Add on-demand fingerprinting function available to mods

pkg/manage/actionsModPerm.go

@@ -2,11 +2,13 @@ package manage
 
 import (
 	"bytes"
+	"database/sql"
 	"errors"
 	"fmt"
 	"net"
 	"net/http"
 	"net/url"
+	"path"
 	"regexp"
 	"strconv"
 
@@ -15,6 +17,7 @@ import (
 	"github.com/gochan-org/gochan/pkg/gcsql"
 	"github.com/gochan-org/gochan/pkg/gctemplates"
 	"github.com/gochan-org/gochan/pkg/gcutil"
+	"github.com/gochan-org/gochan/pkg/posting/uploads"
 	"github.com/gochan-org/gochan/pkg/server/serverutil"
 	"github.com/rs/zerolog"
 )
@@ -671,6 +674,56 @@ func postInfoCallback(_ http.ResponseWriter, request *http.Request, _ *gcsql.Sta
 	return postInfo, nil
 }
 
+type fingerprintJSON struct {
+	Filename    string `json:"file"`
+	Fingerprint string `json:"fingerprint"`
+}
+
+func fingerprintCallback(_ http.ResponseWriter, request *http.Request, _ *gcsql.Staff, _ bool, _ *zerolog.Event, errEv *zerolog.Event) (output interface{}, err error) {
+	postIDstr := request.Form.Get("post")
+	if postIDstr == "" {
+		return "", errors.New("missing 'post' field")
+	}
+	postID, err := strconv.Atoi(postIDstr)
+	if err != nil {
+		errEv.Err(err).Caller().Send()
+		return "", err
+	}
+	const query = `SELECT
+	(SELECT dir from DBPREFIXboards WHERE id = (SELECT thread_id FROM DBPREFIXposts WHERE id = ?))
+	AS board, filename, is_spoilered FROM DBPREFIXfiles WHERE post_id = ? LIMIT 1`
+	var board, filename string
+	var spoiler bool
+	err = gcsql.QueryRowSQL(query, []any{postID, postID}, []any{&board, &filename, &spoiler})
+	if errors.Is(err, sql.ErrNoRows) {
+		return "", errors.New("post has no files")
+	} else if err != nil {
+		errEv.Err(err).Caller().Send()
+		return "", err
+	}
+	fpVideoThumbs := config.GetSiteConfig().FingerprintVideoThumbnails
+	if !uploads.IsImage(filename) && !uploads.IsVideo(filename) {
+		return "", fmt.Errorf(
+			"unable to fingerprint file %q (not an image or a video)", filename)
+	} else if uploads.IsVideo(filename) && !fpVideoThumbs {
+		return "", fmt.Errorf(
+			"unable to fingerprint file %q (video thumbnail fingerprinting not enabled)",
+			filename)
+	}
+	docRoot := config.GetSystemCriticalConfig().DocumentRoot
+	filePath := path.Join(docRoot, board, "src", filename)
+	fingerprintHash, err := uploads.FingerprintFile(filePath)
+	if err != nil {
+		errEv.Err(err).Caller().Send()
+		return "", err
+	}
+
+	return fingerprintJSON{
+		Filename:    filename,
+		Fingerprint: fingerprintHash,
+	}, nil
+}
+
 func registerModeratorPages() {
 	actions = append(actions,
 		Action{
@@ -727,5 +780,12 @@ func registerModeratorPages() {
 			JSONoutput:  AlwaysJSON,
 			Callback:    postInfoCallback,
 		},
+		Action{
+			ID:          "fingerprint",
+			Title:       "Get image/thumbnail fingerprint",
+			Permissions: ModPerms,
+			JSONoutput:  AlwaysJSON,
+			Callback:    fingerprintCallback,
+		},
 	)
 }

pkg/posting/uploads/attach.go

@@ -39,6 +39,26 @@ func RegisterUploadHandler(ext string, handler UploadHandler) {
 	uploadHandlers[ext] = handler
 }
 
+func IsImage(file string) bool {
+	ext := path.Ext(file)
+	for _, iExt := range ImageExtensions {
+		if ext == iExt {
+			return true
+		}
+	}
+	return false
+}
+
+func IsVideo(file string) bool {
+	ext := path.Ext(file)
+	for _, vExt := range VideoExtensions {
+		if ext == vExt {
+			return true
+		}
+	}
+	return false
+}
+
 func init() {
 	uploadHandlers = make(map[string]UploadHandler)
 	for _, ext := range ImageExtensions {

pkg/posting/uploads/fingerprinting.go

@@ -1,10 +1,10 @@
 package uploads
 
 import (
+	"errors"
 	"fmt"
 	"image"
 	"net/http"
-	"path"
 
 	"github.com/devedge/imagehash"
 	"github.com/disintegration/imaging"
@@ -12,8 +12,12 @@ import (
 	"github.com/gochan-org/gochan/pkg/gcsql"
 )
 
+var (
+	ErrVideoThumbFingerprint = errors.New("video thumbnail fingerprinting not enabled")
+)
+
 const (
-	defaultFingerprintHashLength = 16
+	defaultFingerprintHashLength = 8
 )
 
 type FingerprintSource struct {
@@ -22,11 +26,16 @@ type FingerprintSource struct {
 	Request  *http.Request
 }
 
-func fingerprintImage(img image.Image, board string) (*gcsql.FileBan, error) {
+func getHashLength() int {
 	hashLength := config.GetSiteConfig().FingerprintHashLength
 	if hashLength < 1 {
-		hashLength = defaultFingerprintHashLength
+		return defaultFingerprintHashLength
 	}
+	return hashLength
+}
+
+func checkImageFingerprintBan(img image.Image, board string) (*gcsql.FileBan, error) {
+	hashLength := getHashLength()
 	ba, err := imagehash.Ahash(img, hashLength)
 	if err != nil {
 		return nil, err
@@ -50,28 +59,29 @@ func fingerprintImage(img image.Image, board string) (*gcsql.FileBan, error) {
 	return &fileBan, err
 }
 
-func fingerprintFile(filePath string, board string) (*gcsql.FileBan, error) {
+func FingerprintFile(filePath string) (string, error) {
+	img, err := imaging.Open(filePath)
+	if err != nil {
+		return "", err
+	}
+
+	fmt.Println("hash length:", getHashLength())
+	ba, err := imagehash.Ahash(img, getHashLength())
+	if err != nil {
+		return "", err
+	}
+	return fmt.Sprintf("%x", ba), nil
+}
+
+func checkFileFingerprintBan(filePath string, board string) (*gcsql.FileBan, error) {
 	img, err := imaging.Open(filePath)
 	if err != nil {
 		return nil, err
 	}
-	return fingerprintImage(img, board)
+	return checkImageFingerprintBan(img, board)
 }
 
 func canFingerprint(filename string) bool {
 	siteCfg := config.GetSiteConfig()
-	ext := path.Ext(filename)
-	for _, iExt := range ImageExtensions {
-		if iExt == ext {
-			return true
-		}
-	}
-	if siteCfg.FingerprintVideoThumbnails {
-		for _, vExt := range VideoExtensions {
-			if vExt == ext {
-				return true
-			}
-		}
-	}
-	return false
+	return IsImage(filename) || (IsVideo(filename) && siteCfg.FingerprintVideoThumbnails)
 }