I have a shopping cart which shows all the items in it, one per row. The items are pulled in from a data store but the values come from the database. I need to show the total at the bottom but don’t know how best to achieve this in Wappler.
I would normally create a variable and then add the line value to it so it is part of the loop.
How is that done in Wappler?
You can just use the sum formatter applied on the whole data store data to display the total.
That’s what I had previously but I’m now pulling the prices in from the database. The data store would make it too easy to change the figures.
What are you trying to achieve? To show the sum from the server action?
If yes, you can use the serverside formatter options to do this, then you can bind the data on the page.
I have rows which are a repeater which cycles through the records in my data store. Each row then pulls in the prices from the record which matches the product id in the data store. So I don’t have a server action which can simply provide the sum. I’ve created a variable in App Connect which holds the total. I want to add the price from each row to that variable so I end up with the total.
So if you just want to show totals on the page - why not do it as George explained and as it is explained in the tutorial?
Sorry, I am a little confused by your explanation.
Because that method is totalling the figures from the data store and this is easily edited by a visitor. I am now only using the data store to hold the product ID and quantity, everything else is coming from the database.
Don’t use the data store as a source for totals when paying.
Use it only for totals displayed to the users.
The totals for your payment should come from the server side and they should be passed to your payment provider API directly in the server action.
I think you misunderstood the whole idea of having prices client side and security.
You can perfectly display and sum prices to show to the user - no matter when they come from.
Just on checkout don’t pass prices but article id’s and do the final total of purchase server side.
OK, I’ll leave the cart as using the data store data and then re-calculate at the checkout stage once I’ve populated the order table.
Just for future info, how would I add up rows like I described? Something like this within the loop:
$total = $total + $itemprice
I think that this security problem is totally over exaggerated. Think about it.
Do you really think that this buyer would mess around with the data with such ID’s?
Even if it is the case that bogus details have been supplied and the Data Store has been fiddled with, there are possibilities to catch the thief down stream.
If the payment uses server side actions (such as with Stripe and Square), a flag can be raised to show the discrepancy and the payment can either be stopped or the correct values from the database can be inserted.
If the payment uses client side only (such as with PayPal - from memory), then the correct values can be placed in a temporary database table from where a total amount can be easily obtained.
I’ll keep using the Data Store for all - not just for ProductID and Quantity , it is a valuable addition to Wappler.
normally it won't. but consider this: buyer is on a unsecured wifi and the data packets are intercepted and altered with mid way to the server from the browser!
this is indeed a bit of a stretch. but then you can't secure anything enough.
stretching it beyond reason is how we grow, i guess!
Hi all
I’m not exaggerating the issue. Data Store is a TOP addition to Wappler and I am actively using it with great success. But I know that if I were to allow someone to place an order and edit the price then it will cause all kinds of problems. And once a vulnerability like this becomes known, it is spread online and more people will exploit it. So it’s in everyone’s interests to prevent it in the first place.
My solution is to leave the cart using Data Store as it’s incredibly quick and easy. Then, when they proceed to the checkout, the prices and other data is pulled in from the database. So even if the cart has been modified, they can’t pay with the reduced prices.
@nshkrsh - what you’ve suggested doesn’t sound like it could work if the site uses SSL (which all sites these days should) so I don’t think it’s an issue whether you use Data Store or other methods.
Can anyone answer my earlier question?
if you're trying to sum up data from variable within a repeat element. that logic won't work.
you'll have to do a SUM on the server connect item
OR
try this, not sure if this would work: have a variable on page level (outside the repeater) and from within the repeater, do this: varOnPage.setValue(varOnPage.value + varInRepeat.value). also, initialise varOnPage to 0.
Thanks @nshkrsh, I’ll give that a go.