491f0cd08a
* Copyright headers 1 * Licence headers 2 * Copyright Headers 3 * Copyright Headers 4 * Copyright Headers 5 * Copyright Headers 6 * Copyright headers 7 * Add copyright headers for html and config file * Replace license files and update package.json * Update with CLA * lint
97 lines
3.1 KiB
TypeScript
97 lines
3.1 KiB
TypeScript
/*
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Copyright 2024 New Vector Ltd.
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Copyright 2021 The Matrix.org Foundation C.I.C.
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SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only
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Please see LICENSE files in the repository root for full details.
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*/
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export type GetIframeFn = () => HTMLIFrameElement | null;
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export const DEFAULT_STYLES = {
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imgSrc: "",
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imgStyle: null as string | null, // css props
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style: "",
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textContent: "",
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};
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type DownloadOptions = {
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blob: Blob;
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name: string;
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autoDownload?: boolean;
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opts?: typeof DEFAULT_STYLES;
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};
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// set up the iframe as a singleton so we don't have to figure out destruction of it down the line.
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let managedIframe: HTMLIFrameElement;
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let onLoadPromise: Promise<void>;
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function getManagedIframe(): { iframe: HTMLIFrameElement; onLoadPromise: Promise<void> } {
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if (managedIframe) return { iframe: managedIframe, onLoadPromise };
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managedIframe = document.createElement("iframe");
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// Need to append the iframe in order for the browser to load it.
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document.body.appendChild(managedIframe);
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// Dev note: the reassignment warnings are entirely incorrect here.
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managedIframe.style.display = "none";
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// @ts-ignore
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// noinspection JSConstantReassignment
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managedIframe.sandbox = "allow-scripts allow-downloads";
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onLoadPromise = new Promise((resolve) => {
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managedIframe.onload = () => {
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resolve();
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};
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managedIframe.src = "usercontent/"; // XXX: Should come from the skin
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});
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return { iframe: managedIframe, onLoadPromise };
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}
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// TODO: If we decide to keep the download link behaviour, we should bring the style management into here.
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/**
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* Helper to handle safe file downloads. This operates off an iframe for reasons described
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* by the blob helpers. By default, this will use a hidden iframe to manage the download
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* through a user content wrapper, but can be given an iframe reference if the caller needs
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* additional control over the styling/position of the iframe itself.
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*/
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export class FileDownloader {
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private onLoadPromise?: Promise<void>;
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/**
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* Creates a new file downloader
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* @param iframeFn Function to get a pre-configured iframe. Set to null to have the downloader
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* use a generic, hidden, iframe.
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*/
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public constructor(private iframeFn?: GetIframeFn) {}
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private get iframe(): HTMLIFrameElement {
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const iframe = this.iframeFn?.();
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if (!iframe) {
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const managed = getManagedIframe();
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this.onLoadPromise = managed.onLoadPromise;
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return managed.iframe;
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}
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this.onLoadPromise = undefined;
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return iframe;
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}
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public async download({ blob, name, autoDownload = true, opts = DEFAULT_STYLES }: DownloadOptions): Promise<void> {
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const iframe = this.iframe; // get the iframe first just in case we need to await onload
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if (this.onLoadPromise) await this.onLoadPromise;
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iframe.contentWindow?.postMessage(
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{
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...opts,
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blob: blob,
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download: name,
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auto: autoDownload,
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},
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"*",
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);
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}
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}
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