Tcl

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). Tcl

load ./chilkat.dll

set success 0

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

set http [new_CkHttp]

# 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.

set req [new_CkHttpRequest]

CkHttpRequest_AddParam $req "grant_type" "client_credentials"
# Use your actual client ID and client secret...
CkHttpRequest_AddParam $req "client_id" "d0394a9f-0607-40de-a978-2d3eb8375b04"
CkHttpRequest_AddParam $req "client_secret" "6d62315e-d65a-4e41-9112-4195ea834edf"

CkHttpRequest_AddHeader $req "posserial" "1234567899"
CkHttpRequest_AddHeader $req "pososversion" "os"
CkHttpRequest_AddHeader $req "posmodelframework" "1"
CkHttpRequest_AddHeader $req "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"
CkHttpRequest_put_HttpVerb $req "POST"
CkHttpRequest_put_ContentType $req "application/x-www-form-urlencoded"

set resp [new_CkHttpResponse]

set success [CkHttp_HttpReq $http "https://invoicing.eta.gov.eg/connect/token" $req $resp]
if {$success == 0} then {
    puts [CkHttp_lastErrorText $http]
    delete_CkHttp $http
    delete_CkHttpRequest $req
    delete_CkHttpResponse $resp
    exit
}

set sbResponseBody [new_CkStringBuilder]

CkHttpResponse_GetBodySb $resp $sbResponseBody

set jResp [new_CkJsonObject]

CkJsonObject_LoadSb $jResp $sbResponseBody
CkJsonObject_put_EmitCompact $jResp 0

puts "Response Body:"
puts [CkJsonObject_emit $jResp]

set respStatusCode [CkHttpResponse_get_StatusCode $resp]
puts "Response Status Code = $respStatusCode"
if {$respStatusCode >= 400} then {
    puts "Response Header:"
    puts [CkHttpResponse_header $resp]
    puts "Failed."
    delete_CkHttp $http
    delete_CkHttpRequest $req
    delete_CkHttpResponse $resp
    delete_CkStringBuilder $sbResponseBody
    delete_CkJsonObject $jResp
    exit
}

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

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

set token_type [CkJsonObject_stringOf $jResp "token_type"]
set access_token [CkJsonObject_stringOf $jResp "access_token"]
set expires_in [CkJsonObject_stringOf $jResp "expires_in"]
set scope [CkJsonObject_stringOf $jResp "scope"]

delete_CkHttp $http
delete_CkHttpRequest $req
delete_CkHttpResponse $resp
delete_CkStringBuilder $sbResponseBody
delete_CkJsonObject $jResp