---
name: "DownloadTask.onHeadersReceived"
mode: "kit"
versionRequirements:
  - { name: "BaseKit", version: "2.0.1" }
platform:
  - "iOS"
  - "Android"
title: "DownloadTask.onHeadersReceived"
---

## DownloadTask.onHeadersReceived

> [VERSION] BaseKit >= 2.0.1

> [PLATFORM] iOS, Android

### Description

Listen for HTTP Response Header events. Fires earlier than the request completion event

### Parameters

`(listener: Function)`

| Parameter | Type | Required | Default | Description |
| --- | --- | --- | --- | --- |
| `listener` | `(params: Object) => void` | Yes | - | Event listener callback function |

##### DownloadTask.onHeadersReceived.listener(params) properties

| Property | Type | Required | Default | Since | Description |
| --- | --- | --- | --- | --- | --- |
| `header` | `Record<string, string>` | Yes | - | `2.0.1` | HTTP Response Header returned by the developer server |
| `requestId` | `string` | Yes | - | `2.0.1` | Network request ID |


### Examples

```tsx
// Listen for response headers: first use ty.downloadFile to get the download task handle, then register a headers listener on the handle.
const downloadTask = await ty.downloadFile({
  url: "https://airtake-public-data-1254153901.cos.ap-shanghai.myqcloud.com/ttttestfile/test_video.mp4",
});

downloadTask.onHeadersReceived(e => {
  console.log(e);
});
```