| 1 | |
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| 2 | ##################################################################### |
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| 3 | #This software was developed by the University of Tennessee as part of the |
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| 4 | #Distributed Data Analysis of Neutron Scattering Experiments (DANSE) |
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| 5 | #project funded by the US National Science Foundation. |
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| 6 | #See the license text in license.txt |
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| 7 | #copyright 2008, University of Tennessee |
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| 8 | ###################################################################### |
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| 9 | |
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| 10 | """ |
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| 11 | File handler to support different file extensions. |
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| 12 | Uses reflectometry's registry utility. |
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| 13 | |
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| 14 | The default readers are found in the 'readers' sub-module |
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| 15 | and registered by default at initialization time. |
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| 16 | |
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| 17 | To add a new default reader, one must register it in |
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| 18 | the register_readers method found in readers/__init__.py. |
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| 19 | |
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| 20 | A utility method (find_plugins) is available to inspect |
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| 21 | a directory (for instance, a user plug-in directory) and |
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| 22 | look for new readers/writers. |
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| 23 | """ |
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| 24 | |
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| 25 | from data_util.registry import ExtensionRegistry |
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| 26 | import os |
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| 27 | import sys |
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| 28 | import logging |
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| 29 | import time |
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| 30 | from zipfile import ZipFile |
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| 31 | |
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| 32 | # Default readers are defined in the readers sub-module |
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| 33 | import readers |
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| 34 | from readers import ascii_reader |
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| 35 | |
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| 36 | class Registry(ExtensionRegistry): |
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| 37 | """ |
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| 38 | Registry class for file format extensions. |
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| 39 | Readers and writers are supported. |
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| 40 | """ |
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| 41 | |
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| 42 | def __init__(self): |
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| 43 | super(Registry, self).__init__() |
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| 44 | |
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| 45 | ## Writers |
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| 46 | self.writers = {} |
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| 47 | |
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| 48 | ## List of wildcards |
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| 49 | self.wildcards = ['All (*.*)|*.*'] |
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| 50 | |
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| 51 | ## Creation time, for testing |
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| 52 | self._created = time.time() |
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| 53 | |
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| 54 | # Register default readers |
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| 55 | readers.read_associations(self) |
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| 56 | |
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| 57 | #TODO: remove the following line when ready to switch to the new default readers |
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| 58 | #readers.register_readers(self._identify_plugin) |
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| 59 | |
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| 60 | # Look for plug-in readers |
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| 61 | self.find_plugins('plugins') |
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| 62 | |
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| 63 | |
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| 64 | def load(self, path, format=None): |
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| 65 | """ |
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| 66 | Call the loader for the file type of path. |
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| 67 | |
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| 68 | :param path: file path |
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| 69 | :param format: explicit extension, to force the use of a particular reader |
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| 70 | |
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| 71 | Defaults to the ascii (multi-column) reader |
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| 72 | if no reader was registered for the file's |
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| 73 | extension. |
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| 74 | """ |
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| 75 | try: |
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| 76 | return super(Registry, self).load(path, format=format) |
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| 77 | except: |
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| 78 | raise |
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| 79 | # No reader was found. Default to the ascii reader. |
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| 80 | #ascii_loader = ascii_reader.Reader() |
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| 81 | #return ascii_loader.read(path) |
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| 82 | |
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| 83 | def find_plugins(self, dir): |
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| 84 | """ |
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| 85 | Find readers in a given directory. This method |
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| 86 | can be used to inspect user plug-in directories to |
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| 87 | find new readers/writers. |
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| 88 | |
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| 89 | :param dir: directory to search into |
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| 90 | |
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| 91 | :return: number of readers found |
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| 92 | """ |
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| 93 | readers_found = 0 |
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| 94 | |
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| 95 | # Check whether the directory exists |
