Let’s say that you are working on a part of a project that needs to consume some JSON data from a forthcoming HTTP service. That sub-system is being developed by one of your colleagues and is not yet ready for you to stand-up to develop against.
You can use netcat to mock the webservice and return some static JSON data for which you can develop and test against with a simple one-liner.
First, put together your JSON in a file, ‘my.json’ and then run the following command in a terminal:
while true; do echo -e "HTTP/1.1 200 OK\r\n\r\n$(cat my.json)" | nc -l 9998; done
http://localhost:9998 will return your test JSON data.