# DownloadItem

> Control file downloads from remote sources.

`DownloadItem` is an `EventEmitter` that represents a download item in Electron.
It is used in `will-download` event of `Session` class, and allows users to
control the download item.

```javascript
// In the main process.
win.webContents.session.on('will-download', (event, item, webContents) => {
  // Set the save path, making Electron not to prompt a save dialog.
  item.setSavePath('/tmp/save.pdf')

  item.on('updated', (event, state) => {
    if (state === 'interrupted') {
      console.log('Download is interrupted but can be resumed')
    } else if (state === 'progressing') {
      if (item.isPaused()) {
        console.log('Download is paused')
      } else {
        console.log(`Received bytes: ${item.getReceivedBytes()}`)
      }
    }
  })
  item.once('done', (event, state) => {
    if (state === 'completed') {
      console.log('Download successfully')
    } else {
      console.log(`Download failed: ${state}`)
    }
  })
})
```

## Events

### Event: 'updated'

Returns:

* `event` Event
* `state` String

Emitted when the download has been updated and is not done.

The `state` can be one of following:

* `progressing` - The download is in-progress.
* `interrupted` - The download has interrupted and can be resumed.

### Event: 'done'

Returns:

* `event` Event
* `state` String

Emitted when the download is in a terminal state. This includes a completed
download, a cancelled download(via `downloadItem.cancel()`), and interrupted
download that can't be resumed.

The `state` can be one of following:

* `completed` - The download completed successfully.
* `cancelled` - The download has been cancelled.
* `interrupted` - The download has interrupted and can not resume.

## Methods

The `downloadItem` object has the following methods:

### `downloadItem.setSavePath(path)`

* `path` String - Set the save file path of the download item.

The API is only available in session's `will-download` callback function.
If user doesn't set the save path via the API, Electron will use the original
routine to determine the save path(Usually prompts a save dialog).

### `downloadItem.pause()`

Pauses the download.

### `downloadItem.isPaused()`

Returns whether the download is paused.

### `downloadItem.resume()`

Resumes the download that has been paused.

### `downloadItem.canResume()`

Resumes whether the download can resume.

### `downloadItem.cancel()`

Cancels the download operation.

### `downloadItem.getURL()`

Returns a `String` represents the origin url where the item is downloaded from.

### `downloadItem.getMimeType()`

Returns a `String` represents the mime type.

### `downloadItem.hasUserGesture()`

Returns a `Boolean` indicates whether the download has user gesture.

### `downloadItem.getFilename()`

Returns a `String` represents the file name of the download item.

**Note:** The file name is not always the same as the actual one saved in local
disk. If user changes the file name in a prompted download saving dialog, the
actual name of saved file will be different.

### `downloadItem.getTotalBytes()`

Returns a `Integer` represents the total size in bytes of the download item.
If the size is unknown, it returns 0.

### `downloadItem.getReceivedBytes()`

Returns a `Integer` represents the received bytes of the download item.

### `downloadItem.getContentDisposition()`

Returns a `String` represents the Content-Disposition field from the response
header.

### `downloadItem.getState()`

Returns current state as `String`.

Possible values are:

* `progressing` - The download is in-progress.
* `completed` - The download completed successfully.
* `cancelled` - The download has been cancelled.
* `interrupted` - The download has interrupted.