google/appengine/tools/devappserver2/blob_image.py - external/googleappengine/python - Git at Google

 #!/usr/bin/env python
 #
 # Copyright 2007 Google Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #     http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
 """Handles dynamic serving of images from blobstore."""

 import httplib
 import logging
 import re

 from google.appengine.api import apiproxy_stub_map
 from google.appengine.api import datastore
 from google.appengine.api import datastore_errors
 from google.appengine.api.images import images_service_pb
 from google.appengine.ext import blobstore
 from google.appengine.tools.devappserver2 import blob_download
 from google.appengine.tools.devappserver2 import request_rewriter

 BLOBIMAGE_URL_PATTERN = '_ah/img(?:/.*)?'
 _BLOB_SERVING_URL_KIND = '__BlobServingUrl__'
 _DEFAULT_SERVING_SIZE = 512
 _SIZE_LIMIT = 1600
 _OPTIONS_RE = re.compile(r'^s(\d+)(-c)?')
 _PATH_RE = re.compile(r'/_ah/img/([-\w:]+)([=]*)([-\w]+)?')
 _MIME_TYPE_MAP = {images_service_pb.OutputSettings.JPEG: 'image/jpeg',
                   images_service_pb.OutputSettings.PNG: 'image/png',
                   images_service_pb.OutputSettings.WEBP: 'image/webp'}

 # Check there's a working images stub.
 try:
   # pylint: disable=g-import-not-at-top, unused-import
   from google.appengine.api.images import images_stub
   _HAS_WORKING_IMAGES_STUB = True
 except ImportError:
   _HAS_WORKING_IMAGES_STUB = False


 def _get_images_stub():
   return apiproxy_stub_map.apiproxy.GetStub('images')


 class Error(Exception):
   pass


 class InvalidRequestError(Error):
   """The request was invalid."""


 class Application(object):
   """A WSGI application that handles image serving requests."""

   def _transform_image(self, blob_key, resize=None, crop=False):
     """Construct and execute a transform request using the images stub.

     Args:
       blob_key: A str containing the blob_key of the image to transform.
       resize: An integer for the size of the resulting image.
       crop: A boolean determining if the image should be cropped or resized.

     Returns:
       A str containing the tranformed (if necessary) image.
     """
     image_data = images_service_pb.ImageData()
     image_data.set_blob_key(blob_key)
     image = _get_images_stub()._OpenImageData(image_data)
     original_mime_type = image.format
     width, height = image.size

     # Crop to square if necessary
     if crop:
       crop_xform = None
       if width > height:
         # landscape: slice the sides
         crop_xform = images_service_pb.Transform()
         delta = (width - height) / (width * 2.0)
         crop_xform.set_crop_left_x(delta)
         crop_xform.set_crop_right_x(1.0 - delta)
       elif width < height:
         # portrait: slice the top and bottom with bias
         crop_xform = images_service_pb.Transform()
         delta = (height - width) / (height * 2.0)
         top_delta = max(0.0, delta - 0.25)
         bottom_delta = 1.0 - (2.0 * delta) + top_delta
         crop_xform.set_crop_top_y(top_delta)
         crop_xform.set_crop_bottom_y(bottom_delta)
       if crop_xform:
         image = _get_images_stub()._Crop(image, crop_xform)

     # Resize
     if resize is None:
       if width > _DEFAULT_SERVING_SIZE or height > _DEFAULT_SERVING_SIZE:
         resize = _DEFAULT_SERVING_SIZE

     # resize value of 0 is valid and translates to 'serve at original size'.
     if resize:
       # Note that resize transform maintains the image aspect ratio.
       resize_xform = images_service_pb.Transform()
       resize_xform.set_width(resize)
       resize_xform.set_height(resize)
       image = _get_images_stub()._Resize(image, resize_xform)

     output_settings = images_service_pb.OutputSettings()
     # EncodeImage only saves out to JPEG or PNG. All image formats other than
     # GIF or PNG, will be served as a JPEG.
     output_mime_type = images_service_pb.OutputSettings.JPEG
     if original_mime_type in ['PNG', 'GIF']:
       output_mime_type = images_service_pb.OutputSettings.PNG
     output_settings.set_mime_type(output_mime_type)
     return (_get_images_stub()._EncodeImage(image, output_settings),
             _MIME_TYPE_MAP[output_mime_type])

   def _parse_options(self, options):
     """Parse an options string into a tuple containing the options.

