How to Perform Concurrent HTTP Requests in Ruby and Rails

Let’s start by describing what’s a blocking I/O. Long story short, any operation that does not directly use the CPU cycles from its thread, but instead delegates the work to external processes is a blocking I/O. Typical examples in the context of Ruby on Rails web apps are SQL database queries, reading/writing to files, or HTTP requests.To see what’s the practical difference between the CPU bound operation and blocking I/O check out the following code snippets. I encourage you to run them in your local IRB.