Thuban/Model/resource.py

# Copyright (c) 2003 by Intevation GmbH
# Authors:
# Jonathan Coles <[email protected]>
#
# This program is free software under the GPL (>=v2)
# Read the file COPYING coming with Thuban for details.

import os
import os.path

import Thuban
from Thuban import _

from Thuban.Lib.fileutil import get_application_dir

from Thuban.Model.xmlreader import XMLReader
from Thuban.Model.xmlwriter import XMLWriter
from Thuban.Model.proj import Projection, ProjFile
from xml.sax import SAXParseException

projdir = \
        os.path.join(Thuban.__path__[0], os.pardir, "Resources", "Projections")


PROJ_EXT = ".proj"

has_gdal_support = lambda: False
try:
    # first try to see if our extension module is there. if it 
    # wasn't even compiled, we obviously don't have gdal support.
    import gdalwarp

    # now try to import the python extension. if this doesn't
    # exist then we can't do anything.
    import gdal

    """Return True if the gdal library is available."""
    has_gdal_support = lambda: True
except ImportError:
    pass

def read_proj_file(filename):
    """Read a single .proj file and return a ProjFile object.
    
    Raises IOError if the file cannot be opened.
    Raises OSError if the file cannot be read.
    Raises SAXParseException if the file is not valid XML.
    """

    handler = ProjFileReader()
    handler.read(filename)
    return handler.GetProjFile()

def write_proj_file(pf):
    """Write a single .proj file

    Raises IOError if the file cannot be written.
    """

    saver = ProjFileSaver(pf)
    saver.write(pf.GetFilename())

def get_proj_files(dir):
    """Read all .proj files in the given directory and 
    return a list of ProjFile objects.
    """

    list = []
    try:
        dirlist = os.listdir(dir)
    except OSError:
        pass # if we can't get a directory listing just return []
    else:
        for file in filter(lambda s: s.endswith(PROJ_EXT), dirlist):
            try:
                filename = os.path.join(dir, file)
                list.append(read_proj_file(filename))
            except (OSError, IOError, SAXParseException):
                pass # just move onto the next file

    return list

def get_system_proj_files():
    """Return a list of ProjFile objects from files that are 
    supplied by Thuban.

    If no files could not be opened return a list with one
    empty projection file set to store data in the default file.
    """
    filename = os.path.join(projdir, "defaults.proj")
    try:
        return [read_proj_file(filename)]
    except (OSError, IOError, SAXParseException):
        return [ProjFile(filename)]

def get_user_proj_files():
    """Return a list of ProjFile objects from files that are user-defined.

    If no files could not be opened return a list with one
    empty projection file set to store data in the default file.
    """

    usrdir  = get_application_dir()
    filename = os.path.join(usrdir, "user.proj")
    try:
        return [read_proj_file(filename)]
    except (OSError, IOError, SAXParseException):
        return [ProjFile(filename)]

class ProjFileReader(XMLReader):

    def __init__(self):
        XMLReader.__init__(self)
        self.__pf = ProjFile("")

        XMLReader.AddDispatchers(self,
            {'projection': ("start_projection", "end_projection"),
             'parameter':  ("start_parameter", None)})
            
    def read(self, file_or_filename):
        XMLReader.read(self, file_or_filename)

        self.__pf.SetFilename(XMLReader.GetFilename(self))
        
    def start_projection(self, name, qname, attrs):
        self.params = []
        self.name = self.encode(attrs.get((None, 'name'), _("Unknown")))

    def end_projection(self, name, qname):
        self.__pf.Add(Projection(self.params, self.name))

    def start_parameter(self, name, qname, attrs):
        s = attrs.get((None, 'value'))
        s = str(s) # we can't handle unicode in proj
        self.params.append(s)

    def GetProjFile(self):
        return self.__pf

class ProjFileSaver(XMLWriter):

    def __init__(self, pf):
        XMLWriter.__init__(self)
        self.__pf = pf

    def write(self, file_or_filename):
        XMLWriter.write(self, file_or_filename)

        self.write_header("projfile", "projfile.dtd")
        self.write_projfile(self.__pf)
        self.close()

    def write_projfile(self, pf):

        self.open_element("projectionlist")

        for p in pf.GetProjections():
            self.open_element("projection", {"name": p.GetName()})

            for param in p.GetAllParameters():
                self.write_element("parameter", {"value": param})

            self.close_element("projection")

        self.close_element("projectionlist")


