`PropertiesFile` Class

class javaproperties.PropertiesFile(mapping: None | Mapping[str, str] | Iterable[tuple[str, str]] = None, **kwargs: str)[source]

Added in version 0.3.0.

A custom mapping class for reading from, editing, and writing to a .properties file while preserving comments & whitespace in the original input.

A PropertiesFile instance can be constructed from another mapping and/or iterable of pairs, after which it will act like an OrderedDict. Alternatively, an instance can be constructed from a file or string with PropertiesFile.load() or PropertiesFile.loads(), and the resulting instance will remember the formatting of its input and retain that formatting when written back to a file or string with the dump() or dumps() method. The formatting information attached to an instance pf can be forgotten by constructing another mapping from it via dict(pf), OrderedDict(pf), or even PropertiesFile(pf) (Use the copy() method if you want to create another PropertiesFile instance with the same data & formatting).

When not reading or writing, PropertiesFile behaves like a normal MutableMapping class (i.e., you can do props[key] = value and so forth), except that (a) like OrderedDict, key insertion order is remembered and is used when iterating & dumping (and reversed is supported), and (b) like Properties, it may only be used to store strings and will raise a TypeError if passed a non-string object as key or value.

Two PropertiesFile instances compare equal iff both their key-value pairs and comment & whitespace lines are equal and in the same order. When comparing a PropertiesFile to any other type of mapping, only the key-value pairs are considered, and order is ignored.

PropertiesFile currently only supports reading & writing the simple line-oriented format, not XML.

copy() → PropertiesFile[source]: Create a copy of the mapping, including formatting information

dump(fp: TextIO, separator: str = '=', ensure_ascii: bool = True) → None[source]

Write the mapping to a file in simple line-oriented .properties format.

If the instance was originally created from a file or string with PropertiesFile.load() or PropertiesFile.loads(), then the output will include the comments and whitespace from the original input, and any keys that haven’t been deleted or reassigned will retain their original formatting and multiplicity. Key-value pairs that have been modified or added to the mapping will be reformatted with join_key_value() using the given separator and ensure_ascii setting. All key-value pairs are output in the order they were defined, with new keys added to the end.

Changed in version 0.8.0: ensure_ascii parameter added

Note

Serializing a PropertiesFile instance with the dump() function instead will cause all formatting information to be ignored, as dump() will treat the instance like a normal mapping.

Parameters:

fp (TextIO) – A file-like object to write the mapping to. It must have been opened as a text file with a Latin-1-compatible encoding.
separator (str) – The string to use for separating new or modified keys & values. Only " ", "=", and ":" (possibly with added whitespace) should ever be used as the separator.
ensure_ascii (bool) – if true, all non-ASCII characters in new or modified key-value pairs will be replaced with \uXXXX escape sequences in the output; if false, non-ASCII characters will be passed through as-is

Returns:

None

dumps(separator: str = '=', ensure_ascii: bool = True) → str[source]

Convert the mapping to a str in simple line-oriented .properties format.

If the instance was originally created from a file or string with PropertiesFile.load() or PropertiesFile.loads(), then the output will include the comments and whitespace from the original input, and any keys that haven’t been deleted or reassigned will retain their original formatting and multiplicity. Key-value pairs that have been modified or added to the mapping will be reformatted with join_key_value() using the given separator and ensure_ascii setting. All key-value pairs are output in the order they were defined, with new keys added to the end.

Changed in version 0.8.0: ensure_ascii parameter added

Note

Serializing a PropertiesFile instance with the dumps() function instead will cause all formatting information to be ignored, as dumps() will treat the instance like a normal mapping.

Parameters:

separator (str) – The string to use for separating new or modified keys & values. Only " ", "=", and ":" (possibly with added whitespace) should ever be used as the separator.
ensure_ascii (bool) – if true, all non-ASCII characters in new or modified key-value pairs will be replaced with \uXXXX escape sequences in the output; if false, non-ASCII characters will be passed through as-is

Return type:

str

property header_comment: str | None

Added in version 0.7.0.

