package main
import (
"bytes"
"crypto/sha1"
"database/sql"
"encoding/hex"
"errors"
"fmt"
"html/template"
"io"
"io/fs"
"log"
"net"
"net/http"
"os"
"os/exec"
"path/filepath"
"regexp"
"strings"
"time"
_ "github.com/mattn/go-sqlite3"
)
var (
db *sql.DB // sqlite database
gd string // gallery directory
)
func openDB(directory string) error {
var err error
db, err = sql.Open("sqlite3",
"file:"+filepath.Join(directory, "gallery.db?_foreign_keys=1"))
gd = directory
return err
}
func imagePath(sha1 string) string {
return filepath.Join(gd, "images", sha1[:2], sha1)
}
func thumbPath(sha1 string) string {
return filepath.Join(gd, "thumbs", sha1[:2], sha1+".webp")
}
func dbCollectStrings(query string) ([]string, error) {
rows, err := db.Query(query)
if err != nil {
return nil, err
}
defer rows.Close()
var result []string
for rows.Next() {
var sha1 string
if err := rows.Scan(&sha1); err != nil {
return nil, err
}
result = append(result, sha1)
}
if err := rows.Err(); err != nil {
return nil, err
}
return result, nil
}
type directoryManager struct {
cache map[string]int64 // Unix-style paths to directory.id
}
func (dm *directoryManager) IDForDirectoryPath(path string) (int64, error) {
// Relative paths could be handled differently,
// but right now, they're assumed to start at the root.
list := strings.Split(filepath.ToSlash(filepath.Clean(path)), "/")
if len(list) > 1 && list[0] == "" {
list = list[1:]
}
if len(list) == 0 {
return 0, nil
}
var parent sql.NullInt64
for _, name := range list {
if err := db.QueryRow(
`SELECT id FROM directory WHERE name = ? AND parent IS ?`,
name, parent).Scan(&parent); err == nil {
continue
} else if !errors.Is(err, sql.ErrNoRows) {
return 0, err
}
if result, err := db.Exec(
`INSERT INTO directory(name, parent) VALUES (?, ?)`,
name, parent); err != nil {
return 0, err
} else if id, err := result.LastInsertId(); err != nil {
return 0, err
} else {
parent = sql.NullInt64{Int64: id, Valid: true}
}
}
return parent.Int64, nil
}
// cmdInit initializes a "gallery directory" that contains gallery.sqlite,
// images, thumbs.
func cmdInit(args []string) error {
if len(args) != 1 {
return errors.New("usage: GD")
}
if err := openDB(args[0]); err != nil {
return err
}
if _, err := db.Exec(initializeSQL); err != nil {
return err
}
// XXX: There's technically no reason to keep images as symlinks,
// we might just keep absolute paths in the database as well.
if err := os.MkdirAll(filepath.Join(gd, "images"), 0755); err != nil {
return err
}
if err := os.MkdirAll(filepath.Join(gd, "thumbs"), 0755); err != nil {
return err
}
return nil
}
var hashRE = regexp.MustCompile(`^/.*?/([0-9a-f]{40})$`)
var staticHandler http.Handler
var page = template.Must(template.New("/").Parse(`
Gallery
{{ . }}
`))
func handleRequest(w http.ResponseWriter, r *http.Request) {
if r.URL.Path != "/" {
staticHandler.ServeHTTP(w, r)
return
}
// TODO: Include the most elementary contents first.
if err := page.Execute(w, "Hello world"); err != nil {
http.Error(w, err.Error(), 500)
}
}
func handleImages(w http.ResponseWriter, r *http.Request) {
if m := hashRE.FindStringSubmatch(r.URL.Path); m == nil {
http.NotFound(w, r)
} else {
http.ServeFile(w, r, imagePath(m[1]))
}
}
func handleThumbs(w http.ResponseWriter, r *http.Request) {
if m := hashRE.FindStringSubmatch(r.URL.Path); m == nil {
http.NotFound(w, r)
} else {
http.ServeFile(w, r, thumbPath(m[1]))
}
}
// cmdRun runs a web UI against GD on ADDRESS.
func cmdRun(args []string) error {
if len(args) != 2 {
return errors.New("usage: GD ADDRESS")
}
if err := openDB(args[0]); err != nil {
return err
}
address := args[1]
// This separation is not strictly necessary,
// but having an elementary level of security doesn't hurt either.
