downloads.download()

downloads API の download() 関数ではURLとそのほかのオプションの設定を行うことでファイルのダウンロードをすることができます。

• HTTPもしくはHTTPSのプロトコルを使用したURLを指定した場合、対象のホスト名に対応する全てのcookieを含んだリクエストが送られます。
• filename と saveAs が指定されている場合、指定されたfilenameが設定された[名前をつけて保存]のダイアログが開きます。

この関数は非同期に実行され、Promiseを返します。

構文

var downloading = browser.downloads.download(
  options                   // object
)

パラメータ

options

このobjectではダウンロードしたいファイルやその他のダウンロードに関する設定を指定します。指定できるプロパティは以下です。

bodyOptional

リクエストのbodyをstringで指定します。

conflictActionOptional

A string representing the action you want taken if there is a filename conflict, as defined in the downloads.FilenameConflictAction type (defaults to "uniquify" when it is not specified).

filenameOptional

A string representing a file path relative to the default downloads directory — this provides the location where you want the file to be saved, and what filename you want to use. Absolute paths, empty paths, and paths containing back-references (../) will cause an error. If omitted, this value will default to the filename already given to the download file, and a location immediately inside the downloads directory.

headersOptional

An array of objects representing extra HTTP headers to send with the request if the URL uses the HTTP[s] protocol. Each header is represented as a dictionary object containing the keys name and either value or binaryValue, restricted to those allowed by XMLHttpRequest.

incognitoOptional

A boolean: if present and set to true, then associate this download with a private browsing session. This means that it will only appear in the download manager for any private windows that are currently open.

methodOptional

HTTP[S]を使用したURLを指定した際、HTTPメソッドをstringで指定します。GETもしくはPOSTを設定できます。

saveAsOptional

A boolean that specifies whether to provide a file chooser dialog to allow the user to select a filename (true), or not (false).

If this option is omitted, the browser will show the file chooser or not based on the general user preference for this behavior (in Firefox this preference is labeled "Always ask you where to save files" in about:preferences, or browser.download.useDownloadDir in about:config).

url

ダウンロードするURLをstringで指定します。

戻り値

Promiseが返却されます。ダウンロードが成功した場合、new downloads.DownloadItemのidが格納されたpromiseを受け取ります。対して、promiseがrejectされた場合は、エラーメッセージを受け取ります。

ブラウザ実装状況

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

例

以下のダウンロードの例ではファイル名と保存場所を指定し、conflictActionにuniquifyを指定しています。

function onStartedDownload(id) {
  console.log(`Started downloading: ${id}`);
}

function onFailed(error) {
  console.log(`Download failed: ${error}`);
}

var downloadUrl = "https://example.org/image.png";

var downloading = browser.downloads.download({
  url : downloadUrl,
  filename : 'my-image-again.png',
  conflictAction : 'uniquify'
});

downloading.then(onStartedDownload, onFailed);

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