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138 lines
2.9 KiB
138 lines
2.9 KiB
package main
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import (
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"fmt"
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"log"
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"math/rand"
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"net/http"
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"os"
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"path"
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"path/filepath"
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"slices"
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"strings"
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"github.com/fsnotify/fsnotify"
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)
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var images []string
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var validExtensions = getValidExtensions()
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func main() {
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dirPath := os.Getenv("IMAGE_DIR")
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if dirPath == "" {
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dirPath = "/images"
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}
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files, err := os.ReadDir(dirPath)
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if err != nil {
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log.Fatal(err)
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}
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fmt.Printf("Image directory: %s\n", dirPath)
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for _, file := range files {
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if fileIsValid(path.Join(dirPath, file.Name())) {
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images = appendIfNotExists(images, path.Join(dirPath, file.Name()))
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} else {
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log.Printf("File %s unreadable or not an image, ignoring.\n", file.Name())
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}
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}
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watcher, err := fsnotify.NewWatcher()
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if err != nil {
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log.Fatal(err)
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}
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defer watcher.Close()
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go func() {
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for {
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select {
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case event, ok := <-watcher.Events:
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if !ok {
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return
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}
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file := filenameFromEvent(event)
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if event.Has(fsnotify.Create) {
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// happens on rename and new file add
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if fileIsValid(file) {
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images = appendIfNotExists(images, file)
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}
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} else if event.Has(fsnotify.Remove) || event.Has(fsnotify.Rename) {
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// happens on rm or old file rename
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images = remove(images, file)
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} else if event.Has(fsnotify.Chmod) {
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// happens on chmod and rm if file descriptors are open
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// file is deleted or unreadable, remove
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if !fileIsValid(file) {
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images = remove(images, file)
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} else {
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// file was unreadable but now is, add
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images = appendIfNotExists(images, file)
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}
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}
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case err, ok := <-watcher.Errors:
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if !ok {
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return
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}
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log.Println("error:", err)
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}
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}
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}()
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err = watcher.Add(dirPath)
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if err != nil {
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log.Fatal(err)
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}
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http.HandleFunc("/", serveImage)
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log.Println("Listening on :8080")
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log.Fatal(http.ListenAndServe(":8080", nil))
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}
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func serveImage(w http.ResponseWriter, r *http.Request) {
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http.ServeFile(w, r, images[rand.Intn(len(images))])
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}
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// not fast at all but whatever
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func remove(s []string, item string) []string {
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for i, fn := range s {
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if fn == item {
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log.Printf("REMOVE %s\n", item)
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return append(s[:i], s[i+1:]...)
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}
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}
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return s
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}
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func appendIfNotExists(slice []string, element string) []string {
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for _, ele := range slice {
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if ele == element {
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return slice
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}
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}
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log.Printf("ADD %s\n", element)
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return append(slice, element)
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}
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func filenameFromEvent(event fsnotify.Event) string {
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return strings.Split(event.String(), "\"")[1]
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}
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func fileIsValid(file string) bool {
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return slices.Contains(validExtensions, filepath.Ext(file)) && isReadable(file)
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}
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func getValidExtensions() []string {
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env := os.Getenv("ALLOWED_EXTENSIONS")
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if env == "" {
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return []string{".png", ".jpg", ".jpeg", ".webp"}
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} else {
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return strings.Split(env, ",")
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}
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}
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// maybe expensive but works
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// tried file info mode perms, syscall.Access already, didnt work
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func isReadable(file string) bool {
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_, err := os.Open(file)
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return err == nil
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}
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