add gzip response capability to httpd endpoints. fixes #1449

httpd/handler.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
 	"log"
 	"net/http"
 	"net/url"
@@ -12,6 +13,8 @@ import (
 	"strings"
 	"time"
 
+	"compress/gzip"
+
 	"code.google.com/p/go-uuid/uuid"
 
 	"github.com/bmizerany/pat"
@@ -92,6 +95,7 @@ func NewHandler(s *influxdb.Server, requireAuthentication bool, version string)
 			handler = http.HandlerFunc(hf)
 		}
 
+		handler = gzipFilter(handler)
 		handler = versionHeader(handler, version)
 		handler = cors(handler)
 		handler = requestID(handler)
@@ -376,6 +380,29 @@ func authenticate(inner func(http.ResponseWriter, *http.Request, *influxdb.User)
 	})
 }
 
+type gzipResponseWriter struct {
+	io.Writer
+	http.ResponseWriter
+}
+
+func (w gzipResponseWriter) Write(b []byte) (int, error) {
+	return w.Writer.Write(b)
+}
+
+// determines if the client can accept compressed responses, and encodes accordingly
+func gzipFilter(inner http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if !strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
+			inner.ServeHTTP(w, r)
+		}
+		w.Header().Set("Content-Encoding", "gzip")
+		gz := gzip.NewWriter(w)
+		defer gz.Close()
+		gzw := gzipResponseWriter{Writer: gz, ResponseWriter: w}
+		inner.ServeHTTP(gzw, r)
+	})
+}
+
 // versionHeader taks a HTTP handler and returns a HTTP handler
 // and adds the X-INFLUXBD-VERSION header to outgoing responses.
 func versionHeader(inner http.Handler, version string) http.Handler {