Extensions/wms/capabilities.py

# Copyright (c) 2004 by Intevation GmbH
# Authors:
# Martin Schulze <[email protected]>
#
# 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

"""
Maintain WMS Capabilities

Inherits methods from WMSCapabilitiesParser

class WMSCapabilities:
    __init__ (resource xor filename xor nothing)

    getErrorMsg()

    fetchCapabilities(resource)
    saveCapabilities(filename)
    loadCapabilities(filename)
    printCapabilities()

    getVersion()

Requirements:
    - PyOGCLib <http://www.sourceforge.net/projects/pyogclib>

Requires the ogclib installed regularily on the system or checked out
next to the Thuban checkout.

If this module is executed solitarily, it will fetch the capabilities
of the frida service and store them in the local file
frida_capabilities.xml for later processing.

"""

__version__ = "$Revision$"
# $Source$
# $Id$

import os

# ----------------------------------------------------------------------
# FIXME: Temporary code until PyOGCLib is a standard requirement

from sys import path

# Assume the PyOGCLib to be checked out next to the thuban main directory
pyogclib = "../../../PyOGCLib"
if os.path.isdir(pyogclib) and os.path.isdir(pyogclib + "/ogclib"):
    path.insert(0, pyogclib)

# We use gettext, so we need to import it and hence need to adjust the
# path again
if __name__ == "__main__":
    path.insert(0, "../../")

# ----------------------------------------------------------------------

from Thuban import _

from ogclib.WMSClient import WMSClient
from parser import WMSCapabilitiesParser

class WMSCapabilities(WMSClient, WMSCapabilitiesParser):
    """
    Thuban class to maintain capabilities.  This class provides
    methods to fetch, save and load capabilities as well as methods to
    retrieve particular information from the fetched or loaded
    capabilities XML.

    If an error occured during processing an error text is assigned to
    self.errorMsg.  If everything went fine, this variable is set to
    None.  The current value can be retrieved by the getErrorMsg()
    method.
    """

    capabilities = None
    errorMsg = None
    wmsVersion = None

    def __init__(self, *parm):
        """
        Initialises Capabilities with one optional parameter

        param can be either a URL or a filename:

        filename -- load capabilities from file
        url -- fetch capabilities from network
        """

        if parm and parm[0]:
            if os.path.isfile(parm[0]):
                self.loadCapabilities(parm[0])
            else:
                if parm[0].find("http://", 0) == 0:
                    self.fetchCapabilities(parm[0])
                else:
                    self.errorMsg \
                        = _("Resource '%s' is neither local file nor URL") \
                        % parm[0]


    def getErrorMsg(self):
        return self.errorMsg


    def fetchCapabilities(self, resource):
        """
        Fetches the WMS capabilities from an Internet resource

        WMS Protocol version 1.1 is tried first, then 1.0.  The
        protocol version used can be queried by the getVersion()
        method for later use.  If both tries fail, errorMsg will be
        set accordingly, which can be fetched with getErrorMsg().
        """

        self.wmsVersion = "1.1"
        self.capabilities = self.getCapabilities(resource, self.wmsVersion)
        if not self.capabilities:
            self.wmsVersion = "1.0"
            self.capabilities = self.getCapabilities(resource, self.wmsVersion)
            if not self.capabilities:
                self.wmsVersion = None
                self.errorMsg \
                    = _("Resource '%s' "
                        "does support neither WMS version 1.1 nor 1.0") \
                        % resource

        if self.capabilities:
            self.grok(self.capabilities)


    def saveCapabilities(self, fname):
        """Save capabilities to local file"""

        if self.capabilities is None:
            self.errorMsg = _("No capabilities available")
        else:
            try:
                out = open(fname, "w")
                out.write(self.capabilities)
                out.close()
            except IOError:
                self.errorMsg = _("Can't open file '%s' for writing") % fname


    def loadCapabilities(self, fname):
        """Load capabilities from a local file"""

        try:
            input = open(fname, "r")
            self.capabilities = input.read()
            input.close()
            self.grok(self.capabilities)
        except IOError:
            self.errorMsg = _("Can't open file '%s' for reading") % fname


    def printCapabilities(self):
        """Prints capabilities to stdout"""

        print self.capabilities


    def getVersion(self):
        """
        Returns the WMS protocol version

        If no capabilities could be fetched, None is returned.
        """
        return self.wmsVersion


