# Customizing with Lifecycle Hooks

## Background

{% content-ref url="/pages/ANLbxIN4T0Q4YF2llfer" %}
[Lifecycle Hooks](/core-concepts/agent/lifecycle-hooks.md)
{% endcontent-ref %}

## Writing a Lifecycle Hooks Script

1. Write a Python script (e.g. lifecycle\_hooks.py)
2. In this script, define the lifecycle events to hook into
3. Define what kind of behavior to execute for each of those events

Below is a sample script that prints some strings during two lifecycle events.

{% hint style="warning" %}
Manipulating the **context** object will affect the behaviour of the request interception.
{% endhint %}

```python
from stoobly_agent.app.proxy.context import InterceptContext
from stoobly_agent.app.proxy.record.context import RecordContext

def handle_before_request(context: InterceptContext):
    print('Before request!')

def handle_before_record(context: RecordContext):
    print('Before record!')
```

* `handle_before_request` is for **before** a request gets sent
* `handle_before_record` is for **before** a request gets recorded

After a request gets intercepted, the string `"Before request!"` will be printed. After the response returns, but before the request gets recorded, `"Before record!"` will be printed.

## Enabling Lifecycle Hook Script Use

Pass the path to the lifecycle hooks scripts using the `--lifecycle-hooks-path` option:

```bash
stoobly-agent run --lifecycle-hooks-path ~/path-to-file/lifecycle_hooks.py
```

## Example

```python
from stoobly_agent.app.proxy.record.context import RecordContext

def handle_before_record(context: RecordContext):
    request = context.flow.request
    respose = context.flow.response
    
    request.headers['Authorization'] = '<REDACTED>'
    request.headers['Cookie'] = ''
    
    response.headers['Set-Cookie'] = ''
```


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