jProperties is a Java Property file parser and writer for Python. It aims to provide the same functionality
as Java's Properties class <http://docs.oracle.com/javase/7/docs/api/java/util/Properties.html>_, although
currently the XML property format is not supported.
.. sectnum:: .. contents:: Table of Contents
You can install jProperties using pip <https://pip.pypa.io/>_::
pip install jpropertiesGPG-signed Git release tags +++++++++++++++++++++++++++
From version 2.1.2 and newer, all Git release tags such as v2.1.2 are signed with the following GPG key:
Tilman Blumenbach <tilman+git@ax86.net>B67BD719C23DC2A403E15EB102DE477F6DDE8B17Objects of the type Properties can be used like a Python dictionary (but see Caveats_ below).
The load() method populates the object by parsing input in the Java Property file format; the store()
method writes the key-value pairs stored in the object to a stream in the same format.
The load() and store() methods both take an encoding parameter. By default this is set to
iso-8859-1, but it can be set to any encoding supported by Python, including e. g. the widely used
utf-8.
Parsing a property file +++++++++++++++++++++++
.. code:: python
from jproperties import Properties
p = Properties()
with open("foobar.properties", "rb") as f:
p.load(f, "utf-8")That's it, p now can be used like a dictionary containing properties from foobar.properties.
Writing a property file +++++++++++++++++++++++
.. code:: python
from jproperties import Properties
p = Properties()
p["foobar"] = "A very important message from our sponsors: Python is great!"
with open("foobar.properties", "wb") as f:
p.store(f, encoding="utf-8")Reading from and writing to the same file-like object +++++++++++++++++++++++++++++++++++++++++++++++++++++
.. code:: python
from jproperties import Properties
with open("foobar.properties", "r+b") as f:
p = Properties()
p.load(f, "utf-8")
# Do stuff with the p object...
f.seek(0)
f.truncate(0)
p.store(f, encoding="utf-8")Metadata ++++++++
The property file parser supports including programmatically readable and settable metadata in property files.
Metadata for a key is represented as a Python dictionary; the keys and values of this dictionary should be strings,
although when the property file is written, all non-string objects will be converted to strings. This is a
one-way conversion; when the metadata is read back again during a load(), all keys and values will be treated
as simple strings.
By default, the store() method does not write out the metadata. To enable that feature, set the keyword argument
strip_meta=False when calling the method.
Note that metadata support is always enabled. The only thing that is optional is actually writing out the metadata.
Metadata keys beginning with two underscores (__) are not written to the output stream by the store() method.
Thus, they can be used to attach "runtime-only" metadata to properties. Currently, however, metadata with such keys is
still read from the input stream by load(); this should probably be considered erroneous behaviour.
Documenting Properties ^^^^^^^^^^^^^^^^^^^^^^
The comments after a property definition can be added to the metadata
with the key _doc if the metadoc=True optional argument is given
to the load method. This allows properties to be documented in the
properties file. For example, the properties file::
#: _severity=fatal
10001=Fatal internal error: %s
# A fatal internal error occurred. Please re-run the command
# with the -D option to generate additional debug information.The following example code shows how this documentation can be accessed.
.. code:: python
from jproperties import Properties
p = Properties()
with open("foobar.properties", "rb") as f:
p.load(f, "utf-8", metadoc=True)
# Print the explicitly defined '_severity' metadata
print("Severity: ", p.getmeta("10001")['_severity'])
# Print the implicitly defined '_doc' metadata
print("Explanation: ", p.getmeta("10001")['_doc'])The documentation can be extracted from properties files and used to generate pages in the overall system documentation or can be accessed via options for command line utilities.
Caveats ^^^^^^^
Metadata support influences how Properties objects are used as dictionary objects:
prop_object[key] = value or prop_object[key] = value, metadata. The first form
will leave the key's metadata unchanged. You can also use the setmeta() method to set a key's metadata.value, metadata = prop_object[key]. If there is no metadata for a key,
metadata will be an empty dictionary. To retrieve only the metadata for a key, the getmeta() method can
be used.Properties objects will simply return all keys in an unspecified order. No metadata is
returned (but can be retrieved using getmeta()).Setting defaults ++++++++++++++++
The internal dictionary holding the key-value pairs can be accessed using the properties property. Deleting that
property deletes all key-value pairs from the object.
However, modifying properties using this special property will not modify metadata in any way. That means that
deleting properties by doing del prop_obj.properties[key] will not remove the associated metadata from the object.
Instead, do del prop_obj[key].
The properties property is nevertheless useful to set many default values before parsing a property file:
.. code:: python
from jproperties import Properties
prop_obj = Properties()
prop_obj.properties = a_big_dictionary_with_defaults
file_obj = codecs.open("foobar.properties", "rb", "iso-8859-1")
prop_obj.load(file_obj, encoding=None)Development ++++++++++++++++
If you want to help development, there is
overview documentation <./DEVELOPMENT.rst>_
See file CHANGELOG.rst <./CHANGELOG.rst>_.
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