Full-featured, pluggable and middleware-oriented HTTP proxy supporting traffic replay and intercept
Full-featured, pluggable and middleware-oriented HTTP/S and WebSocket proxy with powerful built-in features such as versatile routing layer, traffic interceptor and replay to multiple backends, traffic balancer, traffic retry/backoff, hierarchical configuration, among other features.
Built for node.js/io.js. Compatible connect/express.
rocky can be fluently used programmatically or via command-line interface. It has a modular pluggable design, making it pretty simple to extend and augment through its featured middleware layer.
To get started, take a look to how does it work, basic usage, middleware layer and examples
Requires node.js +0.12 or io.js +1.6
rocky can be useful?npm install rocky --save
Migrating systems if not a trivial thing, and it's even more complex if we're talking about production systems that require high availability. Taking care of consistency and public interface contract should be a premise in most cases.
rocky was originally created to become an useful tool to assist during a backend migration strategy, later on it was extended and improved to cover so many other scenarios.
rocky goal is to provide a full-featured and hackable programmatic HTTP proxy to build other services on it, like you can do with web services using express or connect.
rocky design is influenced by the UNIX philosophy, especially by the rules of composition, modularity and simplicity. As result, rocky tend to be a lightweight package with small core designed for extensibility.
The most important feature in rocky is its nested multi phase middleware layer. Via the middleware layer you can rely in a consistent control flow when performing actions with the HTTP traffic flow, such as modifying, pausing or stopping it, even for both incoming and outgoing traffic flows.
This allows you to plug in intermediate jobs with your custom logic which will be executed among different phases of the HTTP flow live cycle.
Version 0.1.x was designed and written during my free time in less than 10 days (mostly at night during the weekend), therefore it can be considered in beta stage.
Version 0.2.x introduced significant improvements, including a consistent API and new hierarchical middleware layer.
0.3.x and higher versions are production-focused. API consistency is guaranteed between patch releases.
25.06.2015. Beta07.07.2015. Major features and stability improvements.24.07.2015. Production-focused version. |==============|
| HTTP clients |
|==============|
||||
|==============|
| HTTP proxy | -> Via the built-in HTTP server or via connect/express
|~~~~~~~~~~~~~~|
| Rocky Router | -> The built-in featured router matches the proper route
|~~~~~~~~~~~~~~|
| Middleware | -> Dispatch the hierarchical middleware layer
|==============|
|| |
(duplex) // \ (one-way)
// \
/----------\ /----------\ /----------\
| target | | replay 1 | -> | replay 2 | (*N)
\----------/ \----------/ \----------/
Open an issue or send a PR to add your project!
One of the most powerful features in rocky is its build-in domain specific middleware, based on connect/express middleware.
The middleware layer provides a simple and consistent way to augment the proxy functionality very easily, allowing you to attach third-party middleware (also known as plugins) to cover specific tasks which acts between different phases of the proxy, for instance handling incoming/outgoing traffic.
rocky middleware layer has the same interface as connect/express middleware, and it's mostly compatible with existent middleware (see express example).
rocky supports multiple middleware hierarchies:
rocky introduces multiple types of middleware layers based on the same interface and behavior of connect/express middleware.
This was introduced in order to achieve in a more responsive way multiple traffic flows in the specific scope
and behavior nature of a programmatic HTTP proxy with traffic replay.
Those flows are intrinsicly correlated but might be handled in a completely different way. The goal is to allowing you to handle them accordingly, acting in the middle of those phases to augment some functionality or react to some event with better accuracy.
Supported types of middleware:
global.use([path], function (req, res, next))global, route.useForward(function (req, res, next))global, route.useReplay(function (req, res, next))global, routeforward traffic..useResponse(function (req, res, next))global.useParam(function (req, res, next))Middleware functions are always executed in FIFO order. The following diagram represents the internal incoming request flow and how the different middleware layers are involved on it:
↓ ( Incoming request ) ↓
↓ ||| ↓
↓ ---------------- ↓
↓ | Router | ↓ --> Match a route, dispatching its middleware if required
↓ ---------------- ↓
↓ ||| ↓
↓ --------------------- ↓
↓ | Global middleware | ↓ --> Dispatch on every incoming request (router, param)
↓ --------------------- ↓
↓ ||| ↓
↓ / \ ↓
↓ / \ ↓
↓ / \ ↓
↓ [ Forward ] [ Replay ] ↓ --> Dispatch both middleware in separated flows (route forward and replay)
↓ \ / ↓
↓ \ / ↓
↓ \ / ↓
↓ ------------------- ↓
↓ | HTTP dispatcher | ↓ --> Send requests over the network (concurrently or sequentially)
↓ ------------------- ↓
Middleware layer behavies and has the same interface as connect/express.
