70 lines
1.7 KiB
Go
70 lines
1.7 KiB
Go
package reverseproxy
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import (
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"context"
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"net/http"
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"net/http/httputil"
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"net/url"
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"strings"
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)
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type ReverseProxy struct {
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*httputil.ReverseProxy
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}
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type CtxKey string
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func New(ctx context.Context, host string) *ReverseProxy {
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ctxKey := CtxKey("host")
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ctx = context.WithValue(ctx, ctxKey, host)
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reverseproxy := &httputil.ReverseProxy{
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Director: func(r *http.Request) {
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r = r.WithContext(ctx)
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hostFromCtx := ctx.Value(ctxKey).(string)
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target, _ := url.Parse(hostFromCtx)
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targetQuery := target.RawQuery
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r.URL.Scheme = target.Scheme
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r.URL.Host = target.Host
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r.URL.Path, r.URL.RawPath = joinURLPath(target, r.URL)
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if targetQuery == "" || r.URL.RawQuery == "" {
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r.URL.RawQuery = targetQuery + r.URL.RawQuery
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} else {
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r.URL.RawQuery = targetQuery + "&" + r.URL.RawQuery
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}
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},
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}
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return &ReverseProxy{reverseproxy}
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}
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func singleJoiningSlash(a, b string) string {
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aslash := strings.HasSuffix(a, "/")
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bslash := strings.HasPrefix(b, "/")
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switch {
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case aslash && bslash:
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return a + b[1:]
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case !aslash && !bslash:
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return a + "/" + b
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}
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return a + b
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}
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func joinURLPath(a, b *url.URL) (path, rawpath string) {
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if a.RawPath == "" && b.RawPath == "" {
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return singleJoiningSlash(a.Path, b.Path), ""
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}
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// Same as singleJoiningSlash, but uses EscapedPath to determine
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// whether a slash should be added
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apath := a.EscapedPath()
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bpath := b.EscapedPath()
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aslash := strings.HasSuffix(apath, "/")
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bslash := strings.HasPrefix(bpath, "/")
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switch {
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case aslash && bslash:
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return a.Path + b.Path[1:], apath + bpath[1:]
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case !aslash && !bslash:
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return a.Path + "/" + b.Path, apath + "/" + bpath
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}
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return a.Path + b.Path, apath + bpath
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}
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