1

import os, os.path

     2

import pypngtile as pt

     3

     4

from werkzeug import Response, exceptions

     5

     6

from pngtile import render

     7

     8

# path to images

     9

DATA_ROOT = os.environ.get("PNGTILE_DATA_PATH") or os.path.abspath('data/')

    10

    11

# only open each image once

    12

IMAGE_CACHE = {}

    13

    14

### Parse request data

    15

def get_path (req_path) :

    16

    """

    17

        Returns the name and path requested

    18

    """

    19

    20

    # check DATA_ROOT exists..

    21

    if not os.path.isdir(DATA_ROOT) :

    22

        raise exceptions.InternalServerError("Missing DATA_ROOT")

    23

    24

    # path to image

    25

    image_name = req_path.lstrip('/')

    26

    27

    # build absolute path

    28

    image_path = os.path.abspath(os.path.join(DATA_ROOT, image_name))

    29

    30

    # ensure the path points inside the data root

    31

    if not image_path.startswith(DATA_ROOT) :

    32

        raise exceptions.NotFound(image_name)

    33

    34

    return image_name, image_path

    35

    36

def get_image (name, path) :

    37

    """

    38

        Gets an Image object from the cache, ensuring that the cached is available

    39

    """

    40

    41

    # get Image object

    42

    if path in IMAGE_CACHE :

    43

        # get from cache

    44

        image = IMAGE_CACHE[path]

    45

    46

    else :

    47

        # open

    48

        image = pt.Image(path)

    49

    50

        # check

    51

        if image.status() not in (pt.CACHE_FRESH, pt.CACHE_STALE) :

    52

            raise exceptions.InternalServerError("Image cache not available: %s" % name)

    53

    54

        # load

    55

        image.open()

    56

    57

        # cache

    58

        IMAGE_CACHE[path] = image

    59

    60

    return image

    61

    62

    63

### Handle werkzeug.Request objects -> werkzeug.Response

    64

def handle_dir (req, name, path) :

    65

    """

    66

        Handle request for a directory

    67

    """

    68

    69

    prefix = req.script_root

    70

    71

    print "req.script_root:", req.script_root

    72

    print "prefix", prefix

    73

    74

    75

    return Response(render.dir_html(prefix, name, path), content_type="text/html")

    76

    77

    78

    79

def handle_img_viewport (req, image, name) :

    80

    """

    81

        Handle request for image viewport

    82

    """

    83

    84

    prefix = req.script_root

    85

    86

    # viewport

    87

    return Response(render.img_html(prefix, name, image), content_type="text/html")

    88

    89

    90

def handle_img_region (req, image, cache) :

    91

    """

    92

        Handle request for an image region

    93

    """

    94

    95

    # specific image

    96

    width = int(req.args['w'])

    97

    height = int(req.args['h'])

    98

    cx = int(req.args['cx'])

    99

    cy = int(req.args['cy'])

   100

    zoom = int(req.args.get('zl', "0"))

   101

   102

    try :

   103

        # yay full render

   104

        return Response(render.img_png_region(image, cx, cy, zoom, width, height, cache), content_type="image/png")

   105

   106

    except ValueError, ex :

   107

        # too large

   108

        raise exceptions.Forbidden(str(ex))

   109

   110

   111

def handle_img_tile (req, image, cache) :

   112

    """

   113

        Handle request for image tile

   114

    """

   115

   116

    # tile

   117

    x = int(req.args['x'])

   118

    y = int(req.args['y'])

   119

    zoom = int(req.args.get('zl', "0"))

   120

   121

    # cache?

   122

   123

    # yay render

   124

    return Response(render.img_png_tile(image, x, y, zoom, cache), content_type="image/png")

   125

   126

## Dispatch req to handle_img_*

   127

def handle_img (req, name, path, cache) :

   128

    """

   129

        Handle request for an image

   130

    """

   131

   132

    # get image object

   133

    image = get_image(name, path)

   134

   135

    # what view?

   136

    if not req.args :

   137

        return handle_img_viewport(req, image, name)

   138

   139

    elif 'w' in req.args and 'h' in req.args and 'cx' in req.args and 'cy' in req.args :

   140

        return handle_img_region(req, image, cache)

   141

   142

    elif 'x' in req.args and 'y' in req.args :

   143

        return handle_img_tile(req, image, cache)

   144

   145

    else :

   146

        raise exceptions.BadRequest("Unknown args")

   147

   148

   149

   150

## Dispatch request to handle_*

   151

def handle_req (req, cache) :

   152

    """

   153

        Main request handler

   154

    """

   155

   156

    # decode req

   157

    name, path = get_path(req.path)

   158

   159

    # determine dir/image

   160

    if os.path.isdir(path) :

   161

        # directory

   162

        return handle_dir(req, name, path)

   163

   164

    elif not os.path.exists(path) :

   165

        # no such file

   166

        raise exceptions.NotFound(name)

   167

   168

    elif not name or not name.endswith('.png') :

   169

        # invalid file

   170

        raise exceptions.BadRequest("Not a PNG file")

   171

   172

    else :

   173

        # image

   174

        return handle_img(req, name, path, cache)

   175

   176