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package xhandler
import (
"net/http"
"time"
"context"
)
// CloseHandler returns a Handler, cancelling the context when the client
// connection closes unexpectedly.
func CloseHandler(next HandlerC) HandlerC {
return HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) {
// Cancel the context if the client closes the connection
if wcn, ok := w.(http.CloseNotifier); ok {
var cancel context.CancelFunc
ctx, cancel = context.WithCancel(ctx)
defer cancel()
notify := wcn.CloseNotify()
go func() {
select {
case <-notify:
cancel()
case <-ctx.Done():
}
}()
}
next.ServeHTTPC(ctx, w, r)
})
}
// TimeoutHandler returns a Handler which adds a timeout to the context.
//
// Child handlers have the responsability of obeying the context deadline and to return
// an appropriate error (or not) response in case of timeout.
func TimeoutHandler(timeout time.Duration) func(next HandlerC) HandlerC {
return func(next HandlerC) HandlerC {
return HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) {
ctx, _ = context.WithTimeout(ctx, timeout)
next.ServeHTTPC(ctx, w, r)
})
}
}
// If is a special handler that will skip insert the condNext handler only if a condition
// applies at runtime.
func If(cond func(ctx context.Context, w http.ResponseWriter, r *http.Request) bool, condNext func(next HandlerC) HandlerC) func(next HandlerC) HandlerC {
return func(next HandlerC) HandlerC {
return HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) {
if cond(ctx, w, r) {
condNext(next).ServeHTTPC(ctx, w, r)
} else {
next.ServeHTTPC(ctx, w, r)
}
})
}
}