Java

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). Chilkat2 Java

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Http;
import com.chilkatsoft.chilkat2.HttpRequest;
import com.chilkatsoft.chilkat2.HttpResponse;
import com.chilkatsoft.chilkat2.JsonObject;
import com.chilkatsoft.chilkat2.StringBuilder;

public class ChilkatExample {

    public static void main(String[] args) {
        // This example assumes the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

        Http http = new 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.

        HttpRequest req = new 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"
        req.setHttpVerb("POST");
        req.setContentType("application/x-www-form-urlencoded");

        HttpResponse resp = new HttpResponse();
        try {
            http.httpReq("https://invoicing.eta.gov.eg/connect/token", req, resp);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        StringBuilder sbResponseBody = new StringBuilder();
        resp.getBodySb(sbResponseBody);

        JsonObject jResp = new JsonObject();
        jResp.loadSb(sbResponseBody);
        jResp.setEmitCompact(false);

        System.out.println("Response Body:");
        System.out.println(jResp.emit());

        int respStatusCode = resp.getStatusCode();
        System.out.println("Response Status Code = " + respStatusCode);
        if (respStatusCode >= 400) {
            System.out.println("Response Header:");
            System.out.println(resp.getHeader());
            System.out.println("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");
    }
}