Body:");
Debug.WriteLine(jResp.Emit());

int respStatusCode = resp.StatusCode;
Debug.WriteLine("Response Status Code = " + Convert.ToString(respStatusCode));
if (respStatusCode >= 400) {
    Debug.WriteLine("Response Header:");
    Debug.WriteLine(resp.Header);
    Debug.WriteLine("Failed.");

    return;
}

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

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

string token_type = jResp.StringOf("token_type");
string access_token = jResp.StringOf("access_token");
string expires_in = jResp.StringOf("expires_in");
string scope = jResp.StringOf("scope");