This moved a bunch of logic out of http and into the asset package, making it available for gmit too.main
Brian Picciano
1 year ago
parent
7872296b83
commit
5559e01343
@ -0,0 +1,43 @@ |
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package asset |
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import ( |
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"errors" |
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"io" |
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"path/filepath" |
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) |
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var ( |
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ErrCannotResize = errors.New("cannot resize") |
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) |
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// LoadOpts are optional parameters to Loader's Load method. Some may only apply
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// to specific Loader implementations.
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type LoadOpts struct { |
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// ImageWidth is used by the ImageLoader to resize images on the fly.
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ImageWidth int |
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} |
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// Loader is used to load an asset and write its body into the given io.Writer.
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//
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// Errors:
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// - ErrNotFound
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// - ErrCannotResize (only if ImageLoader is used)
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type Loader interface { |
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Load(path string, into io.Writer, opts LoadOpts) error |
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} |
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type storeLoader struct { |
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store Store |
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} |
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// NewStoreLoader returns a Loader which loads assets directly from the given
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// Store, with no transformation.
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func NewStoreLoader(store Store) Loader { |
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return &storeLoader{store} |
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} |
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func (l *storeLoader) Load(path string, into io.Writer, opts LoadOpts) error { |
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id := filepath.Base(path) |
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return l.store.Get(id, into) |
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} |
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@ -0,0 +1,99 @@ |
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package asset |
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import ( |
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"bytes" |
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"compress/gzip" |
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"errors" |
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"fmt" |
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"io" |
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"io/fs" |
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"strings" |
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"github.com/omeid/go-tarfs" |
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) |
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type archiveLoader struct { |
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loader Loader |
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} |
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// NewArchiveLoader wraps an existing Loader in order to support extracting
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// files from within an archive file asset.
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//
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// For example, loading the path `foo.tgz/foo/bar.jpg` will call
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// `Load("foo.tgz")`, load that archive into memory, and serve the file
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// `./foo/bar.jpg` from within the archive.
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func NewArchiveLoader(loader Loader) Loader { |
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return &archiveLoader{loader: loader} |
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} |
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func (l *archiveLoader) Load(path string, into io.Writer, opts LoadOpts) error { |
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id, subPath, ok := strings.Cut(strings.TrimPrefix(path, "/"), "/") |
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if !ok { |
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return l.loader.Load(path, into, opts) |
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} |
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var isGzipped bool |
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switch { |
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case strings.HasSuffix(id, ".tar.gz"), |
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strings.HasSuffix(id, ".tgz"): |
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isGzipped = true |
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case strings.HasSuffix(id, ".tar"): |
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// ok
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default: |
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// unsupported
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return l.loader.Load(path, into, opts) |
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} |
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buf := new(bytes.Buffer) |
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if err := l.loader.Load(id, buf, opts); err != nil { |
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return fmt.Errorf("loading archive into buffer: %w", err) |
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} |
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var ( |
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from io.Reader = buf |
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err error |
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) |
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if isGzipped { |
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if from, err = gzip.NewReader(from); err != nil { |
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return fmt.Errorf("decompressing archive asset with id %q: %w", id, err) |
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} |
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} |
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tarFS, err := tarfs.New(from) |
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if err != nil { |
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return fmt.Errorf("reading archive asset with id %q as fs: %w", id, err) |
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} |
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f, err := tarFS.Open(subPath) |
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if errors.Is(err, fs.ErrExist) { |
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return ErrNotFound |
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} else if err != nil { |
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return fmt.Errorf( |
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"opening path %q from archive asset with id %q as fs: %w", |
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subPath, id, err, |
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) |
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} |
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defer f.Close() |
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if _, err = io.Copy(into, f); err != nil { |
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return fmt.Errorf( |
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"reading %q from archive asset with id %q as fs: %w", |
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subPath, id, err, |
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) |
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} |
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return nil |
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} |
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@ -0,0 +1,85 @@ |
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package asset |
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import ( |
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"bytes" |
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"fmt" |
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"image" |
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"image/jpeg" |
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"image/png" |
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"io" |
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"path/filepath" |
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"strings" |
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"golang.org/x/image/draw" |
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) |
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// IsImageResizable returns whether or not an image can be resized, based on its
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// extension.
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func IsImageResizable(path string) bool { |
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switch strings.ToLower(filepath.Ext(path)) { |
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case ".jpg", ".jpeg", ".png": |
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return true |
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default: |
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return false |
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} |
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} |
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type imageLoader struct { |
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loader Loader |
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} |
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// NewImageLoader wraps an existing Loader in order to perform various
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// image-related transformations on any image assets being loaded. Non-image
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// assets are loaded as-is.
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func NewImageLoader(loader Loader) Loader { |
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return &imageLoader{loader} |
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} |
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func (l *imageLoader) Load(path string, into io.Writer, opts LoadOpts) error { |
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if opts.ImageWidth == 0 { |
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return l.loader.Load(path, into, opts) |
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} |
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if !IsImageResizable(path) { |
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return ErrCannotResize |
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} |
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buf := new(bytes.Buffer) |
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if err := l.loader.Load(path, buf, opts); err != nil { |
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return fmt.Errorf("loading image into buffer: %w", err) |
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} |
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img, format, err := image.Decode(buf) |
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if err != nil { |
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return fmt.Errorf("decoding image: %w", err) |
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} |
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maxWidth := float64(opts.ImageWidth) |
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imgRect := img.Bounds() |
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imgW, imgH := float64(imgRect.Dx()), float64(imgRect.Dy()) |
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if imgW > maxWidth { |
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newH := imgH * maxWidth / imgW |
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newImg := image.NewRGBA(image.Rect(0, 0, int(maxWidth), int(newH))) |
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// Resize
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draw.BiLinear.Scale( |
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newImg, newImg.Bounds(), img, img.Bounds(), draw.Over, nil, |
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) |
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img = newImg |
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} |
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switch format { |
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case "jpeg": |
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return jpeg.Encode(into, img, nil) |
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case "png": |
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return png.Encode(into, img) |
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default: |
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return fmt.Errorf("unknown image format %q", format) |
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} |
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} |
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