105 lines
2.4 KiB
Go
105 lines
2.4 KiB
Go
package handler
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import (
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"fmt"
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"net/http"
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"net/http/httputil"
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"strconv"
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"strings"
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"git.pyer.club/kingecg/gohttpd/model"
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"git.pyer.club/kingecg/gologger"
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)
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type ProxyHandler struct {
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proxy []*httputil.ReverseProxy
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Upstreams []string
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count int
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}
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func (p *ProxyHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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l := gologger.GetLogger("Proxy")
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originalUrl := r.Host + r.URL.String()
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s, err := r.Cookie("s")
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var proxyIndex int
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if err != nil {
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proxyIndex = p.count
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p.count++
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if p.count >= len(p.proxy) {
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p.count = 0
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}
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} else {
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proxyIndex, _ = strconv.Atoi(s.Value)
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}
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l.Info(fmt.Sprintf("proxy %s to %s", originalUrl, p.Upstreams[proxyIndex]))
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p.proxy[proxyIndex].ServeHTTP(w, r)
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}
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/*
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*
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init httputil.ReverseProxy instance and add path rewrite and add session-sticky cookie to response
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@param upstream upstream server url
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@param path http path config
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@param index the proxy index in upstreams
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@return httputil.ReverseProxy instance
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what is the directive? its stands for update of request, like HostSchemas, Path, RemoveCookie, etc.
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eg: HostSchemas $target
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it stande for replace req url host and schema according to $target url. $target == upstream
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*/
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func makeProxy(upstream string, path *model.HttpPath, index int) *httputil.ReverseProxy {
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p := &httputil.ReverseProxy{}
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directiveHandlers := []func(r *http.Request){}
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if len(path.Directives) > 0 {
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for _, directive := range path.Directives {
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d := strings.Replace(string(directive), "$target", upstream, 1)
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dh := GetUpdaterFn(d)
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if dh != nil {
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directiveHandlers = append(directiveHandlers, dh)
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}
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}
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}
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p.Director = func(req *http.Request) {
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for _, handler := range directiveHandlers {
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handler(req)
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}
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}
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p.ModifyResponse = func(resp *http.Response) error {
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hasSticky := false
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for _, cookie := range resp.Cookies() {
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if cookie.Name == "s" {
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hasSticky = true
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break
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}
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}
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if !hasSticky {
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c := http.Cookie{
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Name: "s",
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Value: strconv.Itoa(index),
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}
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resp.Header.Add("Set-Cookie", c.String())
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}
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return nil
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}
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return p
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}
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func NewProxyHandler(p *model.HttpPath) *ProxyHandler {
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upstreamCount := len(p.Upstreams)
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if upstreamCount == 0 {
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panic("no upstream defined")
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}
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ph := &ProxyHandler{
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Upstreams: p.Upstreams,
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}
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ph.proxy = make([]*httputil.ReverseProxy, upstreamCount)
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for index, upstream := range p.Upstreams {
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ph.proxy[index] = makeProxy(upstream, p, index)
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}
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return ph
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}
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