if __name__ == "__main__":
    capabilities \
        = WMSCapabilities("http://frida.intevation.org/cgi-bin/frida_wms?")
    if capabilities.getErrorMsg() is None:
        capabilities.saveCapabilities("frida_capabilities.xml")
    else:
        print "Error: " + capabilities.getErrorMsg()
1	joey	2110	# Copyright (c) 2004 by Intevation GmbH
2			# Authors:
3			# Martin Schulze <[email protected]>
4			#
5			# This program is free software; you can redistribute it and/or modify
6			# it under the terms of the GNU General Public License as published by
7			# the Free Software Foundation; either version 2 of the License, or
8			# (at your option) any later version.
9			#
10			# This program is distributed in the hope that it will be useful,
11			# but WITHOUT ANY WARRANTY; without even the implied warranty of
12			# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13			# GNU General Public License for more details.
14			#
15			# You should have received a copy of the GNU General Public License
16			# along with this program; if not, write to the Free Software
17			# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18
19			"""
20			Maintain WMS Capabilities
21
22	joey	2149	Inherits methods from WMSCapabilitiesParser
23
24	joey	2110	class WMSCapabilities:
25			__init__ (resource xor filename xor nothing)
26
27			getErrorMsg()
28
29	joey	2147	fetchCapabilities(resource)
30	joey	2137	saveCapabilities(filename)
31			loadCapabilities(filename)
32			printCapabilities()
33	joey	2110
34	joey	2150	getVersion()
35
36	joey	2110	Requirements:
37			- PyOGCLib <http://www.sourceforge.net/projects/pyogclib>
38
39			Requires the ogclib installed regularily on the system or checked out
40			next to the Thuban checkout.
41
42			If this module is executed solitarily, it will fetch the capabilities
43			of the frida service and store them in the local file
44			frida_capabilities.xml for later processing.
45
46			"""
47
48			__version__ = "$Revision$"
49			# $Source$
50			# $Id$
51
52			import os
53
54			# ----------------------------------------------------------------------
55			# FIXME: Temporary code until PyOGCLib is a standard requirement
56
57			from sys import path
58
59			# Assume the PyOGCLib to be checked out next to the thuban main directory
60			pyogclib = "../../../PyOGCLib"
61	joey	2137	if os.path.isdir(pyogclib) and os.path.isdir(pyogclib + "/ogclib"):
62			path.insert(0, pyogclib)
63	joey	2110
64			# We use gettext, so we need to import it and hence need to adjust the
65			# path again
66			if __name__ == "__main__":
67	joey	2137	path.insert(0, "../../")
68	joey	2110
69			# ----------------------------------------------------------------------
70
71			from Thuban import _
72
73			from ogclib.WMSClient import WMSClient
74	joey	2149	from parser import WMSCapabilitiesParser
75	joey	2110
76	joey	2149	class WMSCapabilities(WMSClient, WMSCapabilitiesParser):
77	joey	2110	"""
78			Thuban class to maintain capabilities. This class provides
79			methods to fetch, save and load capabilities as well as methods to
80			retrieve particular information from the fetched or loaded
81			capabilities XML.
82
83			If an error occured during processing an error text is assigned to
84			self.errorMsg. If everything went fine, this variable is set to
85			None. The current value can be retrieved by the getErrorMsg()
86			method.
87			"""
88
89			capabilities = None
90			errorMsg = None
91			wmsVersion = None
92
93	joey	2137	def __init__(self, *parm):
94	joey	2110	"""
95			Initialises Capabilities with one optional parameter
96
97	joey	2147	param can be either a URL or a filename:
98
99	joey	2110	filename -- load capabilities from file
100			url -- fetch capabilities from network
101			"""
102
103			if parm and parm[0]:
104	joey	2137	if os.path.isfile(parm[0]):
105			self.loadCapabilities(parm[0])
106	joey	2110	else:
107	joey	2137	if parm[0].find("http://", 0) == 0:
108			self.fetchCapabilities(parm[0])
109	joey	2110	else:
110	joey	2136	self.errorMsg \
111	joey	2147	= _("Resource '%s' is neither local file nor URL") \
112			% parm[0]
113	joey	2110
114
115	joey	2137	def getErrorMsg(self):
116	joey	2110	return self.errorMsg
117
118
119	joey	2137	def fetchCapabilities(self, resource):
120	joey	2151	"""
121			Fetches the WMS capabilities from an Internet resource
122	joey	2110
123	joey	2151	WMS Protocol version 1.1 is tried first, then 1.0. The
124			protocol version used can be queried by the getVersion()
125			method for later use. If both tries fail, errorMsg will be
126			set accordingly, which can be fetched with getErrorMsg().
127			"""
128
129	joey	2110	self.wmsVersion = "1.1"
130	joey	2148	self.capabilities = self.getCapabilities(resource, self.wmsVersion)
131	joey	2110	if not self.capabilities:
132			self.wmsVersion = "1.0"
133	joey	2148	self.capabilities = self.getCapabilities(resource, self.wmsVersion)
134	joey	2150	if not self.capabilities:
135			self.wmsVersion = None
136	joey	2151	self.errorMsg \
137			= _("Resource '%s' "
138	joey	2152	"does support neither WMS version 1.1 nor 1.0") \
139	joey	2151	% resource
140	joey	2110
141	joey	2149	if self.capabilities:
142			self.grok(self.capabilities)
143	joey	2110
144	joey	2149
145	joey	2137	def saveCapabilities(self, fname):
146	joey	2110	"""Save capabilities to local file"""
147
148			if self.capabilities is None:
149			self.errorMsg = _("No capabilities available")
150			else:
151			try:
152	joey	2137	out = open(fname, "w")
153			out.write(self.capabilities)
154	joey	2110	out.close()
155	joey	2147	except IOError:
156	joey	2110	self.errorMsg = _("Can't open file '%s' for writing") % fname
157
158
159	joey	2137	def loadCapabilities(self, fname):
160	joey	2110	"""Load capabilities from a local file"""
161
162			try:
163	joey	2137	input = open(fname, "r")
164	joey	2148	self.capabilities = input.read()
165	joey	2110	input.close()
166	joey	2149	self.grok(self.capabilities)
167	joey	2147	except IOError:
168	joey	2110	self.errorMsg = _("Can't open file '%s' for reading") % fname
169
170
171	joey	2137	def printCapabilities(self):
172	joey	2110	"""Prints capabilities to stdout"""
173
174			print self.capabilities
175
176
177	joey	2150	def getVersion(self):
178			"""
179			Returns the WMS protocol version
180	joey	2110
181	joey	2150	If no capabilities could be fetched, None is returned.
182			"""
183			return self.wmsVersion
184
185
186	joey	2110	if __name__ == "__main__":
187	joey	2136	capabilities \
188			= WMSCapabilities("http://frida.intevation.org/cgi-bin/frida_wms?")
189	joey	2147	if capabilities.getErrorMsg() is None:
190			capabilities.saveCapabilities("frida_capabilities.xml")
191	joey	2110	else:
192	joey	2147	print "Error: " + capabilities.getErrorMsg()
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