(C) Azure AD Service-to-service access token request

Send an Azure AD service-to-service token request to get an access token using a shared secret.

For more information, see https://docs.microsoft.com/en-us/azure/active-directory/develop/v1-oauth2-client-creds-grant-flow#service-to-service-access-token-request

Chilkat C/C++ Library Downloads
MS Visual C/C++ Linux/CentOS C/C++ Alpine Linux C/C++ MAC OS X C/C++	armhf/aarch64 C/C++ C++ Builder iOS C/C++ Android C/C++	Solaris C/C++ MinGW C/C++

#include <C_CkHttp.h>
#include <C_CkHttpRequest.h>
#include <C_CkHttpResponse.h>
#include <C_CkJsonObject.h>

void ChilkatSample(void)
    {
    HCkHttp http;
    HCkHttpRequest req;
    HCkHttpResponse resp;
    int respStatusCode;
    HCkJsonObject json;
    const char *token_type;
    const char *expires_in;
    const char *ext_expires_in;
    const char *expires_on;
    const char *not_before;
    const char *resource;
    const char *access_token;

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

    http = CkHttp_Create();

    // To see the exact HTTP request sent and the response, set the SessionLogFilename property:
    CkHttp_putSessionLogFilename(http,"qa_output/chilkatHttpLog.txt");

    req = CkHttpRequest_Create();

    // Set the following request params:
    // grant_type 	required 	Specifies the requested grant type. In a Client Credentials Grant flow, the value must be client_credentials.
    // 
    // client_id 	required 	Specifies the Azure AD client id of the calling web service. 
    //     To find the calling application's client ID, in the Azure portal, click Azure Active Directory, click App registrations, click the application. 
    //     The client_id is the Application ID
    // 
    // client_secret 	required 	Enter a key registered for the calling web service or daemon application in Azure AD. 
    //     To create a key, in the Azure portal, click Azure Active Directory, click App registrations, click the application, click Settings, click Keys, and add a Key.
    //     URL-encode this secret when providing it.
    // 
    // resource 	required 	Enter the App ID URI of the receiving web service. To find the App ID URI, in the Azure portal, click Azure Active Directory, 
    //     click App registrations, click the service application, and then click Settings and Properties.

    CkHttpRequest_AddParam(req,"grant_type","client_credentials");
    CkHttpRequest_AddParam(req,"client_id","MY_CLIENT_ID");
    CkHttpRequest_AddParam(req,"client_secret","MY_CLIENT_SECRET");
    CkHttpRequest_AddParam(req,"resource","https://service.contoso.com/");

    // The URL passed to PostUrlEncoded has this form:   https://login.microsoftonline.com/<tenant_id>/oauth2/token
    resp = CkHttp_PostUrlEncoded(http,"https://login.microsoftonline.com/<tenant_id>/oauth2/token",req);
    if (CkHttp_getLastMethodSuccess(http) == FALSE) {
        printf("%s\n",CkHttp_lastErrorText(http));
        CkHttp_Dispose(http);
        CkHttpRequest_Dispose(req);
        return;
    }

    respStatusCode = CkHttpResponse_getStatusCode(resp);
    printf("Response Status Code = %d\n",respStatusCode);

    json = CkJsonObject_Create();
    CkJsonObject_putEmitCompact(json,FALSE);
    CkJsonObject_Load(json,CkHttpResponse_bodyStr(resp));
    printf("Response JSON:\n");
    printf("%s\n",CkJsonObject_emit(json));

    if (respStatusCode >= 400) {
        printf("Response Header:\n");
        printf("%s\n",CkHttpResponse_header(resp));
        printf("Failed.\n");
        CkHttpResponse_Dispose(resp);
        CkHttp_Dispose(http);
        CkHttpRequest_Dispose(req);
        CkJsonObject_Dispose(json);
        return;
    }

    // Sample response:

    // {
    //   "token_type": "Bearer",
    //   "expires_in": "3599",
    //   "ext_expires_in": "3599",
    //   "expires_on": "1570059833",
    //   "not_before": "1570055933",
    //   "resource": "https://adminchilkatsoft.onmicrosoft.com/eb1b8ced-76b7-4845-aec5-d3e91776e345",
    //   "access_token": "eyJ0eXAiO ... pmgw"
    // }

    // To get the items from the JSON....
    token_type = CkJsonObject_stringOf(json,"token_type");
    expires_in = CkJsonObject_stringOf(json,"expires_in");
    ext_expires_in = CkJsonObject_stringOf(json,"ext_expires_in");
    expires_on = CkJsonObject_stringOf(json,"expires_on");
    not_before = CkJsonObject_stringOf(json,"not_before");
    resource = CkJsonObject_stringOf(json,"resource");
    access_token = CkJsonObject_stringOf(json,"access_token");

    CkHttpResponse_Dispose(resp);


    CkHttp_Dispose(http);
    CkHttpRequest_Dispose(req);
    CkJsonObject_Dispose(json);

    }