68 lines
1.5 KiB
Go
68 lines
1.5 KiB
Go
package util
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import (
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"embed"
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"errors"
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"io"
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"io/fs"
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"time"
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)
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// CachingEmbedFS is a wrapper around embed.FS that allows setting a ModTime, so that the
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// default static file server can send 304s back. It can be used like this:
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//
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// var (
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// //go:embed docs
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// docsStaticFs embed.FS
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// docsStaticCached = &util.CachingEmbedFS{ModTime: time.Now(), FS: docsStaticFs}
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// )
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//
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// http.FileServer(http.FS(docsStaticCached)).ServeHTTP(w, r)
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//
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type CachingEmbedFS struct {
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ModTime time.Time
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FS embed.FS
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}
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// Open opens a file in the embedded filesystem and returns a fs.File with the static ModTime
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func (f CachingEmbedFS) Open(name string) (fs.File, error) {
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file, err := f.FS.Open(name)
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if err != nil {
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return nil, err
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}
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stat, err := file.Stat()
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if err != nil {
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return nil, err
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}
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return &cachingEmbedFile{file, f.ModTime, stat}, nil
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}
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type cachingEmbedFile struct {
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file fs.File
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modTime time.Time
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fs.FileInfo
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}
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func (f cachingEmbedFile) Stat() (fs.FileInfo, error) {
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return f, nil
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}
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func (f cachingEmbedFile) Read(bytes []byte) (int, error) {
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return f.file.Read(bytes)
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}
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func (f *cachingEmbedFile) Seek(offset int64, whence int) (int64, error) {
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if seeker, ok := f.file.(io.Seeker); ok {
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return seeker.Seek(offset, whence)
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}
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return 0, errors.New("io.Seeker not implemented")
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}
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func (f cachingEmbedFile) ModTime() time.Time {
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return f.modTime // We override this!
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}
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func (f cachingEmbedFile) Close() error {
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return f.file.Close()
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}
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