search as a hash

[eluser]thurting[/eluser]
Hi,

I notice that the search feature on this forum seem to store the queries in a hash table and present the hash in the result URL. I was wondering if anyone could give me insight into why this is done? Thanks.

[eluser]Alex007[/eluser]
It's a pretty common way of doing a search script, when a user submits a search, you store the results in a table, along with a unique search ID.

That way, when the use goes back and forth in your search results pages, there's no load on the database, you just return a different range of the already-known results.

Otherwise that would mean you'd have to search again everytime, and discard the first x results according to the current page.

From time to time you clean up the old search results, with a CRON job or as a part of your search script.

[eluser]Derek Allard[/eluser]
Additionally, if the string is hashed, you can submit anything into it, including characters that normally wouldn't make it through the xss screening of CI, such as % signs and "stuff"

[eluser]thurting[/eluser]
Ok. I see - def. helpful to permit disallowed chars and decrease the load on the server. A couple of questions though...

In what format do you store the results? I imagine that for a large database storing the entire recordset may take up a lot of space.

If you store the results in a table, then they are no longer dynamic. Can't a problem arise if a user bookmarks a search page and returned to it later - there is a potential they will not see any relevant results that may have been created after the initial search.

Otherwise that would mean you’d have to search again everytime, and discard the first x results according to the current page.

Why is this? Can't you just use a LIMIT based on variable that holds current page value?

Thanks.

[eluser]CodeOfficer[/eluser]
I asked this question once before and got squat for an answer. Thanks for clarifying derek and alex. I would also love to see thurting's last few questions answered if you could elaborate more. Thx so much!

[eluser]Michael Wales[/eluser]
It does cause some issues - try searching for a term and then passing the URL off to a friend - they can't access it.

Personally, I think a hashing and comitting the results to a database is a good solution for a 24 hour timespan (depending on how active your forum is). But, the search controller needs to query the database for that search term and/or the hash and share it amongst all users - not just the one that searched for the term.