simpleFastProxy

Nodejs based debugging proxy.

Currently I'm developing only the features I need. I'm open to suggestions and help. The main objective of this project is providing a very flexible and easy to use debugging proxy. Later goals include providing a web based UI for inspecting traffic.

Usage

Import it;

var sfp = require('sfp');

The proxy gets a rule list as an array. Init the proxy with this array and an options object;

var myProxy = new sfp.Proxy(mainRuleList, options);

Each item in the rule list array can have a "match" field that will match a request specific to that rule item. Multiple matches are ORed.

{
    //Optional match property
    match: [
        {
           ...
        },
        ...
    ],
    //Action items when the match is valid
    //(modify, delete, cache)
    ...
}

For example to match a request header;

match: [
    {
        type: "requestHeader",
        name: "origin",
        value: "..."
    }
]

or match a request header without using a value;

match: [
	{
		type: "requestHeader",
		name: "range"
	}
]

Allowed match types are currently; requestHeader, responseHeader or url.

Action Items:

You can modify a header using placeholders from request headers. Inject origin for CORS, or allow credentials;

modify: [
	{
		type: "responseHeader",
		name: "access-control-allow-origin",
		value: '{~{requestHeader.origin}~}'
	},
	{
		type: "responseHeader",
		name: "access-control-allow-credentials",
		value: 'true'
	}
]

Inject origin;

modify: [
	{
		type: "requestHeader",
		name: "origin",
		value: ''
	},
	{
		type: "requestHeader",
		name: "referer",
		value: ''
	}
]

Injecting a cookie;

modify: [
	{
		type: "requestHeader",
		name: "cookie",
		value: ''
	}
]

Prevent cache;

modify: [
	{
		type: "responseHeader",
		name: "cache-control",
		value: 'no-cache, no-store, must-revalidate'
	},
	{
		type: "responseHeader",
		name: "pragma",
		value: 'no-cache'
	},
	{
		type: "responseHeader",
		name: "expires",
		value: '0'
	}
]
	  

Remove headers;

delete: [
	{
		type: "responseHeader",
		name: "x-frame-options",
		value: ''
	},
	{
		type: "responseHeader",
		name: "accept-ranges",
		value: ''
	}
]

Remove accept-ranges response header if a range request arrives;

"modify": [
{
    type: "responseHeader",
    name: "accept-ranges",
    value: "none"
}

You can cache files by setting "cache" property;

cache: true

Modify response body (use search & replace instead of name/value);

modify: [
	{
		type: "responseBody",
		search: "https:",
		replace: "http:"
	}
]

You may use a js regular expression on search. For example to replace the whole response body;

modify: [
	{
		type: "responseBody",
		search: "^[^]*",
		replace: "Hello World"
	}
]

Note: Only gzipped bodies can be manipulated. So it is advised to inject an Accept-Encoding header to the requests.

Options:

{
	"port": 8888 //Proxy port (defaults to 8888),
	"tempFolder": "/tmp/", //Temporary file folder (defaults to "/tmp/"),
	"externalProxyHost": null, //Additional proxy host and port (requests will be further forwarded to this endpoint);
	"externalProxyPort": null,
	"interceptSSL": true, //Should the proxy intercept HTTPS requests? Below options are necessary if this is true.
	"rootCAKey": "path/to/rootCA/key", //root CA key file (.key)
	"rootCACert": "path/to/rootCA/cert", //root CA certificate file (.pem)
	"rootCAPass": "XXXX" //root CA passphrase
}

Note: To be able to use SSL features, openSSL must be installed on your system and available on the command line/shell. (https://wiki.openssl.org/index.php/Binaries for binaries)

CLI

To run the proxy server from the command line, install it globally (npm install -g sfp) and pass a json file name. In the json file there must be an array of two items. The first array will be used as the mainRuleList and second one as the options object.

For example;

[
	[],
	{
		"tempFolder": "/tmp/"
	}
]