diff options
Diffstat (limited to 'src/post/asset/loader_archive.go')
-rw-r--r-- | src/post/asset/loader_archive.go | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/src/post/asset/loader_archive.go b/src/post/asset/loader_archive.go new file mode 100644 index 0000000..1c8697f --- /dev/null +++ b/src/post/asset/loader_archive.go @@ -0,0 +1,99 @@ +package asset + +import ( + "bytes" + "compress/gzip" + "errors" + "fmt" + "io" + "io/fs" + "strings" + + "github.com/omeid/go-tarfs" +) + +type archiveLoader struct { + loader Loader +} + +// NewArchiveLoader wraps an existing Loader in order to support extracting +// files from within an archive file asset. +// +// For example, loading the path `foo.tgz/foo/bar.jpg` will call +// `Load("foo.tgz")`, load that archive into memory, and serve the file +// `./foo/bar.jpg` from within the archive. +func NewArchiveLoader(loader Loader) Loader { + return &archiveLoader{loader: loader} +} + +func (l *archiveLoader) Load(path string, into io.Writer, opts LoadOpts) error { + + id, subPath, ok := strings.Cut(strings.TrimPrefix(path, "/"), "/") + + if !ok { + return l.loader.Load(path, into, opts) + } + + var isGzipped bool + + switch { + + case strings.HasSuffix(id, ".tar.gz"), + strings.HasSuffix(id, ".tgz"): + isGzipped = true + + case strings.HasSuffix(id, ".tar"): + // ok + + default: + // unsupported + return l.loader.Load(path, into, opts) + } + + buf := new(bytes.Buffer) + + if err := l.loader.Load(id, buf, opts); err != nil { + return fmt.Errorf("loading archive into buffer: %w", err) + } + + var ( + from io.Reader = buf + err error + ) + + if isGzipped { + + if from, err = gzip.NewReader(from); err != nil { + return fmt.Errorf("decompressing archive asset with id %q: %w", id, err) + } + } + + tarFS, err := tarfs.New(from) + + if err != nil { + return fmt.Errorf("reading archive asset with id %q as fs: %w", id, err) + } + + f, err := tarFS.Open(subPath) + + if errors.Is(err, fs.ErrExist) { + return ErrNotFound + + } else if err != nil { + return fmt.Errorf( + "opening path %q from archive asset with id %q as fs: %w", + subPath, id, err, + ) + } + + defer f.Close() + + if _, err = io.Copy(into, f); err != nil { + return fmt.Errorf( + "reading %q from archive asset with id %q as fs: %w", + subPath, id, err, + ) + } + + return nil +} |