Lua

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). Lua

local chilkat = require("chilkat")

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

local http = chilkat.Http.new()

-- 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.

local req = chilkat.HttpRequest.new()
req:add_param("grant_type", "client_credentials")
-- Use your actual client ID and client secret...
req:add_param("client_id", "d0394a9f-0607-40de-a978-2d3eb8375b04")
req:add_param("client_secret", "6d62315e-d65a-4e41-9112-4195ea834edf")

req:add_header("posserial", "1234567899")
req:add_header("pososversion", "os")
req:add_header("posmodelframework", "1")
req:add_header("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.http_verb = "POST"
req.content_type = "application/x-www-form-urlencoded"

local resp = chilkat.HttpResponse.new()
local success = http:http_req("https://invoicing.eta.gov.eg/connect/token", req, resp)
if not success then
    print(http.last_error_text)
    return
end

local sbResponseBody = chilkat.StringBuilder.new()
resp:get_body_sb(sbResponseBody)

local jResp = chilkat.JsonObject.new()
jResp:load_sb(sbResponseBody)
jResp.emit_compact = false

print("Response Body:")
print(jResp:emit())

local respStatusCode = resp.status_code
print("Response Status Code = " .. respStatusCode)
if respStatusCode >= 400 then
    print("Response Header:")
    print(resp.header)
    print("Failed.")
    return
end

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

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

local token_type = jResp:string_of("token_type")
local access_token = jResp:string_of("access_token")
local expires_in = jResp:string_of("expires_in")
local scope = jResp:string_of("scope")