httransform

httransform is the library/framework to build your own HTTP proxies. It relies on high-performant and memory-efficient fasthttp library as HTTP base layer and can give you the ability to build a proxy where you can control every aspect.

Main features of this framework:

1. Support of HTTP (plain HTTP) proxy protocol.
2. Support of HTTPS (with CONNECT method) protocol. This library does MITM and provides the possibility to generate TLS certificates for the hosts on-the-fly.
3. Keeps and maintains the order of headers and their case (no normalization).
4. Supports the concept of layers or middlewares which process HTTP requests and responses.
5. Supports custom executors: a function which converts HTTP requests to HTTP responses. Allowing your proxy to fetch the data from other services, which are not necessarily HTTP. The executor simply converts HTTP request structure to HTTP response.
6. Can support connection upgrades (this includes websockets) with an ability to look into them.

Please check the full documentation for more details.

Example

Just a small example to give you the feeling of how it all looks like:

package main
import (
"context""net""os""os/signal""syscall""time""github.com/9seconds/httransform/v2""github.com/9seconds/httransform/v2/auth""github.com/9seconds/httransform/v2/layers"
)
// These are generates examples of self-signed certificates// to simplify the example.varcaCert= []byte(`-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----`)
varcaPrivateKey= []byte(`-----BEGIN PRIVATE KEY-----MIICdwIBADANBgkqhkiG9w0BAQEFAASCAmEwggJdAgEAAoGBAMvsfN+bHvF8VZNGbbq3+UuwJnA6uLpUjOnZ1gzkenR1XhdRn6rrScRsfA3dSysYoAr9Gyv0JpqbcDXxSmfaXLr1PKvb2RUr4+Ww6BJIJScBhypPXrr+PbTmfcIY0ss4+1Ap8BP+Ifd08E5t3w3gVH0WVeJgiICnWikJvK7aaUeLAgMBAAECgYAk+/kR3OJZzcD/evB/wsoV7haqmBvUv2znJLjrkayb3oV4GTeqGg5A76P4J8BwSoEMPSdma1ttAu/w+JgUCchzVPwU34Sr80mYawOmGVGJsDnrrYA2w51Nj42e71pmRc9IqNLwFEhW5Uy7eASf3THJMWDlF2M6xAVYr+X0eKLf4QJBAO8lVIIMnzIReSZukWBPp6GKmXOuEkWeBOfnYC2HOVZq1M/E6naOP2MBk9CWG4o9ysjcZ1hosi3/txxrc8VmBAkCQQDaS651dpQ3TRE//raZs79ZBEdMCMlgXB6CPrZpvLz/3ZPcLih4MJ59oVkeFHCNct7ccQcQu4XHMGNBIRBhkpvzAkEAlS/AjHC7T0y/O052upJ2jLweBqBtHaj6foFE6qIVDugOYp8BdXw/5s+xGsrJ22+49Z0pi2mk3jVMUhpmWprNoQJBANdAT0v2XFpXfQ38bTQMYT82j9MyytdgnpjRm++Rs1AdvoIbZb52OqIoqoaVoxJnVchLD6t5LYXnecesAcok1e8CQEKB7ycJ6yVwnBE3Ua9CHcGmrre6HmEWdPy1Zyb5DQC6duX46zEBzti9oWx0DJIQRZifeCvw4J45NsSQjuuAAWs=-----END PRIVATE KEY-----`)
funcmain() {
// Root context is crucial here. When root context is closed, a// proxy is shutdown.ctx, cancel:=context.WithCancel(context.Background())
defercancel()
// For demo purpose we are going to close by SIGINT and SIGTERM// signals.signals:=make(chan os.Signal, 1)
signal.Notify(signals, syscall.SIGINT, syscall.SIGTERM)
gofunc() {
forrangesignals {
cancel()
}
}()
// Filter layer is required if you want to drop request// which are made to you internal networks.filterLayer, err:=layers.NewFilterSubnetsLayer([]net.IPNet{
{IP: net.ParseIP("127.0.0.0"), Mask: net.CIDRMask(8, 32)},
{IP: net.ParseIP("172.16.0.0"), Mask: net.CIDRMask(12, 32)},
{IP: net.ParseIP("10.0.0.0"), Mask: net.CIDRMask(8, 32)},
{IP: net.ParseIP("192.168.0.0"), Mask: net.CIDRMask(16, 32)},
})
iferr!=nil {
panic(err)
}
opts:= httransform.ServerOpts{
TLSCertCA: caCert,
TLSPrivateKey: caPrivateKey,
// We are going to use basic proxy authorization with username// 'user' and password 'password'.Authenticator: auth.NewBasicAuth(map[string]string{
"user": "password",
}),
Layers: []layers.Layer{
filterLayer,
// This guy will remove Proxy headers from the request.
layers.ProxyHeadersLayer{},
// This guy is going to limit request processing time to 3// minutes.
layers.TimeoutLayer{
Timeout: 3*time.Minute,
},
},
}
proxy, err:=httransform.NewServer(ctx, opts)
iferr!=nil {
panic(err)
}
// We bind our proxy to the port 3128 and all interfaces.listener, err:=net.Listen("tcp", ":3128")
iferr!=nil {
panic(err)
}
iferr:=proxy.Serve(listener); err!=nil {
panic(err)
}
}

This will create an HTTP proxy on 127.0.0.1:3128. It will also require authentication (user and password) and will remove the Proxy-Authorization header before sending the request further.

v1 version

Version 1 is not supported anymore. Please use version 2. Version 2 has a lot of breaking changes but which really help to maintain a package.

Unfortunately, I cannot enumerate all of them and I understand that it is going to make your life painful in some moments. Sorry for that. v2 was a complete rewrite and I assume that given a size of this library, it won't take a lot of time for you to migrate. But if you have any questions, feel free to open an issue. I'm happy to help.