     Currently this only supports resize and crop.

     Args:
       options: A str containing the url resize and crop options.

     Returns:
       A tuple (resize, crop) parsed from the string.

     Raises:
       InvalidRequestError: The requested resize is invalid.
     """
     match = _OPTIONS_RE.search(options)
     resize = None
     crop = False
     if match:
       if match.group(1):
         resize = int(match.group(1))
       if match.group(2):
         crop = True

     # Check size against whitelist
     if resize and (resize > _SIZE_LIMIT or resize < 0):
       logging.error('Invalid resize: %r', resize)
       raise InvalidRequestError()
     return (resize, crop)

   def _parse_path(self, path):
     """Parse the request path into the blobkey and option string.

     Args:
       path: A str containing the path of the request.

     Returns:
       A tuple (blob_key, option) parsed out of the path.

     Raises:
       InvalidRequestError: The request path is invalid.
     """
     match = _PATH_RE.search(path)
     if not match or not match.group(1):
       logging.error('Failed to parse image path "%s"', path)
       raise InvalidRequestError()
     options = ''
     blobkey = match.group(1)
     if match.group(3):
       if match.group(2):
         blobkey += match.group(2)[1:]
       options = match.group(3)
     elif match.group(2):
       blobkey += match.group(2)
     return (blobkey, options)

   def serve_unresized_image(self, blobkey, environ, start_response):
     """Use blob_download to rewrite and serve unresized image directly."""
     state = request_rewriter.RewriterState(environ, '200 OK', [
         (blobstore.BLOB_KEY_HEADER, blobkey)], [])
     blob_download.blobstore_download_rewriter(state)
     start_response(state.status, state.headers.items())
     return state.body

   def serve_image(self, environ, start_response):
     """Dynamically serve an image from blobstore."""
     blobkey, options = self._parse_path(environ['PATH_INFO'])
     # Make sure that the blob URL has been registered by
     # calling get_serving_url
     key = datastore.Key.from_path(_BLOB_SERVING_URL_KIND, blobkey, namespace='')
     try:
       datastore.Get(key)
     except datastore_errors.EntityNotFoundError:
       logging.error('The blobkey %s has not registered for image '
                     'serving. Please ensure get_serving_url is '
                     'called before attempting to serve blobs.', blobkey)
       start_response('404 %s' % httplib.responses[404], [])
       return []

     resize, crop = self._parse_options(options)

     if resize is None and not crop:
       return self.serve_unresized_image(blobkey, environ, start_response)
     elif not _HAS_WORKING_IMAGES_STUB:
       logging.warning('Serving resized images requires a working Python "PIL" '
                       'module. The image is served without resizing.')
       return self.serve_unresized_image(blobkey, environ, start_response)
     else:
       # Use Images service to transform blob.
       image, mime_type = self._transform_image(blobkey, resize, crop)
       start_response('200 OK', [
           ('Content-Type', mime_type),
           ('Cache-Control', 'public, max-age=600, no-transform')])
       return [image]

   def __call__(self, environ, start_response):
     if environ['REQUEST_METHOD'] != 'GET':
       start_response('405 %s' % httplib.responses[405], [])
       return []
     try:
       return self.serve_image(environ, start_response)
     except InvalidRequestError:
       start_response('400 %s' % httplib.responses[400], [])
       return []
	#!/usr/bin/env python
	#
	# Copyright 2007 Google Inc.
	#
	# Licensed under the Apache License, Version 2.0 (the "License");
	# you may not use this file except in compliance with the License.
	# You may obtain a copy of the License at
	#
	# http://www.apache.org/licenses/LICENSE-2.0
	#
	# Unless required by applicable law or agreed to in writing, software
	# distributed under the License is distributed on an "AS IS" BASIS,
	# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	# See the License for the specific language governing permissions and
	# limitations under the License.
	#
	"""Handles dynamic serving of images from blobstore."""

