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tile_source.py
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tile_source.py
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import os
import sys
import sqlite3
import urlparse
import json
from PyQt4.QtGui import QApplication
from PyQt4.QtCore import QObject, pyqtSignal
from log_helper import debug, critical, warn, info
from tile_json import TileJSON
from file_helper import FileHelper
from tile_helper import VectorTile, get_tiles_from_center, get_tile_bounds
_DEFAULT_CRS = "EPSG:3857"
class AbstractSource(QObject):
progress_changed = pyqtSignal(int, name='tileSourceProgressChanged')
max_progress_changed = pyqtSignal(int, name='tileSourceMaxProgressChanged')
message_changed = pyqtSignal('QString', name='tileSourceMessageChanged')
tile_limit_reached = pyqtSignal(name='tile_limit_reached')
def __init__(self):
QObject.__init__(self)
self._cancelling = False
def cancel(self):
self._cancelling = True
def source(self):
raise NotImplementedError
def vector_layers(self):
raise NotImplementedError
def close_connection(self):
pass
def name(self):
raise NotImplementedError
def min_zoom(self):
"""
* Returns the minimum zoom that is found in either the metadata or the tile table
:return:
"""
raise NotImplementedError
def max_zoom(self):
"""
* Returns the maximum zoom that is found in either the metadata or the tile table
:return:
"""
raise NotImplementedError
def mask_level(self):
"""
* Returns the mask level from the metadata table
:return:
"""
raise NotImplementedError
def scheme(self):
raise NotImplementedError
def bounds_tile(self, zoom):
"""
* Returns the tile boundaries
:param zoom:
:return:
"""
raise NotImplementedError
def crs(self):
raise NotImplementedError
def load_tiles(self, zoom_level, tiles_to_load, max_tiles=None):
"""
* Loads the tiles for the specified zoom_level and bounds from the web service this source has been created with
:param tiles_to_load: All tile coordinates which shall be loaded
:param zoom_level: The zoom level which will be loaded
:param max_tiles: The maximum number of tiles to be loaded
:param limit_reacher_handler: A function which will be called, if the potential nr of tiles is greater than the specified limit
:return:
"""
raise NotImplementedError
class ServerSource(AbstractSource):
def __init__(self, url):
AbstractSource.__init__(self)
if not url:
raise RuntimeError("URL is required")
valid, error = FileHelper.url_exists(url)
if not valid:
raise RuntimeError(error)
self.url = url
is_web_source = url.lower().startswith("http://") or url.lower().startswith("https://")
if not is_web_source:
raise RuntimeError("The URL is invalid: {}".format(url))
self.json = TileJSON(url)
self.json.load()
def source(self):
return self.url
def vector_layers(self):
return self.json.vector_layers()
def close_connection(self):
pass
def name(self):
name = self.json.name()
if not name:
name = self.json.id()
if not name:
name = urlparse.urlsplit(self.url)[1]
return name
def min_zoom(self):
return int(self.json.min_zoom())
def max_zoom(self):
return int(self.json.max_zoom())
def mask_level(self):
return self.json.mask_level()
def scheme(self):
return self.json.scheme()
def bounds_tile(self, zoom):
return self.json.bounds_tile(zoom)
def crs(self):
return self.json.crs()
def load_tiles(self, zoom_level, tiles_to_load, max_tiles=None):
self._cancelling = False
base_url = self.json.tiles()[0]
tile_data_tuples = []
urls = []
if len(tiles_to_load) > max_tiles:
tiles_to_load = get_tiles_from_center(max_tiles, tiles_to_load, should_cancel_func=lambda: self._cancelling)
self.tile_limit_reached.emit()
parameters = urlparse.parse_qs(urlparse.urlparse(self.url).query)
api_key = ""
if "api_key" in parameters.keys():
api_key = parameters["api_key"][0]
for t in tiles_to_load:
col = t[0]
row = t[1]
load_url = base_url\
.replace("{z}", str(int(zoom_level)))\
.replace("{x}", str(int(col)))\
.replace("{y}", str(int(row)))\
.replace("{api_key}", str(api_key))
urls.append((load_url, col, row))
self.max_progress_changed.emit(len(urls))
self.message_changed.emit("Getting {} tiles from source...".format(len(urls)))
page_size = 5
results = []
self._do_paged(page_size, urls, results, self._load_urls_async)
for r in results:
content = r[0]
col = r[1][0]
