dev_agent
58e8f30f0e
CI / ci (push) Successful in 1m38s
Co-authored-by: dev_agent <dev_agent@cubecraftlabs.com>
76 lines
2.2 KiB
Go
76 lines
2.2 KiB
Go
package server
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import (
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"context"
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"errors"
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"io/fs"
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"log/slog"
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"net/http"
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"os"
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"strconv"
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"strings"
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"github.com/go-chi/chi/v5"
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)
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// photoCacheControl lets the browser keep a photo for a year without
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// revalidating: a photo's files never change once stored, and a new image
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// gets a new id.
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const photoCacheControl = "private, max-age=31536000, immutable"
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// PhotoFiles opens a cached photo's file at one of its stored sizes. An
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// unknown photo or size is an error matching fs.ErrNotExist.
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type PhotoFiles interface {
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OpenPhoto(ctx context.Context, id string, size int) (*os.File, error)
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}
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// getPhoto answers GET /media/photos/{id}-{size}.jpg with the stored JPEG.
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func getPhoto(logger *slog.Logger, photos PhotoFiles) http.HandlerFunc {
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notFound := apiErrorHandler(logger, http.StatusNotFound, "not_found", "not found")
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return func(w http.ResponseWriter, r *http.Request) {
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id, size, ok := parsePhotoName(chi.URLParam(r, "name"))
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if !ok {
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notFound(w, r)
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return
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}
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f, err := photos.OpenPhoto(r.Context(), id, size)
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if errors.Is(err, fs.ErrNotExist) {
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notFound(w, r)
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return
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}
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if err != nil {
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logger.ErrorContext(r.Context(), "open photo", "id", id, "size", size, "error", err)
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writeError(w, r, logger, http.StatusInternalServerError, "internal", "internal error")
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return
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}
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defer f.Close()
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info, err := f.Stat()
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if err != nil {
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logger.ErrorContext(r.Context(), "stat photo", "id", id, "size", size, "error", err)
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writeError(w, r, logger, http.StatusInternalServerError, "internal", "internal error")
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return
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}
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w.Header().Set("Content-Type", "image/jpeg")
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w.Header().Set("Cache-Control", photoCacheControl)
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http.ServeContent(w, r, "", info.ModTime(), f)
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}
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}
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// parsePhotoName splits "{id}-{size}.jpg" into its id and size, refusing
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// a size not written in its canonical decimal form.
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func parsePhotoName(name string) (id string, size int, ok bool) {
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stem, ok := strings.CutSuffix(name, ".jpg")
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if !ok {
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return "", 0, false
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}
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i := strings.LastIndexByte(stem, '-')
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if i < 0 {
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return "", 0, false
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}
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size, err := strconv.Atoi(stem[i+1:])
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if err != nil || strconv.Itoa(size) != stem[i+1:] {
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return "", 0, false
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}
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return stem[:i], size, true
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}
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