ordigi/elodie/media/photo.py

"""
The photo module contains the :class:`Photo` class, which is used to track
image objects (JPG, DNG, etc.).

.. moduleauthor:: Jaisen Mathai <jaisen@jmathai.com>
"""

import imghdr
import os
import re
import subprocess
import time
from datetime import datetime
from re import compile


from elodie import constants
from elodie import geolocation
from elodie.external.pyexiftool import ExifTool
from media import Media


class Photo(Media):

    """A photo object.

    :param str source: The fully qualified path to the photo file
    """

    __name__ = 'Photo'

    #: Valid extensions for photo files.
    extensions = ('arw', 'dng', 'gif', 'jpeg', 'jpg', 'nef', 'rw2')

    def __init__(self, source=None):
        super(Photo, self).__init__(source)

        # We only want to parse EXIF once so we store it here
        self.exif = None

    def get_duration(self):
        """Get the duration of a photo in seconds. Uses ffmpeg/ffprobe.

        :returns: str or None for a non-photo file
        """
        if(not self.is_valid()):
            return None

        source = self.source
        result = subprocess.Popen(
            ['ffprobe', source],
            stdout=subprocess.PIPE,
            stderr=subprocess.STDOUT
        )
        for key in result.stdout.readlines():
            if 'Duration' in key:
                return re.search(
                    '(\d{2}:\d{2}.\d{2})',
                    key
                ).group(1).replace('.', ':')
        return None

    def get_date_taken(self):
        """Get the date which the photo was taken.

        The date value returned is defined by the min() of mtime and ctime.

        :returns: time object or None for non-photo files or 0 timestamp
        """
        if(not self.is_valid()):
            return None
        
        source = self.source
        seconds_since_epoch = min(os.path.getmtime(source), os.path.getctime(source))  # noqa

        exif = self.get_exiftool_attributes()
        if not exif:
            return seconds_since_epoch

        # We need to parse a string from EXIF into a timestamp.
        # EXIF DateTimeOriginal and EXIF DateTime are both stored
        #   in %Y:%m:%d %H:%M:%S format
        # we use split on a space and then r':|-' -> convert to int -> .timetuple()
        #   the conversion in the local timezone
        # EXIF DateTime is already stored as a timestamp
        # Sourced from https://github.com/photo/frontend/blob/master/src/libraries/models/Photo.php#L500  # noqa
        for key in self.exif_map['date_taken']:
            try:
                if(key in exif):
                    if(re.match('\d{4}(-|:)\d{2}(-|:)\d{2}', exif[key]) is not None):  # noqa
                        dt, tm = exif[key].split(' ')
                        dt_list = compile(r'-|:').split(dt)
                        dt_list = dt_list + compile(r'-|:').split(tm)
                        dt_list = map(int, dt_list)
                        time_tuple = datetime(*dt_list).timetuple()
                        seconds_since_epoch = time.mktime(time_tuple)
                        break
            except BaseException as e:
                if(constants.debug is True):
                    print e
                pass

        if(seconds_since_epoch == 0):
            return None

        return time.gmtime(seconds_since_epoch)

    def is_valid(self):
        """Check the file extension against valid file extensions.

        The list of valid file extensions come from self.extensions. This
        also checks whether the file is an image.

        :returns: bool
        """
        source = self.source

        # gh-4 This checks if the source file is an image.
        # It doesn't validate against the list of supported types.
        if(imghdr.what(source) is None):
            return False

        return os.path.splitext(source)[1][1:].lower() in self.extensions