long filenames can cause 500 exception

[stefanfoulis]

when trying to save the cached thumbnail database entry, it is possible that a 500 error is raised (because the 255 character limit may be exceeded at database level).

[zsoobhan]

As far as I can tell, this happens because the processors are allowed to make the filenames as long as they want to without going through any checks. Was there a workaround?

[stefanfoulis]

In my case it was simply avoiding long source filenames.
But there might be database backends that don't like charfields longer than 255. I'm not sure and my information might be outdated. But I remember having problems with that (many years ago). I think on mysql.

[zsoobhan]

Hmm, good point. I had a quick search of the supported database backends and found the following:

Backend	Support
Oracle 11.1	4000 bytes (1024 - 4096 chars)
Postgres 9.5	1 GB
MySQL	65,535 Chars

I'm not sure of the specifics for each versions of the database backends. On a side note, Django restricts the max_length of VARCHAR fields to 255 when used as unique fields which suggests that it might be best practice to leave it at that?

In any case, I wrote a quick .js script to validate the input from the user and upped the limit on the field since I am using Postgres, but I thought it would be good to have this information somewhere on the web. Here's the pull request: #414

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Sources

https://www.postgresql.org/docs/9.5/static/datatype-character.html
https://docs.oracle.com/cd/B28359_01/server.111/b28320/limits001.htm
http://dev.mysql.com/doc/refman/5.7/en/char.html
https://docs.djangoproject.com/en/dev/ref/databases/#character-fields