mirror of https://github.com/k3s-io/k3s
123 lines
4.7 KiB
Markdown
123 lines
4.7 KiB
Markdown
# Introduction
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[](https://godoc.org/github.com/elazarl/goproxy)
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[](https://gitter.im/elazarl/goproxy?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
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Package goproxy provides a customizable HTTP proxy library for Go (golang),
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It supports regular HTTP proxy, HTTPS through CONNECT, and "hijacking" HTTPS
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connection using "Man in the Middle" style attack.
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The intent of the proxy, is to be usable with reasonable amount of traffic
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yet, customizable and programmable.
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The proxy itself is simply a `net/http` handler.
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In order to use goproxy, one should set their browser to use goproxy as an HTTP
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proxy. Here is how you do that [in Chrome](https://support.google.com/chrome/answer/96815?hl=en)
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and [in Firefox](http://www.wikihow.com/Enter-Proxy-Settings-in-Firefox).
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For example, the URL you should use as proxy when running `./bin/basic` is
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`localhost:8080`, as this is the default binding for the basic proxy.
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## Mailing List
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New features would be discussed on the [mailing list](https://groups.google.com/forum/#!forum/goproxy-dev)
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before their development.
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## Latest Stable Release
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Get the latest goproxy from `gopkg.in/elazarl/goproxy.v1`.
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# Why not Fiddler2?
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Fiddler is an excellent software with similar intent. However, Fiddler is not
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as customable as goproxy intend to be. The main difference is, Fiddler is not
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intended to be used as a real proxy.
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A possible use case that suits goproxy but
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not Fiddler, is, gathering statistics on page load times for a certain website over a week.
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With goproxy you could ask all your users to set their proxy to a dedicated machine running a
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goproxy server. Fiddler is a GUI app not designed to be ran like a server for multiple users.
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# A taste of goproxy
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To get a taste of `goproxy`, a basic HTTP/HTTPS transparent proxy
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```go
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package main
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import (
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"github.com/elazarl/goproxy"
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"log"
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"net/http"
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)
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func main() {
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proxy := goproxy.NewProxyHttpServer()
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proxy.Verbose = true
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log.Fatal(http.ListenAndServe(":8080", proxy))
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}
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```
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This line will add `X-GoProxy: yxorPoG-X` header to all requests sent through the proxy
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```go
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proxy.OnRequest().DoFunc(
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func(r *http.Request,ctx *goproxy.ProxyCtx)(*http.Request,*http.Response) {
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r.Header.Set("X-GoProxy","yxorPoG-X")
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return r,nil
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})
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```
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`DoFunc` will process all incoming requests to the proxy. It will add a header to the request
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and return it. The proxy will send the modified request.
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Note that we returned nil value as the response. Have we returned a response, goproxy would
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have discarded the request and sent the new response to the client.
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In order to refuse connections to reddit at work time
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```go
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proxy.OnRequest(goproxy.DstHostIs("www.reddit.com")).DoFunc(
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func(r *http.Request,ctx *goproxy.ProxyCtx)(*http.Request,*http.Response) {
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if h,_,_ := time.Now().Clock(); h >= 8 && h <= 17 {
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return r,goproxy.NewResponse(r,
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goproxy.ContentTypeText,http.StatusForbidden,
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"Don't waste your time!")
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}
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return r,nil
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})
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```
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`DstHostIs` returns a `ReqCondition`, that is a function receiving a `Request` and returning a boolean
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we will only process requests that matches the condition. `DstHostIs("www.reddit.com")` will return
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a `ReqCondition` accepting only requests directed to "www.reddit.com".
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`DoFunc` will receive a function that will preprocess the request. We can change the request, or
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return a response. If the time is between 8:00am and 17:00pm, we will neglect the request, and
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return a precanned text response saying "do not waste your time".
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See additional examples in the examples directory.
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# What's New
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1. Ability to `Hijack` CONNECT requests. See
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[the eavesdropper example](https://github.com/elazarl/goproxy/blob/master/examples/goproxy-eavesdropper/main.go#L27)
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2. Transparent proxy support for http/https including MITM certificate generation for TLS. See the [transparent example.](https://github.com/elazarl/goproxy/tree/master/examples/goproxy-transparent)
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# License
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I put the software temporarily under the Go-compatible BSD license,
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if this prevents someone from using the software, do let me know and I'll consider changing it.
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At any rate, user feedback is very important for me, so I'll be delighted to know if you're using this package.
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# Beta Software
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I've received a positive feedback from a few people who use goproxy in production settings.
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I believe it is good enough for usage.
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I'll try to keep reasonable backwards compatibility. In case of a major API change,
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I'll change the import path.
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