staticHandler = http.FileServer(http.Dir("public"))
http.HandleFunc("/", handleRequest)
http.HandleFunc("/images/", handleImages)
http.HandleFunc("/thumbs/", handleThumbs)
// TODO: Add a few API endpoints.
host, port, err := net.SplitHostPort(address)
if err != nil {
log.Println(err)
} else if host == "" {
log.Println("http://" + net.JoinHostPort("localhost", port))
} else {
log.Println("http://" + address)
}
s := &http.Server{
Addr: address,
ReadTimeout: 60 * time.Second,
WriteTimeout: 60 * time.Second,
MaxHeaderBytes: 32 << 10,
}
return s.ListenAndServe()
}
func isImage(path string) (bool, error) {
cmd := exec.Command("xdg-mime", "query", "filetype", path)
stdout, err := cmd.StdoutPipe()
if err != nil {
return false, err
}
if err := cmd.Start(); err != nil {
return false, err
}
out, err := io.ReadAll(stdout)
if err != nil {
return false, err
}
if err := cmd.Wait(); err != nil {
return false, err
}
return bytes.HasPrefix(out, []byte("image/")), nil
}
func importFunc(path string, d fs.DirEntry, err error) error {
if err != nil || d.IsDir() {
return err
}
// The input may be a relative path, and we want to remember it as such,
// but symlinks for the images must be absolute.
absPath, err := filepath.Abs(path)
if err != nil {
return err
}
// Skip videos, which ImageMagick can process, but we don't want it to,
// so that they're not converted 1:1 to WebP.
pathIsImage, err := isImage(path)
if err != nil {
return err
}
if !pathIsImage {
return nil
}
f, err := os.Open(path)
if err != nil {
return err
}
defer f.Close()
s, err := f.Stat()
if err != nil {
return err
}
hash := sha1.New()
_, err = io.CopyBuffer(hash, f, make([]byte, 65536))
if err != nil {
return err
}
hexSHA1 := hex.EncodeToString(hash.Sum(nil))
pathImage := imagePath(hexSHA1)
imageDirname, _ := filepath.Split(pathImage)
if err := os.MkdirAll(imageDirname, 0755); err != nil {
return err
}
if err := os.Symlink(absPath, pathImage); err != nil &&
!errors.Is(err, fs.ErrExist) {
return err
}
// TODO: This should all run in a transaction.
if _, err = db.Exec(`INSERT INTO image(sha1) VALUES (?)
ON CONFLICT(sha1) DO NOTHING`, hexSHA1); err != nil {
return err
}
// TODO: Maintain the cache across calls.
dm := directoryManager{}
dbDirname, dbBasename := filepath.Split(path)
dbParent, err := dm.IDForDirectoryPath(dbDirname)
if err != nil {
return err
}
_, err = db.Exec(`INSERT INTO entry(
parent, name, mtime, sha1
) VALUES (?, ?, ?, ?)`, dbParent, dbBasename, s.ModTime().Unix(), hexSHA1)
return err
}
// cmdImport adds files to the "entry" table.
func cmdImport(args []string) error {
if len(args) < 1 {
return errors.New("usage: GD ROOT...")
}
if err := openDB(args[0]); err != nil {
return err
}
// TODO: This would better be done in parallel (making hashes).
// TODO: Show progress in some manner. Perhaps port my propeller code.
for _, name := range args[1:] {
if err := filepath.WalkDir(name, importFunc); err != nil {
return err
}
}
return nil
}
// cmdSync is like import, but clears the "entry" table beforehands.
func cmdSync(args []string) error {
if len(args) < 1 {
return errors.New("usage: GD ROOT...")
}
if err := openDB(args[0]); err != nil {
return err
}
// TODO
return nil
}
// cmdCheck checks if all files tracked in the DB are accessible.
func cmdCheck(args []string) error {
if len(args) != 1 {
return errors.New("usage: GD")
}
if err := openDB(args[0]); err != nil {
return err
}
// TODO: Check if all hashes of DB entries have a statable image file,
// and that all images with thumb{w,h} have a thumbnail file. Perhaps.
return nil
}
func makeThumbnail(pathImage, pathThumb string) (int, int, error) {
thumbDirname, _ := filepath.Split(pathThumb)
if err := os.MkdirAll(thumbDirname, 0755); err != nil {
return 0, 0, err
}
// Create a normalized thumbnail. Since we don't particularly need
// any complex processing, such as surrounding of metadata,
// simply push it through ImageMagick.
