Retrieve JWT Authentication Access Token Using HttpsURLConnection

In JWT Authentication, a token is used to access the API interfaces.  In general, it will be a two-step authentication process. First, it will authenticate the user using the user's credentials such as login id, password, client id, and secret keys. Following is a method on how to get the access token uses HTTPS protocol.

    public JwtAuthenticationResponse getHttpsAuthToken(String hostName, int port,     

                                                                    String   userName, String userPassword,

                                                            String grantType, String clientId, String clientSecret,

                                                               String urlPath) 

        HttpsURLConnection httpConn = null;

        final int BUFFER_SIZE = 4096;

        // Create a trust manager that does not validate certificate chains (should be removed in prod env)

        TrustManager[] trustAllCerts = new TrustManager[]{new X509TrustManager() {

            public java.security.cert.X509Certificate[] getAcceptedIssuers() {

                return null;

            }

            public void checkClientTrusted(X509Certificate[] certs, String authType) {

            }

            public void checkServerTrusted(X509Certificate[] certs, String authType) {

            }

        }

        };

        try {

            // Install the all-trusting trust manager

            SSLContext sc = SSLContext.getInstance("SSL");

            sc.init(null, trustAllCerts, new java.security.SecureRandom());

            HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());

            // Create all-trusting host name verifier

            HostnameVerifier allHostsValid = new HostnameVerifier() {

                public boolean verify(String hostname, SSLSession session) {

                    return true;

                }

            };

            HttpsURLConnection.setDefaultHostnameVerifier(allHostsValid);

        } catch (NoSuchAlgorithmException e) {

            logger.debug(String.format("Cannot connect to Hybris server:  %s ;", e.toString()));

            throw new RuntimeException(e);

        } catch (KeyManagementException e) {

            logger.debug(String.format("Cannot connect to Hybris server:  %s ;", e.toString()));

            throw new RuntimeException(e);

        }

        String url;

url = "https://"+hostName + ":"+String.valueOf(port)+"/services/oauth2/token";

        logger.debug("get authendication using: " + url);

        InputStream inputStream;

        try {

            StringBuilder data = new StringBuilder ( );

            data.append ("grant_type=" + grantType);

            data.append ("&client_id=" + clientId);

            data.append ("&client_secret=" + clientSecret);

            if (userId != null && !userId.equals ("undefined")) {

                data.append ("&username=" + userId);

            }

            if (userPassword != null && !userPassword.equals ("undefined")) {

                data.append ("&password=" + userPassword);

            }

           String auth = clientId + ":" + clientSecret;

            byte[] encodedS = Base64.encodeBase64 (auth.getBytes ( ));

            String authHeader = "Basic " + new String (encodedS);

            // Create a byte array of the data to be sent

            byte[] encodedAuth = data.toString ( ).getBytes ("UTF-8");

            String authId = userId + ":" + userPassword;

            byte[] encodedId = Base64.encodeBase64 (authId.getBytes ( ));

            String authHeaderId = "Basic " + new String (encodedId);

            // Setup the Request

            URL request = new URL (url);

            httpConn = (HttpsURLConnection) request.openConnection ( );

            httpConn.setRequestMethod ("POST");

            httpConn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");

            httpConn.setRequestProperty("Content-Length", "" + encodedAuth.length);

            httpConn.setRequestProperty("Content-Length", "" + encodedAuth.length);

            httpConn.setRequestProperty("Authorization", authHeaderId);

            httpConn.setUseCaches (false);

            httpConn.setDoOutput (true);

            // Write data

            OutputStream postStream = httpConn.getOutputStream ( );

            postStream.write (encodedAuth);

            postStream.flush ( );

            postStream.close ( );

            // For POST only - END

            int responseCode = httpConn.getResponseCode ( );

            String response;

            if (responseCode == 200) {

                inputStream = httpConn.getInputStream ( );

                ObjectMapper mapper = new ObjectMapper ( );

                JsonNode jsonMap = mapper.readTree (inputStream);

                String token = jsonMap.get ("access_token").toString ( ).replaceAll ("\"", "");

                String tokenType = jsonMap.get ("token_type").toString ( ).replaceAll ("\"", "");

                String refreshToken = null;

                return new JwtAuthenticationResponse (jsonMap.get ("access_token").toString ( ));

