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Delphi DLL

Azure OpenID Connect Step 2 -- Get id_token and Validate

See more OIDC Examples

After getting the endpoints by querying the Azure's OIDC well-known discovery document (OpenID Configuration document), we use the authorization_endpoint to get the id_token, and then validate it..

Chilkat Delphi DLL Downloads

Delphi DLL
uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Http, Jwt, Hashtable, Prng, Socket, OAuth2, StringBuilder, JsonObject, PublicKey, HttpRequest, Task;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
authorization_endpoint: PWideChar;
jwks_uri: PWideChar;
req: HCkHttpRequest;
prng: HCkPrng;
encodedParams: PWideChar;
sbUrl: HCkStringBuilder;
url: PWideChar;
listenSock: HCkSocket;
browserSock: HCkSocket;
backLog: Integer;
maxWaitMs: Integer;
task: HCkTask;
oauth2: HCkOAuth2;
startLine: PWideChar;
requestHeader: PWideChar;
sbRequestBody: HCkStringBuilder;
sbResponseHtml: HCkStringBuilder;
sbResponse: HCkStringBuilder;
hashTab: HCkHashtable;
idToken: PWideChar;
jwt: HCkJwt;
leeway: Integer;
bTimeValid: Boolean;
payload: PWideChar;
json: HCkJsonObject;
joseHeader: PWideChar;
jsonJoseHeader: HCkJsonObject;
sbJwks: HCkStringBuilder;
http: HCkHttp;
jwkset: HCkJsonObject;
kid: PWideChar;
jwk: HCkJsonObject;
verified: Boolean;
pubkey: HCkPublicKey;

begin
success := False;

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

// In our previous example (Azure Fetch OpenID Connect metadata document) we fetched
// the OpenID configuration document which is JSON which contains an entry for authorization_endpoint.

authorization_endpoint := 'https://login.microsoftonline.com/{tenant}/oauth2/v2.0/authorize';

// The OpenID Connect metadata document also contained a jwks_uri entry.  This is the JSON Web Key Set (JWKS),
// which is a set of keys containing the public keys used to verify any JSON Web Token (JWT) (in this case the id_token)
// issued by the authorization server and signed using the RS256 signing algorithm. 
jwks_uri := 'https://login.microsoftonline.com/{tenant}/discovery/v2.0/keys';

// We're going to send the following GET request, but it will be sent through an interactive web browser (not by Chilkat).
// The following code will form the URL that is to be programmatically loaded and sent in a browser.

// GET https://login.microsoftonline.com/{tenant}/oauth2/v2.0/authorize?
// client_id=6731de76-14a6-49ae-97bc-6eba6914391e
// &response_type=id_token
// &redirect_uri=http%3A%2F%2Flocalhost%2Fmyapp%2F
// &response_mode=form_post
// &scope=openid
// &state=12345
// &nonce=678910

// Use this object to set params and then get the URL-encoded query params string 
req := CkHttpRequest_Create();
CkHttpRequest_AddParam(req,'client_id','{client_id}');
CkHttpRequest_AddParam(req,'response_type','id_token');
CkHttpRequest_AddParam(req,'redirect_uri','http://localhost:3017/');
CkHttpRequest_AddParam(req,'response_mode','form_post');
CkHttpRequest_AddParam(req,'scope','openid');
prng := CkPrng_Create();
CkHttpRequest_AddParam(req,'state',CkPrng__genRandom(prng,3,'decimal'));
CkHttpRequest_AddParam(req,'nonce',CkPrng__genRandom(prng,4,'decimal'));

encodedParams := CkHttpRequest__getUrlEncodedParams(req);
Memo1.Lines.Add(encodedParams);

// Sample URL encoded params:
// client_id=6731de76-14a6-49ae-97bc-6eba6914391e&redirect_uri=http%3A%2F%2Flocalhost%3A3017%2F&response_mode=form_post&scope=openid&state=3572902&nonce=57352474

// This is the URL to be programmatically loaded and sent in an interactive web browser..
sbUrl := CkStringBuilder_Create();
CkStringBuilder_Append(sbUrl,authorization_endpoint);
CkStringBuilder_Append(sbUrl,'?');
CkStringBuilder_Append(sbUrl,encodedParams);
url := CkStringBuilder__getAsString(sbUrl);

