ZPyChart.py

##############################################################################
#
# Copyright (c) 2003-2006 Nexedi SARL and Contributors. All Rights Reserved.
#                    Sebastien Robin <seb@nexedi.com>
#                    Jean-Paul Smets <jp@nexedi.com>
#
# WARNING: This program as such is intended to be used by professional
# programmers who take the whole responsability of assessing all potential
# consequences resulting from its eventual inadequacies and bugs
# End users who are looking for a ready-to-use solution with commercial
# garantees and support are strongly adviced to contract a Free Software
# Service Company
#
# This program is Free Software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
#
##############################################################################

from Products.Formulator import Widget
from Products.Formulator import Widget, Validator
from Products.Formulator.DummyField import fields
from Products.Formulator.Field import ZMIField
from Selection import Selection

from Products.PythonScripts.PythonScript import PythonScript
import pychart

from zLOG import LOG

class ZPyChartWidget(Widget.Widget):
  """
    A widget to generate pychart charts in multiple formats
    
    Chart definition is defined in a script. Some parameters
    are defined through Web UI. Web UI parameters are intended
    to be specialised through Proxy fields.
  """
  property_names = Widget.Widget.property_names+\
                   [ 'selection_name',
                     'data_method',
                     'chart_title',
                     'x_title',
                     'y_title',]

  default = fields.StringField('default',
                                title='Default',
                                description=(
      "Default value of the text in the widget."),
                                default="",
                                required=0)

  selection_name = fields.StringField('selection_name',
                              title='Selection Name',
                              description=('The name of the selection to store'
                                            'params of selection'),
                              default='',
                              required=0)

  data_method = fields.StringField('data_method',
                              title='Data Method',
                              description=('The method wich returns data'),
                              default='',
                              required=0)

  chart_title = fields.StringField('chart_title',
                              title='Chart Title',
                              description=('The Title on the top of the chart'),
                              default='',
                              required=0)

  x_title = fields.StringField('x_title',
                              title='X Title',
                              description=('The Title for the X axis'),
                              default='',
                              required=0)

  y_title = fields.StringField('y_title',
                              title='Y Title',
                              description=('The Title for the Y axis'),
                              default='',
                              required=0)

  def render(self, field, key, value, REQUEST):
    """
      Here, we just generate tags which will later call download
    """
    # Get standard parameters
    selection_name = field.get_value('selection_name')
    chart_title = field.get_value('chart_title')
    data_method = field.get_value('data_method')
    x_title = field.get_value('x_title')
    y_title = field.get_value('y_title')

    # Retrieve the data and set the selection if data_method is not None
    if data_method:
      if hasattr(here, data_method):
        data_method = getattr(here,data_method)
        # Retrieve selection
        here = REQUEST.get('here', self)
        selection = here.portal_selections.getSelectionFor(selection_name, REQUEST=REQUEST)
        # Define the new selection data_method
        selection.edit(method_id = data_method) # XXX This is probably wrong

    # Return an image field
    return """<img src="%s/download?selection_name=%s&chart_title=%s&data_method=%s&x_title=%s&y_title=%s"/>""" % (self.absolute_url(), selection_name, chart_title, data_method, x_title, y_title)

ZPyChartWidgetInstance = ZPyChartWidget()

class ZPyChartValidator(Validator.Validator):
  property_names = Validator.Validator.property_names

  def validate(self, field, key, REQUEST):
    result = {}
    return result

ZPyChartValidatorInstance = ZPyChartValidator()

class ZPyChart(ZMIField, PythonScript):
    """
      A hybrid between a field and a script

      TODO:
        - implement XML I/O of script
        - make tabs nicer
    """
    
    meta_type = "ZPyChart"

    manage_options = ZMIField.manage_options + PythonScript.manage_options

    widget = ZPyChartWidgetInstance
    validator = ZPyChartValidatorInstance

    def __init__(self, id, **kw):
        ZMIField.__init__(self, id, **kw)
        PythonScript.__init__(self, id)

    def download(self, selection_name=None, data_method=None, **kw):
        """
          This is where we actually render the chart. The main interest
          of doing like this is to accelerate initial rendering

          TODO:
            - add minimal security here
            - implement all pychart options (PNG, PS, SVG, etc.)
            - implement all standard parameters
        """
        # Get the applicable selection
        selection = self.portal_selections.getSelectionFor(selection_name, REQUEST=REQUEST)

        # If selection is None, create a new one
        if selection is None:
          selection = Selection()
        
        # Get the data method if defined
        if data_method is not None:
          data_method = getattr(here, data_method, None)
        
        # This is the default data, this is just in the case there is not method given
        if data_method is None:
          data = selection()
        else:
          data = selection(data_method=data_method)
    
        # Now call the script - XXX implement bindings properly here
        output = self._exec(here=self, pychart=pychart, data=data)
    
        # And return result
        return output