Coverage for python/lsst/obs/base/formatters/filter.py : 79%

Hot-keys on this page
r m x p toggle line displays
j k next/prev highlighted chunk
0 (zero) top of page
1 (one) first highlighted chunk
1# This file is part of obs_base.
2#
3# Developed for the LSST Data Management System.
4# This product includes software developed by the LSST Project
5# (http://www.lsst.org).
6# See the COPYRIGHT file at the top-level directory of this distribution
7# for details of code ownership.
8#
9# This program is free software: you can redistribute it and/or modify
10# it under the terms of the GNU General Public License as published by
11# the Free Software Foundation, either version 3 of the License, or
12# (at your option) any later version.
13#
14# This program is distributed in the hope that it will be useful,
15# but WITHOUT ANY WARRANTY; without even the implied warranty of
16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17# GNU General Public License for more details.
18#
19# You should have received a copy of the GNU General Public License
20# along with this program. If not, see <http://www.gnu.org/licenses/>.
22from __future__ import annotations
24__all__ = ("FilterFormatter",)
26import yaml
27from lsst.afw.image import Filter
29from typing import (
30 Any,
31 Optional,
32 Type,
33)
35from lsst.daf.butler.formatters.file import FileFormatter
38class FilterFormatter(FileFormatter):
39 """Read and write `~lsst.afw.image.Filter` filter information."""
41 extension = ".yaml"
43 unsupportedParameters = None
44 """This formatter does not support any parameters."""
46 def _readFile(self, path: str, pytype: Type[Any] = None) -> Any:
47 """Read a file from the path in YAML format.
49 Parameters
50 ----------
51 path : `str`
52 Path to use to open the file.
53 pytype : `class`, optional
54 The type expected to be returned.
56 Returns
57 -------
58 data : `object`
59 Either data as Python object read from YAML file, or None
60 if the file could not be opened.
61 """
62 try:
63 with open(path, "rb") as fd:
64 data = self._fromBytes(fd.read(), pytype)
65 except FileNotFoundError:
66 data = None
68 return data
70 def _fromBytes(self, serializedDataset: bytes, pytype: Optional[Type[Any]] = None) -> Any:
71 """Read the bytes object as a python object.
73 Parameters
74 ----------
75 serializedDataset : `bytes`
76 Bytes object to unserialize.
77 pytype : `type`, optional
78 Expected python type to be returned.
80 Returns
81 -------
82 inMemoryDataset : `lsst.afw.image.Filter`
83 The requested data as an object.
84 """
85 data = yaml.load(serializedDataset, Loader=yaml.SafeLoader)
87 if pytype is None: 87 ↛ 88line 87 didn't jump to line 88, because the condition on line 87 was never true
88 pytype = Filter
90 # This will be a simple dict so we need to convert it to
91 # the Filter type -- just needs the name
92 filter = pytype(data["canonicalName"], force=True)
94 return filter
96 def _writeFile(self, inMemoryDataset: Any) -> None:
97 """Write the in memory dataset to file on disk.
99 Parameters
100 ----------
101 inMemoryDataset : `lsst.afw.image.Filter`
102 Filter to serialize.
104 Raises
105 ------
106 Exception
107 Raised if the file could not be written or the dataset could not be
108 serialized.
109 """
110 with open(self.fileDescriptor.location.path, "wb") as fd:
111 fd.write(self._toBytes(inMemoryDataset))
113 def _toBytes(self, inMemoryDataset: Any) -> bytes:
114 """Write the in memory dataset to a bytestring.
116 Parameters
117 ----------
118 inMemoryDataset : `lsst.afw.image.Filter`
119 Object to serialize.
121 Returns
122 -------
123 serializedDataset : `bytes`
124 YAML string encoded to bytes.
126 Raises
127 ------
128 Exception
129 Raised if the object could not be serialized.
130 """
132 # Convert the Filter to a dict for dumping
133 # Given the singleton situation, only the name is really
134 # needed but it does not hurt to put some detail in the file
135 # to aid debugging.
136 filter = {}
137 filter["canonicalName"] = inMemoryDataset.getCanonicalName()
138 filter["name"] = inMemoryDataset.getName()
139 filter["aliases"] = inMemoryDataset.getAliases()
141 # This can fail if the filter is no longer available in the
142 # Singleton
143 try:
144 filterProperty = inMemoryDataset.getFilterProperty()
145 except LookupError:
146 pass
147 else:
148 properties = {}
149 properties["lambdaEff"] = filterProperty.getLambdaEff()
150 properties["lambdaMax"] = filterProperty.getLambdaMax()
151 properties["lambdaMin"] = filterProperty.getLambdaMin()
152 filter["properties"] = properties
154 return yaml.dump(filter).encode()