106 lines
3.2 KiB
Go
106 lines
3.2 KiB
Go
// Package mhttp extends the standard package with extra functionality which is
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// commonly useful
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package mhttp
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import (
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"context"
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"net"
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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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"github.com/mediocregopher/mediocre-go-lib/mctx"
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"github.com/mediocregopher/mediocre-go-lib/merr"
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"github.com/mediocregopher/mediocre-go-lib/mlog"
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"github.com/mediocregopher/mediocre-go-lib/mnet"
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"github.com/mediocregopher/mediocre-go-lib/mrun"
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)
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// Server is returned by WithListeningServer and simply wraps an *http.Server.
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type Server struct {
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*http.Server
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ctx context.Context
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}
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// WithListeningServer returns a *Server which will be initialized and have
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// ListenAndServe called on it (asynchronously) when the start event is
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// triggered on the returned Context (see mrun.Start). The Server will have
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// Shutdown called on it when the stop event is triggered on the returned
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// Context (see mrun.Stop).
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//
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// This function automatically handles setting up configuration parameters via
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// mcfg. The default listen address is ":0".
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func WithListeningServer(ctx context.Context, h http.Handler) (context.Context, *Server) {
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srv := &Server{
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Server: &http.Server{Handler: h},
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ctx: mctx.NewChild(ctx, "http"),
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}
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var listener *mnet.Listener
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srv.ctx, listener = mnet.WithListener(srv.ctx, "tcp", "")
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listener.NoCloseOnStop = true // http.Server.Shutdown will do this
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srv.ctx = mrun.WithStartHook(srv.ctx, func(context.Context) error {
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srv.Addr = listener.Addr().String()
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srv.ctx = mrun.WithThread(srv.ctx, func() error {
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mlog.Info("serving requests", srv.ctx)
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if err := srv.Serve(listener); !merr.Equal(err, http.ErrServerClosed) {
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mlog.Error("error serving listener", srv.ctx, merr.Context(err))
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return err
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}
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return nil
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})
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return nil
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})
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srv.ctx = mrun.WithStopHook(srv.ctx, func(innerCtx context.Context) error {
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mlog.Info("shutting down server", srv.ctx)
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if err := srv.Shutdown(innerCtx); err != nil {
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return err
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}
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return mrun.Wait(srv.ctx, innerCtx.Done())
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})
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return mctx.WithChild(ctx, srv.ctx), srv
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}
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// AddXForwardedFor populates the X-Forwarded-For header on the Request to
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// convey that the request is being proxied for IP.
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//
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// If the IP is invalid, loopback, or otherwise part of a reserved range, this
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// does nothing.
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func AddXForwardedFor(r *http.Request, ipStr string) {
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const xff = "X-Forwarded-For"
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ip := net.ParseIP(ipStr)
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if ip == nil || mnet.IsReservedIP(ip) { // IsReservedIP includes loopback
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return
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}
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prev, _ := r.Header[xff]
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r.Header.Set(xff, strings.Join(append(prev, ip.String()), ", "))
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}
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// ReverseProxy returns an httputil.ReverseProxy which will send requests to the
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// given URL and copy their responses back without modification.
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//
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// Only the Scheme and Host of the given URL are used.
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//
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// Any http.ResponseWriters passed into the ServeHTTP call of the returned
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// instance should not be modified afterwards.
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func ReverseProxy(u *url.URL) *httputil.ReverseProxy {
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rp := new(httputil.ReverseProxy)
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rp.Director = func(req *http.Request) {
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if ipStr, _, err := net.SplitHostPort(req.RemoteAddr); err != nil {
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AddXForwardedFor(req, ipStr)
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}
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req.URL.Scheme = u.Scheme
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req.URL.Host = u.Host
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}
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// TODO when this package has a function for creating a Client use that for
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// the default here
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return rp
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}
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