> ## Documentation Index
> Fetch the complete documentation index at: https://docs.codenullapp.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Hooks

> Common: reusable logic

## Hooks types

**Common**: reusable logic

[**Import**: Allows to import excel files](/dev/configurations/hooks/import-excel-files.md)

[Send Notification (web)](/dev/configurations/hooks/notifications.md)

[Scheduled Jobs](/dev/configurations/hooks/scheduled-jobs.md)

[Generate QR Code](/dev/configurations/hooks/generate-qr-code.md)

## Send Emails

* From: Email  address from where you want to send the email, It is not required if was configured in the application designer
* To: Email address of the destination person
* Subject: Subject of the email (text plain)
* Message: The body of the email can be in HTML format or Text Plain.

<Info>
  To know more about the allowed email options please read [nodemailer](https://nodemailer.com/about/) docs
</Info>

```javascript theme={null}
const sendEmail = require("./utils/mailSender").default;

//...
   const options ={
     from: 'correo@gmail.com',
     to: 'correo@gmail.com',
     subject: 'subject of the email',
     message: '<a>message of the email in HTML format or TEXT plain<a>'
   }
   await sendEmail(options);
```

## [Documentation for Sending Emails with Base64 Attachments (backend, hooks)](/dev/configurations/integrations/sending-emails-with-attachments-in-your-application-frontend.md#documentation-for-sending-emails-with-base64-attachments-backend-hooks)

#### Override email provider settings

If you want to use a different mail provider you can pass that configuration as a second parameter of the sendEmail function

```javascript theme={null}
const sendEmail = require("./utils/mailSender").default;

//...
   const options ={
     from: 'correo@gmail.com',
     to: 'correo@gmail.com',
     subject: 'subject of the email',
     message: '<a>message of the email in HTML format or TEXT plain<a>'
   }
   
   const mailSenderOptions = {
      host: '',
      port: '',
      secure: true, //true or false
      user: '',
      pass: '',
      emailFrom: '' //optional if you are already using options.from
   }
   await sendEmail(options, mailSenderOptions);
```

## Async Logic

```javascript theme={null}
const asyncFunctionExample = async (instance) => {
   // implement code here for async functions
}
asyncFunctionExample(instance);
```

## Querying and importing database model

```javascript theme={null}
//import the model
const modelsapp = require("../modelsapp").default;

const asyncFunctionExample = async (instance) => {
    const personas = await modelsapp.Persona.findAll({
        where: { IglesiaId: '123' },
        limit: 100,
    });
   // implement code here for async functions
}

asyncFunctionExample(instance);
```

<Info>
  To see more querying examples you can use any sequelize method: [https://sequelize.org/v4/manual/tutorial/querying.html](https://sequelize.org/v4/manual/tutorial/querying.html)
</Info>

## Hooks Errors

This section will show you how to throw hook errors.

The simplest way to throw an error looks like this

```javascript theme={null}
throw new Error("My error message");
```

### 🔁Redirecting to a different Feature

If you want to allow the user to see a modal with a button that redirects to a new **Feature**, you should throw an exception using the `CodenullError` class with the following parameters:

**✅ Example:**

```js theme={null}
const CodenullError = require("./utils/CodenullError").default;

throw new CodenullError(
  {
    featureId: "6122b2944ee09f001813a6fe", // ID of the Feature to redirect to
    params: [
      {
        type: "hardcoded",   // Type of value (e.g., "hardcoded")
        value: instance.Id,  // Relevant value to pass
        name: "Id"           // Descriptive name of the parameter
      }
    ],
    target: "_blank", //open in a new tab
    okLabel: "Aceptar", //label for ok button
    cancelLabel: "Cancelar", //lable for cancel button
    message: error,          // Error message or object
    type: "navigation"       // Type must be "navigation" to trigger redirection
  },
  "my message"               // Optional message for logs or modal display
);
```

> 💡 `type: "navigation"` is mandatory to trigger the redirect behavior.
>
> The `params` array allows dynamic values to be passed to the destination feature

This is how the error message will look, once the user hit the "Aceptar/Ok" button will be redirected to the new feature

<img src="https://mintcdn.com/codenull/9RtgKoAtzvpYtN-c/images/-MixV091_uukOTp4U6rm.png?fit=max&auto=format&n=9RtgKoAtzvpYtN-c&q=85&s=d76fe054684e8d455e93e4d0b90c16cd" alt="" width="1094" height="300" data-path="images/-MixV091_uukOTp4U6rm.png" />

<Warning>
  This requires the 1.1.9 version or greater
</Warning>

## Executing Store Procedure from Hooks

```javascript theme={null}
//import a database connection
const dbApp = require("../modelsapp/db").default

const ReplicarDatos = async (instance) => {
    //pass a transaction configuration in case you need it
    await dbApp.query(`exec ReplicarDatos '${instance.Id}'`, { transaction: options.transaction })
}
ReplicarDatos(instance);
```

*You can know more about queries here* [*https://sequelize.org/master/manual/raw-queries.html*](https://sequelize.org/master/manual/raw-queries.html)

## Other Import examples

```javascript theme={null}
const axios = require("axios").default;
const sortBy = require("lodash/sortBy");
```

## Troubleshooting

* Timeout doing database operations on the `afterSave` or any other *after* hook

Solution: Add the transaction to the operation as the second parameter

```javascript theme={null}
await modelsapp.Usuario.create(data, { transaction: options.transaction });
```