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| 96 | if not os.path.isdir(dir): |
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| 97 | logging.warning("DataLoader couldn't load from %s" % dir) |
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| 98 | return readers_found |
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| 99 | |
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| 100 | for item in os.listdir(dir): |
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| 101 | full_path = os.path.join(dir, item) |
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| 102 | if os.path.isfile(full_path): |
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| 103 | |
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| 104 | # Process python files |
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| 105 | if item.endswith('.py'): |
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| 106 | toks = os.path.splitext(os.path.basename(item)) |
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| 107 | try: |
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| 108 | sys.path.insert(0, os.path.abspath(dir)) |
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| 109 | module = __import__(toks[0], globals(), locals()) |
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| 110 | if self._identify_plugin(module): |
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| 111 | readers_found += 1 |
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| 112 | except : |
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| 113 | logging.error("Loader: Error importing %s\n %s" % (item, sys.exc_value)) |
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| 114 | |
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| 115 | # Process zip files |
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| 116 | elif item.endswith('.zip'): |
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| 117 | try: |
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| 118 | # Find the modules in the zip file |
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| 119 | zfile = ZipFile(item) |
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| 120 | nlist = zfile.namelist() |
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| 121 | |
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| 122 | sys.path.insert(0, item) |
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| 123 | for mfile in nlist: |
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| 124 | try: |
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| 125 | # Change OS path to python path |
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| 126 | fullname = mfile.replace('/', '.') |
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| 127 | fullname = os.path.splitext(fullname)[0] |
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| 128 | module = __import__(fullname, globals(), locals(), [""]) |
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| 129 | if self._identify_plugin(module): |
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| 130 | readers_found += 1 |
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| 131 | except: |
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| 132 | logging.error("Loader: Error importing %s\n %s" % (mfile, sys.exc_value)) |
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| 133 | |
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| 134 | except: |
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| 135 | logging.error("Loader: Error importing %s\n %s" % (item, sys.exc_value)) |
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| 136 | |
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| 137 | return readers_found |
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| 138 | |
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| 139 | def associate_file_type(self, ext, module): |
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| 140 | """ |
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| 141 | Look into a module to find whether it contains a |
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| 142 | Reader class. If so, APPEND it to readers and (potentially) |
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| 143 | to the list of writers for the given extension |
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| 144 | |
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| 145 | :param ext: file extension [string] |
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| 146 | :param module: module object |
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| 147 | """ |
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| 148 | reader_found = False |
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| 149 | |
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| 150 | if hasattr(module, "Reader"): |
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| 151 | try: |
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| 152 | # Find supported extensions |
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| 153 | loader = module.Reader() |
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| 154 | if ext not in self.loaders: |
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| 155 | self.loaders[ext] = [] |
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| 156 | # Append the new reader to the list |
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| 157 | self.loaders[ext].append(loader.read) |
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| 158 | |
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| 159 | reader_found = True |
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| 160 | |
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| 161 | # Keep track of wildcards |
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| 162 | type_name = module.__name__ |
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| 163 | if hasattr(loader, 'type_name'): |
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| 164 | type_name = loader.type_name |
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| 165 | |
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| 166 | wcard = "%s files (*%s)|*%s" % (type_name, ext.lower(), ext.lower()) |
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| 167 | if wcard not in self.wildcards: |
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| 168 | self.wildcards.append(wcard) |
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| 169 | |
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| 170 | # Check whether writing is supported |
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| 171 | if hasattr(loader, 'write'): |
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| 172 | if ext not in self.writers: |
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| 173 | self.writers[ext] = [] |
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| 174 | # Append the new writer to the list |
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| 175 | self.writers[ext].append(loader.write) |
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| 176 | |
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| 177 | except: |
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| 178 | logging.error("Loader: Error accessing Reader in %s\n %s" % (module.__name__, sys.exc_value)) |
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| 179 | return reader_found |
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| 180 | |
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| 181 | def associate_file_reader(self, ext, loader): |
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| 182 | """ |
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| 183 | Append a reader object to readers |
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| 184 | |
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| 185 | :param ext: file extension [string] |
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| 186 | :param module: reader object |
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| 187 | """ |
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| 188 | reader_found = False |
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| 189 | |
