Plot.py

# -*- coding: utf-8 -*-
#
# Copyright 2012 Institut für Experimentelle Kernphysik - Karlsruher Institut für Technologie
#
#   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.

import hf, time
from sqlalchemy import TEXT, Column

try:
    import imghdr
except ImportError:
    hf.module.ModuleBase.logger.warning("imghdr module not found, Plot module will not be able \
to check if downloaded file is actually an image.")
    imghdr = None

class Plot(hf.module.ModuleBase):
    config_keys = {
        'plot_url': ('URL of the image to display', ''),
        'use_start_end_time': ('Enable the mechanism to include two timestamps in the GET part of the URL', 'False'),
        'starttime_parameter_name': ('Name of the GET argument for the starting timestamp', 'starttime'),
        'endtime_parameter_name': ('Name of the GET argument for the end timestamp, which is now', 'endtime'),
        'timerange_seconds': ('How far in the past is the start timestamp (in seconds)', '259200'),
    }
    config_hint = ''

    table_columns = [
        Column("plot_file", TEXT)
    ], ['plot_file']


    def prepareAcquisition(self):

        url = self.config["plot_url"]
        use_start_end_time = False
        try:
            use_start_end_time = self.config["use_start_end_time"] == "True"
        except hf.ConfigError:
            pass
        if use_start_end_time:
            try:
                url += "&"+self.config["starttime_parameter_name"]+"="+str(int(time.time())-int(self.config["timerange_seconds"]))
            except KeyError:
                pass
            try:
                url += "&"+self.config["endtime_parameter_name"]+"="+str(int(time.time()))
            except KeyError:
                pass

        self.plot = hf.downloadService.addDownload(url)
        self.source_url = self.plot.getSourceUrl()

    def extractData(self):
        data = {
        }
        if self.plot.isDownloaded():
            if imghdr:
                extension = imghdr.what(self.plot.getTmpPath())
            else:
                extension = 'png'
            if extension is not None:
                self.plot.copyToArchive(self, "." + extension)
                data["plot_file"] = self.plot
            else:
                data.update({
                "plot_file": None,
                "status": -1.0,
                "error_string": "Downloaded file was not an image, probably source server failed to deliver file.",
            })
        else:
            data.update({
                "plot_file": None,
                "status": -1.0,
                "error_string": "Plot was not downloaded :"+self.plot.error,
            })
        return data