elazarl/goproxyA customizable HTTP/HTTPS proxy library for Go supporting regular forwarding, CONNECT tunneling, MITM TLS interception, and programmatic request/response modification.
GoProxy is a library to create a customized HTTP/HTTPS proxy server using
Go (aka Golang), with several configurable settings available.
The target of this project is to offer an optimized proxy server, usable with
reasonable amount of traffic, yet customizable and programmable.
The proxy itself is simply a net/http handler, so you can add multiple
middlewares (panic recover, logging, compression, etc.) over it. It can be
easily integrated with any other HTTP network library.
In order to use goproxy, one should set their browser (or any other client)
to use goproxy as an HTTP proxy.
Here is how you do that in Chrome
and in Firefox.
If you decide to start with the base example, the URL you should use as
proxy is localhost:8080, which is the default one in our example.
You also have to trust
the proxy CA certificate, to avoid any certificate issue in the clients.
specific hosts, with a single equality comparison or with regex evaluationrequests and responses before sending them to the browsercustom http.Transport to perform requests to the target serverMITM certificates cache, to reuse them later for other requests to the same host, thus saving CPU. Not enabled by default, but you should use it in production!custom handler, when the target is a relative path (e.g. /ping)Logger interfacedisable the HTTP request headers canonicalization, by setting PreventCanonicalization to trueDoes your company use GoProxy? Help us keep the project maintained and healthy! Supporting GoProxy allows us to dedicate more time to bug fixes and new features. In exchange, if you choose a Gold Supporter or Enterprise plan, we'll proudly display your company logo here.
If you need to integrate GoProxy into your project, or you need some custom features to maintain in your fork, you can contact Erik (the current maintainer) by email, and you can discuss together how he can help you as a paid independent consultant.
If you have any trouble, suggestion, or if you find a bug, feel free to reach
out by opening a GitHub issue.
This is an open source project managed by volunteers, and we're happy
to discuss anything that can improve it.
Make sure to explain everything, including the reason behind the issue
and what you want to change, to make the problem easier to understand.
You can also directly open a Pull Request, if it's a small code change, but
you need to explain in the description everything.
If you open a pull request named refactoring with 5,000 lines changed,
we won't merge it... :D
The code for this project is released under the BSD 3-Clause license,
making it useful for commercial uses as well.
So, you have introduced & integrated GoProxy into one of your personal projects or a project inside the company you work for.
We're happy to learn about new creative solutions made with this library,
so feel free to contact the maintainer listed above via e-mail, to explaining
why you found this project useful for your needs.
If you have signed a Non Disclosure Agreement with the company, you
can propose them to write a blog post on their official website about
this topic, so this information will be public by their choice, and you can
share the link of the blog post with us :)
The purpose of case studies is to share with the community why all the
contributors to this project are improving the world with their help and
what people are building using it.
The codebase uses an automatic lint check over your Pull Request code. Before opening it, you should check if your changes respect it, by running the linter in your local machine, so you won't have any surprise.
To install the linter:
go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest
This will create an executable in your $GOPATH/bin folder
($GOPATH is an environment variable, usually
its value is equivalent to ~/go, check its value in your machine if you
aren't sure about it).
Make sure to include the bin folder in the path of your shell, to be able to
directly use the golangci-lint run command.
To get a taste of goproxy, here you are a basic HTTP/HTTPS proxy
that just forward data to the destination:
package main
import (
"log"
"net/http"
"github.com/elazarl/goproxy"
)
func main() {
proxy := goproxy.NewProxyHttpServer()
proxy.Verbose = true
log.Fatal(http.ListenAndServe(":8080", proxy))
}
This line will add X-GoProxy: yxorPoG-X header to all requests sent through the proxy,
before sending them to the destination:
proxy.OnRequest().DoFunc(
func(r *http.Request,ctx *goproxy.ProxyCtx)(*http.Request,*http.Response) {
r.Header.Set("X-GoProxy","yxorPoG-X")
return r,nil
})
When the OnRequest() input is empty, the function specified in DoFunc
will process all incoming requests to the proxy. In this case, it will add
a header to the request and return it to the caller.
The proxy will send the modified request to the destination.
You can also use Do instead of DoFunc, if you implement the specified
interface in your type.
⚠️ Note we returned a nil value as the response. If the returned response is not nil, goproxy will discard the request and send the specified response to the client.
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