WASAPhoto/service/database/db-likes.go

120 lines
3.3 KiB
Go

package database
import (
"github.com/notherealmarco/WASAPhoto/service/database/db_errors"
"github.com/notherealmarco/WASAPhoto/service/structures"
)
// Get the list of users who liked a photo
func (db *appdbimpl) GetPhotoLikes(uid string, photo int64, requesting_uid string, start_index int, limit int) (QueryResult, *[]structures.UIDName, error) {
// Check if the photo exists, as it could exist but have no likes.
//
// This also checks if the author has banned the requesting user
// as he should not be able to see anything related to his photos
exists, err := db.PhotoExists(uid, photo, requesting_uid)
if err != nil {
return ERR_INTERNAL, nil, err
}
if !exists {
return ERR_NOT_FOUND, nil, nil
}
rows, err := db.c.Query(`SELECT "users"."uid", "users"."name" FROM "likes", "users"
WHERE "likes"."photo_id" = ?
AND "likes"."user" NOT IN (
SELECT "bans"."user" FROM "bans"
WHERE "bans"."user" = "likes"."user"
AND "bans"."ban" = ?
)
AND "likes"."user" = "users"."uid"
LIMIT ?
OFFSET ?`, photo, requesting_uid, limit, start_index)
if err != nil {
return ERR_INTERNAL, nil, err
}
likes := make([]structures.UIDName, 0)
defer rows.Close()
for rows.Next() {
var uid string
var name string
err = rows.Scan(&uid, &name)
if err != nil {
return ERR_INTERNAL, nil, err
}
likes = append(likes, structures.UIDName{UID: uid, Name: name})
}
// We check if the iteration ended prematurely
if err = rows.Err(); err != nil {
return ERR_INTERNAL, nil, err
}
return SUCCESS, &likes, nil
}
// Like a photo
func (db *appdbimpl) LikePhoto(uid string, photo int64, liker_uid string) (QueryResult, error) {
// Check if the photo exists, as API specification requires
// photos to be identified also by the user who posted them.
// But our DB implementation only requires the photo id.
//
// This also checks if the author of the photo has banned the requesting user
// as he should not be able to like his photos
exists, err := db.PhotoExists(uid, photo, liker_uid)
if err != nil || !exists {
return ERR_NOT_FOUND, err
}
_, err = db.c.Exec(`PRAGMA foreign_keys = ON;
INSERT INTO "likes" ("user", "photo_id") VALUES (?, ?)`, liker_uid, photo)
// The photo exists, but the user already liked it
if db_errors.UniqueViolation(err) {
return ERR_EXISTS, nil
}
if db_errors.ForeignKeyViolation(err) {
return ERR_NOT_FOUND, nil
}
if err != nil {
return ERR_INTERNAL, err
}
return SUCCESS, nil
}
// Unlike a photo
func (db *appdbimpl) UnlikePhoto(uid string, photo int64, liker_uid string) (QueryResult, error) {
// Check if the photo exists, as API specification requires
// photos to be identified also by the user who posted them.
// But our DB implementation only requires the photo id.
exists, err := db.photoExists(uid, photo)
if err != nil || !exists {
// The photo does not exist, or the user has been banned
return ERR_NOT_FOUND, err
}
res, err := db.c.Exec(`DELETE FROM "likes" WHERE "user" = ? AND "photo_id" = ?`, liker_uid, photo)
if err != nil {
return ERR_INTERNAL, err
}
rows, err := res.RowsAffected()
if err != nil {
return ERR_INTERNAL, err
}
// The user was not liking the photo
if rows == 0 {
return ERR_NOT_FOUND, nil
}
return SUCCESS, nil
}