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| 190 | try: |
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| 191 | # Find supported extensions |
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| 192 | if ext not in self.loaders: |
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| 193 | self.loaders[ext] = [] |
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| 194 | # Append the new reader to the list |
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| 195 | self.loaders[ext].append(loader.read) |
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| 196 | |
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| 197 | reader_found = True |
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| 198 | |
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| 199 | # Keep track of wildcards |
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| 200 | if hasattr(loader, 'type_name'): |
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| 201 | type_name = loader.type_name |
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| 202 | |
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| 203 | wcard = "%s files (*%s)|*%s" % (type_name, ext.lower(), ext.lower()) |
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| 204 | if wcard not in self.wildcards: |
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| 205 | self.wildcards.append(wcard) |
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| 206 | |
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| 207 | except: |
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| 208 | logging.error("Loader: Error accessing Reader in %s\n %s" % (module.__name__, sys.exc_value)) |
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| 209 | return reader_found |
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| 210 | |
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| 211 | |
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| 212 | def _identify_plugin(self, module): |
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| 213 | """ |
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| 214 | Look into a module to find whether it contains a |
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| 215 | Reader class. If so, add it to readers and (potentially) |
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| 216 | to the list of writers. |
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| 217 | :param module: module object |
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| 218 | |
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| 219 | """ |
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| 220 | reader_found = False |
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| 221 | |
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| 222 | if hasattr(module, "Reader"): |
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| 223 | try: |
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| 224 | # Find supported extensions |
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| 225 | loader = module.Reader() |
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| 226 | for ext in loader.ext: |
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| 227 | if ext not in self.loaders: |
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| 228 | self.loaders[ext] = [] |
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| 229 | # When finding a reader at run time, treat this reader as the new |
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| 230 | # default |
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| 231 | self.loaders[ext].insert(0,loader.read) |
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| 232 | |
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| 233 | reader_found = True |
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| 234 | |
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| 235 | # Keep track of wildcards |
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| 236 | type_name = module.__name__ |
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| 237 | if hasattr(loader, 'type_name'): |
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| 238 | type_name = loader.type_name |
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| 239 | wcard = "%s files (*%s)|*%s" % (type_name, ext.lower(), ext.lower()) |
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| 240 | if wcard not in self.wildcards: |
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| 241 | self.wildcards.append(wcard) |
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| 242 | |
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| 243 | # Check whether writing is supported |
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| 244 | if hasattr(loader, 'write'): |
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| 245 | for ext in loader.ext: |
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| 246 | if ext not in self.writers: |
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| 247 | self.writers[ext] = [] |
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| 248 | self.writers[ext].insert(0,loader.write) |
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| 249 | |
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| 250 | except: |
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| 251 | logging.error("Loader: Error accessing Reader in %s\n %s" % (module.__name__, sys.exc_value)) |
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| 252 | return reader_found |
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| 253 | |
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| 254 | def lookup_writers(self, path): |
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| 255 | """ |
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| 256 | :return: the loader associated with the file type of path. |
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| 257 | |
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| 258 | :Raises ValueError: if file type is not known. |
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| 259 | """ |
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| 260 | # Find matching extensions |
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| 261 | extlist = [ext for ext in self.extensions() if path.endswith(ext)] |
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| 262 | # Sort matching extensions by decreasing order of length |
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| 263 | extlist.sort(lambda a,b: len(a)<len(b)) |
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| 264 | # Combine loaders for matching extensions into one big list |
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| 265 | writers = [] |
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| 266 | for L in [self.writers[ext] for ext in extlist]: |
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| 267 | writers.extend(L) |
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| 268 | # Remove duplicates if they exist |
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| 269 | if len(writers) != len(set(writers)): |
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| 270 | result = [] |
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| 271 | for L in writers: |
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| 272 | if L not in result: result.append(L) |
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| 273 | writers = L |
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| 274 | # Raise an error if there are no matching extensions |
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| 275 | if len(writers) == 0: |
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| 276 | raise ValueError, "Unknown file type for "+path |
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| 277 | # All done |
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| 278 | return writers |
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| 279 | |
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| 280 | def save(self, path, data, format=None): |
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| 281 | """ |
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| 282 | Call the writer for the file type of path. |
