Auto copy-paste with navigator.clipboard API

[akamos]

Hi!
I added the automatical copy-paste function that is available through the navigator.clipboard API in some browsers (e.g. Google Chrome) as mentioned earlier in PR #1174.

Co-authored-by: bulldozier [email protected]

[samhed]

I have yet to test this, but if this is something Chrome specific, we could do with some comments in the code.

[samhed]

I took some time today for testing this. I have tested both Chrome 66 and Chrome 78 on Linux, and Chrome 77 on Windows 10. Things didn't work in any of the browsers, navigator.clipboard was undefined in all cases. Am I missing something?

[akamos]

I don't know how you run the tests, but clipboard is for me defined in normal desktop environment of Chrome 78 on Windows 10 and Chrome 75 on Windows 7.

EDIT: It works only with HTTPS.

[samhed]

EDIT: It works only with HTTPS.

Ah, that's probably it. I'll retest with HTTPS when I have the time

[ericfranz]

Both navigator.clipboard and navigator.clipboard.writeText are defined in Firefox. But Firefox does not support this, so every interaction in NoVNC that invokes writeLocalClipboard will result in the Log.Error being sent to the console. If you do something like below, you can avoid polluting the console when querying the clipboard-write permission would result in a type error:

     writeLocalClipboard(text) {
-        if (typeof navigator.clipboard !== "undefined" && typeof navigator.clipboard.writeText !== "undefined") {
-            navigator.clipboard.writeText(text).then(() => {
+        if (typeof navigator.clipboard !== "undefined" && typeof navigator.clipboard.writeText !== "undefined"
+            && typeof navigator.permissions !== "undefined" && typeof navigator.permissions.query !== "undefined"
+           ) {
+            navigator.permissions.query({name: 'clipboard-write'})
+            .then(() => { return navigator.clipboard.writeText(text) })
+            .then(() => {
                 let debugMessage = text.substr(0, 40) + "...";
                 Log.Debug('>> UI.setClipboardText: navigator.clipboard.writeText with ' + debugMessage);
-            }).catch(() => {
-                Log.Error(">> UI.setClipboardText: Failed to write system clipboard (trying to copy from NoVNC clipboard)");
+            }).catch((err) => {
+                if(err.name !== 'TypeError')
+                    Log.Error(">> UI.setClipboardText: Failed to write system clipboard (trying to copy from NoVNC clipboard)");
             });
         }
     },

[ericfranz]

Another problem with this approach that needs to be addressed is that it makes a preexisting issue worse. Copy to the system clipboard >10232 bytes and paste into the clipboard input field and you will get a RangeError: Invalid typed array length, because that would exceed the queue buffer size for a message (the text + 8 chars for buffer):

noVNC/core/websock.js

Line 35 in 84a8c1b

this._sQbufferSize = 1024 * 10; // 10 KiB

In Chrome with this PR the problem is made worse due to the automation because if you just copy to the system clipboard >10232 bytes the NoVNC browser tab will immediately display the RangeError. Reload the page and you will get the RangeError again.

[samhed]

Let's continue this on #1347