Archive for the ‘General’ Category

Facebook OAuth 2.0, HTTPS, Credits : Implications for developers

July 23, 2011 Comments off

Facebook is migrating to OAuth 2.0 (an open standard for authorization) and HTTPS to provide better security on the world’s largest social network. This has some implications for Facebook developers and users, and there are also some items of concern and others that require clarification.

As announced in May on the Facebook Developer Blog, by October 1, 2011, all Canvas apps on Facebook must have completed transition from the old Facebook authentication system and HTTP to the newer and more secure OAuth 2.0 and obtain an SSL Certificate.

Facebook released updated PHP and Javascript SDK’s to provide OAuth 2.0 support. There is a small snafu that after releasing the Javascript SDK, the PHP SDK which supposedly had OAuth 2.0 support didn’t work with the new cookie format so an updated one is to be released next week.

One of the ambigious requirements for developers is that they “obtain” an SSL certificate for Facebook Canvas and Page Tab apps. It’s not clear what “obtain” mean.

Are developers just to buy an SSL certificate and prove to Facebook that they bought one or are they required to host the Canvas or Page Tab app under HTTPS

Assuming developers have to host their apps under HTTPS, other questions which arise are

  • Will Facebook default to as well enforce HTTPS access for all users on Oct 1 ?
  • Will developers have to cater to both HTTP and HTTPS access to their apps ?
  • Will Facebook ‘map/redirect’ HTTP traffic to HTTPS ?

Whatever it means, Facebook app developers already have a lot on their plate: viral channels on Facebook are diminishing fast and users are getting more expensive to acquire every day. Additionally, the trend to spend more time on mobile channels results in a reduction of time spent on Facebook Canvas games (many of which are built using Flash/Unity and are thus not available on a large number of mobile devices).

Will these changes hurt small to medium developers in particular? SSL has a reputation of being expensive to deploy and, although a lot of work has been done recently to lower this cost, the software tuning and the know-how for high performance SSL stacks typically exist primarily in large corporations.

Advertising snags

Canvas apps can incorporate advertising from Facebook-approved providers, but unfortunately Google AdSense – which offers some of the best eCPM rates – is not one of them. A number of developers have been clamoring for Google AdSense to be included in Facebook’s list of approved ad providers, however nobody seems to be holding their breath waiting for Google and Facebook to come to an agreement.

To ensure a good user experience, all elements in a Canvas page will have to be served over HTTPS; to do otherwise will result in browsers popping up mixed-content warning dialogs that interrupt and bewilder many users.

Additionally, Google’s browser Chrome is moving toward blocking mixed scripting, which is likely to affect non-SSL advertisements on Facebook Canvas pages that are served over SSL.

Are advertising networks ready to serve ads over SSL ? Or will app developers be forced to find some other way to monetize their products if Facebook-approved ad providers are not able to serve ads over SSL?

What will be the impact on their costs if Facebook app developers are forced to use content delivery networks (CDNs) to serve assets over SSL ? Developers also need to be aware that name based virtual hosting is not possible over SSL unless browsers, SSL libraries and server stacks support Server Name Indication.

If Facebook requires developers to provide both HTTP as well as HTTPS access to Canvas apps then that will increase complexity and cost of deployment.

Facebook Credits and impact

Any company or person deploying a game on Facebook must already cope with the mandatory requirement of using Facebook Credits instead of a proprietary currency. Before the requirement to use Facebook Credits, companies offering games and apps via Facebook’s Canvas system would determine their own currency and product pricing, selecting third party payment providers of their choice. For example, a vendor like PayPal used to provide a payment gateway for your Facebook app for a few percent commission on every transaction. The commission on the (mandatory) Facebook Credits system is a whopping 30% on every transaction. So much for the cost advantages of a unified currency!

Facebook Credits provide a fairly liquid unified currency – and that’s good. What’s not so good is that this currency still has a substantial number of zero-value credits in circulation, and users who pay with these “free” credits provide no revenue whatsoever to developers.

Options ?

One option Facebook app developers can consider is to host the application outside of Canvas and use Facebook’s Graph API to access Facebook platform features. Given that Facebook’s own FBML is deprecated and that almost all Canvas apps today are in iframe, the Graph API workaround is relatively easy and does not constrain developers with various rules (including the need to have the app hosted under SSL).

The ability to use Facebook Credits is obviously not useful or available outside of Facebook Canvas but there are alternatives, including the upcoming Google In-App Payments for the Web (5% fee on every transaction). Perhaps the rise of Android will increase the proliferation of Google Checkout accounts and if Google could address the issue of increased mechanisms of adding funds to Google Checkout accounts this can be a good beginning for the much rumored Google+ Games

Categories: General

Google Checkout limited mechanisms of adding funds and its impact on monetizing freemium Android games

Mobile analytics firm Flurry has an interesting chart showing the rise of freemium games and its impact on the list of Top Grossing Games.

