# Download File

### Overview

The **Download File Component** allows users to download a file from a given link and store it in the system. It supports specifying a custom filename for the downloaded file.

### Usage

This component is used to retrieve files from remote URLs and save them for further processing in workflows.

#### Properties

| Property         | Type     | Description                                                                                    |
| ---------------- | -------- | ---------------------------------------------------------------------------------------------- |
| `link`           | `string` | The URL of the file to download.                                                               |
| `customFileName` | `string` | Optional. The custom name for the downloaded file, including its extension (e.g., `file.png`). |

#### Input Ports

| Port | Description                                        |
| ---- | -------------------------------------------------- |
| `in` | Accepts the file URL and optional custom filename. |

#### Output Ports

| Port  | Description                                                                          |
| ----- | ------------------------------------------------------------------------------------ |
| `out` | Emits the downloaded file's metadata, including file ID, filename, and content type. |

#### Processing Logic

1. **Receives Input Data**:
   * Accepts a `link` to a file and an optional `customFileName`.
2. **Validates URL**:
   * Checks if the provided `link` is a valid URL.
   * If invalid, throws an error.
3. **Downloads the File**:
   * Sends an HTTP request to retrieve the file.
   * Extracts the filename from the response headers or URL if no custom filename is provided.
4. **Saves the File**:
   * Stores the file and generates a unique `fileId`.
5. **Handles Success & Errors**:
   * If successful, sends the downloaded file's details to the `out` port.
   * If an error occurs (e.g., invalid URL or download failure), it is logged or raised appropriately.

#### Output Data Schema

| Property      | Type     | Description                                   |
| ------------- | -------- | --------------------------------------------- |
| `fileId`      | `string` | The unique identifier of the downloaded file. |
| `filename`    | `string` | The name of the downloaded file.              |
| `contentType` | `string` | The MIME type of the downloaded file.         |

### Notes

* **Validates URLs Before Downloading**: Ensures the provided `link` is a valid file URL.
* **Supports Custom Filenames**: Users can specify a filename or rely on the original filename from the response.
* **Ideal for Automated File Retrieval**: Useful in workflows that require downloading and storing remote files.

This component is essential for workflows that need to automate file downloads from external sources for further processing.