            } else {

                inputStream = httpConn.getErrorStream ( );

                try (Scanner scanner = new Scanner (inputStream)) {

                    scanner.useDelimiter ("\\Z");

                    response = (scanner.next ( ));

             }

            String exceptionMsg = "Response Code " + String.valueOf (responseCode) + ". " +

                                                  response;

                throw new UserDefinedException (exceptionMsg);

            }

        } catch (IOException | UserDefinedException e) {

            logger.debug(String.format("Cannot connect to server:  %s ;", e.toString()));

            throw new RuntimeException(e);

        }

    }

Enable Logging In Python

Python’s logging module is part of the Python Standard Library. The logging module’s basicConfig() method 
is the quickest way to configure the desired behavior of your logger. However,  applications use file-based or 
dictionary-based logging configuration requires a slightly different configuration.

One simple way to set up file-based logging is to use a config file and fileConfig module to read the log configuration properties. 

The log config file will have a format like the one below:

[loggers]

keys=root,pipeline

[handlers]

keys=fileHandler

[formatters]

keys=simpleFormatter

[logger_root]

level=DEBUG

handlers=fileHandler

[logger_pipeline]

level=DEBUG

handlers=fileHandler

qualname=pipeline

propagate=0

[handler_fileHandler]

class=FileHandler

level=DEBUG

formatter=simpleFormatter

args=('./log/pipeline.log','a')

[formatter_simpleFormatter]

format=%(asctime)s - %(name)s - %(levelname)s - %(message)s

datefmt=

To make it a bit simple to enable logging inside the application, a utility module can be created to handle the logging.

import logging

from logging.config import fileConfig

class AppLogger():

   #ensure a singleton. We only want one log per applcation.

   __instance = None

   #create a static methold to get a logger instance.

   # The staticmethod() built-in function returns a static method for a given function.

   @staticmethod

   def get_applog():

       if AppLogger.__instance is None:

           AppLogger()

       return AppLogger.__instance

   def __init__(self):

       if AppLogger.__instance is not None:

           raise Exception("Only one application log should be activated at a time")

       AppLogger.__instance = AppLogger.create_applogger()

   @staticmethod

   def create_applogger():

       fileConfig('./config/applog_config.cfg', disable_existing_loggers=False)

       logger = logging.getLogger('pipeline')

       return logger

Now, in any of the modules within the application, we can involve the logger by calling the log module.

from util.log import AppLogger

Logger = AppLogger.get_applog()

class TestClass() :

    def  a_fuction():

       try:

           # codes here

       

       except Exception as e:

           Logger.error(“Error occurred {0}“.format(str(e))

         finally:

           #do something

The Python documention provides good reference on how to implement logging:

https://docs.python.org/3/howto/logging-cookbook.html

Related Post: Setup Application Configuration File

Setup An Application Configuration File In Python

it's a common practice to store configuration variables in a configuration file and retrieve the properties while they are needed.

Python provides a module called ConfigParser to help managed application configurations. The configParser module can be used to create a configuration file as well as to retrieve property values from a configuration file.

A configuration file in Python is similar to a Windows version of init (.ini) file. The file is divided by “Sections” and “options”. Following is a sample configuration file:

[DEFAULT]
work_directory =/tmp
Log_directory = /var/logs
app_user = app

[DEVELOPMENT]
hostname = mydevhost.com
database = devdb
user_id =devuser
Password =

[STAGE]
hostname = mystagehost.com
database = stagedb
user_id =stageuser
Password =

In the above example, [DEFAULT], [DEVELOPMENT], and [STAGE] are called section. Work_directory, log_directory, hostname,etc are called option.

Here is an example of how to retrieve the properties from the configuration file assuming the above configuration filename is called config.cfg:

import configparser
class GetConfigProperty():

def get_property(self,config_file: str, section: str, property: str) -> str:
     property_value: str
     config = configparser.ConfigParser()
     config.read_file(open('./config/' + config_file))
     property_value = config.get( section, property,fallback=None)
     return property_value

Now, we can call the above function to get the configuration properties in the application like the following:

getConfigProperty = GetConfigProperty()
working_dir : str = getConfigProperty.get_property("config.cfg", "DEFAULT", "working_dir");
dev_hostname : str = getConfigProperty.get_property("file_config.cfg", "DEVELOPMENT", "hostname");

Related Post: Setup Logging In Python