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| 283 | |
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| 284 | Raises ValueError if no writer is available. |
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| 285 | Raises KeyError if format is not available. |
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| 286 | |
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| 287 | May raise a writer-defined exception if writer fails. |
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| 288 | """ |
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| 289 | if format is None: |
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| 290 | writers = self.lookup_writers(path) |
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| 291 | else: |
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| 292 | writers = self.writers[format] |
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| 293 | for fn in writers: |
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| 294 | try: |
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| 295 | return fn(path, data) |
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| 296 | except: |
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| 297 | pass # give other loaders a chance to succeed |
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| 298 | # If we get here it is because all loaders failed |
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| 299 | raise # reraises last exception |
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| 300 | |
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| 301 | |
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| 302 | class Loader(object): |
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| 303 | """ |
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| 304 | Utility class to use the Registry as a singleton. |
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| 305 | """ |
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| 306 | ## Registry instance |
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| 307 | __registry = Registry() |
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| 308 | |
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| 309 | def associate_file_type(self, ext, module): |
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| 310 | """ |
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| 311 | Look into a module to find whether it contains a |
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| 312 | Reader class. If so, append it to readers and (potentially) |
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| 313 | to the list of writers for the given extension |
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| 314 | |
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| 315 | :param ext: file extension [string] |
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| 316 | :param module: module object |
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| 317 | """ |
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| 318 | return self.__registry.associate_file_type(ext, module) |
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| 319 | |
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| 320 | def associate_file_reader(self, ext, loader): |
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| 321 | """ |
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| 322 | Append a reader object to readers |
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| 323 | |
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| 324 | :param ext: file extension [string] |
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| 325 | :param module: reader object |
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| 326 | """ |
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| 327 | return self.__registry.associate_file_reader(ext, loader) |
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| 328 | |
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| 329 | def load(self, file, format=None): |
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| 330 | """ |
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| 331 | Load a file |
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| 332 | |
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| 333 | :param file: file name (path) |
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| 334 | :param format: specified format to use (optional) |
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| 335 | :return: DataInfo object |
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| 336 | """ |
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| 337 | return self.__registry.load(file, format) |
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| 338 | |
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| 339 | def save(self, file, data, format): |
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| 340 | """ |
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| 341 | Save a DataInfo object to file |
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| 342 | :param file: file name (path) |
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| 343 | :param data: DataInfo object |
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| 344 | :param format: format to write the data in |
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| 345 | """ |
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| 346 | return self.__registry.save(file, data, format) |
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| 347 | |
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| 348 | def _get_registry_creation_time(self): |
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| 349 | """ |
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| 350 | Internal method used to test the uniqueness |
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| 351 | of the registry object |
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| 352 | """ |
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| 353 | return self.__registry._created |
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| 354 | |
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| 355 | def find_plugins(self, dir): |
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| 356 | """ |
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| 357 | Find plugins in a given directory |
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| 358 | |
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| 359 | :param dir: directory to look into to find new readers/writers |
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| 360 | """ |
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| 361 | return self.__registry.find_plugins(dir) |
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| 362 | |
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| 363 | def get_wildcards(self): |
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| 364 | return self.__registry.wildcards |
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| 365 | |
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| 366 | if __name__ == "__main__": |
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| 367 | logging.basicConfig(level=logging.INFO, |
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| 368 | format='%(asctime)s %(levelname)s %(message)s', |
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| 369 | filename='loader.log', |
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| 370 | filemode='w') |
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| 371 | l = Loader() |
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| 372 | data = l.load('test/cansas1d.xml') |
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| 373 | l.save('test_file.xml', data, '.xml') |
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| 374 | |
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| 375 | print l.get_wildcards() |
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| 376 | |
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| 377 | |
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| 378 | |
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