deleteDataset.py

#!/usr/bin/python

# Handles incoming delete requests from iGUESS

# Sample params:
# http://maps.iguess.tudor.lu/cgi-bin/mapserv?map=/srv/mapserv/MapFiles/AB_localOWS.map, AB_building_footprints
# http://maps.aberdeencity.gov.uk/ArcGIS/services/iGUESS_WMS/MapServer/WMSServer, 0
# http://maps.iguess.tudor.lu/cgi-bin/mapserv?map=/srv/mapserv/iGUESSMapFiles/pywps-02d056ba-5037-11e3-b573-005056a52e0d.map, pv_potential

import os
import sys
import mapscript
from owslib.csw import CatalogueServiceWeb
#from checkbox.lib.text import split
pycsw_url = "http://meta.iguess.list.lu/"


if len(sys.argv) != 4:
	raise Exception("Script requires 3 args: dataset_url, dataset_identifier and dataset_id")

scriptName, serverUrl, datasetIdentifier, datasetId = sys.argv

try:
	id = "meta-" + str(datasetId)
	csw = CatalogueServiceWeb(pycsw_url)
	csw.transaction(ttype='delete', typename='gmd:MD_Metadata', identifier=id)
except:
	print "Warning: transaction error while deleting the catalogue record"
	continue

# Check the database to see if the server/identifier combo is still registered elsewhere
try:
    # connect to iGUESS database
    conn=psycopg2.connect( "host={0} dbname={1} user={2} password={3}".format(dbServer, dbName, dbUsername, dbPassword))
    cur = conn.cursor()
    cur.execute("SELECT d.id FROM iguess_dev.datasets d where d.server_url = '" + serverUrl + "' and d.identifier = '" + datasetIdentifier +"'")
    datasets = cur.fetchall()
    
    # Only if there is a single occurrence of the same combination of dataset identifier and server_url, 
    # the dataset and layer in mapfile will be deleted
    if len(datasets) == 1:
    	# Get the path to the map file
		filePath = serverUrl.split("=")
		print "This is the file path: " + str(filePath)
		if len(filePath) < 2:
			raise Exception("Incorrect map file path.")

		# Remove the layer from the map file
		mapobject = mapscript.mapObj(filePath[1])
		layer =	mapobject.getLayerByName(datasetIdentifier)
		layerData = layer.data
		mapobject.removeLayer(layer.index)
		mapobject.save(filePath[1])

		# Delete data file if it exists
		if os.path.exists(layerData):
		    os.remove(layerData)
		else:
		    raise Exception("Sorry, I cannot remove %s file." % layerData)
		
		# Delete map file if no layers are left
		if mapobject.numlayers <= 0: 
			if os.path.exists(filePath[1]):
			    os.remove(filePath[1])
			else:
			    raise Exception("Sorry, I cannot remove %s file." % filePath[1]) 
except:
	print "I am unable to connect to the database."