Gzip: Added compression level, extension and path filters.

config/setup/gzip.go

 package setup
 
 import (
+	"fmt"
+	"strconv"
+	"strings"
+
 	"github.com/mholt/caddy/middleware"
 	"github.com/mholt/caddy/middleware/gzip"
 )
 
 // Gzip configures a new gzip middleware instance.
 func Gzip(c *Controller) (middleware.Middleware, error) {
+	configs, err := gzipParse(c)
+	if err != nil {
+		return nil, err
+	}
+
 	return func(next middleware.Handler) middleware.Handler {
-		return gzip.Gzip{Next: next}
+		return gzip.Gzip{Next: next, Configs: configs}
 	}, nil
 }
+
+func gzipParse(c *Controller) ([]gzip.Config, error) {
+	var configs []gzip.Config
+
+	for c.Next() {
+		config := gzip.Config{}
+
+		pathFilter := gzip.PathFilter{make(gzip.Set)}
+		extFilter := gzip.DefaultExtFilter()
+
+		// no extra args expected
+		if len(c.RemainingArgs()) > 0 {
+			return configs, c.ArgErr()
+		}
+
+		for c.NextBlock() {
+			switch c.Val() {
+			case "ext":
+				exts := c.RemainingArgs()
+				if len(exts) == 0 {
+					return configs, c.ArgErr()
+				}
+				for _, e := range exts {
+					if !strings.HasPrefix(e, ".") {
+						return configs, fmt.Errorf(`Invalid extension %v. Should start with "."`, e)
+					}
+					extFilter.Exts.Add(e)
+				}
+			case "not":
+				paths := c.RemainingArgs()
+				if len(paths) == 0 {
+					return configs, c.ArgErr()
+				}
+				for _, p := range paths {
+					if !strings.HasPrefix(p, "/") {
+						return configs, fmt.Errorf(`Invalid path %v. Should start with "/"`, p)
+					}
+					pathFilter.IgnoredPaths.Add(p)
+					// Warn user if / is used
+					if p == "/" {
+						fmt.Println("Warning: Paths ignored by gzip includes wildcard(/). No request will be gzipped.\nRemoving gzip directive from Caddyfile is preferred if this is intended.")
+					}
+				}
+			case "level":
+				if !c.NextArg() {
+					return configs, c.ArgErr()
+				}
+				level, _ := strconv.Atoi(c.Val())
+				config.Level = level
+			default:
+				return configs, c.ArgErr()
+			}
+		}
+
+		// put pathFilter in front to filter with path first
+		config.Filters = []gzip.Filter{pathFilter, extFilter}
+
+		configs = append(configs, config)
+	}
+
+	return configs, nil
+}

config/setup/gzip_test.go

@@ -26,4 +26,47 @@ func TestGzip(t *testing.T) {
 	if !sameNext(myHandler.Next, emptyNext) {
 		t.Error("'Next' field of handler was not set properly")
 	}
+
+	tests := []struct {
+		input     string
+		shouldErr bool
+	}{
+		{`gzip {`, true},
+		{`gzip {}`, true},
+		{`gzip a b`, true},
+		{`gzip a {`, true},
+		{`gzip { not f } `, true},
+		{`gzip { not } `, true},
+		{`gzip { not /file
+		 ext .html
+		 level 1
+		} `, false},
+		{`gzip { level 9 } `, false},
+		{`gzip { ext } `, true},
+		{`gzip { ext /f
+		} `, true},
+		{`gzip { not /file
+		 ext .html
+		 level 1
+		}
+		gzip`, false},
+		{`gzip { not /file
+		 ext .html
+		 level 1
+		}
+		gzip { not /file1
+		 ext .htm
+		 level 3
+		}
+		`, false},
+	}
+	for i, test := range tests {
+		c := newTestController(test.input)
+		_, err := gzipParse(c)
+		if test.shouldErr && err == nil {
+			t.Errorf("Text %v: Expected error but found nil", i)
+		} else if !test.shouldErr && err != nil {
+			t.Errorf("Text %v: Expected no error but found error: ", i, err)
+		}
+	}
 }

