e6af6a708c
Always close the output file; previously this was not done when the JPEG encoding would fail.
84 lines
2.0 KiB
Go
84 lines
2.0 KiB
Go
package last_rendered
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// SPDX-License-Identifier: GPL-3.0-or-later
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import (
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"bytes"
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"errors"
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"fmt"
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"image"
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"image/jpeg"
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"os"
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"path/filepath"
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// Import for side-effect of registering decoder.
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_ "image/png"
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"github.com/disintegration/imaging"
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"github.com/rs/zerolog/log"
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)
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var (
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supportedMimeTypes = map[string]bool{
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"image/jpeg": true,
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"image/png": true,
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}
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ErrMimeTypeUnsupported = errors.New("mime type unsupported")
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)
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// decodeImage checks the payload mime type, and if okay, decodes the image and returns it.
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// Returns `ErrMimeTypeUnsupported` if the mime type is unsupported.
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func decodeImage(payload Payload) (image.Image, error) {
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if !supportedMimeTypes[payload.MimeType] {
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return nil, ErrMimeTypeUnsupported
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}
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reader := bytes.NewReader(payload.Image)
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img, _, err := image.Decode(reader)
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if err != nil {
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return nil, fmt.Errorf("decoding image: %w", err)
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}
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return img, nil
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}
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// saveJPEG writes the given image to a JPEG file.
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func saveJPEG(targetpath string, img image.Image) error {
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// Ensure the directory exists.
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targetdir := filepath.Dir(targetpath)
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err := os.MkdirAll(targetdir, os.ModePerm)
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if err != nil {
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return fmt.Errorf("creating directory %s: %w", targetdir, err)
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}
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file, err := os.Create(targetpath)
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if err != nil {
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return fmt.Errorf("creating file: %w", err)
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}
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defer func() {
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err = file.Close()
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if err != nil {
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log.Warn().Err(err).Str("filename", targetpath).Msg("last-rendered: error closing file")
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}
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}()
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options := jpeg.Options{
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Quality: thumbnailJPEGQuality,
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}
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err = jpeg.Encode(file, img, &options)
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if err != nil {
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return fmt.Errorf("encoding as JPEG: %w", err)
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}
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return nil
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}
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func downscaleImage(spec thumbspec, img image.Image) image.Image {
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// Fill out the entire frame, cropping the image if necessary:
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// return imaging.Fill(img, spec.maxWidth, spec.maxHeight, imaging.Center, imaging.Lanczos)
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// Fit the image to the frame, potentially resulting in either a narrower or lower image:
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return imaging.Fit(img, spec.maxWidth, spec.maxHeight, imaging.Lanczos)
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}
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