(Swift 2) 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..

For more information, see https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-protocols-oidc

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

    var success: Bool

    // 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.

    var authorization_endpoint: String? = "https://login.microsoftonline.com/6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd/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. 
    var jwks_uri: String? = "https://login.microsoftonline.com/6d8ddd66-68d1-44b0-af5c-e31b4b7ee5cd/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 
    let req = CkoHttpRequest()
    req.AddParam("client_id", value: "f125d695-c50e-456e-a579-a486f06d1213")
    req.AddParam("response_type", value: "id_token")
    req.AddParam("redirect_uri", value: "http://localhost:3017/")
    req.AddParam("response_mode", value: "form_post")
    req.AddParam("scope", value: "openid")
    let prng = CkoPrng()
    req.AddParam("state", value: prng.GenRandom(3, encoding: "decimal"))
    req.AddParam("nonce", value: prng.GenRandom(4, encoding: "decimal"))

    var encodedParams: String? = req.GetUrlEncodedParams()
    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..
    let sbUrl = CkoStringBuilder()
    sbUrl.Append(authorization_endpoint)
    sbUrl.Append("?")
    sbUrl.Append(encodedParams)
    var url: String? = sbUrl.GetAsString()

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

    let listenSock = CkoSocket()

    // Listen at the port indicated by the redirect_uri above.
    var backLog: Int = 5
    success = listenSock.BindAndListen(3017, backlog: backLog)
    if success != true {
        print("\(listenSock.LastErrorText)")
        return
    }

    // 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.
    var maxWaitMs: Int = 60000
    var task: CkoTask? = listenSock.AcceptNextConnectionAsync(maxWaitMs)
    task!.Run()

    // -------------------------------------------------------------------
    // At this point, your application should load the URL in a browser.
    // You'll need to add code here to do it..

    // For example, 
    // in C#: System.Diagnostics.Process.Start(url);
    // in Java: Desktop.getDesktop().browse(new URI(url));
    // in VBScript: Set wsh=WScript.CreateObject("WScript.Shell")
    //              wsh.Run url
    // in Xojo: ShowURL(url)  (see http://docs.xojo.com/index.php/ShowURL)
    // in Dataflex: Runprogram Background "c:\Program Files\Internet Explorer\iexplore.exe" sUrl        
    // The account owner would interactively accept or deny the authorization request.

    // Add the code to load the url in a web browser here...
    // Add the code to load the url in a web browser here...
    // Add the code to load the url in a web browser here...
    // System.Diagnostics.Process.Start(url);

    // -------------------------------------------------------------------

    // Wait for the listenSock's task to complete.
    success = task!.Wait(maxWaitMs)
    if !success || (task!.StatusInt.intValue != 7) || (task!.TaskSuccess != true) {
        if !success {
            // The task.LastErrorText applies to the Wait method call.
            print("\(task!.LastErrorText)")
        }
        else {
            // The ResultErrorText applies to the underlying task method call (i.e. the AcceptNextConnection)
            print("\(task!.Status)")
            print("\(task!.ResultErrorText)")
        }

        task = nil
        return
    }

    // 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.
    listenSock.Close(10)

    // Get the connected socket.
    let sock = CkoSocket()
    sock.LoadTaskResult(task)
    task = nil

    // 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")
    var startLine: String? = sock.ReceiveUntilMatch("\r\n")
    if sock.LastMethodSuccess != true {
        print("\(sock.LastErrorText)")
        return
    }

    // Read the request header.
    var requestHeader: String? = sock.ReceiveUntilMatch("\r\n\r\n")
    if sock.LastMethodSuccess != true {
        print("\(sock.LastErrorText)")
        return
    }

    print("\(requestHeader!)")
    print("----")

    // Read the body.
    // The body will contain "id_token= eyJ......"
    let sbRequestBody = CkoStringBuilder()
    success = sock.ReceiveSb(sbRequestBody)
    if success == false {
        print("\(sock.LastErrorText)")
        return
    }

    print("\(sbRequestBody.GetAsString())")

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

    let sbResponse = CkoStringBuilder()
    sbResponse.Append("HTTP/1.1 200 OK\r\n")
    sbResponse.Append("Content-Length: ")
    sbResponse.AppendInt(sbResponseHtml.Length.intValue)
    sbResponse.Append("\r\n")
    sbResponse.Append("Content-Type: text/html\r\n")
    sbResponse.Append("\r\n")
    sbResponse.AppendSb(sbResponseHtml)

    sock.SendString(sbResponse.GetAsString())
    sock.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..)
    let hashTab = CkoHashtable()
    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..
    var idToken: String? = hashTab.LookupStr("id_token")

    let jwt = CkoJwt()

    // 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.
    var leeway: Int = 60
    var bTimeValid: Bool = jwt.IsTimeValid(idToken, leeway: leeway)
    print("time constraints valid: \(bTimeValid)")

    // Now let's recover the original claims JSON (the payload).
    var payload: String? = jwt.GetPayload(idToken)
    // The payload will likely be in compact form:
    print("\(payload!)")

    // We can format for human viewing by loading it into Chilkat's JSON object
    // and emit.
    let json = CkoJsonObject()
    success = json.Load(payload)
    json.EmitCompact = false
    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:
    var joseHeader: String? = jwt.GetHeader(idToken)
    // The payload will likely be in compact form:
    print("\(joseHeader!)")

    // We can format for human viewing by loading it into Chilkat's JSON object
    // and emit.
    let jsonJoseHeader = CkoJsonObject()
    success = jsonJoseHeader.Load(joseHeader)
    jsonJoseHeader.EmitCompact = false
    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.
    let sbJwks = CkoStringBuilder()
    let http = CkoHttp()
    success = http.QuickGetSb(jwks_uri, sbContent: sbJwks)
    if success == false {
        print("\(http.LastErrorText)")
        return
    }

    let jwkset = CkoJsonObject()
    success = jwkset.LoadSb(sbJwks)
    jwkset.EmitCompact = false
    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..
    var kid: String? = jsonJoseHeader.StringOf("kid")

    // Find the RSA key with the specified key id
    var jwk: CkoJsonObject? = jwkset.FindRecord("keys", relPath: "kid", value: kid, caseSensitive: true)
    if jwkset.LastMethodSuccess == false {
        print("Failed to find a matching RSA key in the JWK key set...")
        return
    }

    var verified: Bool
    let pubkey = CkoPublicKey()

    success = pubkey.LoadFromString(jwk!.Emit())
    if success == false {
        print("\(pubkey.LastErrorText)")
        print("\(jwk!.Emit())")
    }
    else {
        verified = jwt.VerifyJwtPk(idToken, key: pubkey)
        print("Verified: \(verified)")
    }

    jwk = nil

}