middleware/gzip/filter.go

+package gzip
+
+import (
+	"net/http"
+	"path"
+
+	"github.com/mholt/caddy/middleware"
+)
+
+// Filter determines if a request should be gzipped.
+type Filter interface {
+	// ShouldCompress tells if compression gzip compression
+	// should be done on the request.
+	ShouldCompress(*http.Request) bool
+}
+
+// ExtFilter is Filter for file name extensions.
+type ExtFilter struct {
+	// Exts is the file name extensions to accept
+	Exts Set
+}
+
+// textExts is a list of extensions for text related files.
+var textExts = []string{
+	".html", ".htm", ".css", ".json", ".php", ".js", ".txt", ".md", ".xml",
+}
+
+// extWildCard is the wildcard for extensions.
+const extWildCard = "*"
+
+// DefaultExtFilter creates a default ExtFilter with
+// file extensions for text types.
+func DefaultExtFilter() ExtFilter {
+	e := ExtFilter{make(Set)}
+	for _, ext := range textExts {
+		e.Exts.Add(ext)
+	}
+	return e
+}
+
+func (e ExtFilter) ShouldCompress(r *http.Request) bool {
+	ext := path.Ext(r.URL.Path)
+	return e.Exts.Contains(extWildCard) || e.Exts.Contains(ext)
+}
+
+// PathFilter is Filter for request path.
+type PathFilter struct {
+	// IgnoredPaths is the paths to ignore
+	IgnoredPaths Set
+}
+
+// ShouldCompress checks if the request path matches any of the
+// registered paths to ignore. If returns false if an ignored path
+// is found and true otherwise.
+func (p PathFilter) ShouldCompress(r *http.Request) bool {
+	return !p.IgnoredPaths.ContainsFunc(func(value string) bool {
+		return middleware.Path(r.URL.Path).Matches(value)
+	})
+}
+
+// Set stores distinct strings.
+type Set map[string]struct{}
+
+// Add adds an element to the set.
+func (s Set) Add(value string) {
+	s[value] = struct{}{}
+}
+
+// Remove removes an element from the set.
+func (s Set) Remove(value string) {
+	delete(s, value)
+}
+
+// Contains check if the set contains value.
+func (s Set) Contains(value string) bool {
+	_, ok := s[value]
+	return ok
+}
+
+// ContainsFunc is similar to Contains. It iterates all the
+// elements in the set and passes each to f. It returns true
+// on the first call to f that returns true and false otherwise.
+func (s Set) ContainsFunc(f func(string) bool) bool {
+	for k, _ := range s {
+		if f(k) {
+			return true
+		}
+	}
+	return false
+}

