Migration from the old page? about qed HOT 17 CLOSED

Oops, I had not foreseen this consequence of migrating the file. Strangely, when I go to the old URL on chrome and it gets redirected, it seems that my progress has been saved (not sure how that works, some quirk of local storage?).

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If I read the discussion at https://stackoverflow.com/questions/12489999/response-redirect-kills-local-storage correctly, it seems that if one lingers on the original page long enough for local storage to load, then when one is redirected, all the storage (i.e., progress on the text) is saved. It's clunky, but perhaps that is enough of a workaround for now...

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@TTimo can you try it again now, waiting the full amount of time for it to redirect? The "redirect" part of the QED.html file wasn't present for the past couple hours (by mistake I believe).

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Tried again .. still the same. I load http://www.math.ucla.edu/~tao/QED/QED.html, give it plenty of time, then click on the link at the top (https://teorth.github.io/QED) and end up at the new page but with none of my progress.

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Oh, I thought you were referring to the automatic redirect change last night from--
http://teorth.github.io/QED/QED.html to
http://teorth.github.io/QED/
I did confirm that works on Mac with Firefox.

For the old ucla.edu page, maybe something can be done on that page to permit transferring the data -- I'm not sure.

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I've tried replacing the http://www.math.ucla.edu/~tao/QED/QED.html page with a copy of the redirect page at http://teorth.github.io/QED/QED.html . Strangely, it does not seem that the local storage copied over this time (but perhaps this is because I already have some local storage for the new page?).

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Someone could try "resetting" on the target page to clear out their local storage there, but I'm guessing local storage doesn't propagate cross-domain by default for security reasons. There is probably a way to do it, but I'm guessing not straightforward.

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Yeah, I just tried resetting and it does indeed seem that localstorage doesn't propagate from one domain to another. There may be a way to export the localstorage keys to some file that one can then import to another page, perhaps.

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OK, after using the answer at this page https://stackoverflow.com/questions/13335967/export-data-in-localstorage-for-later-re-import I found a way for a user to move over the data manually, though it is a bit tricky. I put the instructions on the old page http://math.ucla.edu/~tao/QED/QED.html - they worked for me, hopefully they work for you also!

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The procedure worked! Thanks!

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To make it a bit more convenient/easy to use, you could do something like this:

function import_export() {
  let input = window.prompt('Import/Export', JSON.stringify(window.localStorage));
  if (input !== null) {
    new_data = JSON.parse(input);
    for (i in new_data) { // for in loop should'nt be a problem in this case
      window.localStorage.setItem(i, new_data[i]);
    }
  }
}
import_export();

You could add this as a button to both the old and the new page:

<button onclick="import_export();">import/export</button>

To export, you would click the button, copy the text in the text field (ctrl-a), and press cancel (or ok, doesn't matter, really).

To import, you would click the button, paste the text (possibly replace the old text), press ok, and refresh.

e: forgot to mention refreshing

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I've implemented this suggestion now. Actually it is also a useful tool for debugging (I've needed to reset the text a few times and it was a pain to restore all the previous progress; now I can just save the state to an external text file and restore when needed.)

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Unfortunately I found an annoying issue with the button for editing localstorage: it seems that (in Chrome at least) the window.prompt string input can only be up to about 2000 characters in length before it starts truncating the string with ellipses, making it useless for copy/paste purposes once the local storage gets decently large. Not yet sure what the best fix is (simplest would be to have direct access to the clipboard, but not sure if the javascript sandbox actually has permission to do this).

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You could perhaps also do something like use a text area to transfer the text to and from instead of a prompt box.

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I didn't know Chrome had a limit. Firefox doesn't appear to and MDN doesn't specify any limit.

Unless <input type="text"> also has a maximum length (I tested a length of ~4000 with Chromium 68), this works as a PoC (don't know about bootstrap, have never used it).

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Thanks, I think I managed to implement this code successfully.

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