In other words, you can create or use middleware as you already know with the typical notation function(req, res, next)
As a kind of inversion of control, rocky exposes a tiny API in every http.ClientRequest passed via the middleware layer:
object
object - Expose the configuration options for the current request.Rocky - Expose the rocky instance. Use only for hacking purposes!Route - Expose the current running route. Only available in route type middlewareboolean - Optional field internally checked by rocky to stop the request replay process.This allows you way to extend or modify specific values from the middleware layer with HTTP request flow accuracy level, and therefore without having side-effects with other routes.
Example replacing the target server URL:
rocky()
.get('/users/:name')
.forward('http://old.server.net')
.use(function (req, res, next) {
if (req.params.name === 'admin') {
// Overwrite the target URL only for this user
req.rocky.options.target = 'http://new.server.net'
}
next()
})
Note that you can use any other existent middleware plug in rocky as part of your connect/express app.
Additionally, rocky provides some built-in middleware functions that you can plug in different types of middleware.
For command-line usage, you must install rocky-cli
npm install -g rocky-cli
Start rocky HTTP proxy server
Usage: rocky [options]
Options:
--help, -h Show help [boolean]
--config, -c File path to TOML config file
--port, -p rocky HTTP server port
--forward, -f Default forward server URL
--replay, -r Define a replay server URL
--route, -t Define one or multiple routes, separated by commas
--key, -k Path to SSL key file
--cert, -e Path to SSL certificate file
--secure, -s Enable SSL certification validation
--balance, -b Define server URLs to balance between, separated by commas
--mute, -m Disable HTTP traffic log in stdout [boolean]
--debug, -d Enable debug mode [boolean]
-v, --version Show version number [boolean]
Examples:
rocky -c rocky.toml \
-f http://127.0.0.1:9000 \
-r http://127.0.0.1
Passing the config file:
rocky --config rocky.toml --port 8080
Reading config from stdin:
cat rocky.toml | rocky --port 8080
Transparent rocky.toml file discovery in current and higher directories:
rocky --port 8080
Alternatively rocky can find the config file passing the ROCKY_CONFIG environment variable:
ROCKY_CONFIG=path/to/rocky.toml rocky --port 8080
Or for simple configurations you can setup a proxy without a config file, defining the routes via flag:
rocky --port --forward http://server --route "/download/*, /images/*, /*"
Default configuration file name: rocky.toml
The configuration file must be declared in TOML language
port = 8080
forward = "http://google.com"
replay = ["http://duckduckgo.com"]
[ssl]
cert = "server.crt"
key = "server.key"
["/users/:id"]
method = "all"
forward = "http://new.server"
["/oauth"]
method = "all"
forward = "http://auth.server"
["/*"]
method = "GET"
forward = "http://old.server"
["/download/:file"]
method = "GET"
timeout = 5000
balance = ["http://1.file.server", "http://2.file.server"]
["/photo/:name"]
method = "GET"
replayAfterForward = true
[[replay]]
target = "http://old.server"
forwardHost = true
[[replay]]
target = "http://backup.server"
Example using Express
var rocky = require('rocky')
var express = require('express')
// Set up the express server
var app = express()
// Set up the rocky proxy
var proxy = rocky()
// Default proxy config
proxy
.forward('http://new.server')
.replay('http://old.server')
.replay('http://log.server')
.options({ forwardHost: true })
// Configure the routes to forward/replay
proxy
.get('/users/:id')
proxy
.get('/download/:file')
.balance(['http://1.file.server', 'http://2.file.server'])
// Plug in the rocky middleware
app.use(proxy.middleware())
// Old route (won't be called since it will be intercepted by rocky)
app.get('/users/:id', function () { /* ... */ })
app.listen(3000)
Example using the built-in HTTP server
var rocky = require('rocky')
var proxy = rocky()
// Default proxy config
proxy
.forward('http://new.server')
.replay('http://old.server', { replayOriginalBody: true })
.options({ forwardHost: true })
.on('proxy:error', function (err) {
console.error('Error:', err)
})
.on('proxyReq', function (proxyReq, req, res, opts) {
console.log('Proxy request:', req.url, 'to', opts.target)
})
.on('proxyRes', function (proxyRes, req, res) {
console.log('Proxy response:', req.url, 'with status', res.statusCode)
})
// Configure the routes to forward/replay
proxy
.get('/users/:id')
// Overwrite the path
.toPath('/profile/:id', { id: '0123' })
// Add custom headers
.headers({
'Authorization': 'Bearer 0123456789'
})
proxy
.get('/search')
// Overwrite the forward URL for this route