// Before we launch the browser with the contents of sbUrl, create a socket to listen for the eventual callback..

listenSock := CkSocket_Create();

// This is the connection received from the browser.
browserSock := CkSocket_Create();

// Listen at the port indicated by the redirect_uri above.
backLog := 5;
success := CkSocket_BindAndListen(listenSock,3017,backLog);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(listenSock));
    Exit;
  end;

// Wait for the browser's connection in a background thread.
// (We'll send load the URL into the browser following this..)
// Wait a max of 60 seconds before giving up.
maxWaitMs := 30000;
task := CkSocket_AcceptNextAsync(listenSock,maxWaitMs,browserSock);
CkTask_Run(task);

// -------------------------------------------------------------------
// At this point, your application should load the URL in a browser.
oauth2 := CkOAuth2_Create();
success := CkOAuth2_LaunchBrowser(oauth2,url);
if (success = False) then
  begin
    Memo1.Lines.Add(CkOAuth2__lastErrorText(oauth2));
    Exit;
  end;
// -------------------------------------------------------------------

// Wait for the listenSock's task to complete.
success := CkTask_Wait(task,maxWaitMs);
if (not success or (CkTask_getStatusInt(task) <> 7) or (CkTask_getTaskSuccess(task) <> True)) then
  begin
    if (not success) then
      begin
        // The task.LastErrorText applies to the Wait method call.
        Memo1.Lines.Add(CkTask__lastErrorText(task));
      end
    else
      begin
        // The ResultErrorText applies to the underlying task method call (i.e. the AcceptNextConnection)
        Memo1.Lines.Add(CkTask__status(task));
        Memo1.Lines.Add(CkTask__resultErrorText(task));
      end;
    CkTask_Dispose(task);
    Exit;
  end;

// If we get to this point, a connection on listenSock was accepted, and the redirected POST
// is waiting to be read on the connected socket.
// The POST we are going to read contains the following:

// POST /myapp/ HTTP/1.1
// Host: localhost
// Content-Type: application/x-www-form-urlencoded
// 
// id_token=eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsIng1dCI6Ik1uQ19WWmNB...&state=12345

// But first.. we no longer need the listen socket...
// Stop listening on port 3017.
CkSocket_Close(listenSock,10);

CkTask_Dispose(task);

// We're acting as a temporary web server to receive this one redirected HTTP request..
// Read the start line of the request.. (i.e. the "POST /myapp/ HTTP/1.1")
startLine := CkSocket__receiveUntilMatch(browserSock,#13#10);
if (CkSocket_getLastMethodSuccess(browserSock) = False) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(browserSock));
    Exit;
  end;

// Read the request header.
requestHeader := CkSocket__receiveUntilMatch(browserSock,#13#10 + #13#10);
if (CkSocket_getLastMethodSuccess(browserSock) = False) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(browserSock));
    Exit;
  end;

Memo1.Lines.Add(requestHeader);
Memo1.Lines.Add('----');

// Read the body.
// The body will contain "id_token= eyJ......"
sbRequestBody := CkStringBuilder_Create();
success := CkSocket_ReceiveSb(browserSock,sbRequestBody);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(browserSock));
    Exit;
  end;

Memo1.Lines.Add(CkStringBuilder__getAsString(sbRequestBody));

// Given that we're acting as a web server, we must send a response..
// We can now send our HTTP response.
sbResponseHtml := CkStringBuilder_Create();
CkStringBuilder_Append(sbResponseHtml,'<html><body><p>Thank you!</b></body</html>');

sbResponse := CkStringBuilder_Create();
CkStringBuilder_Append(sbResponse,'HTTP/1.1 200 OK' + #13#10);
CkStringBuilder_Append(sbResponse,'Content-Length: ');
CkStringBuilder_AppendInt(sbResponse,CkStringBuilder_getLength(sbResponseHtml));
CkStringBuilder_Append(sbResponse,#13#10);
CkStringBuilder_Append(sbResponse,'Content-Type: text/html' + #13#10);
CkStringBuilder_Append(sbResponse,#13#10);
CkStringBuilder_AppendSb(sbResponse,sbResponseHtml);