According to them, at the end of June 2011 65% of the revenue generated by the Top 100 Grossing games in the US App Store were freemium games. This is in large part due to Apple having access to over 200 million credit card on file. Apple also makes it convoluted to activate an iOS device without providing a credit card. There is also the ability to buy iTunes gift cards as well as link the iTunes account with Paypal

Compare this to the Android Market where Google provides in-app billing service via Google Checkout. Android usage is booming and activation requires a Google account. However there is no need to create or associate a Google Checkout account during activation.

Also, prior to it use for Android Market the only reason one would have funds in a Google Checkout account would be to pay for extra storage for Gmail or Picasa or buy a premium plan for Google Apps. That’s a fraction of the Android userbase.

If freemium gaming is going to be one of the big drivers for increased Android apps and particularly ports from iOS thereby  increasing usage of Google Checkout then it becomes very important to have lots of mechanisms to add funds to Google Checkout in a  relatively frictionless manner.

My personal example, I have handed down my old HTC Hero to my daughter and she has activated it with her own Google account but I can’t add any funds to her Google Checkout account which isn’t linked to a credit card.

Facebook has spent a lot of effort partnering with alternative top-up mechanisms and now Facebook Credit pre-paid cards are available in a ton of places particularly in South East Asia where credit card penetration is very low and there are established infrastructure for topping up funds to use for micro-transaction payment. Carrier billing is very expensive and this can easily be seen when buying Facebook Credits which cost 3x as much via mobile payments compared to walking to the neighbourhood shop and buying a scratch card.

Categories: General

PowerDNS does not as yet support GPD as an upstream forwarder

December 6, 2009 Comments off

My last post explained how Dan Bernstein’s dnscache could be used alongwith Google Public DNS (GPD) as an upstream forwarder.

For those who spend time with DNS, they are likely to be aware of Bert Hubert’s PowerDNS which comes in two flavours, an authorative nameserver and a recursive nameserver

PowerDNS currently hard-codes the RD (recursion desired) bit to 0 when it sends DNS packets to nameservers configured in its forward-zones/forward-zones-file configuration parameter. This makes it impossible for one to configure an open recursive nameserver such as GPD as a forwarder. There is a ticket open in PowerDNS about it and Bert has mentioned on the mailing list that he is close to making the changes to provide the required functionality. Maybe this feature might come in a future PoweDNS recursor release

Categories: General Tags: , ,

Combining DJB’s dnscache and Google’s Public DNS

December 6, 2009 2 comments

Most of the comments which I’m reading about Google Public DNS (GPD) performance centers around round trip latency from an end-users location to GPD’s resolvers vis-a-vis their network location and comparing the round trip time to their local ISP DNS cache. Ping time is only one part of the time taken for DNS resolution, one needs to factor in DNS resolution time also which can be affected by cache locality and sizing as well as how connected the requested authorative nameserver for the query is relative to the DNS resolver. IMHO, an effective way for setting up an office DNS cache is to setup a local caching nameserver such as Dan Bernstein’s dnscache and use GPD as an upstream forwarder.

Thus domains which are repeatedly asked are answered from your local dnscache and the long tail of domains can be answered by GPD which may have its in its cache because what may be infrequent for your organisation is frequent for someone else who is using GPD thus giving you the best of both worlds. Fast local caching, and a fast recursive resolver when you have no locally cached results.

I’m assuming that in the coming weeks, Google will reach out to a number of organisations who use anycast DNS such as Content Delivery Network operators (Akamai, Limelight, CDNetworks etc) and authorative DNS servers operators (Dynect,UltraDNS,DNSMadeEasy etc) and work out better network routing amongst them.

These instructions assume that you have setup dnscache as an external forwarding cache for your organisation.
Then run the following commands (asssumes that you have installed dnscache as per DJB’s setup. Ubuntu/Debian users may have to adjust paths if they use packages from these distributions

echo 1 > /service/dnscache/env/FORWARDONLY
echo '' > /service/dnscache/root/servers/@
svc -t /service/dnscache
Categories: General Tags: , ,

Using Google Public DNS in conjunction with DD-WRT/DNSMasq

December 5, 2009 2 comments

There has been a lot of buzz regarding Google Public DNS herafter called GPD.  Google’s instructions are designed for end users modifying their own computers.  I think GPD can be very useful if used in conjunction with a forwarding cache on a router. This is the mechanism I used on my Linksys WRT54GL running DD-WRT
v24 to combine using DNSMasq and use GPD’s provided IP addresses and as the upstream DNS.

I assume that you have enabled SSH access to the router so you can login via SSH and take backups of the old values of the upstream DNS

  1. SSH into your router and run cat /tmp/resolv.dnsmasq . Save the IP addresses listed somewhere in case you want to revert back
  2. Go to the Commands tab under Administration.
  3. In the Commands box paste the following:
  4. echo "nameserver
    nameserver" > /tmp/resolv.dnsmasq
    sleep 1
    killall -HUP dnsmasq
  5. Click Save Firewall (note: your WAN interface will be restarted)

Now, you can take advantage of the DNS caching on your router and misses on the routers DNS cache are sent to GPD for resolution. Note that websites which use CDN will now determine the closest node based on where the anycasted GPD addresses and  resolve to relative to your network.