row = r[1][1]
tile = VectorTile(self.scheme(), zoom_level, col, row)
tile_data_tuples.append((tile, content))
return tile_data_tuples
def _load_urls_async(self, page_offset, urls_with_col_and_row):
replies = map(lambda url: (FileHelper.load_url_async(url[0]), (url[1], url[2])), urls_with_col_and_row)
all_finished = False
nr_finished_before = 0
while not all_finished and not self._cancelling:
QApplication.processEvents()
nr_finished = sum(map(lambda r: r[0].isFinished(), replies), 0)
if nr_finished != nr_finished_before:
self.progress_changed.emit(page_offset + nr_finished)
all_finished = nr_finished == len(replies)
results = []
for r in replies:
reply = r[0]
content = reply.readAll().data()
reply.deleteLater()
tile_coord = r[1]
results.append((content, tile_coord))
return results
def _do_paged(self, page_size, all_items, result_set, func, *args):
page_nr = 0
items = []
while page_nr == 0 or len(items) > 0:
items = all_items[page_nr:page_nr + page_size]
if self._cancelling or len(items) == 0:
break
page_offset = page_nr*page_size
results = func(page_offset, items, *args)
result_set.extend(results)
page_nr += page_size
class MBTilesSource(AbstractSource):
def __init__(self, path):
AbstractSource.__init__(self)
if not os.path.isfile(path):
raise RuntimeError("The file does not exist: {}".format(path))
is_sqlite_db = FileHelper.is_sqlite_db(path)
if not is_sqlite_db:
raise RuntimeError(
"The file '{}' is not a valid Mapbox vector tile file and cannot be loaded.".format(path))
self.path = path
self.conn = None
self._metadata_cache = {}
def source(self):
return self.path
def crs(self):
return self._get_metadata_value("crs", _DEFAULT_CRS)
def vector_layers(self):
data = self._get_metadata_value("json")
layers = []
if data:
json_data = json.loads(data)
if "vector_layers" in json_data:
layers = json_data["vector_layers"]
return layers
def bounds_tile(self, zoom):
bounds = self._get_metadata_value("bounds")
if bounds:
bounds = bounds\
.replace(" ", "")\
.replace("[", "")\
.replace("]", "")\
.split(",")
bounds = map(lambda s: float(s), bounds)
scheme = self.scheme()
return get_tile_bounds(zoom=zoom, bounds=bounds, scheme=scheme)
def name(self):
base_name = os.path.splitext(os.path.basename(self.path))[0]
return base_name
def scheme(self):
return self._get_metadata_value("scheme", default="tms")
def min_zoom(self):
return self._get_zoom(max_zoom=False)
def max_zoom(self):
return self._get_zoom(max_zoom=True)
def mask_level(self):
return self._get_metadata_value("maskLevel")
def load_tiles(self, zoom_level, tiles_to_load, max_tiles=None):
self._cancelling = False
debug("Reading tiles of zoom level {}", zoom_level)
if max_tiles:
center_tiles = get_tiles_from_center(nr_of_tiles=max_tiles,
available_tiles=tiles_to_load,
should_cancel_func=lambda: self._cancelling)
else:
center_tiles = tiles_to_load
where_clause = self._get_where_clause(tiles_to_load=center_tiles, zoom_level=zoom_level)
sql_command = "SELECT zoom_level, tile_column, tile_row, tile_data FROM tiles {};"
sql = sql_command.format(where_clause)
tile_data_tuples = []
rows = self._get_from_db(sql=sql)
no_tiles_in_current_extent = not rows or len(rows) == 0
if no_tiles_in_current_extent:
where_clause = self._get_where_clause(tiles_to_load=None, zoom_level=zoom_level)
sql = sql_command.format(where_clause)
rows = self._get_from_db(sql=sql)
if rows:
if max_tiles and len(rows) > max_tiles:
if no_tiles_in_current_extent:
rows = rows[:max_tiles]
if no_tiles_in_current_extent:
self.tile_limit_reached.emit()
self.max_progress_changed.emit(len(rows))
for index, row in enumerate(rows):
if self._cancelling or (max_tiles and len(tile_data_tuples) >= max_tiles):
break
tile, data = self._create_tile(row)
tile_data_tuples.append((tile, data))
self.progress_changed.emit(index+1)
return tile_data_tuples
@staticmethod
def _get_where_clause(tiles_to_load, zoom_level):
where_clause = ""
if zoom_level is not None or tiles_to_load:
where_clause = "WHERE"
if zoom_level is not None:
where_clause += " zoom_level = {}".format(zoom_level)
if tiles_to_load:
where_clause += " AND"
if tiles_to_load:
tile_coords = str(map(lambda x: "{};{}".format(x[0], x[1]), tiles_to_load)).replace("[", "").replace(
"]", "")
where_clause += " tile_column || \";\" || tile_row IN ({})".format(tile_coords)
