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@sify21
Forked from gbbr/middleware_full.go
Created November 26, 2019 09:18
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package main
import (
"fmt"
"log"
"net/http"
)
func init() {
log.SetFlags(log.Lshortfile)
}
// middleware provides a convenient mechanism for filtering HTTP requests
// entering the application. It returns a new handler which performs various
// operations and finishes with calling the next HTTP handler.
type middleware func(http.HandlerFunc) http.HandlerFunc
// chainMiddleware provides syntactic sugar to create a new middleware
// which will be the result of chaining the ones received as parameters.
func chainMiddleware(mw ...middleware) middleware {
return func(final http.HandlerFunc) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
last := final
for i := len(mw) - 1; i >= 0; i-- {
last = mw[i](last)
}
last(w, r)
}
}
}
func withLogging(next http.HandlerFunc) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
log.Printf("Logged connection from %s", r.RemoteAddr)
next.ServeHTTP(w, r)
}
}
func withTracing(next http.HandlerFunc) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
log.Printf("Tracing request for %s", r.RequestURI)
next.ServeHTTP(w, r)
}
}
func home(w http.ResponseWriter, r *http.Request) {
log.Println("reached home")
fmt.Fprintf(w, "welcome")
}
func main() {
mw := chainMiddleware(withLogging, withTracing)
http.Handle("/", mw(home))
log.Fatal(http.ListenAndServe(":8080", nil))
}
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