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"""

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    Image handling.

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"""

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from werkzeug import Request, Response, exceptions

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from werkzeug.utils import html, redirect

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import pngtile.tile

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from pngtile.application import url, BaseApplication

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import pypngtile

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import json

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import os, os.path

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def dir_list (root):

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    """

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        Yield a series of directory items to show for the given dir

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    """

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    for name in os.listdir(root):

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        path = os.path.join(root, name)

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        # skip dotfiles

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        if name.startswith('.'):

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            continue

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        # show dirs

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        if os.path.isdir(path):

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            yield name + '/'

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        # examine ext

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        if '.' in name:

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            name_base, name_type = name.rsplit('.', 1)

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        else:

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            name_base = name

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            name_type = None

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        # show .png files with a .cache file

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        if name_type in ImageApplication.IMAGE_TYPES and os.path.exists(os.path.join(root, name_base + '.cache')):

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            yield name

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class ImageApplication (BaseApplication):

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    STYLESHEETS = (

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        'https://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css',

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        'https://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap-theme.min.css',

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        'http://cdn.leafletjs.com/leaflet-0.7.3/leaflet.css',

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        '/static/pngtile/map.css',

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    )

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    SCRIPTS = (

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        'https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js',

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        'https://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js',

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        'http://cdn.leafletjs.com/leaflet-0.7.3/leaflet.js',

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        '/static/pngtile/map.js',

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    )

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    def __init__ (self, tile_server=None, **opts):

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        """

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            http://.../ path to tileserver root

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        """

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        BaseApplication.__init__(self, **opts)

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        self.tile_server = tile_server

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    def render_dir_breadcrumb (self, name):

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        path = []

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        yield html.li(html.a(href='/', *[u"Index"]))

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        if name:

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            for part in name.split('/'):

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                path.append(part)

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                yield html.li(html.a(href=url('/', *path), *[part]))

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    def render_dir (self, request, name, items):

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        """

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            request:    werkzeug.Request

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            name:       /.../... url to dir

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            items:      [...] items in dir

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        """

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        if name:

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            title = name

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        else:

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            title = "Index"

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        return self.render_html(

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            title       = name,

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            body        = (

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                html.div(class_='container', *[

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                    html.h1(title),

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                    html.div(*[

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                        html.ol(class_='breadcrumb', *self.render_dir_breadcrumb(name)),

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                    ]),

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                    html.div(class_='list', *[

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                        html.ul(class_='list-group', *[html.li(class_='list-group-item', *[

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                                html.a(href=item, *[item])

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                            ]) for item in items]

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                        ),

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                    ]),

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                ]),

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            ),

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        )

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    def render_image (self, request, image, name):

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        """

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            request:    werkzeug.Request

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            image:      pypngtile.Image

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            name:       request path for .../.../*.png image

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        """

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        image_info = image.info()

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        map_config = dict(

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            tile_url        = '{server}/{name}?x={x}&y={y}&zoom={z}',

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            tile_server     = self.tile_server.rstrip('/'),

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            tile_name       = name,

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            tile_size       = pngtile.tile.TILE_SIZE,

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            tile_zoom       = pngtile.tile.MAX_ZOOM,

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            image_url       = '{server}/{name}?w={w}&h={h}&x={x}&y={y}&zoom={z}',

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            image_server    = self.tile_server.rstrip('/'),

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            image_name      = name,

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            image_width     = image_info['img_width'],

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            image_height    = image_info['img_height'],

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        )

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        return self.render_html(

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            title       = name,

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            body        = (

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                html.div(id='wrapper', *[

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                    html.div(id='map')

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                ]),

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            ),

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            end         = (

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                html.script("""$(function() {{ map_init({map_config}); }});""".format(map_config=json.dumps(map_config))),

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            ),

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        )

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    def handle_dir (self, request, name, path):

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        """

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            Generate response for directory listing.

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        """

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        if not request.path.endswith('/'):

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            # we generate HTML with relative links

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            return redirect(request.path + '/')

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        items = sorted(dir_list(path))

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        html = self.render_dir(request, name, items)

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        return Response(html, content_type="text/html")

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    def handle_image (self, request, name, path):

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        """

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            Generate Response for image request.

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        """

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        # backwards-compat redirect from frontend -> tile-server

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        if all(attr in request.args for attr in ('cx', 'cy', 'w', 'h', 'zl')):

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            return redirect(url(self.tile_server, name,

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                w       = request.args['w'],

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                h       = request.args['h'],

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                x       = request.args['cx'],

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                y       = request.args['cy'],

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                zoom    = request.args['zl'],

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            ))

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        try:

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            image, name = self.get_image(request.path)

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        except pypngtile.Error as error:

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            raise exceptions.BadRequest(str(error))

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        html = self.render_image(request, image, name)

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        return Response(html, content_type="text/html")

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    def handle (self, request):

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        """

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            Handle request for an image

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        """

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        name, path = self.lookup_path(request.path)

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        # determine type

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        if '/' in name:

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            _, name_base = name.rsplit('/', 1)

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        else:

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            name_base = name

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        if '.' in name_base:

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            name_base, name_type = name_base.rsplit('.', 1)

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        else:

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            name_type = None

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        # determine handler

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        if os.path.isdir(path):

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            return self.handle_dir(request, name, path)

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        elif name_type and name_type in self.IMAGE_TYPES:

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            return self.handle_image(request, name, path)

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        else:

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            raise exceptions.NotFound(path)

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