return where_clause
def _create_tile(self, row):
zoom_level = row["zoom_level"]
tile_col = row["tile_column"]
tile_row = row["tile_row"]
binary_data = row["tile_data"]
tile = VectorTile(self.scheme(), zoom_level, tile_col, tile_row)
return tile, binary_data
def close_connection(self):
"""
* Closes the current db connection
:return:
"""
if self.conn:
try:
self.conn.close()
debug("Connection closed")
except:
warn("Closing connection failed: {}".format(sys.exc_info()))
self.conn = None
def _get_zoom(self, max_zoom=True):
if max_zoom:
field_name = "maxzoom"
else:
field_name = "minzoom"
if field_name not in self._metadata_cache:
zoom = self._get_metadata_value(field_name)
if zoom is None:
zoom = self._get_zoom_from_tiles_table(max_zoom=max_zoom)
if zoom is not None:
zoom = int(zoom)
self._metadata_cache[field_name] = zoom
return self._metadata_cache[field_name]
def _get_zoom_from_tiles_table(self, max_zoom=True):
if max_zoom:
order = "desc"
else:
order = "asc"
query = ("select zoom_level as 'zoom_level'"
"from tiles"
"order by zoom_level {}"
"limit 1").format(order)
return self._get_single_value(sql_query=query, field_name="zoom_level")
def _get_metadata_value(self, field_name, default=None):
if field_name not in self._metadata_cache:
debug("Loading metadata value '{}'", field_name)
sql = "select value as '{0}' from metadata where name = '{0}'".format(field_name)
value = self._get_single_value(sql_query=sql, field_name=field_name)
if default and not value:
value = default
self._metadata_cache[field_name] = value
return self._metadata_cache[field_name]
def _get_single_value(self, sql_query, field_name):
"""
* Helper function that can be used to safely load a single value from the db
* Returns the value or None if result is empty or execution of query failed
:param sql_query:
:param field_name:
:return:
"""
value = None
try:
rows = self._get_from_db(sql=sql_query)
if rows:
value = rows[0][field_name]
debug("Value is: {}".format(value))
except:
critical("Loading metadata value '{}' failed: {}", field_name, sys.exc_info())
return value
def _get_from_db(self, sql):
if not self.conn:
debug("Not connected yet.")
self._connect_to_db()
try:
debug("Execute SQL: {}", sql)
cur = self.conn.cursor()
cur.execute(sql)
return cur.fetchall()
except:
critical("Getting data from db failed: {}", sys.exc_info())
def _connect_to_db(self):
"""
* Since an mbtile file is a sqlite database, we can connect to it
"""
debug("Connecting to: {}", self.path)
try:
self.conn = sqlite3.connect(self.path)
self.conn.row_factory = sqlite3.Row
debug("Successfully connected")
except:
critical("Db connection failed:", sys.exc_info())
class TrexCacheSource(AbstractSource):
def __init__(self, path):
AbstractSource.__init__(self)
if not os.path.isdir(path):
raise RuntimeError("The folder does not exist: {}".format(path))
self.path = path
metadata_path = os.path.join(path, "metadata.json")
self.json = TileJSON(metadata_path)
self.json.load()
def source(self):
return self.path
def vector_layers(self):
data = json.loads(self.json.get_value("json"))["vector_layers"]
return data
def name(self):
name = self.json.name()
if not name:
name = self.json.id()
if not name:
name = os.path.basename(self.path)
return name
def min_zoom(self):
return self.json.min_zoom()
def max_zoom(self):
return self.json.max_zoom()
def mask_level(self):
return self.json.mask_level()
def scheme(self):
return self.json.scheme()
def bounds_tile(self, zoom):
return self.json.bounds_tile(zoom)
def crs(self):
return self.json.crs()
def load_tiles(self, zoom_level, tiles_to_load, max_tiles=None):
self._cancelling = False
tile_data_tuples = []
if len(tiles_to_load) > max_tiles:
tiles_to_load = get_tiles_from_center(max_tiles, tiles_to_load, should_cancel_func=lambda: self._cancelling)
self.tile_limit_reached.emit()
self.max_progress_changed.emit(tiles_to_load)
for index, t in enumerate(tiles_to_load):
self.progress_changed.emit(index)
tile_path = "{}/{}/{}.pbf".format(int(zoom_level), t[0], t[1])
full_path = os.path.join(self.path, tile_path)
col = t[0]
row = t[1]
tile = VectorTile(self.scheme(), zoom_level, col, row)
if os.path.isfile(full_path):
with open(full_path, 'rb') as f:
encoded_data = f.read()
tile_data_tuples.append((tile, encoded_data))
return tile_data_tuples