Posts

Okta - PKCE Verification Failed while requesting token

Let me clear a few concepts before I dive into the resolution for " PKCE Verification Failed " " Authorization Code " flow is an OAuth 2.0 flow , wherein an authorization code is issued by the Authorization Server . This code is used for requesting access tokens, used for accessing the protected resources. Authorization code is exchanged through the front-channel and is susceptible to interception attacks.

How to rename an AWS Lambda function?

 As of writing this article, there is no support in AWS to rename a Lambda function. However, there is an option to set an alias . And you can create multiple of them. The actual purpose of an alias , though, is to act as a pointer to a specific version of the lambda function. It can also act as a router to route traffic between two versions of the function with weight assignment e.g. to test it as a canary. If alias does not meet your needs, then the only other way is to delete the function and recreate it with the desired name.

Groovy - What is Memoization?

Image
Memoization (a.k.a tabling) is a technique in programming where the result of a function call is stored in cache and when the function is subsequently called with the same parameters, the result is returned from the cache instead of executing the function again.

Groovy - How to read and write to excel sheets with Groovy?

Image
Scriptom provides a simple COM library for Groovy. It is a Groovy wrapper around JACOB (Java COM Bridge) which provides access to COM Automation components. Scriptom can be used to work with MS Office tools, Internet Explorer or any other Microsoft Windows COM based components. In this article, you will use Scriptom to read and write to excel files.

Spring MVC - How to handle errors from a controller?

Image
In a web application, it is very important to handle errors. Proper error handling would protect the application from several vulnerabilities, including Security Misconfiguration . In this post, you will see how you can handle exceptions that arise out of a Spring MVC based application.

Java - How to find the IP Address of a host in Java ?

In Java, if you are looking to resolve an IP Address from the given hostname, then you can leverage the capabilities provided by InetAddress . It belongs to the "java.net" package and provides various utilities related to resolving addresses and IPs.

Spring - Initializing a Spring Bean

Image
It is often required to run some custom code on initialization of a Spring bean. e.g. to check for mandatory properties or establish initial connections. Spring provides a few constructs to initialize the beans after they are injected with the properties.