mime: new package, use in http

R=rsc
CC=golang-dev
http://codereview.appspot.com/186160

Committer: Russ Cox <rsc@golang.org>

4 files changed, 129 insertions, 0 deletions

diff --git a/src/pkg/mime/Makefile b/src/pkg/mime/Makefile
new file mode 100644
index 000000000..57fc7db44
--- /dev/null
+++ b/src/pkg/mime/Makefile
@@ -0,0 +1,11 @@
+# Copyright 2009 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+include ../../Make.$(GOARCH)
+
+TARG=mime
+GOFILES=\
+	type.go\
+
+include ../../Make.pkg
diff --git a/src/pkg/mime/mime_test.go b/src/pkg/mime/mime_test.go
new file mode 100644
index 000000000..24c54e0e8
--- /dev/null
+++ b/src/pkg/mime/mime_test.go
@@ -0,0 +1,27 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Tests for type.go
+
+package mime
+
+import "testing"
+
+var typeTests = map[string]string{
+	".t1": "application/test",
+	".t2": "text/test; charset=utf-8",
+	".png": "image/png",
+}
+
+func TestType(t *testing.T) {
+	typeFiles = []string{"test.types"}
+
+	for ext, want := range typeTests {
+		val := TypeByExtension(ext)
+		if val != want {
+			t.Errorf("TypeByExtension(%q) = %q, want %q", ext, val, want)
+		}
+
+	}
+}
diff --git a/src/pkg/mime/test.types b/src/pkg/mime/test.types
new file mode 100644
index 000000000..9b040edd7
--- /dev/null
+++ b/src/pkg/mime/test.types
@@ -0,0 +1,8 @@
+# Copyright 2010 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+
+ # mime package test
+application/test	t1	# Simple test
+text/test		t2	# Text test
diff --git a/src/pkg/mime/type.go b/src/pkg/mime/type.go
new file mode 100644
index 000000000..7024417cb
--- /dev/null
+++ b/src/pkg/mime/type.go
@@ -0,0 +1,83 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The mime package translates file name extensions to MIME types.
+// It consults the local system's mime.types file, which must be installed
+// under one of these names:
+//
+//   /etc/mime.types
+//   /etc/apache2/mime.types
+//   /etc/apache/mime.types
+//
+package mime
+
+import (
+	"bufio"
+	"once"
+	"os"
+	"strings"
+)
+
+var typeFiles = []string{
+	"/etc/mime.types",
+	"/etc/apache2/mime.types",
+	"/etc/apache/mime.types",
+}
+
+var mimeTypes = map[string]string{
+	".css": "text/css",
+	".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",
+}
+
+func loadMimeFile(filename string) {
+	f, err := os.Open(filename, os.O_RDONLY, 0666)
+	if err != nil {
+		return
+	}
+
+	reader := bufio.NewReader(f)
+	for {
+		line, err := reader.ReadString('\n')
+		if err != nil {
+			f.Close()
+			return
+		}
+		fields := strings.Fields(line)
+		if len(fields) <= 1 || fields[0][0] == '#' {
+			continue
+		}
+		typename := fields[0]
+		if strings.HasPrefix(typename, "text/") {
+			typename += "; charset=utf-8"
+		}
+		for _, ext := range fields[1:] {
+			if ext[0] == '#' {
+				break
+			}
+			mimeTypes["."+ext] = typename
+		}
+	}
+}
+
+func initMime() {
+	for _, filename := range typeFiles {
+		loadMimeFile(filename)
+	}
+}
+
+// TypeByExtension returns the MIME type associated with the file extension ext.
+// The extension ext should begin with a leading dot, as in ".html".
+// When ext has no associated type, TypeByExtension returns "".
+func TypeByExtension(ext string) string {
+	once.Do(initMime)
+	typ, _ := mimeTypes[ext]
+	return typ
+}