The concatenated values of all comments at the top of the file, up to (but not including) the first key-value pair or timestamp comment, whichever comes first. The comments are returned with comment markers and the whitespace leading up to them removed, with line endings changed to \n, and with the line ending on the final comment (if any) removed. Blank/all-whitespace lines among the comments are ignored.

The header comment can be changed by assigning to this property. Assigning a string s causes everything before the first key-value pair or timestamp comment to be replaced by the output of to_comment(s). Assigning None causes the header comment to be deleted (also achievable with del pf.header_comment).

>>> pf = PropertiesFile.loads('''\
... #This is a comment.
...   ! This is also a comment.
... #Tue Feb 25 19:13:27 EST 2020
... key = value
... zebra: apple
... ''')
>>> pf.header_comment
'This is a comment.\n This is also a comment.'
>>> pf.header_comment = 'New comment'
>>> print(pf.dumps(), end='')
#New comment
#Tue Feb 25 19:13:27 EST 2020
key = value
zebra: apple
>>> del pf.header_comment
>>> pf.header_comment is None
True
>>> print(pf.dumps(), end='')
#Tue Feb 25 19:13:27 EST 2020
key = value
zebra: apple

classmethod load(fp: IO) → PropertiesFile[source]

Parse the contents of the readline-supporting file-like object fp as a simple line-oriented .properties file and return a PropertiesFile instance.

fp may be either a text or binary filehandle, with or without universal newlines enabled. If it is a binary filehandle, its contents are decoded as Latin-1.

Changed in version 0.5.0: Invalid \uXXXX escape sequences will now cause an InvalidUEscapeError to be raised

Parameters:: fp (IO) – the file from which to read the .properties document
Return type:: PropertiesFile
Raises:: InvalidUEscapeError – if an invalid \uXXXX escape sequence occurs in the input

classmethod loads(s: AnyStr) → PropertiesFile[source]

Parse the contents of the string s as a simple line-oriented .properties file and return a PropertiesFile instance.

s may be either a text string or bytes string. If it is a bytes string, its contents are decoded as Latin-1.

Changed in version 0.5.0: Invalid \uXXXX escape sequences will now cause an InvalidUEscapeError to be raised

Parameters:: s (Union[str,bytes]) – the string from which to read the .properties document
Return type:: PropertiesFile
Raises:: InvalidUEscapeError – if an invalid \uXXXX escape sequence occurs in the input

property timestamp: str | None

Added in version 0.7.0.

The value of the timestamp comment, with the comment marker, any whitespace leading up to it, and the trailing newline removed. The timestamp comment is the first comment that appears to be a valid timestamp as produced by Java 8’s Date.toString() and that does not come after any key-value pairs; if there is no such comment, the value of this property is None.

The timestamp can be changed by assigning to this property. Assigning a string s replaces the timestamp comment with the output of to_comment(s); no check is made as to whether the result is a valid timestamp comment. Assigning None or False causes the timestamp comment to be deleted (also achievable with del pf.timestamp). Assigning any other value x replaces the timestamp comment with the output of to_comment(java_timestamp(x)).

>>> pf = PropertiesFile.loads('''\
... #This is a comment.
... #Tue Feb 25 19:13:27 EST 2020
... key = value
... zebra: apple
... ''')
>>> pf.timestamp
'Tue Feb 25 19:13:27 EST 2020'
>>> pf.timestamp = 1234567890
>>> pf.timestamp
'Fri Feb 13 18:31:30 EST 2009'
>>> print(pf.dumps(), end='')
#This is a comment.
#Fri Feb 13 18:31:30 EST 2009
key = value
zebra: apple
>>> del pf.timestamp
>>> pf.timestamp is None
True
>>> print(pf.dumps(), end='')
#This is a comment.
key = value
zebra: apple

PropertiesFile Class

`PropertiesFile` Class