Use static assets for HTML templates

- implement custom http.Filesystem boardvoting.AssetFS
- replace "footer" and "header" with "footer.html" and "header.html"
- change renderTemplate to use Assets
- use boardvoting.GetAssetFS() with http.Fileserver

1 files changed, 140 insertions, 0 deletions

diff --git a/boardvoting/main.go b/boardvoting/main.go
index 5c8e6eb..7cc6005 100644
--- a/boardvoting/main.go
+++ b/boardvoting/main.go
@@ -1,3 +1,143 @@
 package boardvoting
 
 //go:generate go-bindata -pkg $GOPACKAGE -o assets.go ./migrations/... ./static/... ./templates/...
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+var defaultFileTimestamp = time.Now()
+
+type AssetFS struct {
+	Asset     func(path string) ([]byte, error)
+	AssetDir  func(path string) ([]string, error)
+	AssetInfo func(path string) (os.FileInfo, error)
+}
+
+type FakeFile struct {
+	Path      string
+	Dir       bool
+	Len       int64
+	Timestamp time.Time
+}
+
+func (f *FakeFile) Name() string {
+	_, name := filepath.Split(f.Path)
+	return name
+}
+
+func (f *FakeFile) Size() int64 { return f.Len }
+
+func (f *FakeFile) Mode() os.FileMode {
+	mode := os.FileMode(0644)
+	if f.Dir {
+		return mode | os.ModeDir
+	}
+	return mode
+}
+
+func (f *FakeFile) ModTime() time.Time { return f.Timestamp }
+func (f *FakeFile) IsDir() bool        { return f.Dir }
+func (f *FakeFile) Sys() interface{}   { return nil }
+
+type AssetFile struct {
+	*bytes.Reader
+	io.Closer
+	FakeFile
+}
+
+func NewAssetFile(name string, content []byte, timestamp time.Time) *AssetFile {
+	if timestamp.IsZero() {
+		timestamp = defaultFileTimestamp
+	}
+	return &AssetFile{
+		bytes.NewReader(content),
+		ioutil.NopCloser(nil),
+		FakeFile{name, false, int64(len(content)), timestamp},
+	}
+}
+
+func (f *AssetFile) Readdir(count int) ([]os.FileInfo, error) {
+	return nil, errors.New("not a directory")
+}
+
+func (f *AssetFile) Size() int64 {
+	return f.FakeFile.Size()
+}
+
+func (f *AssetFile) Stat() (os.FileInfo, error) {
+	return f, nil
+}
+
+type AssetDirectory struct {
+	AssetFile
+	ChildrenRead int
+	Children     []os.FileInfo
+}
+
+func (f *AssetDirectory) Readdir(count int) ([]os.FileInfo, error) {
+	if count <= 0 {
+		return f.Children, nil
+	}
+	if f.ChildrenRead+count > len(f.Children) {
+		count = len(f.Children) - f.ChildrenRead
+	}
+	rv := f.Children[f.ChildrenRead : f.ChildrenRead+count]
+	f.ChildrenRead += count
+	return rv, nil
+}
+
+func (f *AssetDirectory) Stat() (os.FileInfo, error) {
+	return f, nil
+}
+
+func NewAssetDirectory(name string, children []string, fs *AssetFS) *AssetDirectory {
+	fileInfos := make([]os.FileInfo, 0, len(children))
+	for _, child := range children {
+		_, err := fs.AssetDir(filepath.Join(name, child))
+		fileInfos = append(fileInfos, &FakeFile{child, err == nil, 0, time.Time{}})
+	}
+	return &AssetDirectory{
+		AssetFile{
+			bytes.NewReader(nil),
+			ioutil.NopCloser(nil),
+			FakeFile{name, true, 0, time.Time{}},
+		},
+		0,
+		fileInfos}
+}
+
+func (f *AssetFS) Open(name string) (http.File, error) {
+	if len(name) > 0 && name[0] == '/' {
+		name = name[1:]
+	}
+	if b, err := f.Asset(name); err == nil {
+		timestamp := defaultFileTimestamp
+		if f.AssetInfo != nil {
+			if info, err := f.AssetInfo(name); err == nil {
+				timestamp = info.ModTime()
+			}
+		}
+		return NewAssetFile(name, b, timestamp), nil
+	}
+	if children, err := f.AssetDir(name); err == nil {
+		return NewAssetDirectory(name, children, f), nil
+	} else {
+		if strings.Contains(err.Error(), "not found") {
+			return nil, os.ErrNotExist
+		}
+		return nil, err
+	}
+}
+
+func GetAssetFS() *AssetFS {
+	return &AssetFS{Asset: Asset, AssetDir: AssetDir, AssetInfo: AssetInfo}
+}