bikemap/tracking/management/commands/import_gpx.py

__author__ = 'tyrel'
from django.core.management.base import BaseCommand, CommandError
from django.contrib.auth.models import User
from tracking.models import Track, Segment, Point
from django.contrib.gis import geos
import xmltodict

import os


class Command(BaseCommand):
    help = 'Import a gpx file'

    def add_arguments(self, parser):
        parser.add_argument('username', help="Username to import to.")
        parser.add_argument('filepath', help="File or directory to import a gpx file.")

    def handle(self, *args, **options):
        self.username = options['username']
        filepath = options['filepath']

        try:
            self.user = User.objects.get(username=self.username)
        except User.DoesNotExist:
            raise CommandError("User {0} does not exist".format(self.username))

        if os.path.isfile(filepath):
            self.import_file(filepath)
        else:
            raise CommandError("{0} is neither an existing file, nor a path.".format(filepath))

    def import_file(self, filename):
        with open(filename) as fd:
            obj = dict(xmltodict.parse(fd.read()))['gpx']
        user = self.user

        create_points_segments_tracks(obj, user)


def create_points_segments_tracks(obj, user):
    # Get some Meta data from the gpx file.
    metadata = obj['metadata']
    start_time = metadata['time']
    # Get the the track and segments from the gpx file.
    tracks = obj['trk']
    name = tracks['name']
    segments = tracks['trkseg']
    # Check unimplemented features
    if isinstance(segments, list):
        raise NotImplemented(
            "Haven't run across one that has multiple segments. "
            "Contribute a patch if you have.")
    elif isinstance(segments, dict):
        track = Track.objects.create(user=user,
                                     start=start_time,
                                     name=name)
        points = segments['trkpt']
        segment = Segment(track=track, time=points[0]['time'])
        segment.save()
        for pt in points:
            lat, lon = float(pt['@lat']), float(pt['@lon'])
            poly_pt = geos.Point(lon, lat)
            Point.objects.create(segment=segment,
                                 time=pt['time'],
                                 elevation=pt['ele'],
                                 point=poly_pt)