Description:
I am creating comment/reply functionality to a web app that I built. I have a post that I want to link these comments too. To decrease spam and encourage community involvement I want to implement a voting system on each comment/reply.
Problem:
I know how to set up the database and I know how to show upvotes/downvotes. The only thing I don’t know what to do is to keep the vote… voted even if the user refreshes the page. I don’t want a user to be able to vote up more than once on a single post. Something like the voting on this site, it tracks that you have already voted with a yellow upvote.
What I have thought of:
- Place post id in cookie with the user_id appended to it. A simple check of the cookie can stop the user from voting again
- Place a unique constraint in table post id… but this is where I get confused. Should I have a separate table just for voted posts? Database schema idea ( I think ) here: https://stackoverflow.com/a/12350981/185672
- Keep all the ids in a session array and check against all voted on ids… but that would get huge.
- Combination of cookie and database to reduce number of db calls.
In the future there may be 1000s of votes cast by a single user.
edit:
I figured out that storing the results in a database is a must. How can I check for every reply/comment if the user has valid voting privileges without making 1000s of calls?
Resources:
Helped with some further spamming problems, but didn’t answer initial question:
https://stackoverflow.com/a/2333085/185672
Old solution that explains how to count votes but not keep the “upvote” checked.
http://www.9lessons.info/2009/08/vote-with-jquery-ajax-and-php.html
Bonus question:
If you guys know of a great script that can allow me to sync up a commenting system ( with votes ) into my already built app?
Also, I tried to find duplicates, but I just can’t.
Yeah, just keep a separate table to track user votes. Since you know which user is requesting the page, you can easily join the votes table to determine the current user’s eligibility to vote on each post on the page. For each post, if they’re eligible, output one version of html, if they’re not then output another.
Once the ajax request asks for the php file that does the vote, you can then check once more that that user is eligible to vote – I.e they’re changing their vote, or they haven’t voted before.
Take yahoo’s news stories for example – when you request a page that you’ve made a comment on, your own comment has disabled voting buttons. With some hacking of the page inside the browser’s dev tools, you can enable the buttons. You can even click on them and vote for your own post – though only once.
So, you can see that they got 2/3rds of it right, and output html based on the user’s eligibility to vote. They also prevent multiple voting (server-side), they just don’t do a server-side check to ensure you’re not voting for your own comment.
Stack Overflow on the other hand, always shows the same html – but when you click to vote for your own comment, the server-side code baulks at the idea and the response is basically ‘bugger-off! you can’t do that’ having received a negative result from the server, the javascript on the page pops up the message, rather than updating the vote count.