113 lines
2.3 KiB
Go
113 lines
2.3 KiB
Go
package httptoo
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import (
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"context"
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"io"
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"net/http"
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"sync"
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"github.com/anacrolix/missinggo"
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)
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type responseWriter struct {
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mu sync.Mutex
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r http.Response
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headerWritten missinggo.Event
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bodyWriter io.WriteCloser
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bodyClosed missinggo.SynchronizedEvent
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}
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var _ interface {
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http.ResponseWriter
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// We're able to emulate this easily enough.
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http.CloseNotifier
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} = &responseWriter{}
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// Use Request.Context.Done instead.
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func (me *responseWriter) CloseNotify() <-chan bool {
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ret := make(chan bool, 1)
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go func() {
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<-me.bodyClosed.C()
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ret <- true
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}()
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return ret
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}
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func (me *responseWriter) Header() http.Header {
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if me.r.Header == nil {
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me.r.Header = make(http.Header)
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}
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return me.r.Header
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}
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func (me *responseWriter) Write(b []byte) (int, error) {
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me.mu.Lock()
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if !me.headerWritten.IsSet() {
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me.writeHeader(200)
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}
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me.mu.Unlock()
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return me.bodyWriter.Write(b)
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}
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func (me *responseWriter) WriteHeader(status int) {
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me.mu.Lock()
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me.writeHeader(status)
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me.mu.Unlock()
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}
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func (me *responseWriter) writeHeader(status int) {
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if me.headerWritten.IsSet() {
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return
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}
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me.r.StatusCode = status
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me.headerWritten.Set()
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}
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func (me *responseWriter) runHandler(h http.Handler, req *http.Request) {
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var pr *io.PipeReader
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pr, me.bodyWriter = io.Pipe()
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me.r.Body = struct {
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io.Reader
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io.Closer
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}{pr, eventCloser{pr, &me.bodyClosed}}
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// Shouldn't be writing to the response after the handler returns.
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defer me.bodyWriter.Close()
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// Send a 200 if nothing was written yet.
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defer me.WriteHeader(200)
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// Wrap the context in the given Request with one that closes when either
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// the handler returns, or the response body is closed.
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ctx, cancel := context.WithCancel(req.Context())
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defer cancel()
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go func() {
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<-me.bodyClosed.C()
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cancel()
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}()
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h.ServeHTTP(me, req.WithContext(ctx))
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}
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type eventCloser struct {
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c io.Closer
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closed *missinggo.SynchronizedEvent
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}
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func (me eventCloser) Close() (err error) {
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err = me.c.Close()
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me.closed.Set()
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return
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}
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func RoundTripHandler(req *http.Request, h http.Handler) (*http.Response, error) {
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rw := responseWriter{}
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go rw.runHandler(h, req)
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<-rw.headerWritten.LockedChan(&rw.mu)
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return &rw.r, nil
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}
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type InProcRoundTripper struct {
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Handler http.Handler
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}
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func (me *InProcRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
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return RoundTripHandler(req, me.Handler)
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}
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