From 96eab1202717e073782ec399a4e0820cae15b1bb Mon Sep 17 00:00:00 2001
From: Christopher Speller <crspeller@gmail.com>
Date: Thu, 17 Aug 2017 17:19:06 -0700
Subject: Updating server dependancies. (#7246)

---
 vendor/github.com/NYTimes/gziphandler/gzip.go | 91 ++++++++++++++++++++++++---
 1 file changed, 83 insertions(+), 8 deletions(-)

(limited to 'vendor/github.com/NYTimes/gziphandler/gzip.go')

diff --git a/vendor/github.com/NYTimes/gziphandler/gzip.go b/vendor/github.com/NYTimes/gziphandler/gzip.go
index ea6dba1e7..c47039fd3 100644
--- a/vendor/github.com/NYTimes/gziphandler/gzip.go
+++ b/vendor/github.com/NYTimes/gziphandler/gzip.go
@@ -80,6 +80,8 @@ type GzipResponseWriter struct {
 
 	minSize int    // Specifed the minimum response size to gzip. If the response length is bigger than this value, it is compressed.
 	buf     []byte // Holds the first part of the write before reaching the minSize or the end of the write.
+
+	contentTypes []string // Only compress if the response is one of these content-types. All are accepted if empty.
 }
 
 // Write appends data to the gzip writer.
@@ -100,8 +102,10 @@ func (w *GzipResponseWriter) Write(b []byte) (int, error) {
 	// On the first write, w.buf changes from nil to a valid slice
 	w.buf = append(w.buf, b...)
 
-	// If the global writes are bigger than the minSize, compression is enable.
-	if len(w.buf) >= w.minSize {
+	// If the global writes are bigger than the minSize and we're about to write
+	// a response containing a content type we want to handle, enable
+	// compression.
+	if len(w.buf) >= w.minSize && handleContentType(w.contentTypes, w) {
 		err := w.startGzip()
 		if err != nil {
 			return 0, err
@@ -230,14 +234,25 @@ func NewGzipLevelHandler(level int) (func(http.Handler) http.Handler, error) {
 // NewGzipLevelAndMinSize behave as NewGzipLevelHandler except it let the caller
 // specify the minimum size before compression.
 func NewGzipLevelAndMinSize(level, minSize int) (func(http.Handler) http.Handler, error) {
-	if level != gzip.DefaultCompression && (level < gzip.BestSpeed || level > gzip.BestCompression) {
-		return nil, fmt.Errorf("invalid compression level requested: %d", level)
+	return GzipHandlerWithOpts(CompressionLevel(level), MinSize(minSize))
+}
+
+func GzipHandlerWithOpts(opts ...option) (func(http.Handler) http.Handler, error) {
+	c := &config{
+		level:   gzip.DefaultCompression,
+		minSize: DefaultMinSize,
 	}
-	if minSize < 0 {
-		return nil, fmt.Errorf("minimum size must be more than zero")
+
+	for _, o := range opts {
+		o(c)
 	}
+
+	if err := c.validate(); err != nil {
+		return nil, err
+	}
+
 	return func(h http.Handler) http.Handler {
-		index := poolIndex(level)
+		index := poolIndex(c.level)
 
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			w.Header().Add(vary, acceptEncoding)
@@ -246,7 +261,8 @@ func NewGzipLevelAndMinSize(level, minSize int) (func(http.Handler) http.Handler
 				gw := &GzipResponseWriter{
 					ResponseWriter: w,
 					index:          index,
-					minSize:        minSize,
+					minSize:        c.minSize,
+					contentTypes:   c.contentTypes,
 				}
 				defer gw.Close()
 
@@ -258,6 +274,48 @@ func NewGzipLevelAndMinSize(level, minSize int) (func(http.Handler) http.Handler
 	}, nil
 }
 
+// Used for functional configuration.
+type config struct {
+	minSize      int
+	level        int
+	contentTypes []string
+}
+
+func (c *config) validate() error {
+	if c.level != gzip.DefaultCompression && (c.level < gzip.BestSpeed || c.level > gzip.BestCompression) {
+		return fmt.Errorf("invalid compression level requested: %d", c.level)
+	}
+
+	if c.minSize < 0 {
+		return fmt.Errorf("minimum size must be more than zero")
+	}
+
+	return nil
+}
+
+type option func(c *config)
+
+func MinSize(size int) option {
+	return func(c *config) {
+		c.minSize = size
+	}
+}
+
+func CompressionLevel(level int) option {
+	return func(c *config) {
+		c.level = level
+	}
+}
+
+func ContentTypes(types []string) option {
+	return func(c *config) {
+		c.contentTypes = []string{}
+		for _, v := range types {
+			c.contentTypes = append(c.contentTypes, strings.ToLower(v))
+		}
+	}
+}
+
 // GzipHandler wraps an HTTP handler, to transparently gzip the response body if
 // the client supports it (via the Accept-Encoding header). This will compress at
 // the default compression level.
@@ -273,6 +331,23 @@ func acceptsGzip(r *http.Request) bool {
 	return acceptedEncodings["gzip"] > 0.0
 }
 
+// returns true if we've been configured to compress the specific content type.
+func handleContentType(contentTypes []string, w http.ResponseWriter) bool {
+	// If contentTypes is empty we handle all content types.
+	if len(contentTypes) == 0 {
+		return true
+	}
+
+	ct := strings.ToLower(w.Header().Get(contentType))
+	for _, c := range contentTypes {
+		if c == ct {
+			return true
+		}
+	}
+
+	return false
+}
+
 // parseEncodings attempts to parse a list of codings, per RFC 2616, as might
 // appear in an Accept-Encoding header. It returns a map of content-codings to
 // quality values, and an error containing the errors encountered. It's probably
-- 
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