mime: Make filename extensions case-insensitive

Fixes #8350.

LGTM=bradfitz
R=golang-codereviews, bradfitz, dave
CC=golang-codereviews
https://golang.org/cl/127380043

diff --git a/src/pkg/mime/type.go b/src/pkg/mime/type.go
index 00cff263bad95646190c43d735584526d6e610d7..d1e403f0224c9b1ba1ce9a5b99eae810143c78d9 100644 (file)
--- a/src/pkg/mime/type.go
+++ b/src/pkg/mime/type.go
@@ -11,19 +11,28 @@ import (
        "sync"
 )
 
-var mimeTypes = map[string]string{
-       ".css":  "text/css; charset=utf-8",
-       ".gif":  "image/gif",
-       ".htm":  "text/html; charset=utf-8",
-       ".html": "text/html; charset=utf-8",
-       ".jpg":  "image/jpeg",
-       ".js":   "application/x-javascript",
-       ".pdf":  "application/pdf",
-       ".png":  "image/png",
-       ".xml":  "text/xml; charset=utf-8",
-}
+var (
+       mimeLock       sync.RWMutex
+       mimeTypes      = map[string]string{}
+       mimeTypesLower = map[string]string{}
+)
 
-var mimeLock sync.RWMutex
+func init() {
+       mimeTypes := map[string]string{
+               ".css":  "text/css; charset=utf-8",
+               ".gif":  "image/gif",
+               ".htm":  "text/html; charset=utf-8",
+               ".html": "text/html; charset=utf-8",
+               ".jpg":  "image/jpeg",
+               ".js":   "application/x-javascript",
+               ".pdf":  "application/pdf",
+               ".png":  "image/png",
+               ".xml":  "text/xml; charset=utf-8",
+       }
+       for ext, typ := range mimeTypes {
+               AddExtensionType(ext, typ)
+       }
+}
 
 var once sync.Once
 
@@ -31,6 +40,8 @@ var once sync.Once
 // The extension ext should begin with a leading dot, as in ".html".
 // When ext has no associated type, TypeByExtension returns "".
 //
+// Extensions are looked up first case-sensitively, then case-insensitively.
+//
 // The built-in table is small but on unix it is augmented by the local
 // system's mime.types file(s) if available under one or more of these
 // names:
@@ -39,7 +50,7 @@ var once sync.Once
 //   /etc/apache2/mime.types
 //   /etc/apache/mime.types
 //
-// Windows system mime types are extracted from registry.
+// Windows system MIME types are extracted from registry.
 //
 // Text types have the charset parameter set to "utf-8" by default.
 func TypeByExtension(ext string) string {
@@ -47,15 +58,21 @@ func TypeByExtension(ext string) string {
        mimeLock.RLock()
        typename := mimeTypes[ext]
        mimeLock.RUnlock()
+       if typename == "" {
+               lower := strings.ToLower(ext)
+               mimeLock.RLock()
+               typename = mimeTypesLower[lower]
+               mimeLock.RUnlock()
+       }
        return typename
 }
 
 // AddExtensionType sets the MIME type associated with
-// the extension ext to typ.  The extension should begin with
+// the extension ext to typ. The extension should begin with
 // a leading dot, as in ".html".
 func AddExtensionType(ext, typ string) error {
-       if ext == "" || ext[0] != '.' {
-               return fmt.Errorf(`mime: extension "%s" misses dot`, ext)
+       if !strings.HasPrefix(ext, ".") {
+               return fmt.Errorf(`mime: extension %q misses dot`, ext)
        }
        once.Do(initMime)
        return setExtensionType(ext, typ)
@@ -70,8 +87,11 @@ func setExtensionType(extension, mimeType string) error {
                param["charset"] = "utf-8"
                mimeType = FormatMediaType(mimeType, param)
        }
+       extLower := strings.ToLower(extension)
+
        mimeLock.Lock()
        mimeTypes[extension] = mimeType
+       mimeTypesLower[extLower] = mimeType
        mimeLock.Unlock()
        return nil
 }

diff --git a/src/pkg/mime/type_plan9.go b/src/pkg/mime/type_plan9.go
index b8f0511ee7d6530b1aca49cda88819f7502e67ce..8cbf6777f19258fc719b7c3a523ba31229d955e6 100644 (file)
--- a/src/pkg/mime/type_plan9.go
+++ b/src/pkg/mime/type_plan9.go
@@ -48,6 +48,6 @@ func initMimeForTests() map[string]string {
        return map[string]string{
                ".t1":  "application/test",
                ".t2":  "text/test; charset=utf-8",
-               ".png": "image/png",
+               ".pNg": "image/png",
        }
 }

diff --git a/src/pkg/mime/type_test.go b/src/pkg/mime/type_test.go
index 07e1cd5daecfbfb84896a582fd1c1b3be9eb1705..3ec86fbb54789a0dc74c6d9596863c5d0d8e0701 100644 (file)
--- a/src/pkg/mime/type_test.go
+++ b/src/pkg/mime/type_test.go
@@ -4,7 +4,9 @@
 
 package mime
 
-import "testing"
+import (
+       "testing"
+)
 
 var typeTests = initMimeForTests()
 
@@ -14,16 +16,20 @@ func TestTypeByExtension(t *testing.T) {
                if val != want {
                        t.Errorf("TypeByExtension(%q) = %q, want %q", ext, val, want)
                }
-
        }
 }
 
 func TestCustomExtension(t *testing.T) {
-       custom := "text/xml; charset=iso-8859-1"
-       if error := AddExtensionType(".xml", custom); error != nil {
+       custom := "test/test; charset=iso-8859-1"
+       if error := AddExtensionType(".tesT", custom); error != nil {
                t.Fatalf("error %s for AddExtension(%s)", error, custom)
        }
-       if registered := TypeByExtension(".xml"); registered != custom {
+       // test with same capitalization
+       if registered := TypeByExtension(".tesT"); registered != custom {
+               t.Fatalf("registered %s instead of %s", registered, custom)
+       }
+       // test with different capitalization
+       if registered := TypeByExtension(".Test"); registered != custom {
                t.Fatalf("registered %s instead of %s", registered, custom)
        }
 }

diff --git a/src/pkg/mime/type_unix.go b/src/pkg/mime/type_unix.go
index 1d394315a49b0cafd80d0177340a6f6c1d983e55..3e404cf742997c7c85c08cdf19033171ed90ce3f 100644 (file)
--- a/src/pkg/mime/type_unix.go
+++ b/src/pkg/mime/type_unix.go
@@ -53,7 +53,7 @@ func initMime() {
 func initMimeForTests() map[string]string {
        typeFiles = []string{"testdata/test.types"}
        return map[string]string{
-               ".t1":  "application/test",
+               ".T1":  "application/test",
                ".t2":  "text/test; charset=utf-8",
                ".png": "image/png",
        }

diff --git a/src/pkg/mime/type_windows.go b/src/pkg/mime/type_windows.go
index 180f948d16fe91bc7a98478ef58219927e5d2945..ae758d78b31aaf4dc979b78af705473562bf453b 100644 (file)
--- a/src/pkg/mime/type_windows.go
+++ b/src/pkg/mime/type_windows.go
@@ -58,6 +58,6 @@ func initMime() {
 
 func initMimeForTests() map[string]string {
        return map[string]string{
-               ".png": "image/png",
+               ".PnG": "image/png",
        }
 }