Richy's Random Ramblings – Page 51 – Random ramblings and ravings of Richy B

Paypal Express Checkout and Recurring Payments

February 4, 2009

Are you, like me, using Paypal Express Checkout for integration into your shopping cart/ecommerce site?
Are you, like me, utilising the Paypal Subscriptions (Recurring Payments) options to set up future payments?
Are you, like me, getting a blank page when you are trying to setup a Recurring payment (maybe using the PHP NVP kit) after clicking “Agree and Pay” on the “Review your payment” page of the Paypal sandbox or live site)?

If so, the problem may be because you are sending an “AMT” (Amount) of 0 to Paypal: I did this because I didn’t want to actually take any money now…

It appears this is a long standing issue with the SetExpressCheckout section and RecurringPayments on Paypal and to avoid the blank white page, you’ll need to just send a nominal amount (such as 0.01) for Paypal to process “now”. However, Paypal does charge you a 20p transaction fee on the live system, so you may need to adjust your entire Paypal Express Checkout integration.

Internal Server – Firewall workaround needed

February 3, 2009

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At work, we’re developing something on an internal server which is behind several firewalls and routers, but we need to allow a third party website (Paypal to be exact) to be able to connect to the web server.

It is nearly impossible for me to put this machine either on the public internet or make a hole in the firewall tables (basically, it’s behind our internal NAT providing router, which is then on a NATted firewalled building router, which is then on another NATted firewalled building providers router/VPN – and then the ISPs NATted firewalled router). As you can imagine, being behind 4 routers each with their own firewall configuration and us being unable to get the rules changes makes this a bit difficult.

However, along with the Linux based web server within our LAN, I do also have a remote Linux server with spare IPs. But how can I setup a connection so that the 3rd party can go to http://testdomain.myserver.example.com which then connects to my remote Linux server which then, somehow, connects to the LANed server.

We can make as many outbound connections on whichever ports we like from our LAN (so I can connect the LAN server to the remote server), but then how do I do the connection and how do I then forward the requests inbound?

Any ideas?

Net: Shortest Valid Domain Names

January 22, 2009

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For the system I’m building, I’m putting in a check for valid domain names (technically URI/URLs) and one of the checks is for the length of the domain name. So what is the shortest domain name around?

Well, I suspect in the uk it’s the British library at bl.uk [5 characters] and in the .com range I suspect it’s Paypal’s x.com [6 characters], but an article on Valleywag has just altered me to the fact that Google has one of the shortest Chinese domain names g.cn [4 characters] and Ulster Television has u.tv, but even those are beaten by both the Western Samoa top level domain name has a website making ws [2 characters] and the Vatican’s va [2 characters] – making them the shortest domain name I’m aware of.

Why have some of them got full stops at the end of the links ( such as http://ws. and http://va. ): it’s to stop your browser trying to “fix the links” and change them to http://ws.com and http://va.com which are different sites.

The answer to the question of “how short can a domain name be” is currently 2 characters (unless a top level domain is started with less than 2). A full web based URI/URL has a minimum length of 9 (4 for the protocol ‘http’, 3 for the protocol separation ‘://’ and then 2 for the domain/host name). Of course, you could also use the FTP protocol which brings it down to 8 or be pedantic and insist the shortest web orientated URL is http://va.:80/ at 14 characters.

Game: Zilch – Don’t get nothing!

January 18, 2009

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Just my luck, just when I think I’ll spend a weekend doing work, I find another addictive Flash game online! Zilch is a basic game where you score points by rolling dice (very similar to Yahtzee), with the aim of getting 10,000 points. However, if you fail to score 3 times in a row (scoring nothing means you get “Zilch”), you lose another 500 points.

Quite a fun game trying to decide whether to “Bank” (which you can only do once you have 300 points) or rolling again and risk losing everything (but standing to gain a few more hundred or even thousand points).

Google Transit Maps

January 16, 2009

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Cool – I’ve been thinking about something like this for a couple of days ago, and Google has just announced nearly what I was thinking: a transit/transport map of London showing where the tubes/lines actually go so you can easily plot alternative routes from not being underground – see London’s map.

Now they just need the following options and they’ve saved me a development job:
* Distance between stations: yes, I can see Regent Street is an inch away from Great Portland Street by “the crow flies”, but I’ve still got to do the conversion using the manual scale. If I could just click on “Great Portland Street” and get a list of “Walking distance to nearby stations: Regent Street 0.5miles (10 minutes), Euston Square 1mile (20 minutes)” etc it’ll be brilliant.
* Alternative routing. I travel from Harrow on The Hill to Great Portland Street, so what are the routes I could take (Metropolitan Line from HOH to GPS, Metropolitan to Wembley Park then Jubilee to Baker Street then Metropolitan/Circle/Hammersmith to GPS, Walk to Harrow and Wealdstone and then catch overground to Euston…): perfect if a line or station is closed (as has happened with the Metropolitan and Great Portland Street several times this year. If it includes additional distance travelled/time needed, it’ll be perfect.