plesty.server.model.yaml_edit

Change values in a YAML configuration’s text, and nothing else.

A form that edits two values of a configuration must not re-serialise the whole file: that drops every comment and rewrites what nobody touched ([a, b] into a block list, 1.0e+9 into 1000000000.0). So a value is replaced where it stands, on its own line, with the rest of the line — its comment — kept; a key the file does not have is added at the end of its group.

Only what this can do safely is done this way: a key one or two levels deep. A value written as a block below its key is replaced by one flow line, so only that key is laid out anew. Anything else — a block scalar, an anchor, a result that does not parse back to what was asked — returns None, and the caller falls back to re-serialising.

Attributes

`Change`
`_LINE`

Functions

`flow`(→ str)	value as one line of YAML: `0.5`, `[1, 2]`, `{a: 1}`, `'yes'`.
`set_values`(→ str \| None)	text with each change made in place, or `None` when one cannot be.
`_set_one`(→ bool)	Make one change in lines; `False` when it cannot be made in place.
`_find`(→ tuple[int, re.Match[str]] \| None)	The line in `lines[start:end]` holding key at exactly indent.
`_block_end`(→ int)	Where the block opened by the key on line index ends.
`_child_indent`(→ str)	The indentation of the first key in `lines[start:end]`.
`_append`(→ None)	Insert `indent + line` before at, ending the line before it if it is open.

Module Contents

plesty.server.model.yaml_edit.Change

plesty.server.model.yaml_edit._LINE

plesty.server.model.yaml_edit.flow(value: Any) → str

value as one line of YAML: 0.5, [1, 2], {a: 1}, 'yes'.

Parameters:: value (Any)
Return type:: str

plesty.server.model.yaml_edit.set_values(text: str, changes: collections.abc.Sequence[Change]) → str | None

text with each change made in place, or None when one cannot be.

Parameters:

text (str) – The configuration as written.
changes (collections.abc.Sequence[Change]) – What to set, each (group, key, value).

Returns:

The edited text, which parses to the document with the changes made; None when a change cannot be placed on a line of its own.

Return type:

str | None

plesty.server.model.yaml_edit._set_one(lines: list[str], group: str | None, key: str, value: Any) → bool

Make one change in lines; False when it cannot be made in place.

Parameters:

lines (list[str])
group (str | None)
key (str)
value (Any)

Return type:

bool

plesty.server.model.yaml_edit._find(lines: list[str], start: int, end: int, indent: str, key: str) → tuple[int, re.Match[str]] | None

The line in lines[start:end] holding key at exactly indent.

Parameters:

lines (list[str])
start (int)
end (int)
indent (str)
key (str)

Return type:

tuple[int, re.Match[str]] | None

plesty.server.model.yaml_edit._block_end(lines: list[str], index: int) → int

Where the block opened by the key on line index ends.

Parameters:

lines (list[str])
index (int)

Return type:

int

plesty.server.model.yaml_edit._child_indent(lines: list[str], start: int, end: int) → str

The indentation of the first key in lines[start:end].

Parameters:

lines (list[str])
start (int)
end (int)

Return type:

str

plesty.server.model.yaml_edit._append(lines: list[str], at: int, indent: str, line: str) → None

Insert indent + line before at, ending the line before it if it is open.

Parameters:

lines (list[str])
at (int)
indent (str)
line (str)

Return type:

None