(MFC) Decode Microsoft Graph ID Token

Demonstrates how to decode a Microsoft Graph ID token.

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkJsonObject.h>
#include <CkJwt.h>

void ChilkatSample(void)
    {
    CkString strOut;

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

    // In a previous example, we obtained a Microsoft Graph OAuth2 access token.
    // This example loads the JSON saved from the previous example and decodes the id_token.

    // Our Microsoft Graph OAuth2 token looks like this:

    // {
    //   "token_type": "Bearer",
    //   "scope": "openid profile User.ReadWrite Mail.ReadWrite Mail.Send Files.ReadWrite User.Read Calendars.ReadWrite Group.ReadWrite.All",
    //   "expires_in": 3600,
    //   "ext_expires_in": 3600,
    //   "access_token": "EwCQA8l6...0HhMKYwC",
    //   "refresh_token": "MCWulIvzi2yD0S...igEFn51mqcByhZtAJg",
    //   "id_token": "eyJ0eXAiOiJKV1...Q7lRDaR-7A",
    //   "expires_on": "1562862714"
    // }

    CkJsonObject jsonToken;
    bool success = jsonToken.LoadFile("qa_data/tokens/microsoftGraph.json");
    if (success == false) {
        strOut.append("Failed to load the JSON file...");
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Use Chilkat's JWT API to examine the id_token..
    CkJwt jwt;
    const char *idToken = jsonToken.stringOf("id_token");

    // Extract the JOSE header..
    const char *jose = jwt.getHeader(idToken);

    CkJsonObject jsonHeader;
    jsonHeader.Load(jose);
    jsonHeader.put_EmitCompact(false);
    strOut.append(jsonHeader.emit());
    strOut.append("\r\n");

    // The JOSE header looks like this:

    // {
    //   "typ": "JWT",
    //   "alg": "RS256",
    //   "kid": "1LTMzakihiRla_8z2BEJVXeWMqo"
    // }

    const char *claims = jwt.getPayload(idToken);

    CkJsonObject jsonClaims;
    jsonClaims.Load(claims);
    jsonClaims.put_EmitCompact(false);
    strOut.append(jsonClaims.emit());
    strOut.append("\r\n");

    // The claims look like this:

    // {
    //   "ver": "2.0",
    //   "iss": "https://login.microsoftonline.com/9188040d-6c67-4c5b-b112-36a304b66dad/v2.0",
    //   "sub": "AAAAAAAAAAAAAAAAAAAAAHJFryd6Gydo-XtTd1nhUNQ",
    //   "aud": "18c456bd-db75-43fe-9724-9e5d821c68ff",
    //   "exp": 1562945513,
    //   "iat": 1562858813,
    //   "nbf": 1562858813,
    //   "name": "Matt Chilkat",
    //   "preferred_username": "matt@example.com",
    //   "oid": "00000000-0000-0000-3a33-fceb9b74cc15",
    //   "tid": "9188040d-6c67-4c5b-b112-36a304b66dad",
    //   "aio": "DfibJqKnWC1c0FS6G ... W6pvTrQuYzyq16ghY$"
    // }
    // 

    // Use this online tool to generate parsing code from sample JSON: 
    // Generate Parsing Code from JSON

    // Get each of the claims..
    const char *ver = jsonClaims.stringOf("ver");
    const char *iss = jsonClaims.stringOf("iss");
    const char *sub = jsonClaims.stringOf("sub");
    const char *aud = jsonClaims.stringOf("aud");
    int exp = jsonClaims.IntOf("exp");
    int iat = jsonClaims.IntOf("iat");
    int nbf = jsonClaims.IntOf("nbf");
    const char *name = jsonClaims.stringOf("name");
    const char *preferred_username = jsonClaims.stringOf("preferred_username");
    const char *oid = jsonClaims.stringOf("oid");
    const char *tid = jsonClaims.stringOf("tid");
    const char *aio = jsonClaims.stringOf("aio");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }