goproxy

package module
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 Go to latest Published: Nov 18, 2021 License: BSD-3-Clause Imports: 32 Imported by: 3

README

Introduction

GoDoc Status

Package goproxy provides a customizable HTTP proxy library for Go (golang),

It supports regular HTTP proxy, HTTPS through CONNECT, and "hijacking" HTTPS connection using "Man in the Middle" style attack.

The intent of the proxy is to be usable with reasonable amount of traffic, yet customizable and programmable.

The proxy itself is simply a net/http handler.

In order to use goproxy, one should set their browser to use goproxy as an HTTP proxy. Here is how you do that in Chrome and in Firefox.

For example, the URL you should use as proxy when running ./bin/basic is localhost:8080, as this is the default binding for the basic proxy.

Mailing List

New features will be discussed on the mailing list before their development.

Latest Stable Release

Get the latest goproxy from gopkg.in/elazarl/goproxy.v1.

Why not Fiddler2?

Fiddler is an excellent software with similar intent. However, Fiddler is not as customizable as goproxy intends to be. The main difference is, Fiddler is not intended to be used as a real proxy.

A possible use case that suits goproxy but not Fiddler, is gathering statistics on page load times for a certain website over a week. With goproxy you could ask all your users to set their proxy to a dedicated machine running a goproxy server. Fiddler is a GUI app not designed to be run like a server for multiple users.

A taste of goproxy

To get a taste of goproxy, a basic HTTP/HTTPS transparent proxy

package main

import (
    "github.com/moond4rk/goproxy"
    "log"
    "net/http"
)

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

proxy.OnRequest().DoFunc(
    func(r *http.Request,ctx *goproxy.ProxyCtx)(*http.Request,*http.Response) {
        r.Header.Set("X-GoProxy","yxorPoG-X")
        return r,nil
    })

DoFunc will process all incoming requests to the proxy. It will add a header to the request and return it. The proxy will send the modified request.

Note that we returned nil value as the response. Had we returned a response, goproxy would have discarded the request and sent the new response to the client.

In order to refuse connections to reddit at work time

proxy.OnRequest(goproxy.DstHostIs("www.reddit.com")).DoFunc(
    func(r *http.Request,ctx *goproxy.ProxyCtx)(*http.Request,*http.Response) {
        if h,_,_ := time.Now().Clock(); h >= 8 && h <= 17 {
            return r,goproxy.NewResponse(r,
                    goproxy.ContentTypeText,http.StatusForbidden,
                    "Don't waste your time!")
        }
        return r,nil
})

DstHostIs returns a ReqCondition, that is a function receiving a Request and returning a boolean. We will only process requests that match the condition. DstHostIs("www.reddit.com") will return a ReqCondition accepting only requests directed to "www.reddit.com".

DoFunc will receive a function that will preprocess the request. We can change the request, or return a response. If the time is between 8:00am and 17:00pm, we will reject the request, and return a precanned text response saying "do not waste your time".

See additional examples in the examples directory.

Type of handlers for manipulating connect/req/resp behavior

There are 3 kinds of useful handlers to manipulate the behavior, as follows:

// handler called after receiving HTTP CONNECT from the client, and before proxy establish connection 
// with destination host
httpsHandlers   []HttpsHandler
    
// handler called before proxy send HTTP request to destination host
reqHandlers     []ReqHandler 
    
// handler called after proxy receives HTTP Response from destination host, and before proxy forward 
// the Response to the client.
respHandlers    []RespHandler

Depending on what you want to manipulate, the ways to add handlers to each handler list are:

// Add handlers to httpsHandlers 
proxy.OnRequest(Some ReqConditions).HandleConnect(YourHandlerFunc())

// Add handlers to reqHandlers
proxy.OnRequest(Some ReqConditions).Do(YourReqHandlerFunc())

// Add handlers to respHandlers
proxy.OnResponse(Some RespConditions).Do(YourRespHandlerFunc())

For example:

// This rejects the HTTPS request to *.reddit.com during HTTP CONNECT phase
proxy.OnRequest(goproxy.ReqHostMatches(regexp.MustCompile("reddit.*:443$"))).HandleConnect(goproxy.AlwaysReject)

// This will NOT reject the HTTPS request with URL ending with gif, due to the fact that proxy 
// only got the URL.Hostname and URL.Port during the HTTP CONNECT phase if the scheme is HTTPS, which is
// quiet common these days.
proxy.OnRequest(goproxy.UrlMatches(regexp.MustCompile(`.*gif$`))).HandleConnect(goproxy.AlwaysReject)

// The correct way to manipulate the HTTP request using URL.Path as condition is:
proxy.OnRequest(goproxy.UrlMatches(regexp.MustCompile(`.*gif$`))).Do(YourReqHandlerFunc())

What's New

  1. Ability to Hijack CONNECT requests. See the eavesdropper example
  2. Transparent proxy support for http/https including MITM certificate generation for TLS. See the transparent example.

License

I put the software temporarily under the Go-compatible BSD license. If this prevents someone from using the software, do let me know and I'll consider changing it.

At any rate, user feedback is very important for me, so I'll be delighted to know if you're using this package.

Beta Software

I've received positive feedback from a few people who use goproxy in production settings. I believe it is good enough for usage.

I'll try to keep reasonable backwards compatibility. In case of a major API change, I'll change the import path.

Documentation

Overview

Taken from $GOROOT/src/pkg/net/http/chunked needed to write https responses to client.

Package goproxy provides a customizable HTTP proxy, supporting hijacking HTTPS connection.

The intent of the proxy, is to be usable with reasonable amount of traffic yet, customizable and programable.

The proxy itself is simply an `net/http` handler.

Typical usage is 

proxy := goproxy.NewProxyHttpServer()
proxy.OnRequest(..conditions..).Do(..requesthandler..)
proxy.OnRequest(..conditions..).DoFunc(..requesthandlerFunction..)
proxy.OnResponse(..conditions..).Do(..responesHandler..)
proxy.OnResponse(..conditions..).DoFunc(..responesHandlerFunction..)
http.ListenAndServe(":8080", proxy)

Adding a header to each request 

proxy.OnRequest().DoFunc(func(r *http.Request,ctx *goproxy.ProxyCtx) (*http.Request, *http.Response){
	r.Header.Set("X-GoProxy","1")
	return r, nil
})

Note that the function is called before the proxy sends the request to the server

For printing the content type of all incoming responses 

proxy.OnResponse().DoFunc(func(r *http.Response, ctx *goproxy.ProxyCtx)*http.Response{
	println(ctx.Req.Host,"->",r.Header.Get("Content-Type"))
	return r
})

note that we used the ProxyCtx context variable here. It contains the request and the response (Req and Resp, Resp is nil if unavailable) of this specific client interaction with the proxy.

To print the content type of all responses from a certain url, we'll add a ReqCondition to the OnResponse function: 

proxy.OnResponse(goproxy.UrlIs("golang.org/pkg")).DoFunc(func(r *http.Response, ctx *goproxy.ProxyCtx)*http.Response{
	println(ctx.Req.Host,"->",r.Header.Get("Content-Type"))
	return r
})

We can write the condition ourselves, conditions can be set on request and on response 

var random = ReqConditionFunc(func(r *http.Request) bool {
	return rand.Intn(1) == 0
})
var hasGoProxyHeader = RespConditionFunc(func(resp *http.Response,req *http.Request)bool {
	return resp.Header.Get("X-GoProxy") != ""
})

Caution! If you give a RespCondition to the OnRequest function, you'll get a run time panic! It doesn't make sense to read the response, if you still haven't got it!

Finally, we have convenience function to throw a quick response 

proxy.OnResponse(hasGoProxyHeader).DoFunc(func(r*http.Response,ctx *goproxy.ProxyCtx)*http.Response {
	r.Body.Close()
	return goproxy.NewResponse(ctx.Req, goproxy.ContentTypeText, http.StatusForbidden, "Can't see response with X-GoProxy header!")
})

we close the body of the original repsonse, and return a new 403 response with a short message.

Example use cases:

1. https://github.com/moond4rk/goproxy/tree/master/examples/goproxy-avgsize

To measure the average size of an Html served in your site. One can ask all the QA team to access the website by a proxy, and the proxy will measure the average size of all text/html responses from your host.

2. [not yet implemented]

All requests to your web servers should be directed through the proxy, when the proxy will detect html pieces sent as a response to AJAX request, it'll send a warning email.

3. https://github.com/moond4rk/goproxy/blob/master/examples/goproxy-httpdump/

Generate a real traffic to your website by real users using through proxy. Record the traffic, and try it again for more real load testing.

4. https://github.com/moond4rk/goproxy/tree/master/examples/goproxy-no-reddit-at-worktime

Will allow browsing to reddit.com between 8:00am and 17:00pm

5. https://github.com/moond4rk/goproxy/tree/master/examples/goproxy-jquery-version

Will warn if multiple versions of jquery are used in the same domain.

6. https://github.com/moond4rk/goproxy/blob/master/examples/goproxy-upside-down-ternet/

Modifies image files in an HTTP response via goproxy's image extension found in ext/.

Index

Constants

View Source 
const (
	ConnectAccept = iota
	ConnectReject
	ConnectMitm
	ConnectHijack
	ConnectHTTPMitm
	ConnectProxyAuthHijack
)
View Source 
const (
	ContentTypeText = "text/plain"
	ContentTypeHtml = "text/html"
)

Variables

View Source 
var (
	OkConnect       = &ConnectAction{Action: ConnectAccept, TLSConfig: TLSConfigFromCA(&GoproxyCa)}
	MitmConnect     = &ConnectAction{Action: ConnectMitm, TLSConfig: TLSConfigFromCA(&GoproxyCa)}
	HTTPMitmConnect = &ConnectAction{Action: ConnectHTTPMitm, TLSConfig: TLSConfigFromCA(&GoproxyCa)}
	RejectConnect   = &ConnectAction{Action: ConnectReject, TLSConfig: TLSConfigFromCA(&GoproxyCa)}
)
View Source 
var CA_CERT = []byte(`-----BEGIN CERTIFICATE-----
MIIF9DCCA9ygAwIBAgIJAODqYUwoVjJkMA0GCSqGSIb3DQEBCwUAMIGOMQswCQYD
VQQGEwJJTDEPMA0GA1UECAwGQ2VudGVyMQwwCgYDVQQHDANMb2QxEDAOBgNVBAoM
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bvTOeWl1/uoFTPYiWR/ww7QEPLq23yDFY04Q7Un0qjIk8ExvaY8lCkXMgc8i7sGY
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BUnFpB/Atptqr4CUlTXrc5IPLAqAfmwk5IKcwy3EXUbruf9Dwz69YA==
-----END CERTIFICATE-----`)
View Source 
var CA_KEY = []byte(`-----BEGIN RSA PRIVATE KEY-----
MIIJKAIBAAKCAgEAnhDL4fqGGhjWzRBFy8iHGuNIdo79FtoWPevCpyek6AWrTuBF
0j3dzRMUpAkemC/p94tGES9f9iWUVi7gnfmUz1lxhjiqUoW5K1xfwmbx+qmC2YAw
HM+yq2oOLwz1FAYoQ3NT0gU6cJXtIB6Hjmxwy4jfDPzCuMFwfvOq4eS+pRJhnPTf
m31XpZOsfJMS9PjD6UU5U3ZsD/oMAjGuMGIXoOGgmqeFrRJm0N+/vtenAYbcSED+
qiGGJisOu5grvMl0RJAvjgvDMw+6lWKCpqV+/5gd9CNuFP3nUhW6tbY0mBHIETrZ
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AmhawnO1gPDnjc3NLLlb79yrhdFiC2rVvRFbC5SKzB7OYyh7IdnwFAl7bEyMA6WU
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4/avCJ8IutT+FcMM+GbGazOm5ALWqUyhrnbLGc4CQMPfe7Il6NxwcrOxT8w=
-----END RSA PRIVATE KEY-----`)
View Source 
var GoproxyCa, _ = tls.X509KeyPair(CA_CERT, CA_KEY)

Functions

func NewResponse 

func NewResponse(r *http.Request, contentType string, status int, body string) *http.Response

Will generate a valid http response to the given request the response will have the given contentType, and http status. Typical usage, refuse to process requests to local addresses: 

proxy.OnRequest(IsLocalHost()).DoFunc(func(r *http.Request, ctx *goproxy.ProxyCtx) (*http.Request,*http.Response) {
	return nil,NewResponse(r,goproxy.ContentTypeHtml,http.StatusUnauthorized,
		`<!doctype html><html><head><title>Can't use proxy for local addresses</title></head><body/></html>`)
})

func TLSConfigFromCA 

func TLSConfigFromCA(ca *tls.Certificate) func(host string, ctx *ProxyCtx) (*tls.Config, error)

func TextResponse 

func TextResponse(r *http.Request, text string) *http.Response

Alias for NewResponse(r,ContentTypeText,http.StatusAccepted,text)

Types

type CertStorage 

type CertStorage interface {
	Fetch(hostname string, gen func() (*tls.Certificate, error)) (*tls.Certificate, error)
}

type ConnectAction 

type ConnectAction struct {
	Action    ConnectActionLiteral
	Hijack    func(req *http.Request, client net.Conn, ctx *ProxyCtx)
	TLSConfig func(host string, ctx *ProxyCtx) (*tls.Config, error)
}

ConnectAction enables the caller to override the standard connect flow. When Action is ConnectHijack, it is up to the implementer to send the HTTP 200, or any other valid http response back to the client from within the Hijack func

type ConnectActionLiteral 

type ConnectActionLiteral int

type CounterEncryptorRand 

type CounterEncryptorRand struct {
	// contains filtered or unexported fields
}

func NewCounterEncryptorRandFromKey 

func NewCounterEncryptorRandFromKey(key interface{}, seed []byte) (r CounterEncryptorRand, err error)

func (*CounterEncryptorRand) Read 

func (c *CounterEncryptorRand) Read(b []byte) (n int, err error)

func (*CounterEncryptorRand) Seed 

func (c *CounterEncryptorRand) Seed(b []byte)

type FuncHttpsHandler 

type FuncHttpsHandler func(host string, ctx *ProxyCtx) (*ConnectAction, string)

A wrapper that would convert a function to a HttpsHandler interface type 

var AlwaysMitm FuncHttpsHandler = func(host string, ctx *ProxyCtx) (*ConnectAction, string) {
	return MitmConnect, host
}

AlwaysMitm is a HttpsHandler that always eavesdrop https connections, for example to eavesdrop all https connections to www.google.com, we can use 

proxy.OnRequest(goproxy.ReqHostIs("www.google.com")).HandleConnect(goproxy.AlwaysMitm)

var AlwaysReject FuncHttpsHandler = func(host string, ctx *ProxyCtx) (*ConnectAction, string) {
	return RejectConnect, host
}

AlwaysReject is a HttpsHandler that drops any CONNECT request, for example, this code will disallow connections to hosts on any other port than 443 

proxy.OnRequest(goproxy.Not(goproxy.ReqHostMatches(regexp.MustCompile(":443$"))).
	HandleConnect(goproxy.AlwaysReject)

func (FuncHttpsHandler) HandleConnect 

func (f FuncHttpsHandler) HandleConnect(host string, ctx *ProxyCtx) (*ConnectAction, string)

FuncHttpsHandler should implement the RespHandler interface

type FuncReqHandler 

type FuncReqHandler func(req *http.Request, ctx *ProxyCtx) (*http.Request, *http.Response)

A wrapper that would convert a function to a ReqHandler interface type

func (FuncReqHandler) Handle 

func (f FuncReqHandler) Handle(req *http.Request, ctx *ProxyCtx) (*http.Request, *http.Response)

FuncReqHandler.Handle(req,ctx) <=> FuncReqHandler(req,ctx)

type FuncRespHandler 

type FuncRespHandler func(resp *http.Response, ctx *ProxyCtx) *http.Response

A wrapper that would convert a function to a RespHandler interface type

func (FuncRespHandler) Handle 

func (f FuncRespHandler) Handle(resp *http.Response, ctx *ProxyCtx) *http.Response

FuncRespHandler.Handle(req,ctx) <=> FuncRespHandler(req,ctx)

type HttpsHandler 

type HttpsHandler interface {
	HandleConnect(req string, ctx *ProxyCtx) (*ConnectAction, string)
}

When a client send a CONNECT request to a host, the request is filtered through all the HttpsHandlers the proxy has, and if one returns true, the connection is sniffed using Man in the Middle attack. That is, the proxy will create a TLS connection with the client, another TLS connection with the destination the client wished to connect to, and would send back and forth all messages from the server to the client and vice versa. The request and responses sent in this Man In the Middle channel are filtered through the usual flow (request and response filtered through the ReqHandlers and RespHandlers)

type Logger 

type Logger interface {
	Printf(format string, v ...interface{})
}

type ProxyConds 

type ProxyConds struct {
	// contains filtered or unexported fields
}

ProxyConds is used to aggregate RespConditions for a ProxyHttpServer. Upon calling ProxyConds.Do, it will register a RespHandler that would handle the HTTP response from remote server if all conditions on the HTTP response are met.

func (*ProxyConds) Do 

func (pcond *ProxyConds) Do(h RespHandler)

ProxyConds.Do will register the RespHandler on the proxy, h.Handle(resp,ctx) will be called on every request that matches the conditions aggregated in pcond.

func (*ProxyConds) DoFunc 

func (pcond *ProxyConds) DoFunc(f func(resp *http.Response, ctx *ProxyCtx) *http.Response)

ProxyConds.DoFunc is equivalent to proxy.OnResponse().Do(FuncRespHandler(f))

type ProxyCtx 

type ProxyCtx struct {
	// Will contain the client request from the proxy
	Req *http.Request
	// Will contain the remote server's response (if available. nil if the request wasn't send yet)
	Resp         *http.Response
	RoundTripper RoundTripper
	// will contain the recent error that occurred while trying to send receive or parse traffic
	Error error
	// A handle for the user to keep data in the context, from the call of ReqHandler to the
	// call of RespHandler
	UserData interface{}
	// Will connect a request to a response
	Session int64

	Proxy *ProxyHttpServer
	// contains filtered or unexported fields
}

ProxyCtx is the Proxy context, contains useful information about every request. It is passed to every user function. Also used as a logger.

func (*ProxyCtx) Charset 

func (ctx *ProxyCtx) Charset() string

Will try to infer the character set of the request from the headers. Returns the empty string if we don't know which character set it used. Currently it will look for charset=<charset> in the Content-Type header of the request.

func (*ProxyCtx) Logf 

func (ctx *ProxyCtx) Logf(msg string, argv ...interface{})

Logf prints a message to the proxy's log. Should be used in a ProxyHttpServer's filter This message will be printed only if the Verbose field of the ProxyHttpServer is set to true 

proxy.OnRequest().DoFunc(func(r *http.Request,ctx *goproxy.ProxyCtx) (*http.Request, *http.Response){
	nr := atomic.AddInt32(&counter,1)
	ctx.Printf("So far %d requests",nr)
	return r, nil
})

func (*ProxyCtx) RoundTrip 

func (ctx *ProxyCtx) RoundTrip(req *http.Request) (*http.Response, error)

func (*ProxyCtx) Warnf 

func (ctx *ProxyCtx) Warnf(msg string, argv ...interface{})

Warnf prints a message to the proxy's log. Should be used in a ProxyHttpServer's filter This message will always be printed. 

proxy.OnRequest().DoFunc(func(r *http.Request,ctx *goproxy.ProxyCtx) (*http.Request, *http.Response){
	f,err := os.OpenFile(cachedContent)
	if err != nil {
		ctx.Warnf("error open file %v: %v",cachedContent,err)
		return r, nil
	}
	return r, nil
})

type ProxyHttpServer 

type ProxyHttpServer struct {

	// KeepDestinationHeaders indicates the proxy should retain any headers present in the http.Response before proxying
	KeepDestinationHeaders bool
	// setting Verbose to true will log information on each request sent to the proxy
	Verbose         bool
	Logger          Logger
	NonproxyHandler http.Handler

	Tr *http.Transport
	// ConnectDial will be used to create TCP connections for CONNECT requests
	// if nil Tr.Dial will be used
	ConnectDial func(network string, addr string) (net.Conn, error)
	CertStore   CertStorage
	KeepHeader  bool
	// contains filtered or unexported fields
}

The basic proxy type. Implements http.Handler.

func NewProxyHttpServer 

func NewProxyHttpServer() *ProxyHttpServer

NewProxyHttpServer creates and returns a proxy server, logging to stderr by default

func (*ProxyHttpServer) NewConnectDialToProxy 

func (proxy *ProxyHttpServer) NewConnectDialToProxy(https_proxy string) func(network, addr string) (net.Conn, error)

func (*ProxyHttpServer) NewConnectDialToProxyWithHandler 

func (proxy *ProxyHttpServer) NewConnectDialToProxyWithHandler(https_proxy string, connectReqHandler func(req *http.Request)) func(network, addr string) (net.Conn, error)

func (*ProxyHttpServer) OnRequest 

func (proxy *ProxyHttpServer) OnRequest(conds ...ReqCondition) *ReqProxyConds

ProxyHttpServer.OnRequest Will return a temporary ReqProxyConds struct, aggregating the given condtions. You will use the ReqProxyConds struct to register a ReqHandler, that would filter the request, only if all the given ReqCondition matched. Typical usage: 

proxy.OnRequest(UrlIs("example.com/foo"),UrlMatches(regexp.MustParse(`.*\.exampl.\com\./.*`)).Do(...)

func (*ProxyHttpServer) OnResponse 

func (proxy *ProxyHttpServer) OnResponse(conds ...RespCondition) *ProxyConds

OnResponse is used when adding a response-filter to the HTTP proxy, usual pattern is 

proxy.OnResponse(cond1,cond2).Do(handler) // handler.Handle(resp,ctx) will be used
			// if cond1.HandleResp(resp) && cond2.HandleResp(resp)

func (*ProxyHttpServer) ServeHTTP 

func (proxy *ProxyHttpServer) ServeHTTP(w http.ResponseWriter, r *http.Request)

Standard net/http function. Shouldn't be used directly, http.Serve will use it.

type ReqCondition 

type ReqCondition interface {
	RespCondition
	HandleReq(req *http.Request, ctx *ProxyCtx) bool
}

ReqCondition.HandleReq will decide whether or not to use the ReqHandler on an HTTP request before sending it to the remote server

func SrcIpIs 

func SrcIpIs(ips ...string) ReqCondition

SrcIpIs returns a ReqCondition testing whether the source IP of the request is one of the given strings

type ReqConditionFunc 

type ReqConditionFunc func(req *http.Request, ctx *ProxyCtx) bool

ReqConditionFunc.HandleReq(req,ctx) <=> ReqConditionFunc(req,ctx) 

var IsLocalHost ReqConditionFunc = func(req *http.Request, ctx *ProxyCtx) bool {
	return req.URL.Host == "::1" ||
		req.URL.Host == "0:0:0:0:0:0:0:1" ||
		localHostIpv4.MatchString(req.URL.Host) ||
		req.URL.Host == "localhost"
}

