This plugin is marvellous: it allows the importer to check the correctness of the math blocks, sending them to the restbase service of wikitolearn.org .
Unfortunately this requires a huuge number of requests to the restbase service, and this takes time (a couple of equations per second when it is fast). The problem is that as soon as the connection has a slight problem, the connection to the restbase service times out, and texla crashes, without keeping a cache of the checked equations.
One solution may be building a cache of the checked equations, but I understand that this may be hard.
Another solution, proposed by @tomaluca, is changing the server that we use to check the math. We may use a local installation of WTL for checking it.
At the current stage, it seems that the only reference to the server that runs restbase in math_check_online is in `./texla/Renderers/plugins/math_check_online.py` and it is
url_check = 'http://restbase.wikitolearn.org/pool.wikitolearn.org/v1/media/math/check/tex'
I tried changing it into
url_check = 'http://restbase.tuttorotto.biz/pool.tuttorotto.biz/v1/media/math/check/tex'
and, with a running local environment of WTL, it works.
The problem is that this requires an intenet connection to resolve tuttorotto.biz, and this does not sove the problem, we are still dependent from the internet connection, which may have troubles.
I tried changing that line into
url_check = 'http://127.0.0.1/127.0.0.1/v1/media/math/check/tex'
But again this does not work offline. Understanding why is a bit harder now, and i have not found the cause yet.
I have pasted the errors that texla spits out [here](https://arin.ga/xPC4nR) .
The problem may be that there still is some rference to `wikitolearn.org` somewhere, but I do not know where.
requests.packages.urllib3.exceptions.MaxRetryError: HTTPSConnectionPool(host='www.wikitolearn.org', port=443): Max retries exceeded with url: / (Caused by NewConnectionError('<requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x7f6f252ebc50>: Failed to establish a new connection: [Errno -2] Name or service not known',))
It would be very nice to solve this problem, since it would:
* make the math check more stable (not dependant on the stability internet connection)
* speed the math checking
EDIT: I tried changing the `/etc/hosts` file adding there the resolution of the `www.wikitolearn.org` domain adding athe end of the file
127.0.0.1 www.wikitolearn.org wtl
but this does not works, since there are some problems with the certificates, you can see them [here](https://arin.ga/QJwM0Z)