In a future post, I’ll write about how GPD can be integrated as an upstream forwarder using dnscache and why PowerDNS recursor doesn’t support using an open resolver as an upstream forwarder at present

Categories: General Tags: , ,

Why I think Chrome is coming out of beta now

December 12, 2008 Comments off

There have been a lot of discussions, blog posts describing how Chrome is one of the shortest if not the shortest beta cycle from Google. Most of the discussion has centered around the business requirements from OEM of having a non-beta software for pre-installation. Whilst this is valid, in my opinion this pre-deployment would still take a while to go through since I expect the earliest manufacturers will start a new build will be after Chinese New Year (end of Jan) and subsequently with another QA cycle could be March-April before boxes with Chrome pre-installed show up in stores

In my opinion, Google wants to take advantage of the holiday season where everyone is visiting family and doing the usual “tech support”. A lot of early adopters would like to get their parents computer cleaned up and install alternative browsers. Google’s Chrome is clean and with the search box integrated nicely with the address bar would be very useful to many who don’t care about the lack of extensions.

I for one would really like for sites to actively discourage use of Internet Explorer 6 and push their users to alternatives such as Firefox, IE7, Chrome, Opera.

It will however be interesting to see how Chrome’s mechanism of being chatty with Google for its auto-suggestion may impact usage in markets where people have bandwidth limits.

Categories: General

The IT Crowd is side splittingly funny

December 11, 2008 Comments off

I’m having a great time watching Season 3 of the IT Crowd. I loved Season 1 and Season 2 and converted a lot of my colleagues to be watchers of the show.

Season 3 hasn’t disappointed so far and I had a great time watching Episode 3 with a brilliant moment when Moss recovers from his concussion and there is a Windows startup sound to signify his brain being “rebooted”

Categories: General, Humor

Explaining Velocix's value proposition for the technically inclined

July 22, 2008 Comments off

I was introduced to uber-smart hacker and phenomenally successful serial entrepreneur Adam Twiss who originally wrote ApacheBench whilst he was at Zeus and subsequently donated to the Apache Foundation.

Adam is the co-founder and CTO of Velocix which was formerly known as CacheLogic.

Velocix is well known for its hybrid P2P based CDN network and I was trying to get a better understanding of how things worked behind the scenes in order to evaluate its suitability for various projects at work.

This is really oversimplifying their value proposition but for a technical person I would say that Velocix basically can provide a constant backfill to a BitTorrent swarm should a client want to use BitTorrent as a content delivery protocol.

Obviously Velocix can do a lot more than the above but it was hard for me to extract the above value proposition which was interesting to me from their website.

Hopefully this blog post can get some Google karma and help prospective Velocix customers

Categories: General

Firefox 3 and its impact on servers particularly those serving static content

June 18, 2008 Comments off

Firefox 3 has been released and by all accounts there has been enormous uptake of this fine browser.

If you aren’t familiar with the browser, I would encourage you to visit Deb Richardson’s brilliant Field Guide to Firefox 3 which describes a number of key Firefox 3 features in a very accessible manner.

One thing I would like to mention is that Firefox 3 has improved connection parallelism. The default limit for concurrent connections per hostname has been increased from 2 to 6 which is similar to IE8. Details can be found in this bug report here and for the technically inclined these are the new defaults

pref(“network.http.max-connections”, 30);
pref(“network.http.max-connections-per-server”, 15);
pref(“network.http.max-persistent-connections-per-server”, 6);
pref(“network.http.max-persistent-connections-per-proxy”, 8);

Whilst the improved connection parallelism is one factor in improved page load performance, web server administrators who are currently serving content via Apache need to factor in increased concurrent connections from Firefox 3 and tweak their MaxClients setting appropiately.

If they are using Apache to serve static content, maybe they should consider switching to lighttpd and nginx for serving such content.

Google’s Steve Souder has a great roundup on Parallel Connections in this blog entry.

Categories: General, Mozilla

Twitter's use for SMS sending and receiving

June 7, 2008 Comments off

Hong Kong is unique in the sense that whilst we have insane mobile penetration of 154.4 %, there is a huge price difference between voice plans and SMS plans.

Depending on a third party long distance provider, it is actually cheaper to call up somebody and speak for a few minutes (HK-US charges are 7 cents/min and an SMS costs at minimum HK$ 2) and convey more than send a SMS to that person

Thus, I find Twitter’s SMS integration very useful. I tell my family members to sign up to Twitter and then also enable their mobile devices. In India, Twitter has a shortcode 5566511.

In HongKong, wifi access is very ubiquitous via the GovWiFi program as well as efforts by FON as well as PCCW, HongKong’s dominant telco provider so hopefully with the upcoming launch of the iPhone in Hong Kong it can help me by allowing me to have access to Twitter

Technorati Tags:
%d bloggers like this: