Episerver and Page Languages

We’ve been doing some work recently using EpiServer, extending it to fit our needs, to support our new website look which is one of many new features coming soon. Having website content in more than one language reflects the international coverage that Esendex has.

We ran into a bug today which initially wasn’t easy to spot where adding a Page Language to an existing page was causing EpiServer to hang as it entered an endless loop of calls to a stored procedure called ‘netPropertySearchStringMeta’.

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Stored procedure error handling in SQL Server 2000

Today, we’re continuing work on our multipart message aggregation upgrade for a future Esendex release.

One part of the investigations this morning has been looking into how we manage the database access as we add parts of an incoming message to it for later processing. As we have multiple servers processing inbound messages, there was the potential for two threads trying to write to the database simultanously with different parts of the same message. Both could look at the database and think there were no existing parts of a multipart message, and decide to try and insert a new multipart message record.

During this work we found out that SQL Server 2000 will still raise an SQLException error despite error handling put in T-SQL.
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Credit card regular expressions

Following on from my previous post about credit card authentication with regular expressions, I thought I’d share my other discovery.
The BIN Ranges list I found showed a list of Visa cards which were designated ‘ATMOnly. Figuring these would be a good thing to filter out during validation.
There’s plenty of regular expression help about joining pattern matches with logical OR clauses, but what about wanting to specify patterns which prevent certain things coming through?
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Maestro, music please

We’ve been working on a change request to add Maestro to the credit cards that we accept for ecommerce payments. Switch started in 1988 but has now merged with the Maestro network owned by MasterCard in the UK.

Until recently, if you took Switch payments then UK customers who had new Maestro cards would still be ok (as long as you accepted the new 6759 prefix for your payments) however with the merging of the worldwide card base there’s a whole new set of card numbers which need validating.

A quick search on 18-digit Maestro cards that HSBC have been issuing raised a few e-commerce shopping cart forums where people were confused about these new card types. So I thought I’d share my findings:
Continue reading Maestro, music please

Credit card validation

We’ve been updating the e-commerce side of the website to work with Maestro cards in the near future. As a result, I’ve had my first delve into card processing and some of the simple techniques that you can use to validate a card before submitting details to a bank / online card processing service.

The strange sounding Luhn Algorithm is used as a quick checksum of the credit card digits (and a few other things) and will detect most transposed digits. Continue reading Credit card validation