middleware/gzip/filter_test.go

+package gzip
+
+import (
+	"net/http"
+	"testing"
+)
+
+func TestSet(t *testing.T) {
+	set := make(Set)
+	set.Add("a")
+	if len(set) != 1 {
+		t.Errorf("Expected 1 found %v", len(set))
+	}
+	set.Add("a")
+	if len(set) != 1 {
+		t.Errorf("Expected 1 found %v", len(set))
+	}
+	set.Add("b")
+	if len(set) != 2 {
+		t.Errorf("Expected 2 found %v", len(set))
+	}
+	if !set.Contains("a") {
+		t.Errorf("Set should contain a")
+	}
+	if !set.Contains("b") {
+		t.Errorf("Set should contain a")
+	}
+	set.Add("c")
+	if len(set) != 3 {
+		t.Errorf("Expected 3 found %v", len(set))
+	}
+	if !set.Contains("c") {
+		t.Errorf("Set should contain c")
+	}
+	set.Remove("a")
+	if len(set) != 2 {
+		t.Errorf("Expected 2 found %v", len(set))
+	}
+	if set.Contains("a") {
+		t.Errorf("Set should not contain a")
+	}
+	if !set.ContainsFunc(func(v string) bool {
+		return v == "c"
+	}) {
+		t.Errorf("ContainsFunc should return true")
+	}
+}
+
+func TestExtFilter(t *testing.T) {
+	var filter Filter = DefaultExtFilter()
+	_ = filter.(ExtFilter)
+	for i, e := range textExts {
+		r := urlRequest("file" + e)
+		if !filter.ShouldCompress(r) {
+			t.Errorf("Test %v: Should be valid filter", i)
+		}
+	}
+	var exts = []string{
+		".html", ".css", ".md",
+	}
+	for i, e := range exts {
+		r := urlRequest("file" + e)
+		if !filter.ShouldCompress(r) {
+			t.Errorf("Test %v: Should be valid filter", i)
+		}
+	}
+	exts = []string{
+		".htm1", ".abc", ".mdx",
+	}
+	for i, e := range exts {
+		r := urlRequest("file" + e)
+		if filter.ShouldCompress(r) {
+			t.Errorf("Test %v: Should not be valid filter", i)
+		}
+	}
+}
+
+func TestPathFilter(t *testing.T) {
+	paths := []string{
+		"/a", "/b", "/c", "/de",
+	}
+	var filter Filter = PathFilter{make(Set)}
+	for _, p := range paths {
+		filter.(PathFilter).IgnoredPaths.Add(p)
+	}
+	for i, p := range paths {
+		r := urlRequest(p)
+		if filter.ShouldCompress(r) {
+			t.Errorf("Test %v: Should not be valid filter", i)
+		}
+	}
+	paths = []string{
+		"/f", "/g", "/h", "/ed",
+	}
+	for i, p := range paths {
+		r := urlRequest(p)
+		if !filter.ShouldCompress(r) {
+			t.Errorf("Test %v: Should be valid filter", i)
+		}
+	}
+}
+
+func urlRequest(url string) *http.Request {
+	r, _ := http.NewRequest("GET", url, nil)
+	return r
+}

middleware/gzip/gzip.go

@@ -17,7 +17,14 @@ import (
 // specifies the Content-Type, otherwise some clients will assume
 // application/x-gzip and try to download a file.
 type Gzip struct {
-	Next middleware.Handler
+	Next    middleware.Handler
+	Configs []Config
+}
+
+// Config holds the configuration for Gzip middleware
+type Config struct {
+	Filters []Filter // Filters to use
+	Level   int      // Compression level
 }
 
 // ServeHTTP serves a gzipped response if the client supports it.
@@ -26,27 +33,56 @@ func (g Gzip) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
 		return g.Next.ServeHTTP(w, r)
 	}
 
-	// Delete this header so gzipping isn't repeated later in the chain
-	r.Header.Del("Accept-Encoding")
-
-	w.Header().Set("Content-Encoding", "gzip")
-	gzipWriter := gzip.NewWriter(w)
-	defer gzipWriter.Close()
-	gz := gzipResponseWriter{Writer: gzipWriter, ResponseWriter: w}
-
-	// Any response in forward middleware will now be compressed
-	status, err := g.Next.ServeHTTP(gz, r)
-
-	// If there was an error that remained unhandled, we need
-	// to send something back before gzipWriter gets closed at
-	// the return of this method!
-	if status >= 400 {
-		gz.Header().Set("Content-Type", "text/plain") // very necessary
-		gz.WriteHeader(status)
-		fmt.Fprintf(gz, "%d %s", status, http.StatusText(status))
-		return 0, err
+outer:
+	for _, c := range g.Configs {
+
+		// Check filters to determine if gzipping is permitted for this
+		// request
+		for _, filter := range c.Filters {
+			if !filter.ShouldCompress(r) {
+				continue outer
+			}
+		}
+
+		// Delete this header so gzipping is not repeated later in the chain
+		r.Header.Del("Accept-Encoding")
+
+		w.Header().Set("Content-Encoding", "gzip")
+		gzipWriter, err := newWriter(c, w)
+		if err != nil {
+			// should not happen
+			return http.StatusInternalServerError, err
+		}
+		defer gzipWriter.Close()
+		gz := gzipResponseWriter{Writer: gzipWriter, ResponseWriter: w}
+
+		// Any response in forward middleware will now be compressed
+		status, err := g.Next.ServeHTTP(gz, r)
+
+		// If there was an error that remained unhandled, we need
+		// to send something back before gzipWriter gets closed at
+		// the return of this method!
+		if status >= 400 {
+			gz.Header().Set("Content-Type", "text/plain") // very necessary
+			gz.WriteHeader(status)
+			fmt.Fprintf(gz, "%d %s", status, http.StatusText(status))
+			return 0, err
+		}
+		return status, err
+	}
+
+	// no matching filter
+	return g.Next.ServeHTTP(w, r)
+}
+
+// newWriter create a new Gzip Writer based on the compression level.
+// If the level is valid (i.e. between 1 and 9), it uses the level.
+// Otherwise, it uses default compression level.
+func newWriter(c Config, w http.ResponseWriter) (*gzip.Writer, error) {
+	if c.Level >= gzip.BestSpeed && c.Level <= gzip.BestCompression {
+		return gzip.NewWriterLevel(w, c.Level)
 	}
-	return status, err
+	return gzip.NewWriter(w), nil
 }
 