.forward('http://another.server')
// Use a custom middleware for validation purposes
.use(function (req, res, next) {
if (req.headers['Autorization'] !== 'Bearer 012345678') {
res.statusCode = 401
return res.end()
}
next()
})
// Intercept and transform the response body before sending it to the client
.transformResponseBody(function (req, res, next) {
// Get the body buffer and parse it (assuming it's a JSON)
var body = JSON.parse(res.body.toString())
// Compose the new body
var newBody = JSON.stringify({ salutation: 'hello ' + body.hello })
// Send the new body in the request
next(null, newBody)
})
proxy.listen(3000)
For more usage cases, take a look to the examples
Supported configuration params:
string - Default forward URLboolean - Enable debug mode. Default falsestring - <url string to be parsed with the url modulearray<string|object> - Optional replay server URLs. You can use the replay() method to configure itarray<url> - Define the URLs to balance. Via API you should use the balance() methodnumber - Timeout for request socketnumber - Timeout for proxy request socketobject - Enable retry/backoff logic for forward/replay traffic. See allowed params. Default: nullobject - Enable retry logic for replay traffic with custom options. Default: nullobject - object to be passed to http(s).request. See node.js https docsobject - object to be passed to https.createServer()
string - Path to SSL certificate filestring - Path to SSL key fileboolean - true/false, if you want to proxy websocketsboolean - true/false, adds x-forward headersboolean - true/false, verify SSL certificateboolean - true/false, explicitly specify if we are proxying to another proxyboolean - true/false, Default: true - specify whether you want to prepend the target's path to the proxy pathboolean - true/false, Default: false - specify whether you want to ignore the proxy path of the incoming requestboolean - <Local interface string to bind for outgoing connectionsboolean - <true/false, Default: false - changes the origin of the host header to the target URLstring - Basic authentication i.e. 'user:password' to compute an Authorization header.string - rewrites the location hostname on (301/302/307/308) redirects, Default: null.boolean - rewrites the location host/port on (301/302/307/308) redirects based on requested host/port. Default: false.string - rewrites the location protocol on (301/302/307/308) redirects to 'http' or 'https'. Default: null.boolean - Only valid for forward request. Forward the original body instead of the transformed one.boolean - Only valid for replay request. Forward the original body instead of the transformed one.object - Specific router params
boolean - When false trailing slashes are optional (default: false)boolean - When true the routing will be case sensitive. (default: false)boolean - When true any req.params passed to the router will be
merged into the router's req.params. (default: false)Creates a new rocky instance with the given options.
You can pass any of the allowed params at configuration level and any supported http-proxy options
Aliases: target, forwardTo
Define a default target URL to forward the request
Alias: replayTo
Add a server URL to replay the incoming request
opts param provide specific replay options, overwritting the parent options.
Define/overwrite rocky server options.
You can pass any of the supported options by http-proxy.
Alias: useIncoming
Use the given middleware to handle all http methods on the given path, defaulting to the root path.
Alias: param()
Maps the specified path parameter name to a specialized param-capturing middleware.
The middleware stack is the same as .use().
Use a middleware for all the incoming traffic in the HTTP replay phase. This middleware stack can be useful to differ between forward/replay traffic, applying separated flows of middleware.
Use a middleware for all the incoming traffic only for the HTTP request forward phase.
For most cases you will only use .use(), but for particular modifications only for the forwarded traffic, this middleware can be useful.
Alias: useOutgoing
Use a middleware for the outgoing response traffic of the forwarded request.
This middleware stack is useful to handle intercept and modify server responses before sending it to the end client in the other side of the proxy.
Use a custom middleware for a specific phase. Supported phase names are: forward, 'replay'.
This method is used internally, however it's also public since it could be useful
for dynamic middleware configurations instead of using the shortcut methods such as: useReplay or useForward.
Define a set of URLs to balance between with a simple round-robin like scheduler.
