# Rasa SDK

Rasa SDK provides the tools you need to write custom actions in python.

- **Installation**  
  Use `pip` to install `rasa-sdk` on your action server.
```bash
pip install rasa-sdk
```

Note: You do not need to install `rasa` for your action server.
E.g. if you are running Rasa in a docker container, it is recommended to create a separate container for your action server. In this separate container, you only need to install `rasa-sdk`.

## Running the Action Server  
If you have `rasa` installed, run this command to start your action server:
```bash
rasa run actions
```
Otherwise, if you do not have `rasa` installed, run this command:
```bash
python -m rasa_sdk --actions actions
```
You can verify that the action server is up and running with the command:
```bash
curl http://localhost:5055/health
```
You can get the list of registered custom actions with the command:
```bash
curl http://localhost:5055/actions
```
The file that contains your custom actions should be called `actions.py`. Alternatively, you can use a package directory called `actions` or else manually specify an actions module or package with the `--actions` flag.

### Actions  
The `Action` class is the base class for any custom action. It has two methods that both need to be overwritten, `name()` and `run()`.

Example:
```python
from rasa_sdk import Action
from rasa_sdk.events import SlotSet

class ActionCheckRestaurants(Action):
   def name(self) -> Text:
      return "action_check_restaurants"

def run(self,
           dispatcher: CollectingDispatcher,
           tracker: Tracker,
           domain: Dict[Text, Any]) -> List[Dict[Text, Any]]:

cuisine = tracker.get_slot('cuisine')
      q = "select * from restaurants where cuisine='{0}' limit 1".format(cuisine)
      result = db.query(q)

return [SlotSet("matches", result if result is not None else [])]
```
You should add the action name `action_check_restaurants` to the actions in your domain file. The action’s `run()` method receives three arguments. You can access the values of slots and the latest message sent by the user using the `tracker` object, and you can send messages back to the user with the `dispatcher` object, by calling `dispatcher.utter_message`.

### Details of the `run()` Method  
Execute the side effects of this action.

**Parameters**  
- **dispatcher** – the dispatcher which is used to send messages back to the user. Use `dipatcher.utter_message()` or any other `rasa_sdk.executor.CollectingDispatcher` method.  
- **tracker** – the state tracker for the current user. You can access slot values using `tracker.get_slot(slot_name)`, the most recent user message is `tracker.latest_message.text` and any other `rasa_sdk.Tracker` property.  
- **domain** – the bot’s domain

**Returns**  
A dictionary of `rasa_sdk.events.Event` instances that is returned through the endpoint.

### Events  
An action’s `run()` method returns a list of events. For more information on the different types of events, see [Events](https://legacy-docs-v1.rasa.com/1.10.20/api/events/#events). If the action should not trigger any other events, it should return an empty list.

### Tracker  
The `rasa_sdk.Tracker` lets you access the bot’s memory in your custom actions. You can get information about past events and the current state of the conversation through `Tracker` attributes and methods.

**Available attributes:**  
- `sender_id` - The unique ID of person talking to the bot.
- `slots` - The list of slots that can be filled as defined in the domains.
- `latest_message` - The attributes of the latest message: `intent`, `entities` and `text`.
- `events` - A list of all previous events.
- `active_form` - The name of the currently active form.
- `latest_action_name` - The name of the last action the bot executed.

**Available methods:**  
- `Tracker.get_slot(key)` - Retrieves the value of a slot.  
- `Tracker.latest_message` - Access latest user message.

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