#216 HTTP Mock Response

Using Sinatra to craft simple HTTP web responses for mock integration testing.

Notes

Sometimes you need a web site to return a specific response - for example certain error codes and payloads. Maybe one is trying to diagnose or verify a correct behaviour.

Sinatra is a very convenient way to whip up something suitable. A couple of lines of code may be all that is required.

The app.rb script is a very simple Sinatra app that will run by default on http://localhost:4567. In a few lines, it shows how to handle arbitrary GET and PORT requests and render a suitable response.

The parameters provided in the URL of the request will determine the HTTP status code and content type of the response.

Running the Example

To run the app locally:

$ gem install bundler
$ bundle install
$ ruby app.rb
[2018-05-01 21:09:53] INFO  WEBrick 1.3.1
[2018-05-01 21:09:53] INFO  ruby 2.3.3 (2016-11-21) [x86_64-darwin14]
== Sinatra (v2.0.1) has taken the stage on 4567 for development with backup from WEBrick
[2018-05-01 21:09:53] INFO  WEBrick::HTTPServer#start: pid=32888 port=4567

Making Arbitrary GET Requests

Making a GET request to http://localhost:4567/:code:.:format: will respond according to the :code: and :format: specified. Where:

:code: sets the HTTP Status of the response e.g. 200, 401, 500
:format: sets the content type of the response: html, txt, xml or json are supported

Examples with curl:

$ curl -v http://localhost:4567/500.json
*   Trying ::1...
* Connected to localhost (::1) port 4567 (#0)
> GET /500.json HTTP/1.1
> Host: localhost:4567
> User-Agent: curl/7.43.0
> Accept: */*
>
< HTTP/1.1 500 Internal Server Error
< Content-Type: application/json
< Content-Length: 53
< X-Content-Type-Options: nosniff
< Server: WEBrick/1.3.1 (Ruby/2.3.3/2016-11-21)
< Date: Tue, 01 May 2018 13:02:59 GMT
< Connection: Keep-Alive
<
{
  "message": "Returning code 500 in json format"
}
* Connection #0 to host localhost left intact

Making Arbitrary POST Requests

Making a POST request to http://localhost:4567/:code:.:format: will respond according to the :code: and :format: specified. Where:

:code: sets the HTTP Status of the response e.g. 200, 401, 500
:format: sets the content type of the response: html, txt, xml or json are supported