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package reqctx
import (
"context"
"net/http"
"github.com/anacrolix/missinggo/expect"
)
func NewValue() *contextValue {
return &contextValue{new(byte)}
}
type contextValue struct {
key interface{}
}
func (me contextValue) Get(ctx context.Context) interface{} {
return ctx.Value(me.key)
}
// Sets the value on the Request. It must not have been already set.
func (me contextValue) SetRequestOnce(r *http.Request, val interface{}) *http.Request {
expect.Nil(me.Get(r.Context()))
return r.WithContext(context.WithValue(r.Context(), me.key, val))
}
// Returns a middleware that sets the value in the Request's Context.
func (me contextValue) SetMiddleware(val interface{}) func(http.Handler) http.Handler {
return func(h http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
r = me.SetRequestOnce(r, val)
h.ServeHTTP(w, r)
})
}
}
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