#!/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.

#

"""Simple datastore view and interactive console, for use in dev_appserver."""

import cgi

import csv

import cStringIO

import datetime

import logging

import math

import mimetypes

import os

import os.path

import pickle

import pprint

import random

import sys

import time

import traceback

import types

import urllib

import urlparse

import wsgiref.handlers

from google.appengine.api import datastore

from google.appengine.api import datastore_admin

from google.appengine.api import datastore_types

from google.appengine.api import datastore_errors

from google.appengine.api import memcache

from google.appengine.api import users

from google.appengine.ext import db

from google.appengine.ext import webapp

from google.appengine.ext.webapp import template

_DEBUG = True

class ImageHandler(webapp.RequestHandler):

  """Serves a static image.

  This exists because we don't want to burden the user with specifying

  a static file handler for the image resources used by the admin tool.

  """

  PATH = '/images/.*'

  def get(self):

    image_name = os.path.basename(self.request.path)

    content_type, encoding = mimetypes.guess_type(image_name)

    if not content_type or not content_type.startswith('image/'):

      logging.debug('image_name=%r, content_type=%r, encoding=%r',

                    image_name, content_type, encoding)

      self.error(404)

      return

    directory = os.path.dirname(__file__)

    path = os.path.join(directory, 'templates', 'images', image_name)

    try:

      image_stream = open(path, 'rb')

    except IOError, e:

      logging.error('Cannot open image %s: %s', image_name, e)

      self.error(404)

      return

    try:

      image_data = image_stream.read()

    finally:

      image_stream.close()

    self.response.headers['Content-Type'] = content_type

    self.response.out.write(image_data)

class BaseRequestHandler(webapp.RequestHandler):

  """Supplies a common template generation function.

  When you call generate(), we augment the template variables supplied with

  the current user in the 'user' variable and the current webapp request

  in the 'request' variable.

  """

  def generate(self, template_name, template_values={}):

    base_path = self.base_path()

    values = {

      'application_name': self.request.environ['APPLICATION_ID'],

      'user': users.get_current_user(),

      'request': self.request,

      'home_path': base_path + DefaultPageHandler.PATH,

      'datastore_path': base_path + DatastoreQueryHandler.PATH,

      'datastore_edit_path': base_path + DatastoreEditHandler.PATH,

      'datastore_batch_edit_path': base_path + DatastoreBatchEditHandler.PATH,

      'interactive_path': base_path + InteractivePageHandler.PATH,

      'interactive_execute_path': base_path + InteractiveExecuteHandler.PATH,

      'memcache_path': base_path + MemcachePageHandler.PATH,

    }

    values.update(template_values)

    directory = os.path.dirname(__file__)

    path = os.path.join(directory, os.path.join('templates', template_name))

    self.response.out.write(template.render(path, values, debug=_DEBUG))

  def base_path(self):

    """Returns the base path of this admin app, which is chosen by the user.

    The user specifies which paths map to this application in their app.cfg.

    You can get that base path with this method. Combine with the constant

    paths specified by the classes to construct URLs.

    """

    path = self.__class__.PATH

    return self.request.path[:-len(path)]

  def filter_url(self, args):

    """Filters the current URL to only have the given list of arguments.

    For example, if your URL is /search?q=foo&num=100&start=10, then

       self.filter_url(['start', 'num']) => /search?num=100&start=10

       self.filter_url(['q']) => /search?q=10

       self.filter_url(['random']) => /search?

    """

    queries = []

    for arg in args:

      value = self.request.get(arg)

      if value:

        queries.append(arg + '=' + urllib.quote_plus(self.request.get(arg)))

    return self.request.path + '?' + '&'.join(queries)

  def in_production(self):

    """Detects if app is running in production.

    Returns a boolean.

    """

    server_software = os.environ['SERVER_SOFTWARE']

    return not server_software.startswith('Development')

class DefaultPageHandler(BaseRequestHandler):

  """Redirects to the Datastore application by default."""

  PATH = '/'

  def get(self):

    if self.request.path.endswith('/'):

      base = self.request.path[:-1]

    else:

      base = self.request.path

    self.redirect(base + DatastoreQueryHandler.PATH)

class InteractivePageHandler(BaseRequestHandler):

  """Shows our interactive console HTML."""

  PATH = '/interactive'

  def get(self):

    self.generate('interactive.html')

class InteractiveExecuteHandler(BaseRequestHandler):

  """Executes the Python code submitted in a POST within this context.

  For obvious reasons, this should only be available to administrators

  of the applications.