IsLocalHost checks whether the destination host is explicitly local host (buggy, there can be IPv6 addresses it doesn't catch)

func DstHostIs 

func DstHostIs(host string) ReqConditionFunc

DstHostIs returns a ReqCondition testing wether the host in the request url is the given string

func Not 

func Not(r ReqCondition) ReqConditionFunc

Not returns a ReqCondition negating the given ReqCondition

func ReqHostIs 

func ReqHostIs(hosts ...string) ReqConditionFunc

ReqHostIs returns a ReqCondition, testing whether the host to which the request is directed to equal to one of the given strings

func ReqHostMatches 

func ReqHostMatches(regexps ...*regexp.Regexp) ReqConditionFunc

ReqHostMatches returns a ReqCondition, testing whether the host to which the request was directed to matches any of the given regular expressions.

func UrlHasPrefix 

func UrlHasPrefix(prefix string) ReqConditionFunc

UrlHasPrefix returns a ReqCondition checking wether the destination URL the proxy client has requested has the given prefix, with or without the host. For example UrlHasPrefix("host/x") will match requests of the form 'GET host/x', and will match requests to url 'http://host/x'

func UrlIs 

func UrlIs(urls ...string) ReqConditionFunc

UrlIs returns a ReqCondition, testing whether or not the request URL is one of the given strings with or without the host prefix. UrlIs("google.com/","foo") will match requests 'GET /' to 'google.com', requests `'GET google.com/' to any host, and requests of the form 'GET foo'.

func UrlMatches 

func UrlMatches(re *regexp.Regexp) ReqConditionFunc

UrlMatches returns a ReqCondition testing whether the destination URL of the request matches the given regexp, with or without prefix

func (ReqConditionFunc) HandleReq 

func (c ReqConditionFunc) HandleReq(req *http.Request, ctx *ProxyCtx) bool

func (ReqConditionFunc) HandleResp 

func (c ReqConditionFunc) HandleResp(resp *http.Response, ctx *ProxyCtx) bool

ReqConditionFunc cannot test responses. It only satisfies RespCondition interface so that to be usable as RespCondition.

type ReqHandler 

type ReqHandler interface {
	Handle(req *http.Request, ctx *ProxyCtx) (*http.Request, *http.Response)
}

ReqHandler will "tamper" with the request coming to the proxy server If Handle returns req,nil the proxy will send the returned request to the destination server. If it returns nil,resp the proxy will skip sending any requests, and will simply return the response `resp` to the client.

type ReqProxyConds 

type ReqProxyConds struct {
	// contains filtered or unexported fields
}

ReqProxyConds aggregate ReqConditions for a ProxyHttpServer. Upon calling Do, it will register a ReqHandler that would handle the request if all conditions on the HTTP request are met.

func (*ReqProxyConds) Do 

func (pcond *ReqProxyConds) Do(h ReqHandler)

ReqProxyConds.Do will register the ReqHandler on the proxy, the ReqHandler will handle the HTTP request if all the conditions aggregated in the ReqProxyConds are met. Typical usage: 

proxy.OnRequest().Do(handler) // will call handler.Handle(req,ctx) on every request to the proxy
proxy.OnRequest(cond1,cond2).Do(handler)
// given request to the proxy, will test if cond1.HandleReq(req,ctx) && cond2.HandleReq(req,ctx) are true
// if they are, will call handler.Handle(req,ctx)

func (*ReqProxyConds) DoFunc 

func (pcond *ReqProxyConds) DoFunc(f func(req *http.Request, ctx *ProxyCtx) (*http.Request, *http.Response))

