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Improve readability pack and unpack template examples (#20734)

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Co-authored-by: Franck Nijhof <frenck@frenck.nl>
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Jan Bouwhuis 2021-12-17 11:01:15 +01:00 committed by GitHub
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source/_docs/configuration/templating.markdown
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@ -578,11 +578,14 @@ These functions are used to process raw value's in a `bytes` format to values in
The `pack` and `unpack` functions can also be used as a filter. They make use of the Python 3 `struct` library.
See: https://docs.python.org/3/library/struct.html
- Filter `value | pack(format_string)` will convert a native type to a `bytes` type object. This will call function `struct.pack(format_string, value)`. Returns `None` if an error occurs or the `format_string` is invalid.
- Function `pack(value, format_string)` will convert a native type to a `bytes` type object. This will call function `struct.pack(format_string, value)`. Returns `None` if an error occurs or the `format_string` is invalid.
- Filter `value | unpack(format_string, offset=0)` will try to convert a `bytes` object into a native Python object. The `offset` parameter defines the offset position in bytes from the start of the input `bytes` based buffer. This will call function `struct.unpack_from(format_string, value, offset=offset)`. Returns `None` if an error occurs or the `format_string` is invalid.
- Function `unpack(value, format_string, offset=0)` will try to convert a `bytes` object into a native Python object. The `offset` parameter defines the offset position in bytes from the start of the input `bytes` based buffer. This will call function `struct.unpack_from(format_string, value, offset=offset)`. Returns `None` if an error occurs or the `format_string` is invalid.
- Filter `value | pack(format_string)` will convert a native type to a `bytes` type object. This will call function `struct.pack(format_string, value)`. Returns `None` if an error occurs or when `format_string` is invalid.
- Function `pack(value, format_string)` will convert a native type to a `bytes` type object. This will call function `struct.pack(format_string, value)`. Returns `None` if an error occurs or when `format_string` is invalid.
- Filter `value | unpack(format_string, offset=0)` will try to convert a `bytes` object into a native Python object. The `offset` parameter defines the offset position in bytes from the start of the input `bytes` based buffer. This will call function `struct.unpack_from(format_string, value, offset=offset)`. Returns `None` if an error occurs or when `format_string` is invalid.
- Function `unpack(value, format_string, offset=0)` will try to convert a `bytes` object into a native Python object. The `offset` parameter defines the offset position in bytes from the start of the input `bytes` based buffer. This will call function `struct.unpack_from(format_string, value, offset=offset)`. Returns `None` if an error occurs or when `format_string` is invalid.
<div class='note'>
Some examples:
{% raw %}
- `{{ 0xDEADBEEF | pack(">I") }}` - renders as `b"\xde\xad\xbe\xef"`
@ -592,6 +595,8 @@ See: https://docs.python.org/3/library/struct.html
{% endraw %}
</div>
### String filters
- Filter `urlencode` will convert an object to a percent-encoded ASCII text string (e.g., for HTTP requests using `application/x-www-form-urlencoded`).