	import httplib
	import logging
	import re

	from google.appengine.api import apiproxy_stub_map
	from google.appengine.api import datastore
	from google.appengine.api import datastore_errors
	from google.appengine.api.images import images_service_pb
	from google.appengine.ext import blobstore
	from google.appengine.tools.devappserver2 import blob_download
	from google.appengine.tools.devappserver2 import request_rewriter

	BLOBIMAGE_URL_PATTERN = '_ah/img(?:/.*)?'
	_BLOB_SERVING_URL_KIND = '__BlobServingUrl__'
	_DEFAULT_SERVING_SIZE = 512
	_SIZE_LIMIT = 1600
	_OPTIONS_RE = re.compile(r'^s(\d+)(-c)?')
	_PATH_RE = re.compile(r'/_ah/img/([-\w:]+)([=]*)([-\w]+)?')
	_MIME_TYPE_MAP = {images_service_pb.OutputSettings.JPEG: 'image/jpeg',
	images_service_pb.OutputSettings.PNG: 'image/png',
	images_service_pb.OutputSettings.WEBP: 'image/webp'}

	# Check there's a working images stub.
	try:
	# pylint: disable=g-import-not-at-top, unused-import
	from google.appengine.api.images import images_stub
	_HAS_WORKING_IMAGES_STUB = True
	except ImportError:
	_HAS_WORKING_IMAGES_STUB = False


	def _get_images_stub():
	return apiproxy_stub_map.apiproxy.GetStub('images')


	class Error(Exception):
	pass


	class InvalidRequestError(Error):
	"""The request was invalid."""


	class Application(object):
	"""A WSGI application that handles image serving requests."""

	def _transform_image(self, blob_key, resize=None, crop=False):
	"""Construct and execute a transform request using the images stub.

	Args:
	blob_key: A str containing the blob_key of the image to transform.
	resize: An integer for the size of the resulting image.
	crop: A boolean determining if the image should be cropped or resized.

	Returns:
	A str containing the tranformed (if necessary) image.
	"""
	image_data = images_service_pb.ImageData()
	image_data.set_blob_key(blob_key)
	image = _get_images_stub()._OpenImageData(image_data)
	original_mime_type = image.format
	width, height = image.size

	# Crop to square if necessary
	if crop:
	crop_xform = None
	if width > height:
	# landscape: slice the sides
	crop_xform = images_service_pb.Transform()
	delta = (width - height) / (width * 2.0)
	crop_xform.set_crop_left_x(delta)
	crop_xform.set_crop_right_x(1.0 - delta)
	elif width < height:
	# portrait: slice the top and bottom with bias
	crop_xform = images_service_pb.Transform()
	delta = (height - width) / (height * 2.0)
	top_delta = max(0.0, delta - 0.25)
	bottom_delta = 1.0 - (2.0 * delta) + top_delta
	crop_xform.set_crop_top_y(top_delta)
	crop_xform.set_crop_bottom_y(bottom_delta)
	if crop_xform:
	image = _get_images_stub()._Crop(image, crop_xform)

	# Resize
	if resize is None:
	if width > _DEFAULT_SERVING_SIZE or height > _DEFAULT_SERVING_SIZE:
	resize = _DEFAULT_SERVING_SIZE