DoFunc is equivalent to proxy.OnRequest().Do(FuncReqHandler(f))

func (*ReqProxyConds) HandleConnect 

func (pcond *ReqProxyConds) HandleConnect(h HttpsHandler)

HandleConnect is used when proxy receives an HTTP CONNECT request, it'll then use the HttpsHandler to determine what should it do with this request. The handler returns a ConnectAction struct, the Action field in the ConnectAction struct returned will determine what to do with this request. ConnectAccept will simply accept the request forwarding all bytes from the client to the remote host, ConnectReject will close the connection with the client, and ConnectMitm, will assume the underlying connection is an HTTPS connection, and will use Man in the Middle attack to eavesdrop the connection. All regular handler will be active on this eavesdropped connection. The ConnectAction struct contains possible tlsConfig that will be used for eavesdropping. If nil, the proxy will use the default tls configuration. 

proxy.OnRequest().HandleConnect(goproxy.AlwaysReject) // rejects all CONNECT requests

func (*ReqProxyConds) HandleConnectFunc 

func (pcond *ReqProxyConds) HandleConnectFunc(f func(host string, ctx *ProxyCtx) (*ConnectAction, string))

HandleConnectFunc is equivalent to HandleConnect, for example, accepting CONNECT request if they contain a password in header 

io.WriteString(h,password)
passHash := h.Sum(nil)
proxy.OnRequest().HandleConnectFunc(func(host string, ctx *ProxyCtx) (*ConnectAction, string) {
	c := sha1.New()
	io.WriteString(c,ctx.Req.Header.Get("X-GoProxy-Auth"))
	if c.Sum(nil) == passHash {
		return OkConnect, host
	}
	return RejectConnect, host
})

func (*ReqProxyConds) HijackConnect 

func (pcond *ReqProxyConds) HijackConnect(f func(req *http.Request, client net.Conn, ctx *ProxyCtx))

type RespCondition 

type RespCondition interface {
	HandleResp(resp *http.Response, ctx *ProxyCtx) bool
}

RespCondition.HandleReq will decide whether or not to use the RespHandler on an HTTP response before sending it to the proxy client. Note that resp might be nil, in case there was an error sending the request.

func ContentTypeIs 

func ContentTypeIs(typ string, types ...string) RespCondition

ContentTypeIs returns a RespCondition testing whether the HTTP response has Content-Type header equal to one of the given strings.

func StatusCodeIs 

func StatusCodeIs(codes ...int) RespCondition

StatusCodeIs returns a RespCondition, testing whether or not the HTTP status code is one of the given ints

type RespConditionFunc 

type RespConditionFunc func(resp *http.Response, ctx *ProxyCtx) bool

RespConditionFunc.HandleResp(resp,ctx) <=> RespConditionFunc(resp,ctx)

func (RespConditionFunc) HandleResp 

func (c RespConditionFunc) HandleResp(resp *http.Response, ctx *ProxyCtx) bool

type RespHandler 

type RespHandler interface {
	Handle(resp *http.Response, ctx *ProxyCtx) *http.Response
}

after the proxy have sent the request to the destination server, it will "filter" the response through the RespHandlers it has. The proxy server will send to the client the response returned by the RespHandler. In case of error, resp will be nil, and ctx.RoundTrip.Error will contain the error

func HandleBytes 

func HandleBytes(f func(b []byte, ctx *ProxyCtx) []byte) RespHandler

HandleBytes will return a RespHandler that read the entire body of the request to a byte array in memory, would run the user supplied f function on the byte arra, and will replace the body of the original response with the resulting byte array.

type RoundTripper 

type RoundTripper interface {
	RoundTrip(req *http.Request, ctx *ProxyCtx) (*http.Response, error)
}

type RoundTripperFunc 

type RoundTripperFunc func(req *http.Request, ctx *ProxyCtx) (*http.Response, error)

func (RoundTripperFunc) RoundTrip 

func (f RoundTripperFunc) RoundTrip(req *http.Request, ctx *ProxyCtx) (*http.Response, error)

Source Files

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