1	jonathan	696	# Copyright (c) 2003 by Intevation GmbH
2			# Authors:
3			# Jonathan Coles <[email protected]>
4			#
5			# This program is free software under the GPL (>=v2)
6			# Read the file COPYING coming with Thuban for details.
7
8			import os
9	frank	1132	import os.path
10
11	jonathan	696	import Thuban
12	jonathan	875	from Thuban import _
13
14	frank	1149	from Thuban.Lib.fileutil import get_application_dir
15
16	jonathan	1161	from Thuban.Model.xmlreader import XMLReader
17			from Thuban.Model.xmlwriter import XMLWriter
18	jonathan	696	from Thuban.Model.proj import Projection, ProjFile
19	jonathan	727	from xml.sax import SAXParseException
20	jonathan	696
21			projdir = \
22			os.path.join(Thuban.__path__[0], os.pardir, "Resources", "Projections")
23
24
25			PROJ_EXT = ".proj"
26
27	jonathan	1161	has_gdal_support = lambda: False
28			try:
29	jonathan	1230	# first try to see if our extension module is there. if it
30			# wasn't even compiled, we obviously don't have gdal support.
31			import gdalwarp
32
33			# now try to import the python extension. if this doesn't
34			# exist then we can't do anything.
35	jonathan	1161	import gdal
36	jonathan	1230
37	jonathan	1161	"""Return True if the gdal library is available."""
38			has_gdal_support = lambda: True
39			except ImportError:
40			pass
41
42			def read_proj_file(filename):
43	jonathan	718	"""Read a single .proj file and return a ProjFile object.
44
45			Raises IOError if the file cannot be opened.
46			Raises OSError if the file cannot be read.
47			Raises SAXParseException if the file is not valid XML.
48			"""
49	jonathan	696
50	jonathan	718	handler = ProjFileReader()
51			handler.read(filename)
52			return handler.GetProjFile()
53	jonathan	696
54	jonathan	1161	def write_proj_file(pf):
55	jonathan	727	"""Write a single .proj file
56
57			Raises IOError if the file cannot be written.
58			"""
59
60	jonathan	696	saver = ProjFileSaver(pf)
61	jonathan	739	saver.write(pf.GetFilename())
62	jonathan	696
63	jonathan	1161	def get_proj_files(dir):
64	jonathan	696	"""Read all .proj files in the given directory and
65			return a list of ProjFile objects.
66			"""
67
68			list = []
69			try:
70	jonathan	718	dirlist = os.listdir(dir)
71	jonathan	696	except OSError:
72	jonathan	718	pass # if we can't get a directory listing just return []
73			else:
74			for file in filter(lambda s: s.endswith(PROJ_EXT), dirlist):
75			try:
76			filename = os.path.join(dir, file)
77	jonathan	1179	list.append(read_proj_file(filename))
78	jonathan	718	except (OSError, IOError, SAXParseException):
79			pass # just move onto the next file
80	jonathan	696
81			return list
82
83	jonathan	1161	def get_system_proj_files():
84	jonathan	696	"""Return a list of ProjFile objects from files that are
85			supplied by Thuban.
86	jonathan	727
87			If no files could not be opened return a list with one
88			empty projection file set to store data in the default file.
89	jonathan	696	"""
90	jonathan	727	filename = os.path.join(projdir, "defaults.proj")
91			try:
92	jonathan	1179	return [read_proj_file(filename)]
93	jonathan	727	except (OSError, IOError, SAXParseException):
94			return [ProjFile(filename)]
95	jonathan	696
96	jonathan	1161	def get_user_proj_files():
97	jonathan	727	"""Return a list of ProjFile objects from files that are user-defined.
98	jonathan	696
99	jonathan	727	If no files could not be opened return a list with one
100			empty projection file set to store data in the default file.
101			"""
102
103	jonathan	1189	usrdir = get_application_dir()
104	jonathan	727	filename = os.path.join(usrdir, "user.proj")
105			try:
106	jonathan	1179	return [read_proj_file(filename)]
107	jonathan	727	except (OSError, IOError, SAXParseException):
108			return [ProjFile(filename)]
109
110	jonathan	709	class ProjFileReader(XMLReader):
111	jonathan	696
112	jonathan	709	def __init__(self):
113			XMLReader.__init__(self)
114			self.__pf = ProjFile("")
115
116			XMLReader.AddDispatchers(self,
117			{'projection': ("start_projection", "end_projection"),
118			'parameter': ("start_parameter", None)})
119
120			def read(self, file_or_filename):
121			XMLReader.read(self, file_or_filename)
122
123	jonathan	739	self.__pf.SetFilename(XMLReader.GetFilename(self))
124	jonathan	696
125			def start_projection(self, name, qname, attrs):
126			self.params = []
127	jonathan	875	self.name = self.encode(attrs.get((None, 'name'), _("Unknown")))
128	jonathan	696
129			def end_projection(self, name, qname):
130	jonathan	709	self.__pf.Add(Projection(self.params, self.name))
131	jonathan	696
132			def start_parameter(self, name, qname, attrs):
133			s = attrs.get((None, 'value'))
134			s = str(s) # we can't handle unicode in proj
135			self.params.append(s)
136
137			def GetProjFile(self):
138	jonathan	709	return self.__pf
139	jonathan	696
140	jonathan	709	class ProjFileSaver(XMLWriter):
141	jonathan	696
142			def __init__(self, pf):
143	jonathan	709	XMLWriter.__init__(self)
144			self.__pf = pf
145	jonathan	696
146			def write(self, file_or_filename):
147	jonathan	709	XMLWriter.write(self, file_or_filename)
148	jonathan	696
149	jonathan	875	self.write_header("projfile", "projfile.dtd")
150	jonathan	709	self.write_projfile(self.__pf)
151	jonathan	696	self.close()
152
153			def write_projfile(self, pf):
154
155			self.open_element("projectionlist")
156
157			for p in pf.GetProjections():
158			self.open_element("projection", {"name": p.GetName()})
159
160	jonathan	709	for param in p.GetAllParameters():
161	jonathan	696	self.write_element("parameter", {"value": param})
162
163			self.close_element("projection")
164
165			self.close_element("projectionlist")
166
167
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