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")

usrdir  = get_application_dir()

PROJ_EXT = ".proj"

has_gdal_support = lambda: False
try:
    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(ReadProjFile(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 [ReadProjFile(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.
    """

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