CkSocket_SendString(browserSock,CkStringBuilder__getAsString(sbResponse));
CkSocket_Close(browserSock,50);

// Get the id_token from the sbRequestBody that we just received.
// (Remember, we're acting as the web server, thus we received the redirect request..)
hashTab := CkHashtable_Create();
CkHashtable_AddQueryParams(hashTab,CkStringBuilder__getAsString(sbRequestBody));

// See https://docs.microsoft.com/en-us/azure/active-directory/develop/id-tokens#validating-an-id-token
// for more information about ID tokens..
idToken := CkHashtable__lookupStr(hashTab,'id_token');

jwt := CkJwt_Create();

// Let's see if the time constraints, if any, are valid.
// The above JWT was created on the afternoon of 16-May-2016, with an expiration of 1 hour.
// If the current system time is before the "nbf" time, or after the "exp" time,
// then IsTimeValid will return false/0.
// Also, we'll allow a leeway of 60 seconds to account for any clock skew.
// Note: If the token has no "nbf" or "exp" claim fields, then IsTimeValid is always true.
leeway := 60;
bTimeValid := CkJwt_IsTimeValid(jwt,idToken,leeway);
Memo1.Lines.Add('time constraints valid: ' + IntToStr(Ord(bTimeValid)));

// Now let's recover the original claims JSON (the payload).
payload := CkJwt__getPayload(jwt,idToken);
// The payload will likely be in compact form:
Memo1.Lines.Add(payload);

// We can format for human viewing by loading it into Chilkat's JSON object
// and emit.
json := CkJsonObject_Create();
success := CkJsonObject_Load(json,payload);
CkJsonObject_putEmitCompact(json,False);
Memo1.Lines.Add(CkJsonObject__emit(json));

// Sample output:

// {
//   "aud": "f125d695-c50e-456e-a579-a486f06d1213",
//   "iss": "https://login.microsoftonline.com/6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd/v2.0",
//   "iat": 1626535322,
//   "nbf": 1626535322,
//   "exp": 1626539222,
//   "aio": "AWQAm/8TAAAAHQncmY0VvhgyMIhfleHX3DjsGfmlPM1CopkJ3mPnBUnCxrJ0ubruaACEhwGO7NsoHBhqFEzRzPxOq7MtuGVFsql+qJKZx8vQCszKYEPX9Wb3b5+d5KJTABHCIH48bTFd",
//   "idp": "https://sts.windows.net/9188040d-6c67-4c5b-b112-36a304b66dad/",
//   "nonce": "1519043321",
//   "rh": "0.ARgAZt2NbdFosEOvXOMbS33VzZXWJfEOxW5FpXmkhvBtEhMYALQ.",
//   "sub": "RMIZlHJ7hfsJmL8Qq3h6M0nPi4g-HEavnAFgxzaT2KM",
//   "tid": "6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd",
//   "uti": "-BXGHxvfREW-r9HI5NBiAA",
//   "ver": "2.0"
// }

// We can recover the original JOSE header in the same way:
joseHeader := CkJwt__getHeader(jwt,idToken);
// The payload will likely be in compact form:
Memo1.Lines.Add(joseHeader);

// We can format for human viewing by loading it into Chilkat's JSON object
// and emit.
jsonJoseHeader := CkJsonObject_Create();
success := CkJsonObject_Load(jsonJoseHeader,joseHeader);
CkJsonObject_putEmitCompact(jsonJoseHeader,False);
Memo1.Lines.Add(CkJsonObject__emit(jsonJoseHeader));

// Sample output:

// {
//   "typ": "JWT",
//   "alg": "RS256",
//   "kid": "nOo3ZDrODXEK1jKWhXslHR_KXEg"
// }

// Finally, we need to fetch the JSON Web Key Sets from the jwks_uri
// and use it to verify the id_token's RSA signature.
sbJwks := CkStringBuilder_Create();
http := CkHttp_Create();
success := CkHttp_QuickGetSb(http,jwks_uri,sbJwks);
if (success = False) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

jwkset := CkJsonObject_Create();
success := CkJsonObject_LoadSb(jwkset,sbJwks);
CkJsonObject_putEmitCompact(jwkset,False);
Memo1.Lines.Add(CkJsonObject__emit(jwkset));

// A sample jwkset:

// {
//   "keys": [
//     {
//       "kty": "RSA",
//       "use": "sig",
//       "kid": "nOo3ZDrODXEK1jKWhXslHR_KXEg",
//       "x5t": "nOo3ZDrODXEK1jKWhXslHR_KXEg",
//       "n": "oaLLT9hkcSj ... NVrZdUdTBQ",
//       "e": "AQAB",
//       "x5c": [
//         "MIIDBTC ... MRku44Dw7R"
//       ],
//       "issuer": "https://login.microsoftonline.com/6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd/v2.0"
//     },
//     {
//       "kty": "RSA",
//       "use": "sig",
//       "kid": "l3sQ-50cCH4xBVZLHTGwnSR7680",
//       "x5t": "l3sQ-50cCH4xBVZLHTGwnSR7680",
//       "n": "sfsXMXW ... AYkwb6xUQ",
//       "e": "AQAB",
//       "x5c": [
//         "MIIDBTCCA ... BWrh+/vJ"
//       ],
//       "issuer": "https://login.microsoftonline.com/6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd/v2.0"
//     },
//     {
//       "kty": "RSA",
//       "use": "sig",
//       "kid": "DqUu8gf-nAgcyjP3-SuplNAXAnc",
//       "x5t": "DqUu8gf-nAgcyjP3-SuplNAXAnc",
//       "n": "1n7-nWSL ... V3pFWhQ",
//       "e": "AQAB",
//       "x5c": [
//         "MIIC8TC ... 9pIcnkPQ=="
//       ],
//       "issuer": "https://login.microsoftonline.com/6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd/v2.0"
//     },
//     {
//       "kty": "RSA",
//       "use": "sig",
//       "kid": "OzZ5Dbmcso9Qzt2ModGmihg30Bo",
//       "x5t": "OzZ5Dbmcso9Qzt2ModGmihg30Bo",
//       "n": "01re9a2BU ... 5OzQ6Q",
//       "e": "AQAB",
//       "x5c": [
//         "MIIC8TC ... YmwJ6sDdRvQ=="
//       ],
//       "issuer": "https://login.microsoftonline.com/6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd/v2.0"
//     }
//   ]
// }

// We should have an RSA key with kid matching the kid from the joseHeader..
kid := CkJsonObject__stringOf(jsonJoseHeader,'kid');

// Find the RSA key with the specified key id
jwk := CkJsonObject_FindRecord(jwkset,'keys','kid',kid,True);
if (CkJsonObject_getLastMethodSuccess(jwkset) = False) then
  begin
    Memo1.Lines.Add('Failed to find a matching RSA key in the JWK key set...');
    Exit;
  end;

pubkey := CkPublicKey_Create();

success := CkPublicKey_LoadFromString(pubkey,CkJsonObject__emit(jwk));
if (success = False) then
  begin
    Memo1.Lines.Add(CkPublicKey__lastErrorText(pubkey));
    Memo1.Lines.Add(CkJsonObject__emit(jwk));
  end
else
  begin
    verified := CkJwt_VerifyJwtPk(jwt,idToken,pubkey);
    Memo1.Lines.Add('Verified: ' + IntToStr(Ord(verified)));
  end;

CkJsonObject_Dispose(jwk);

CkHttpRequest_Dispose(req);
CkPrng_Dispose(prng);
CkStringBuilder_Dispose(sbUrl);
CkSocket_Dispose(listenSock);
CkSocket_Dispose(browserSock);
CkOAuth2_Dispose(oauth2);
CkStringBuilder_Dispose(sbRequestBody);
CkStringBuilder_Dispose(sbResponseHtml);
CkStringBuilder_Dispose(sbResponse);
CkHashtable_Dispose(hashTab);
CkJwt_Dispose(jwt);
CkJsonObject_Dispose(json);
CkJsonObject_Dispose(jsonJoseHeader);
CkStringBuilder_Dispose(sbJwks);
CkHttp_Dispose(http);
CkJsonObject_Dispose(jwkset);
CkPublicKey_Dispose(pubkey);

end;