  """

  PATH = InteractivePageHandler.PATH + '/execute'

  def post(self):

    save_stdout = sys.stdout

    results_io = cStringIO.StringIO()

    try:

      sys.stdout = results_io

      code = self.request.get('code')

      code = code.replace("\r\n", "\n")

      try:

        compiled_code = compile(code, '<string>', 'exec')

        exec(compiled_code, globals())

      except Exception, e:

        traceback.print_exc(file=results_io)

    finally:

      sys.stdout = save_stdout

    results = results_io.getvalue()

    self.generate('interactive-output.html', {'output': results})

class MemcachePageHandler(BaseRequestHandler):

  """Shows stats about memcache and query form to get values."""

  PATH = '/memcache'

  TYPES = ((str, str, 'String'),

           (unicode, unicode, 'Unicode String'),

           (bool, lambda value: MemcachePageHandler._ToBool(value), 'Boolean'),

           (int, int, 'Integer'),

           (long, long, 'Long Integer'),

           (float, float, 'Float'))

  DEFAULT_TYPESTR_FOR_NEW = 'String'

  @staticmethod

  def _ToBool(string_value):

    """Convert string to boolean value.

    Args:

      string_value: A string.

    Returns:

      Boolean.  True if string_value is "true", False if string_value is

      "false".  This is case-insensitive.

    Raises:

      ValueError: string_value not "true" or "false".

    """

    string_value_low = string_value.lower()

    if string_value_low not in ('false', 'true'):

      raise ValueError('invalid literal for boolean: %s' % string_value)

    return string_value_low == 'true'

  def _GetValueAndType(self, key):

    """Fetch value from memcache and detect its type.

    Args:

      key: String

    Returns:

      (value, type), value is a Python object or None if the key was not set in

      the cache, type is a string describing the type of the value.

    """

    try:

      value = memcache.get(key)

    except (pickle.UnpicklingError, AttributeError, EOFError, ImportError,

            IndexError), e:

      msg = 'Failed to retrieve value from cache: %s' % e

      return msg, 'error'

    if value is None:

      return None, self.DEFAULT_TYPESTR_FOR_NEW

    for typeobj, _, typestr in self.TYPES:

      if isinstance(value, typeobj):

        break

    else:

      typestr = 'pickled'

      value = pprint.pformat(value, indent=2)

    return value, typestr

  def _SetValue(self, key, type_, value):

    """Convert a string value and store the result in memcache.

    Args:

      key: String

      type_: String, describing what type the value should have in the cache.

      value: String, will be converted according to type_.

    Returns:

      Result of memcache.set(ket, converted_value).  True if value was set.

    Raises:

      ValueError: Value can't be converted according to type_.

    """

    for _, converter, typestr in self.TYPES:

      if typestr == type_:

        value = converter(value)

        break

    else:

      raise ValueError('Type %s not supported.' % type_)

    return memcache.set(key, value)

  def get(self):

    """Show template and prepare stats and/or key+value to display/edit."""

    values = {'request': self.request,

              'message': self.request.get('message')}

    edit = self.request.get('edit')

    key = self.request.get('key')

    if edit:

      key = edit

      values['show_stats'] = False

      values['show_value'] = False

      values['show_valueform'] = True

      values['types'] = [typestr for _, _, typestr in self.TYPES]

    elif key:

      values['show_stats'] = True

      values['show_value'] = True

      values['show_valueform'] = False

    else:

      values['show_stats'] = True

      values['show_valueform'] = False

      values['show_value'] = False

    if key:

      values['key'] = key

      values['value'], values['type'] = self._GetValueAndType(key)

      values['key_exists'] = values['value'] is not None

      if values['type'] in ('pickled', 'error'):

        values['writable'] = False

      else:

        values['writable'] = True

    if values['show_stats']:

      memcache_stats = memcache.get_stats()

      if not memcache_stats:

        memcache_stats = {'hits': 0, 'misses': 0, 'byte_hits': 0, 'items': 0,

                          'bytes': 0, 'oldest_item_age': 0}

      values['stats'] = memcache_stats

      try:

        hitratio = memcache_stats['hits'] * 100 / (memcache_stats['hits']

                                                   + memcache_stats['misses'])

      except ZeroDivisionError:

        hitratio = 0

      values['hitratio'] = hitratio

      delta_t = datetime.timedelta(seconds=memcache_stats['oldest_item_age'])

      values['oldest_item_age'] = datetime.datetime.now() - delta_t

    self.generate('memcache.html', values)

  def _urlencode(self, query):

    """Encode a dictionary into a URL query string.

    In contrast to urllib this encodes unicode characters as UTF8.

    Args:

      query: Dictionary of key/value pairs.

    Returns:

      String.

