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50 lines
1.2 KiB
50 lines
1.2 KiB
4 years ago
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package middleware
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import (
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"context"
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"net/http"
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"time"
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)
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// Timeout is a middleware that cancels ctx after a given timeout and return
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// a 504 Gateway Timeout error to the client.
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//
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// It's required that you select the ctx.Done() channel to check for the signal
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// if the context has reached its deadline and return, otherwise the timeout
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// signal will be just ignored.
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//
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// ie. a route/handler may look like:
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//
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// r.Get("/long", func(w http.ResponseWriter, r *http.Request) {
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// ctx := r.Context()
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// processTime := time.Duration(rand.Intn(4)+1) * time.Second
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//
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// select {
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// case <-ctx.Done():
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// return
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//
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// case <-time.After(processTime):
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// // The above channel simulates some hard work.
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// }
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//
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// w.Write([]byte("done"))
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// })
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//
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func Timeout(timeout time.Duration) func(next http.Handler) http.Handler {
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return func(next http.Handler) http.Handler {
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fn := func(w http.ResponseWriter, r *http.Request) {
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ctx, cancel := context.WithTimeout(r.Context(), timeout)
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defer func() {
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cancel()
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if ctx.Err() == context.DeadlineExceeded {
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w.WriteHeader(http.StatusGatewayTimeout)
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}
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}()
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r = r.WithContext(ctx)
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next.ServeHTTP(w, r)
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}
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return http.HandlerFunc(fn)
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}
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}
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