//
// - http://www.ericbrasseur.org/gamma.html
// - https://www.imagemagick.org/Usage/thumbnails/
// - https://imagemagick.org/script/command-line-options.php#layers
//
// TODO: See if we can optimize resulting WebP animations.
// (Do -layers optimize* apply to this format at all?)
cmd := exec.Command("convert", pathImage, "-coalesce", "-colorspace", "RGB",
"-auto-orient", "-strip", "-resize", "256x128>", "-colorspace", "sRGB",
"-format", "%w %h", "+write", "info:", pathThumb)
stdout, err := cmd.StdoutPipe()
if err != nil {
return 0, 0, err
}
if err := cmd.Start(); err != nil {
return 0, 0, err
}
out, err := io.ReadAll(stdout)
if err != nil {
return 0, 0, err
}
if err := cmd.Wait(); err != nil {
return 0, 0, err
}
var w, h int
_, err = fmt.Fscanf(bytes.NewReader(out), "%d %d", &w, &h)
return w, h, err
}
// cmdThumbnail generates missing thumbnails, in parallel.
func cmdThumbnail(args []string) error {
if len(args) < 1 {
return errors.New("usage: GD [SHA1...]")
}
if err := openDB(args[0]); err != nil {
return err
}
hexSHA1 := args[1:]
if len(hexSHA1) == 0 {
// Get all unique images in the database with no thumbnail.
var err error
hexSHA1, err = dbCollectStrings(`SELECT sha1 FROM image
WHERE thumbw IS NULL OR thumbh IS NULL`)
if err != nil {
return err
}
}
// TODO: Try to run the thumbnailer in parallel, somehow.
// Then run convert with `-limit thread 1`.
// TODO: Show progress in some manner. Perhaps port my propeller code.
for _, sha1 := range hexSHA1 {
pathImage := imagePath(sha1)
pathThumb := thumbPath(sha1)
w, h, err := makeThumbnail(pathImage, pathThumb)
if err != nil {
return err
}
_, err = db.Exec(`UPDATE image SET thumbw = ?, thumbh = ?
WHERE sha1 = ?`, w, h, sha1)
if err != nil {
return err
}
}
return nil
}
func makeDhash(hasher, pathThumb string) (uint64, error) {
cmd := exec.Command(hasher, pathThumb)
stdout, err := cmd.StdoutPipe()
if err != nil {
return 0, err
}
if err := cmd.Start(); err != nil {
return 0, err
}
out, err := io.ReadAll(stdout)
if err != nil {
return 0, err
}
if err := cmd.Wait(); err != nil {
return 0, err
}
var hash uint64
_, err = fmt.Fscanf(bytes.NewReader(out), "%x", &hash)
return hash, err
}
// cmdDhash generates perceptual hash from thumbnails.
func cmdDhash(args []string) error {
if len(args) < 1 {
return errors.New("usage: GD HASHER [SHA1...]")
}
if err := openDB(args[0]); err != nil {
return err
}
hasher, hexSHA1 := args[1], args[2:]
if len(hexSHA1) == 0 {
var err error
hexSHA1, err = dbCollectStrings(`SELECT sha1 FROM image
WHERE dhash IS NULL`)
if err != nil {
return err
}
}
// TODO: Try to run the hasher in parallel, somehow.
// TODO: Show progress in some manner. Perhaps port my propeller code.
for _, sha1 := range hexSHA1 {
pathThumb := thumbPath(sha1)
hash, err := makeDhash(hasher, pathThumb)
if err != nil {
return err
}
_, err = db.Exec(`UPDATE image SET dhash = ? WHERE sha1 = ?`,
int64(hash), sha1)
if err != nil {
return err
}
}
return nil
}
var commands = map[string]struct {
handler func(args []string) error
}{
"init": {cmdInit},
"run": {cmdRun},
"import": {cmdImport},
"sync": {cmdSync},
"check": {cmdCheck},
"thumbnail": {cmdThumbnail},
"dhash": {cmdDhash},
}
func main() {
if len(os.Args) <= 2 {
log.Fatalln("Missing arguments")
}
cmd, ok := commands[os.Args[1]]
if !ok {
log.Fatalln("Unknown command: " + os.Args[1])
}
err := cmd.handler(os.Args[2:])
// Note that the database object has a closing finalizer,
// we just additionally print any errors coming from there.
if db != nil {
if err := db.Close(); err != nil {
log.Println(err)
}
}
if err != nil {
log.Fatalln(err)
}
}