Disable replay logic.
Enable and define a custom retry logic as global configuration.
See Route#retry for details.
Subscribe to a proxy event. See support events here
Remove an event by its handler function. See support events here
Remove an event by its handler function. See support events here
Remove all the subscribers to the given event. See support events here
Return: Function(req, res, next)
Return a connect/express compatible middleware
Raw HTTP request/response handler.
Starts a HTTP proxy server in the given port
Close the HTTP proxy server, if exists.
Shortcut to rocky#server.close(cb)
Return: Route
Add a route handler for the given path for all HTTP methods
Return: Route
Configure a new route the given path with GET method
Return: Route
Configure a new route the given path with POST method
Return: Route
Configure a new route the given path with PUT method
Return: Route
Configure a new route the given path with DELETE method
Return: Route
Configure a new route the given path with PATCH method
Return: Route
Configure a new route the given path with HEAD method
Parse and expose the query params in http.IncomingMessage object via req.query = Object.
Additionally you can pass an object with additional params to add or a middleware function(req, res, next) to work in details with query params.
Add/extend custom headers to the incoming request before forward/replay it.
Define a custom timeout for forward/replay traffic in miliseconds.
Internal router instance
HTTP/HTTPS server instance.
Only present if listen() was called starting the built-in server.
Exposes the MiddlewarePool instance.
Aliases: target, forwardTo
Overwrite forward server for the current route.
Alias: replyTo
Overwrite replay servers for the current route.
opts param provide specific replay options, overwritting the parent options.
Define a set of URLs to balance between with a simple round-robin like scheduler.
urls param must be an array of strings.
Disable replay logic for the current route.
Shortcut method to intercept and reply the incoming request.
If used, body param must be a string or buffer
Unregister the current route. If the route if matched by the router, it will be ignored, continuing to the next route in the stack.
Define a custom timeout for forward/replay traffic in miliseconds.
Overwrite the request path, defining additional optional params.
Define or overwrite request headers for the current route.
Parse and expose the query params in http.IncomingMessage object via req.query = Object.
Additionally you can pass an object with additional params to add or a middleware function(req, res, next) to work in details with query params.
Overwrite the Host header value when forward the request.
Redirect the incoming request for the current route.
Alias: sequential
Dispatch the replay phase after the forward request ends (either with success or fail status).
Note: this will buffer all the body data. Avoid using it with large payloads
Enable sequential replay process executed in FIFO order: if some replay request fails, the queue is empty and the process will stop
Note: this will buffer all the body data. Avoid using it with large payloads
Enable retry logic for forward traffic. See allowed options here.
You can also define additional retry validations passing an array of function via strategies field in opts object argument.
Note: enabling retry logic will forces buffering all the body payload. Be careful when using it with large payloads
var customRetryStrategies = [
function invalidCodes(err, res) {
return !err && [404, 406].indexOf(res.statusCode) !== -1
}
]
rocky()
.get('/download/:id')
.retry({
retries: 3,
factor: 2,
minTimeout: 100,
maxTimeout: 30 * 1000,
randomize: true,
strategies: customRetryStrategies
})
rocky.forward('http://inconsistent-server')
Alias: interceptBody
Intercept and cache in a buffer the request payload data.
Body will be exposed in req.body.
Note: use it only for small payloads, since the whole body will be buffered in memory
Alias: transformRequestBody()
This method implements a non-instrusive native http.IncommingMessage stream wrapper that allow you to intercept and transform the request body received from the client before sending it to the target server.
The middleware argument must a function which accepts the following arguments: function(req, res, next)
The filter arguments is optional and it can be a string, regexp or function(req) which should return boolean if the request passes the filter. The default check value by string or regexp test is the Content-Type header.
In the middleware function must call the next function, which accepts the following arguments: err, newBody, encoding
You can see an usage example here.
Caution: using this middleware could generate in some scenarios negative performance side-effects, since the whole payload data will be buffered in the heap until it's finished. Don't use it if you need to handle large payloads.
The body will be exposed as raw Buffer or String on both properties body and originalBody in http.ClientRequest:
rocky
.post('/users')
.transformRequest(function (req, res, next) {
// Get the body buffer and parse it (assuming it's a JSON)
var body = JSON.parse(req.body.toString())
// Compose the new body
var newBody = JSON.stringify({ salutation: 'hello ' + body.hello })
// Set the new body
next(null, newBody, 'utf8')
}, function (req) {
// Custom filter
return /application\/json/i.test(req.headers['content-type'])
})
Alias: transformResponseBody()
This method implements a non-instrusive native http.RequestResponse stream wrapper that allow you to intercept and transform the response body received from the target server before sending it to the client.
