Prosthetic

Prosthetic is a Node web proxy that allows you to manipulate web sites with simple (yet flexible) JSON configuration files. As a node module, it exposes an express-compatible server function (the module export) and a suite of operations for manipulating (inserting, removing and replacing) response body content.

Running the proxy

To run a proxy, just run server.js with node:

$ node server.js --proxy http://example.com
# or
$ ./server.js --proxy http://example.com

Then visit localhost:8001 in your browser. Run node server.js --help (or without any arguments) to see the full usage:

Syringe usage:

1. with a proxy URL and one or more injections:

   node ./server.js --proxy URL [injections]

2. with a JSON config and proxy URL:

   node ./server.js -c config.json --proxy URL [options] [injections]

3. with a JSON config that includes the 'proxy' option:

   node ./server.js -c config.json [options] [injections]

where [injections] is an optional list of JSON filenames
containing injection specs.

Options:
  --proxy, -p    the URL to proxy (e.g. http://example.com)       
  --rewrite, -r  whether to rewrite the proxy URL in each response
  --config, -c   the config file to load                          
  --port, -P     the port on which to listen (default: 8001)      

The included config.sample.json is a good place to start for building a configuration.

The ops directory contains some examples of operations to run in your proxy. For instance, the included d3.json simply adds d3.js to the proxied web page, and reset-css.json pulls in the YUI CSS Reset.

Operations

Operations are what Prosthesis does to the contents of proxied web pages. Positional arguments to server.js are interpreted as filenames parsed as JSON operation specs. Supported operations include inserting text, HTML elements, scripts and stylesheets; and replacing or removing content.

Add a script (e.g., d3.js):

{
  "type": "script",
  "url": "http://d3js.org/d3.v3.min.js"
}

Add a stylesheet (e.g., reset css):

{
  "type": "style",
  "url": "http://yui.yahooapis.com/3.14.0/build/cssreset/cssreset-min.css"
}

To propose a redesign for a web site with your own stylesheets, you could remove all of the CSS from each page first (the "comment" fields are ignored):

[
  {
    "comment": "replace all <link rel=stylesheet> elements",
    "type": "remove",
    "text": "<link[^>]+rel=.?stylesheet.?[^>]*>(</link>)?"
  },
  {
    "comment": "replace all <style> elements",
    "type": "remove",
    "text": "<style[^>]*>[^<]*</style>"
  }
]