nloko/moxy

An HTTP proxy that can mock request responses

#Moxy

Moxy is an HTTP proxy that allows mocking of HTTP responses, including support for delays and conditional statements.

##What and Why?

Moxy has 2 main goals:

• Be simple, it's real easy to get it up and running
• Improve developer efficiency, allow a client application developer to work even without a fully developed backend HTTP service they require

Sometimes when working in a team, a service required by the client application development team may take some time to develop. Since the client team can code without the service existing (as long as the interface for the service has been defined), the client team should be able to test without the service existing as well.

This, hopefully, removes the need for temporary code, preprocessing statements, etc. for the purposes of testing networking code.

##How?

Start Moxy from the command line by issuing:

./moxy.py

...from the directory where Moxy resides. Moxy has no external dependancies.
By default, Moxy uses port 8888 for the proxy and port 8889 for its configuration service.

Now, configure your system to use localhost:8888 as an HTTP proxy and you're ready to start mocking HTTP responses.

All behaviour is defined in moxy.conf. Let's examine the default moxy.conf to learn how we can alter the responses to HTTP requests.

url http://api.awesomeapp.com/v1/awesome/?$
  get 200 awesome.json

url http://api.awesomeapp.com/v1/awesome/add
  if delay_add: delay 13000
  get 400 awesome_add_error.json
  post 200 awesome_add.json

url http://api.awesomeapp.com/v1/awesome/?\?id\=.+
  get 400 awesome_id_error.json
  if created: get 200 awesome_id.json

URL

Each entry in moxy.conf must start with a url statement The format is:

url regex

regex is a regular expression that matches the URL of an HTTP request.

Any non-matching requests will simply pass through as if Moxy wasn't there.

Response

A different response can be specified for each supported HTTP method.

The format is:

method code [file]

method is the HTTP method. GET, POST, PUT, and DELETE are supported.
code is the response code to return for the matched request.
file is optional. It specifies a file in the directory where moxy is running. Its contents will be used for the response body.

Headers

The format is:

header name value

name is the name part of the header field
value is the value part of the header field

Delay

The format is:

delay [n]

n is optional. It's the number of milliseconds to wait before servicing the request. If not specified, the delay will be 5000ms or 5 seconds.

Conditional Statements

Conditional statements can be prefixed to any line except url. Remember that the first conditonal statement to evaluate to true will be the one used. Order of statements is important.

The format is:

if expr: config

expr is a logical expression. Valid operators are not, and, and or.
Parentheses are supported.
config is any configuration setting except url.

Each operand in the expression will create a condition within Moxy. Conditions can be reused in more than one statement.

Conditions can be viewed at http://localhost:8889/conditions. Here, values can be toggled in order to satisfy/unsatisfy conditional statements.

##Configuration Service

Moxy has a web-based configuration interface. It can be accessed at http://localhost:8889/. From here, the configuration can be viewed, refreshed, and conditions can be modified.