    """

    return '&'.join('%s=%s' % (urllib.quote_plus(k.encode('utf8')),

                               urllib.quote_plus(v.encode('utf8')))

                    for k, v in query.iteritems())

  def post(self):

    """Handle modifying actions and/or redirect to GET page."""

    next_param = {}

    if self.request.get('action:flush'):

      if memcache.flush_all():

        next_param['message'] = 'Cache flushed, all keys dropped.'

      else:

        next_param['message'] = 'Flushing the cache failed.  Please try again.'

    elif self.request.get('action:display'):

      next_param['key'] = self.request.get('key')

    elif self.request.get('action:edit'):

      next_param['edit'] = self.request.get('key')

    elif self.request.get('action:delete'):

      key = self.request.get('key')

      result = memcache.delete(key)

      if result == memcache.DELETE_NETWORK_FAILURE:

        next_param['message'] = ('ERROR: Network failure, key "%s" not deleted.'

                                 % key)

      elif result == memcache.DELETE_ITEM_MISSING:

        next_param['message'] = 'Key "%s" not in cache.' % key

      elif result == memcache.DELETE_SUCCESSFUL:

        next_param['message'] = 'Key "%s" deleted.' % key

      else:

        next_param['message'] = ('Unknown return value.  Key "%s" might still '

                                 'exist.' % key)

    elif self.request.get('action:save'):

      key = self.request.get('key')

      value = self.request.get('value')

      type_ = self.request.get('type')

      next_param['key'] = key

      try:

        if self._SetValue(key, type_, value):

          next_param['message'] = 'Key "%s" saved.' % key

        else:

          next_param['message'] = 'ERROR: Failed to save key "%s".' % key

      except ValueError, e:

        next_param['message'] = 'ERROR: Unable to encode value: %s' % e

    elif self.request.get('action:cancel'):

      next_param['key'] = self.request.get('key')

    else:

      next_param['message'] = 'Unknown action.'

    next = self.request.path_url

    if next_param:

      next = '%s?%s' % (next, self._urlencode(next_param))

    self.redirect(next)

class DatastoreRequestHandler(BaseRequestHandler):

  """The base request handler for our datastore admin pages.

  We provide utility functions for quering the datastore and infering the

  types of entity properties.

  """

  def start(self):

    """Returns the santized "start" argument from the URL."""

    return self.request.get_range('start', min_value=0, default=0)

  def num(self):

    """Returns the sanitized "num" argument from the URL."""

    return self.request.get_range('num', min_value=1, max_value=100,

                                  default=10)

  def execute_query(self, start=0, num=0, no_order=False):

    """Parses the URL arguments and executes the query.

    We return a tuple (list of entities, total entity count).

    If the appropriate URL arguments are not given, we return an empty

    set of results and 0 for the entity count.

    """

    kind = self.request.get('kind')

    if not kind:

      return ([], 0)

    query = datastore.Query(kind)

    order = self.request.get('order')

    order_type = self.request.get('order_type')

    if order and order_type:

      order_type = DataType.get_by_name(order_type).python_type()

      if order.startswith('-'):

        direction = datastore.Query.DESCENDING

        order = order[1:]

      else:

        direction = datastore.Query.ASCENDING

      try:

        query.Order((order, order_type, direction))

      except datastore_errors.BadArgumentError:

        pass

    if not start:

      start = self.start()

    if not num:

      num = self.num()

    total = query.Count()

    entities = query.Get(start + num)[start:]

    return (entities, total)

  def get_key_values(self, entities):

    """Returns the union of key names used by the given list of entities.

    We return the union as a dictionary mapping the key names to a sample

    value from one of the entities for the key name.

    """

    key_dict = {}

    for entity in entities:

      for key, value in entity.iteritems():

        if key_dict.has_key(key):

          key_dict[key].append(value)

        else:

          key_dict[key] = [value]

    return key_dict

class DatastoreQueryHandler(DatastoreRequestHandler):

  """Our main request handler that executes queries and lists entities.

  We use execute_query() in our base request handler to parse URL arguments

  and execute the datastore query.

  """

  PATH = '/datastore'

  def get_kinds(self):

    """Get sorted list of kind names the datastore knows about.

    This should only be called in the development environment as GetSchema is

    expensive and no caching is done.

    """

    schema = datastore_admin.GetSchema()

    kinds = []

    for entity_proto in schema:

      kinds.append(entity_proto.key().path().element_list()[-1].type())

    kinds.sort()

    return kinds

  def get(self):

    """Formats the results from execute_query() for datastore.html.

    The only complex part of that process is calculating the pager variables

    to generate the Gooooogle pager at the bottom of the page.

    """

    result_set, total = self.execute_query()

    key_values = self.get_key_values(result_set)

    keys = key_values.keys()

    keys.sort()

    headers = []

    for key in keys:

      sample_value = key_values[key][0]

      headers.append({

        'name': key,

        'type': DataType.get(sample_value).name(),

      })