Better handling of updated items

[mbonetti]

As of now Gregarius checks for updates by comparing the length of the "description" field in the feed agains the stored length. This is far from optimal.

Olivier suggests we compute an MD5 hash for each description and store it in the database.

He sent me the patch below.

Personally I'm happy with how it's done right now, but we shall track this issue in this ticket.

[mbonetti]

Modifies the schema to store an md5 hash of each item's description

[mdodoo]

I like the use of md5 to check if the description has changed, but I am not sure that it needs to be stored in the database. Are there compelling reasons against Gregarius generating md5 hashes of the 'old' description on-the-fly?

[mdodoo]

Also, the current "update" check looks like it will not be tripped if the new description is shorter than the existing one.

[oruffin]

First reason to store MD5 in DB is performance: no need to recalculate each time the MD5 of the DB stored description. Also we can imagine that some plugin in the future change the content of the description before storing it (or is it already like that today?) and if so, it would mean that if we don't store MD5 of the "raw" text, then each time we would have to apply all plugins to new text and then build an MD5 to see if it's match or not... Would be really really not nice;)

[sdcosta]

Fixed in [1155]