The middleware argument must a function which accepts the following arguments: function(req, res, next)
The filter arguments is optional and it can be a string, regexp or function(res) which should return boolean if the request passes the filter. The default check value by string or regexp test is the Content-Type header.
In the middleware function must call the next function, which accepts the following arguments: err, newBody, encoding
You can see an usage example here.
Caution: using this middleware could generate in some scenarios negative performance side-effects since the whole payload data will be buffered in the heap until it's finished. Don't use it if you need to handle large payloads.
The body will be exposed as raw Buffer or String on both properties body and originalBody in http.ClientResponse:
rocky
.post('/users')
.transformResponse(function (req, res, next) {
// Get the body buffer and parse it (assuming it's a JSON)
var body = JSON.parse(res.body.toString())
// Compose the new body
var newBody = JSON.stringify({ salutation: 'hello ' + body.hello })
// Set the new body
next(null, newBody, 'utf8')
}, function (res) {
// Custom filter
return /application\/json/i.test(res.getHeader('content-type'))
})
Overwrite default proxy options for the current route. You can pass any supported option by http-proxy
Use a middleware for the incoming traffic for the current route for both replay/forward phases.
Use a middleware for current route incoming traffic in the HTTP replay phase. This middleware stack can be useful to differ between forward/replay traffic, applying separated flows of middleware.
Use a middleware for current route incoming traffic only for the HTTP request forward phase.
For most cases you will only use .use(), but for particular modifications only for the forwarded traffic, this middleware can be useful.
This method is used internally, however it's also public since it could be useful
for dynamic middleware configurations instead of using the shortcut methods such as: useReplay or useForward.
Subscribes to a specific event for the given route. Useful to incercept the status or modify the options on-the-fly
opts, proxyReq, req, res - Fired when the request forward startsopts, proxyRes, req, res - Fired when the target server respondreq, res - Fired when the proxy receives the response from the servererr, req, res - Fired when the proxy request failserr, req, res - Fired before perform a retry request attemptparams, opts, req - Fired before a replay request startsopts, err, req, res - Fired when a replay request failsparams, opts, req - Fired when a replay request endsparams, opts, req - Fired when a replay request process is stoppedparams, opts, req - Fired before perform a retry request attempt for replay trafficerr, req, res - Fired on server middleware error. Only available if running as standalone HTTP serverreq, res - Fired on missing route. Only available if running as standalone HTTP serverFor more information about events, see the events fired by http-proxy
Subscribes to a specific event for the given route, and unsubscribes after dispatched
Remove an event by its handler function in the current route
Exposes the MiddlewarePool instance used for the route scope.
Expose the built-in internal middleware functions.
You can reuse them as standard middleware in diferent ways, like this:
rocky()
.all('/*')
.use(rocky.middleware.headers({
'Authorization': 'Bearer 0123456789'
}))
.useReplay(rocky.middleware.host('replay.server.net'))
Intercept and optionally transform/replace the request body before forward it to the target server.
See rocky#transformRequestBody for more details.
Intercept and optionally transform/replace the response body from the server before send it to the client.
See rocky#transformResponseBody for more details.
Overrites the request URL path of the incoming request before forward/replay it.
Add/extend custom headers to the incoming request before forward/replay it.
Add/extend custom query string params to the incoming request.
Overwrite the Host header before forwarding/replaying the request. Useful for some scenarios (e.g Heroku).
Shortcut method to reply the intercepted request from the middleware, with optional headers and body data.
Shortcut method to redirect the current request.
Accessor for the Route module
Accessor for the Base module
Accessor for the Dispatcher module
Accessor for the passthrough module
For hacking purposes, you can add additional HTTP traffic passthrough phases pushing the pass function via passthrough.passes.push()
Accessor for the http-proxy API
Middleware pool abstraction layer used internally by rocky.
See the code for API docs.
Current rocky package semver
MIT - Tomas Aparicio
FAQs
Full-featured, middleware-oriented, hackable HTTP and WebSocket proxy
The npm package rocky receives a total of 1,785 weekly downloads. As such, rocky popularity was classified as popular.
We found that rocky demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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