main_test.py

#!/usr/bin/env python3
import os, shutil, time, socket
import tkinter
import tkinter.filedialog as tkfiledialog
from urllib.request import urlopen
from urllib.error import URLError

MAX_TILE_DL_ATTEMPT = 5

tkRoot = tkinter.Tk()
tkRoot.withdraw()

import pygame

from pyleaflet import Wrapper
from pyleaflet import event
from pyleaflet.tiles import tiles
from pyleaflet import tools

leafletWrapper = Wrapper()
leafletWrapper.start()
while 1:
    e = leafletWrapper.waitEvent()

    if e.eventId==event.QUIT:
        exit()

    if e.eventId==event.KEYUP:
        if e.key == pygame.K_d:
            pathToSave = tkfiledialog.askdirectory(title="Choose a folder to save tiles")
            if pathToSave:

                newPid = os.fork()
                if newPid==0:
                    tilesToDownload = list()
                    #here we are in a child process, we download data then quit
                    if not os.path.exists(pathToSave):
                        os.makedirs(pathToSave)

                    latTop = e.visible["latTop"]
                    lonRight = e.visible["lonRight"]
                    latBottom = e.visible["latBottom"]
                    lonLeft = e.visible["lonLeft"]

                    for zoom in range(tiles.ZOOM_MIN,tiles.ZOOM_MAX+1):
                        x_min, y_min = tools.deg2num(latTop,lonLeft,zoom)
                        x_max, y_max = tools.deg2num(latBottom,lonRight,zoom)

                        for x in range(x_min,x_max+1):
                            for y in range(y_min,y_max+1):
                                nbrTiles = 2**zoom
                                x%=nbrTiles
                                y%=nbrTiles
                                tilesToDownload.append({"x":x,"y":y,"z":zoom,"attempt":0})
                    nbrTileTotal=len(tilesToDownload)
                    failedTiles = list()
                    while len(tilesToDownload)>0:
                        print("Download : {}%".format(int(((nbrTileTotal-len(tilesToDownload))/nbrTileTotal)*100.0)))
                        tileInfo = tilesToDownload.pop(0)
                        x,y,zoom = tileInfo["x"], tileInfo["y"], tileInfo["z"]

                        if not os.path.exists(os.path.join(pathToSave,"{z}/{x}/".format(z=zoom,x=x))):
                            os.makedirs(os.path.join(pathToSave,"{z}/{x}/".format(z=zoom,x=x)))
                        imgPath = tiles.CACHE_PATH.format(x=x,y=y,z=zoom)
                        imgFolder = os.path.dirname(imgPath)
                        dlDest = os.path.join(pathToSave,"{z}/{x}/{y}.png".format(z=zoom,x=x,y=y))
                        if not os.path.isfile(dlDest):
                            if os.path.isfile(imgPath):
                                shutil.copy(imgPath,dlDest)
                            else:
                                try:
                                    response = urlopen(tiles.SOURCE_URL.format(x=x,y=y,z=zoom),timeout=0.5)   #load online file
                                    img = response.read()
                                except (URLError, socket.timeout) as e:
                                    tileInfo["attempt"]+=1
                                    if tileInfo["attempt"]>=MAX_TILE_DL_ATTEMPT:
                                        failedTiles.append(tileInfo)
                                    else:
                                        tilesToDownload.append(tileInfo)
                                else:                                           #save loaded image in cache
                                    with open(dlDest,"wb") as imgFD:   #save image
                                        imgFD.write(img)
                                time.sleep(0.5)
                    if failedTiles:
                        print("The following tiles coundn't be downloaded :")
                        for tile in failedTiles:
                            print("\t {x:%d,y:%d,z:%d"%(tile["x"],tile["y"],tile["z"]))
                    else:
                        print("All tiles downloaded successfuly")
                    os._exit(0)

            else:
                print("Download cancelled")