Refactor controller and handlers

controller/handler/gzip.go

@@ -0,0 +1,59 @@
+package handler
+
+import (
+	"compress/gzip"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"strings"
+	"sync"
+)
+
+var gzPool = sync.Pool{
+	New: func() interface{} {
+		return gzip.NewWriter(ioutil.Discard)
+	},
+}
+
+type gzipResponseWriter struct {
+	io.Writer
+	http.ResponseWriter
+}
+
+// WriteHeader sends an HTTP response header with the provided status code.
+// It also deletes the Content-Length header, since the GZIP compression may modify the size of the payload
+func (w *gzipResponseWriter) WriteHeader(status int) {
+	w.Header().Del("Content-Length")
+	w.ResponseWriter.WriteHeader(status)
+}
+
+// Write writes len(b) bytes from b to the underlying data stream.
+func (w *gzipResponseWriter) Write(b []byte) (int, error) {
+	return w.Writer.Write(b)
+}
+
+// GzipHandler compresses the response of a given http.Handler if the request's headers specify that the client
+// supports gzip encoding
+func GzipHandler(next http.Handler) http.Handler {
+	return GzipHandlerFunc(func(writer http.ResponseWriter, r *http.Request) {
+		next.ServeHTTP(writer, r)
+	})
+}
+
+// GzipHandlerFunc compresses the response of a given http.HandlerFunc if the request's headers specify that the client
+// supports gzip encoding
+func GzipHandlerFunc(next http.HandlerFunc) http.HandlerFunc {
+	return func(writer http.ResponseWriter, r *http.Request) {
+		// If the request doesn't specify that it supports gzip, then don't compress it
+		if !strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
+			next.ServeHTTP(writer, r)
+			return
+		}
+		writer.Header().Set("Content-Encoding", "gzip")
+		gz := gzPool.Get().(*gzip.Writer)
+		defer gzPool.Put(gz)
+		gz.Reset(writer)
+		defer gz.Close()
+		next.ServeHTTP(&gzipResponseWriter{ResponseWriter: writer, Writer: gz}, r)
+	}
+}