refactor: refactor controllers and use standard library (#385)

handlerutil/handlerutil.go

@@ -0,0 +1,133 @@
+package handlerutil
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"strings"
+)
+
+type Middleware func(http.Handler) http.Handler
+
+func Chain(middlewares ...Middleware) Middleware {
+	return func(final http.Handler) http.Handler {
+		for i := len(middlewares) - 1; i >= 0; i-- {
+			final = middlewares[i](final)
+		}
+		return final
+	}
+}
+
+func TrimPathSuffix(suffix string) Middleware {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			r.URL.Path = strings.TrimSuffix(r.URL.Path, suffix)
+			next.ServeHTTP(w, r)
+		})
+	}
+}
+
+func Log(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		sw := &statusWriter{ResponseWriter: w}
+		next.ServeHTTP(sw, r)
+		log.Printf("response %s %s %v", statusToBlock(sw.status), r.Method, r.URL)
+	})
+}
+
+func BasicCORS(next http.Handler) http.Handler {
+	allowMethods := strings.Join(
+		[]string{http.MethodPost, http.MethodGet, http.MethodOptions, http.MethodPut, http.MethodDelete},
+		", ",
+	)
+	allowHeaders := strings.Join(
+		[]string{"Accept", "Content-Type", "Content-Length", "Accept-Encoding", "X-CSRF-Token", "Authorization"},
+		", ",
+	)
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Access-Control-Allow-Origin", "*")
+		w.Header().Set("Access-Control-Allow-Methods", allowMethods)
+		w.Header().Set("Access-Control-Allow-Headers", allowHeaders)
+		if r.Method == http.MethodOptions {
+			return
+		}
+		next.ServeHTTP(w, r)
+	})
+}
+
+func Redirect(to string) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		http.Redirect(w, r, to, http.StatusSeeOther)
+	})
+}
+
+func Message(message string) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintln(w, message)
+	})
+}
+
+func BaseURL(r *http.Request) string {
+	fallbackProtocoll := "http"
+	if r.TLS != nil {
+		fallbackProtocoll = "https"
+	}
+	fallbackHost := "localhost:4747"
+	scheme := first(
+		r.Header.Get("X-Forwarded-Proto"),
+		r.Header.Get("X-Forwarded-Scheme"),
+		r.URL.Scheme,
+		fallbackProtocoll,
+	)
+	host := first(
+		r.Header.Get("X-Forwarded-Host"),
+		r.Host,
+		fallbackHost,
+	)
+	return fmt.Sprintf("%s://%s", scheme, host)
+}
+
+type statusWriter struct {
+	http.ResponseWriter
+	status int
+}
+
+func (w *statusWriter) WriteHeader(status int) {
+	w.status = status
+	w.ResponseWriter.WriteHeader(status)
+}
+
+func (w *statusWriter) Write(b []byte) (int, error) {
+	if w.status == 0 {
+		w.status = 200
+	}
+	return w.ResponseWriter.Write(b)
+}
+
+func statusToBlock(code int) string {
+	var bg int
+	switch {
+	case code >= 500:
+		bg = 41 // bright red
+	case code >= 400:
+		bg = 43 // bright orange
+	case code >= 300:
+		bg = 46 // bright cyan
+	case code >= 200:
+		bg = 42 // bright green
+	default:
+		bg = 47 // bright white (grey)
+	}
+	return fmt.Sprintf("\u001b[%d;1m %d \u001b[0m", bg, code)
+}
+
+func first[T comparable](vs ...T) T {
+	var z T
+	for _, s := range vs {
+		if s != z {
+			return s
+		}
+	}
+	return z
+}