 // gzipResponeWriter wraps the underlying Write method

middleware/gzip/gzip_test.go

+package gzip
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/mholt/caddy/middleware"
+)
+
+func Test(t *testing.T) {
+
+	pathFilter := PathFilter{make(Set)}
+	badPaths := []string{"/bad", "/nogzip", "/nongzip"}
+	for _, p := range badPaths {
+		pathFilter.IgnoredPaths.Add(p)
+	}
+	gz := Gzip{Configs: []Config{
+		Config{Filters: []Filter{DefaultExtFilter(), pathFilter}},
+	}}
+
+	w := httptest.NewRecorder()
+	gz.Next = nextFunc(true)
+	for _, e := range textExts {
+		url := "/file" + e
+		r, err := http.NewRequest("GET", url, nil)
+		if err != nil {
+			t.Error(err)
+		}
+		r.Header.Set("Accept-Encoding", "gzip")
+		_, err = gz.ServeHTTP(w, r)
+		if err != nil {
+			t.Error(err)
+		}
+	}
+
+	w = httptest.NewRecorder()
+	gz.Next = nextFunc(false)
+	for _, p := range badPaths {
+		for _, e := range textExts {
+			url := p + "/file" + e
+			r, err := http.NewRequest("GET", url, nil)
+			if err != nil {
+				t.Error(err)
+			}
+			r.Header.Set("Accept-Encoding", "gzip")
+			_, err = gz.ServeHTTP(w, r)
+			if err != nil {
+				t.Error(err)
+			}
+		}
+	}
+
+	w = httptest.NewRecorder()
+	gz.Next = nextFunc(false)
+	exts := []string{
+		".htm1", ".abc", ".mdx",
+	}
+	for _, e := range exts {
+		url := "/file" + e
+		r, err := http.NewRequest("GET", url, nil)
+		if err != nil {
+			t.Error(err)
+		}
+		r.Header.Set("Accept-Encoding", "gzip")
+		_, err = gz.ServeHTTP(w, r)
+		if err != nil {
+			t.Error(err)
+		}
+	}
+
+}
+
+func nextFunc(shouldGzip bool) middleware.Handler {
+	return middleware.HandlerFunc(func(w http.ResponseWriter, r *http.Request) (int, error) {
+		if shouldGzip {
+			if r.Header.Get("Accept-Encoding") != "" {
+				return 0, fmt.Errorf("Accept-Encoding header not expected")
+			}
+			if w.Header().Get("Content-Encoding") != "gzip" {
+				return 0, fmt.Errorf("Content-Encoding must be gzip, found %v", r.Header.Get("Content-Encoding"))
+			}
+			if _, ok := w.(gzipResponseWriter); !ok {
+				return 0, fmt.Errorf("ResponseWriter should be gzipResponseWriter, found %T", w)
+			}
+			return 0, nil
+		}
+		if r.Header.Get("Accept-Encoding") == "" {
+			return 0, fmt.Errorf("Accept-Encoding header expected")
+		}
+		if w.Header().Get("Content-Encoding") == "gzip" {
+			return 0, fmt.Errorf("Content-Encoding must not be gzip, found gzip")
+		}
+		if _, ok := w.(gzipResponseWriter); ok {
+			return 0, fmt.Errorf("ResponseWriter should not be gzipResponseWriter")
+		}
+		return 0, nil
+	})
+}