Add a separate package to encapsulate http related stuff

http/http.go

@@ -0,0 +1,58 @@
+package http
+
+import (
+	"fmt"
+	"net/http"
+	"strconv"
+
+	"github.com/minio/minio/legacy/crypto"
+)
+
+type (
+	HTTPResponseWriter struct {
+		serverName   string
+		serverRegion string
+	}
+
+	// MimeType represents various MIME type used API responses.
+	MimeType string
+
+	// ContextKey is a custom type used to pass values within contexts.
+	ContextKey string
+)
+
+const BearerTokenContextKey ContextKey = "bearer-token"
+
+const (
+	// MimeType_None means no response type.
+	MimeType_None MimeType = ""
+	// MimeType_ApplicationJSON means response type is JSON.
+	MimeType_ApplicationJSON MimeType = "application/json"
+	// MimeType_ApplicationXML means response type is XML.
+	MimeType_ApplicationXML MimeType = "application/xml"
+)
+
+func NewHTTPResponseWriter(appName, appVersion, region string) *HTTPResponseWriter {
+	return &HTTPResponseWriter{
+		serverName:   fmt.Sprintf("%s/%s", appName, appVersion),
+		serverRegion: region,
+	}
+}
+
+func (rw *HTTPResponseWriter) writeResponse(w http.ResponseWriter, statusCode int, response []byte, mimeType MimeType) {
+	w.Header().Set("Server", rw.serverName)
+	if len(rw.serverRegion) > 0 {
+		w.Header().Set("X-Amz-Bucket-Region", rw.serverRegion)
+	}
+	w.Header().Set("Accept-Ranges", "bytes")
+	crypto.RemoveSensitiveHeaders(w.Header())
+	if mimeType != MimeType_None {
+		w.Header().Set("Content-Type", string(mimeType))
+	}
+	w.Header().Set("Content-Length", strconv.Itoa(len(response)))
+	w.WriteHeader(statusCode)
+	if response != nil {
+		w.Write(response)
+		w.(http.Flusher).Flush()
+	}
+}