70 lines
1.9 KiB
Markdown
70 lines
1.9 KiB
Markdown
---
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title: Expressions
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---
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Expressions allow you to write custom logic using Python code.
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Expressions are used in different places throughout passbook, and can do different things.
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:::info
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These functions/objects are available wherever expressions are used. For more specific information, see [Expression Policies](../policies/expression.md) and [Property Mappings](../property-mappings/expression.md)
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:::
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## Global objects
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- `pb_logger`: structlog BoundLogger. ([ref](https://www.structlog.org/en/stable/api.html#structlog.BoundLogger))
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- `requests`: requests Session object. ([ref](https://requests.readthedocs.io/en/master/user/advanced/))
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## Generally available functions
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### `regex_match(value: Any, regex: str) -> bool`
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Check if `value` matches Regular Expression `regex`.
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Example:
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```python
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return regex_match(request.user.username, '.*admin.*')
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```
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### `regex_replace(value: Any, regex: str, repl: str) -> str`
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Replace anything matching `regex` within `value` with `repl` and return it.
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Example:
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```python
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user_email_local = regex_replace(request.user.email, '(.+)@.+', '')
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```
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### `pb_is_group_member(user: User, **group_filters) -> bool`
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Check if `user` is member of a group matching `**group_filters`.
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Example:
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```python
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return pb_is_group_member(request.user, name="test_group")
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```
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### `pb_user_by(**filters) -> Optional[User]`
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Fetch a user matching `**filters`. Returns "None" if no user was found.
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Example:
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```python
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other_user = pb_user_by(username="other_user")
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```
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## Comparing IP Addresses
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To compare IP Addresses or check if an IP Address is within a given subnet, you can use the functions `ip_address('192.0.2.1')` and `ip_network('192.0.2.0/24')`. With these objects you can do [arithmetic operations](https://docs.python.org/3/library/ipaddress.html#operators).
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You can also check if an IP Address is within a subnet by writing the following:
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```python
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ip_address('192.0.2.1') in ip_network('192.0.2.0/24')
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# evaluates to True
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```
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