Add scripting framework to post-process request

[visola]

User story

As a user, I want to execute some Javascript after a request to process the results.

Description

A very useful feature from Postman is the ability to execute a script after a request is executed to check the results or extract data from it. Read more here.

To make this work, it's required to add a javascript engine, possibly embed V8 or use an existing API bindings like go-v8.

Acceptance Criteria

• Add Javascript engine
• On the CLI, add a --post-process option that receives a file that will be used to post-process the executed request
• From profiles, have two ways to execute post process scripts:
  • add requests.postProcessFile loads a file to be executed
  • add requests.postProcessScript that can be used to inline javascript inside the YAML
• Post process scripts can access the following:
  • From the response:
    • status code
    • body as string
    • headers
  • From the Request
    • URL
    • body
    • headers
• Post process scripts needs to have the ability to:
  • set a session variable
  • set a global variable
  • [ ] set a cookie on the current session
  • add a new request to be executed, pushing one of the following to the requests queue:
    • by request name, loaded from the active profiles
    • by creating a request object, following the same structure as in the profile YAML

[visola]

Given the complexity involved in building V8, duktape sounds like a much better option for this project. Still investigating.

[visola]

Stepping back on the complexity even more. Going to go with Otto, which is ES5 compliant, except for some regexp details.
Fully written in Go, sounds like a more mature and well maintained project.