	# resize value of 0 is valid and translates to 'serve at original size'.
	if resize:
	# Note that resize transform maintains the image aspect ratio.
	resize_xform = images_service_pb.Transform()
	resize_xform.set_width(resize)
	resize_xform.set_height(resize)
	image = _get_images_stub()._Resize(image, resize_xform)

	output_settings = images_service_pb.OutputSettings()
	# EncodeImage only saves out to JPEG or PNG. All image formats other than
	# GIF or PNG, will be served as a JPEG.
	output_mime_type = images_service_pb.OutputSettings.JPEG
	if original_mime_type in ['PNG', 'GIF']:
	output_mime_type = images_service_pb.OutputSettings.PNG
	output_settings.set_mime_type(output_mime_type)
	return (_get_images_stub()._EncodeImage(image, output_settings),
	_MIME_TYPE_MAP[output_mime_type])

	def _parse_options(self, options):
	"""Parse an options string into a tuple containing the options.

	Currently this only supports resize and crop.

	Args:
	options: A str containing the url resize and crop options.

	Returns:
	A tuple (resize, crop) parsed from the string.

	Raises:
	InvalidRequestError: The requested resize is invalid.
	"""
	match = _OPTIONS_RE.search(options)
	resize = None
	crop = False
	if match:
	if match.group(1):
	resize = int(match.group(1))
	if match.group(2):
	crop = True

	# Check size against whitelist
	if resize and (resize > _SIZE_LIMIT or resize < 0):
	logging.error('Invalid resize: %r', resize)
	raise InvalidRequestError()
	return (resize, crop)

	def _parse_path(self, path):
	"""Parse the request path into the blobkey and option string.

	Args:
	path: A str containing the path of the request.

	Returns:
	A tuple (blob_key, option) parsed out of the path.

	Raises:
	InvalidRequestError: The request path is invalid.
	"""
	match = _PATH_RE.search(path)
	if not match or not match.group(1):
	logging.error('Failed to parse image path "%s"', path)
	raise InvalidRequestError()
	options = ''
	blobkey = match.group(1)
	if match.group(3):
	if match.group(2):
	blobkey += match.group(2)[1:]
	options = match.group(3)
	elif match.group(2):
	blobkey += match.group(2)
	return (blobkey, options)

	def serve_unresized_image(self, blobkey, environ, start_response):
	"""Use blob_download to rewrite and serve unresized image directly."""
	state = request_rewriter.RewriterState(environ, '200 OK', [
	(blobstore.BLOB_KEY_HEADER, blobkey)], [])
	blob_download.blobstore_download_rewriter(state)
	start_response(state.status, state.headers.items())
	return state.body

	def serve_image(self, environ, start_response):
	"""Dynamically serve an image from blobstore."""
	blobkey, options = self._parse_path(environ['PATH_INFO'])
	# Make sure that the blob URL has been registered by
	# calling get_serving_url
	key = datastore.Key.from_path(_BLOB_SERVING_URL_KIND, blobkey, namespace='')
	try:
	datastore.Get(key)
	except datastore_errors.EntityNotFoundError:
	logging.error('The blobkey %s has not registered for image '
	'serving. Please ensure get_serving_url is '
	'called before attempting to serve blobs.', blobkey)
	start_response('404 %s' % httplib.responses[404], [])
	return []

	resize, crop = self._parse_options(options)

	if resize is None and not crop:
	return self.serve_unresized_image(blobkey, environ, start_response)
	elif not _HAS_WORKING_IMAGES_STUB:
	logging.warning('Serving resized images requires a working Python "PIL" '
	'module. The image is served without resizing.')
	return self.serve_unresized_image(blobkey, environ, start_response)
	else:
	# Use Images service to transform blob.
	image, mime_type = self._transform_image(blobkey, resize, crop)
	start_response('200 OK', [
	('Content-Type', mime_type),
	('Cache-Control', 'public, max-age=600, no-transform')])
	return [image]

	def __call__(self, environ, start_response):
	if environ['REQUEST_METHOD'] != 'GET':
	start_response('405 %s' % httplib.responses[405], [])
	return []
	try:
	return self.serve_image(environ, start_response)
	except InvalidRequestError:
	start_response('400 %s' % httplib.responses[400], [])
	return []