noVNC/core/clipboard.js

85 lines
2.7 KiB
JavaScript

export default class Clipboard {
/**
* @type {string}
*/
_remoteClipboard
constructor(target) {
this._target = target;
this._eventHandlers = {
'copy': this._handleCopy.bind(this),
'paste': this._handlePaste.bind(this)
};
// ===== EVENT HANDLERS =====
this.onpaste = () => {};
}
// ===== PRIVATE METHODS =====
_handleCopy(e) {
this._remoteClipboard = e.clipboardData.getData('text/plain');
this._copy(this._remoteClipboard)
}
/**
* Has a better browser support compared with navigator.clipboard.writeText.
* Also, no permission required.
*/
_copy(text) {
const textarea = document.createElement('textarea');
textarea.innerHTML = text;
document.body.appendChild(textarea);
textarea.select();
const result = document.execCommand('copy');
document.body.removeChild(textarea);
}
/**
* @param {ClipboardEvent} e
*/
_handlePaste(e) {
if(!this._isVncEvent()){
return;
}
if(e.clipboardData){
const localClipboard = e.clipboardData.getData('text/plain');
if(localClipboard === this._remoteClipboard){
this._pasteVncServerInternalClipboard();
return;
}
this.onpaste(localClipboard);
}
}
/**
* The vnc server clipboard can be non ascii text and server might only support ascii code.
* In that case, localClipboard received from the vnc server is garbled.
* For example, if you copied chinese text "你好" in the vnc server the local clipboard will be changed to "??".
* If you press Ctrl+V, the vnc server should paste "你好" instead of "??".
* So, we shouldn't send the local clipboard to the vnc server because the local clipboard is garbled in this case.
*/
_pasteVncServerInternalClipboard(){
this.onpaste("", false);
}
_isVncEvent(){
const isTargetFocused = document.activeElement === this._target;
return isTargetFocused;
}
// ===== PUBLIC METHODS =====
grab() {
if (!Clipboard.isSupported) return;
this._target.addEventListener('copy', this._eventHandlers.copy);
// _target can not listen the paste event.
document.body.addEventListener('paste', this._eventHandlers.paste);
}
ungrab() {
if (!Clipboard.isSupported) return;
this._target.removeEventListener('copy', this._eventHandlers.copy);
document.body.removeEventListener('paste', this._eventHandlers.paste);
}
}
Clipboard.isSupported = (navigator && navigator.clipboard) ? true : false;