cleanmedia/cleanmedia

#!/usr/bin/env python3

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
import argparse
import logging
from datetime import datetime, timedelta
from functools import cached_property
from pathlib import Path
from typing import Optional, Union, List, Tuple
try:
    import psycopg2, psycopg2.extensions  # noqa: E401
    import yaml
except ImportError:
    raise Exception("Please install psycopg2 and pyyaml")


# ------------------------------------------------------------------------
class File:
    """A file in our db together with (hopefully) a physical file and thumbnails"""

    def __init__(self, media_repo: 'MediaRepository', media_id: str, creation_ts: int, base64hash: str):
        # The MediaRepository in which this file is recorded
        self.repo = media_repo
        self.media_id = media_id
        # creation_ts is seconds since the epoch
        self.create_date = datetime.fromtimestamp(creation_ts)
        self.base64hash = base64hash

    @cached_property
    def fullpath(self) -> Optional[Path]:
        """returns the directory in which the "file" and all thumbnails are located, or None if no file is known"""
        if not self.base64hash:
            return None
        return self.repo.media_path / self.base64hash[0:1] / self.base64hash[1:2] / self.base64hash[2:]

    def delete(self) -> bool:
        """Delete db entries, and the file itself

        :returns: True on successful delete of file,
                  False or Exception on failure"""
        res = True
        if self.fullpath is None:
            logging.info(f"No known path for file id '{self.media_id}', cannot delete file.")
            res = False
        elif not self.fullpath.is_dir():
            logging.debug(f"Path for file id '{self.media_id}' is not a directory or does not exist, not deleting.")
            res = False
        else:
            for file in self.fullpath.glob('*'):
                # note: this does not handle directories in fullpath
                file.unlink()
            self.fullpath.rmdir()
            logging.debug(f"Deleted directory {self.fullpath}")

        with self.repo.conn.cursor() as cur:
            cur.execute("DELETE from mediaapi_thumbnail WHERE media_id=%s;", (self.media_id,))
            num_thumbnails = cur.rowcount
            cur.execute("DELETE from mediaapi_media_repository WHERE media_id=%s;", (self.media_id,))
            num_media = cur.rowcount
        self.repo.conn.commit()
        logging.debug(f"Deleted {num_media} + {num_thumbnails} db entries for media id {self.media_id}")
        return res

    def exists(self) -> bool:
        """returns True if the media file itself exists on the file system"""
        if self.fullpath is None:
            return False
        return (self.fullpath / 'file').exists()

    def has_thumbnail(self) -> int:
        """Returns the number of thumbnails associated with this file"""
        with self.repo.conn.cursor() as cur:
            cur.execute(f"select COUNT(media_id) from mediaapi_thumbnail WHERE media_id='{self.media_id}';")
            row = cur.fetchone()
            if row is None:
                return 0
        return int(row[0])


class MediaRepository:
    """A dendrite media repository"""
    def __init__(self, media_path: Path, connection_string: str):
        self.media_path = media_path
        if not self.media_path.is_absolute():
            logging.warn("The media path is relative, make sure you run this script in the correct directory!")
        if not self.media_path.is_dir():
            raise Exception("The configured media dir cannot be found!")
        # List of current avatar imgs. init empty
        self._avatar_media_ids: List[str] = []

        self.db_conn_string = connection_string  # psql db connection
        self.conn = self.connect_db()

    def connect_db(self) -> psycopg2.extensions.connection:
        # postgresql://user:pass@localhost/database?params
        if self.db_conn_string is None \
           or not self.db_conn_string.startswith(("postgres://",
                                                  "postgresql://")):
            errstr = "DB connection not a postgres one"
            logging.error(errstr)
            raise ValueError(errstr)
        return psycopg2.connect(self.db_conn_string)

    def get_single_media(self, mxid: str) -> Optional[File]:
        """Return `File` or `None`"""
        with self.conn.cursor() as cur:
            sql_str = "SELECT media_id, creation_ts, base64hash from mediaapi_media_repository WHERE media_id = %s;"
            cur.execute(sql_str, (mxid,))
            row = cur.fetchone()
            if row is None:
                return None
            # creation_ts is ms since the epoch, so convert to seconds
            return File(self, row[0], row[1] // 1000, row[2])

    def get_all_media(self, local: bool = False) -> List[File]:
        """Return List[File] of remote media or ALL media if local==True"""
        with self.conn.cursor() as cur:
            # media_id | media_origin | content_type | file_size_bytes |  creation_ts  | upload_name | base64hash | user_id
            sql_str = "SELECT media_id, creation_ts, base64hash from mediaapi_media_repository"
            if not local:
                # only fetch remote media where user_id is empty
                sql_str += " WHERE user_id = ''"
            sql_str += ";"
            cur.execute(sql_str)
            files = []
            for row in cur.fetchall():
                # creation_ts is ms since the epoch, so convert to seconds
                f = File(self, row[0], row[1] // 1000, row[2])
                files.append(f)
        return files

    def get_avatar_images(self) -> List[str]:
        """Get a list of media_id which are current avatar images

