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Visual Basic 6.0 Requires Chilkat v11.0.0+

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 Visual Basic 6.0 Downloads

Visual Basic 6.0
Dim success As Long
success = 0

'  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.

Dim authorization_endpoint As String
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. 
Dim jwks_uri As String
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 
Dim req As New ChilkatHttpRequest
req.AddParam "client_id","{client_id}"
req.AddParam "response_type","id_token"
req.AddParam "redirect_uri","http://localhost:3017/"
req.AddParam "response_mode","form_post"
req.AddParam "scope","openid"
Dim prng As New ChilkatPrng
req.AddParam "state",prng.GenRandom(3,"decimal")
req.AddParam "nonce",prng.GenRandom(4,"decimal")

Dim encodedParams As String
encodedParams = req.GetUrlEncodedParams()
Debug.Print 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..
Dim sbUrl As New ChilkatStringBuilder
success = sbUrl.Append(authorization_endpoint)
success = sbUrl.Append("?")
success = sbUrl.Append(encodedParams)
Dim url As String
url = sbUrl.GetAsString()

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

Dim listenSock As New ChilkatSocket

'  This is the connection received from the browser.
Dim browserSock As New ChilkatSocket

'  Listen at the port indicated by the redirect_uri above.
Dim backLog As Long
backLog = 5
success = listenSock.BindAndListen(3017,backLog)
If (success = 0) Then
    Debug.Print listenSock.LastErrorText
    Exit Sub
End If

'  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.
Dim maxWaitMs As Long
maxWaitMs = 30000
Dim task As ChilkatTask
Set task = listenSock.AcceptNextAsync(maxWaitMs,browserSock)
success = task.Run()

'  -------------------------------------------------------------------
'  At this point, your application should load the URL in a browser.
Dim oauth2 As New ChilkatOAuth2
success = oauth2.LaunchBrowser(url)
If (success = 0) Then
    Debug.Print oauth2.LastErrorText
    Exit Sub
End If

'  -------------------------------------------------------------------

'  Wait for the listenSock's task to complete.
success = task.Wait(maxWaitMs)
If (Not success Or (task.StatusInt <> 7) Or (task.TaskSuccess <> 1)) Then
    If (Not success) Then
        '  The task.LastErrorText applies to the Wait method call.
        Debug.Print task.LastErrorText
    Else
        '  The ResultErrorText applies to the underlying task method call (i.e. the AcceptNextConnection)
        Debug.Print task.Status
        Debug.Print task.ResultErrorText
    End If

    Exit Sub
End If

'  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.
success = listenSock.Close(10)

'  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")
Dim startLine As String
startLine = browserSock.ReceiveUntilMatch(vbCrLf)
If (browserSock.LastMethodSuccess = 0) Then
    Debug.Print browserSock.LastErrorText
    Exit Sub
End If

'  Read the request header.
Dim requestHeader As String
requestHeader = browserSock.ReceiveUntilMatch(vbCrLf & vbCrLf)
If (browserSock.LastMethodSuccess = 0) Then
    Debug.Print browserSock.LastErrorText
    Exit Sub
End If

Debug.Print requestHeader
Debug.Print "----"

'  Read the body.
'  The body will contain "id_token= eyJ......"
Dim sbRequestBody As New ChilkatStringBuilder
success = browserSock.ReceiveSb(sbRequestBody)
If (success = 0) Then
    Debug.Print browserSock.LastErrorText
    Exit Sub
End If

Debug.Print sbRequestBody.GetAsString()

'  Given that we're acting as a web server, we must send a response..
'  We can now send our HTTP response.
Dim sbResponseHtml As New ChilkatStringBuilder
success = sbResponseHtml.Append("<html><body><p>Thank you!</b></body</html>")

Dim sbResponse As New ChilkatStringBuilder
success = sbResponse.Append("HTTP/1.1 200 OK" & vbCrLf)
success = sbResponse.Append("Content-Length: ")
success = sbResponse.AppendInt(sbResponseHtml.Length)
success = sbResponse.Append(vbCrLf)
success = sbResponse.Append("Content-Type: text/html" & vbCrLf)
success = sbResponse.Append(vbCrLf)
success = sbResponse.AppendSb(sbResponseHtml)

success = browserSock.SendString(sbResponse.GetAsString())
success = browserSock.Close(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..)
Dim hashTab As New ChilkatHashtable
success = hashTab.AddQueryParams(sbRequestBody.GetAsString())

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

Dim jwt As New ChilkatJwt

'  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.
Dim leeway As Long
leeway = 60
Dim bTimeValid As Long
bTimeValid = jwt.IsTimeValid(idToken,leeway)
Debug.Print "time constraints valid: " & bTimeValid

'  Now let's recover the original claims JSON (the payload).
Dim payload As String
payload = jwt.GetPayload(idToken)
'  The payload will likely be in compact form:
Debug.Print payload

'  We can format for human viewing by loading it into Chilkat's JSON object
'  and emit.
Dim json As New ChilkatJsonObject
success = json.Load(payload)
json.EmitCompact = 0
Debug.Print json.Emit()

'  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:
Dim joseHeader As String
joseHeader = jwt.GetHeader(idToken)
'  The payload will likely be in compact form:
Debug.Print joseHeader

'  We can format for human viewing by loading it into Chilkat's JSON object
'  and emit.
Dim jsonJoseHeader As New ChilkatJsonObject
success = jsonJoseHeader.Load(joseHeader)
jsonJoseHeader.EmitCompact = 0
Debug.Print jsonJoseHeader.Emit()

'  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.
Dim sbJwks As New ChilkatStringBuilder
Dim http As New ChilkatHttp
success = http.QuickGetSb(jwks_uri,sbJwks)
If (success = 0) Then
    Debug.Print http.LastErrorText
    Exit Sub
End If

Dim jwkset As New ChilkatJsonObject
success = jwkset.LoadSb(sbJwks)
jwkset.EmitCompact = 0
Debug.Print jwkset.Emit()

'  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..
Dim kid As String
kid = jsonJoseHeader.StringOf("kid")

'  Find the RSA key with the specified key id
Dim jwk As ChilkatJsonObject
Set jwk = jwkset.FindRecord("keys","kid",kid,1)
If (jwkset.LastMethodSuccess = 0) Then
    Debug.Print "Failed to find a matching RSA key in the JWK key set..."
    Exit Sub
End If

Dim verified As Long
Dim pubkey As New PublicKey

success = pubkey.LoadFromString(jwk.Emit())
If (success = 0) Then
    Debug.Print pubkey.LastErrorText
    Debug.Print jwk.Emit()
Else
    verified = jwt.VerifyJwtPk(idToken,pubkey)
    Debug.Print "Verified: " & verified
End If