        We don't want to clean up those. Save & cache them internally.
        """
        media_id = []
        with self.conn.cursor() as cur:
            cur.execute("SELECT avatar_url FROM userapi_profiles WHERE avatar_url > '';")
            for row in cur.fetchall():
                url = row[0]  # mxc://matrix.org/6e627f4c538563
                try:
                    media_id.append(url[url.rindex("/") + 1:])
                except ValueError:
                    logging.warn("No slash in URL '%s'!", url)
            self._avatar_media_ids = media_id
        return self._avatar_media_ids

    def sanity_check_thumbnails(self) -> None:
        """Warn if we have thumbnails in the db that do not refer to existing media"""
        with self.conn.cursor() as cur:
            cur.execute("SELECT COUNT(media_id) from mediaapi_thumbnail WHERE media_id NOT IN (SELECT media_id FROM mediaapi_media_repository);")
            row = cur.fetchone()
            if row is not None and row[0]:
                logging.error("You have {} thumbnails in your db that do not refer to media. This needs fixing (we don't do that)!".format(row[0]))

    def clean_media_files(self, days: int, local: bool = False, dryrun: bool = False) -> int:
        """Clean out old media files from this repository

        :params:
           :days: (int) delete media files older than N days.
           :local: (bool) Also delete media originating from local users
           :dryrun: (bool) Do not actually delete any files (just count)
        :returns: (int) The number of files that were/would be deleted
        """
        if local:
            # populate the cache of current avt img. so we don't delete them
            mr.get_avatar_images()

        cleantime = datetime.today() - timedelta(days=days)
        logging.info("Deleting remote media older than %s", cleantime)
        num_deleted = 0
        files = mr.get_all_media(local)
        for file in [f for f in files if f.media_id not in mr._avatar_media_ids]:
            if file.create_date < cleantime:
                num_deleted += 1
                if dryrun:  # the great pretender
                    logging.info(f"Pretending to delete file id {file.media_id} on path {file.fullpath}.")
                    if not file.exists():
                        logging.info(f"File id {file.media_id} does not physically exist (path {file.fullpath}).")
                else:
                    file.delete()
        info_str = "Deleted %d files during the run."
        if dryrun:
            info_str = "%d files would have been deleted during the run."
        logging.info(info_str, num_deleted)

        return num_deleted


# --------------------------------------------------------------
def read_config(conf_file: Union[str, Path]) -> Tuple[Path, str]:
    """Read in the dendrite config file and return db creds and media path"""
    try:
        with open(conf_file) as f:
            config = yaml.safe_load(f)
    except FileNotFoundError:
        errstr = f"Config file {conf_file} not found. Use the --help option to find out more."
        logging.error(errstr)
        exit(1)

    if "media_api" not in config:
        logging.error("Missing section media_api")
        exit(1)

    CONN_STR = None
    if "global" in config and "database" in config["global"]:
        CONN_STR = config["global"]["database"].get("connection_string", None)
    elif "database" in config["media_api"]:
        logging.debug("No database section in global, but one in media_api, using that")
        CONN_STR = config["media_api"]["database"].get("connection_string", None)

    if CONN_STR is None:
        logging.error("Did not find connection string to media database.")
        exit(1)

    BASE_PATH = Path(config["media_api"].get("base_path", None))

    if BASE_PATH is None:
        logging.error("Missing base_path in media_api")
        exit(1)
    return (BASE_PATH, CONN_STR)


def parse_options() -> argparse.Namespace:
    loglevel = logging.INFO  # default logging level
    parser = argparse.ArgumentParser(
        prog='cleanmedia',
        description='Deletes 30 day old remote media files from dendrite servers')
    parser.add_argument('-c', '--config', default="config.yaml", help="location of the dendrite.yaml config file.")
    parser.add_argument('-m', '--mxid', dest="mxid",
                        help="Just delete media <MXID>. (no cleanup otherwise)")
    parser.add_argument('-t', '--days', dest="days",
                        default="30", type=int,
                        help="Keep remote media for <DAYS> days.")
    parser.add_argument('-l', '--local', action='store_true',
                        help="Also include local (ie, from *our* users) media files when purging.")
    parser.add_argument('-n', '--dryrun', action='store_true',
                        help="Dry run (don't actually modify any files).")
    parser.add_argument('-q', '--quiet', action='store_true', help="Reduce output verbosity.")
    parser.add_argument('-d', '--debug', action='store_true', help="Increase output verbosity.")
    args: argparse.Namespace = parser.parse_args()
    if args.debug:
        loglevel = logging.DEBUG
    elif args.quiet:
        loglevel = logging.WARNING
    logging.basicConfig(level=loglevel, format='%(levelname)s - %(message)s')
    return args


if __name__ == '__main__':
    args = parse_options()
    (MEDIA_PATH, CONN_STR) = read_config(args.config)
    mr = MediaRepository(MEDIA_PATH, CONN_STR)

    if args.mxid:
        # Just clean a single media
        file = mr.get_single_media(args.mxid)
        if file:
            logging.info("Found media with id '%s'", args.mxid)
            if not args.dryrun:
                file.delete()
    else:          # main clean out...
        # Sanity checks
        mr.sanity_check_thumbnails()  # warn in case of superfluous thumbnails

        mr.clean_media_files(args.days, args.local, args.dryrun)