After floundering a bit with the WPF Dispatcher I've come up with a simple way to make sure an event handler executes on the UI thread without paying the overhead of always invoking a delegate.

This has the benefit (for me at least) of being very easy to remember. Hook up the event handler and then if there's a chance it could be called from a different thread wrap it using the pattern above. It's easier to read than an anonymous delegate and much faster than defining a specific delegate for the event in question.

I haven't tested the various methods to see which is the fastest yet… will get round to this at some point.

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(Published to the Fediverse as: Use WPF Dispatcher to invoke event handler only when needed #code #wpf #tips How to Invoke or BeginInvoke an event handler to the UI thread using the WPF Dispatcher. )

5. Validation

The metadata required to use the like button looks like this:

[code:html]

[/code]

But the property attribute isn't valid html or xhtml. The “Open” Graph Protocol says that it's inspired by Dublin Core. DC manages to get by using the name attribute like any other meta tag - why can't Open Graph? It's not the worst problem but it just seems needlessly irksome. Facebook has published a presentation describing their design decisions. This would be great, but it's in that Lessig one word per slide style and so it's attractive but completely useless without the presenter.

4. Fragility

Facebook's documentation is frustratingly sparse. For example you need to specify the owner of the page using a Facebook ID, and once you've chosen a name for your profile this is hard to find. The information vacuum has been filled with many erroneous blog posts saying to use the name, or some number from a shared photo (the best source is http://graph.facebook.com/robert.ellison, substituting your own username). Once you've got the admin ID wrong, you can't correct it - the first admin specified is fixed forever. What happens if a site is hacked and a bad actor sets themselves up as the admin? Surely something like the Google Webmaster Tools authentication scheme could have been used instead?

3. Pages with more than one object

Describing the object being liked in the head element limits you to one object per page. For some sites this is perfect, but what about a blog where you have many posts on the home page? It would be useful to have a like button per post, pointing at the permalink for the post in question. I've worked around this by having a like button for the blog on the home page, and a like button for each post on the post pages. Not ideal. I'm using the iframe version of the gadget, possibly there's some more flexibility with the XBML variant.

2. Duplicating existing pages

Let's say you've spent the past couple of years building up a Facebook page for your site/band/blog/movie and have thousands of fans. When you click your new like button for the first time you create a whole new page. There's no way to tell the like button about the existing page or the existing page about the like button. You now have at least two pages to worry about managing and potentially many, many more. You're also starting from scratch on the ‘like’ count, so even if your brand is already popular on Facebook it's back to Billy no-mates for you.

I can't believe this won't be fixed at some point. As with admin authentication above there must be a better way to establish ownership of various objects in the social graph.

1. Vocabulary

For better or worse Facebook has the inexorable pull to start making the semantic web a reality. Given this, and that there are something like twenty-four thousand verbs in the English language it's time for more expressiveness than ‘like’. You also can't comment on the ‘liked’ item in your stream (yet) so no clarification or discussion is possible.

--

Having said all that, if you enjoyed this post please click the ‘like’ button above ;)

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(Published to the Fediverse as: Top 5 reasons to hate the Facebook like button #etc #facebook #like #lessig #dublincore #semanticweb #opengraph #metadata Why can't you link to an existing page? How can you have a like button per blog post on your home page? Are we headed towards a world with only one verb? )

When testing out a WPF app on XP I got an unhelpful XamlParseException error report. 

I was a little puzzled because I was hooking up error reporting in App.xaml.cs:

My error handler was attempting to create a XAML window to report the error, and evidently this was bombing out as well triggering the good doctor Watson. I added a MessageBox call instead and discovered that the XamlParseException was wrapping a FileFormatException and the stack trace indicated that the problem was with setting the icon for the window. After removing the icon the app started up fine. Weird.

It turns out that WPF chokes on a compressed 256x256 icon on XP and Vista (Windows 7 seems to cope fine). Saving the icon without compression fixes the problem. I use IcoFX and you can set this at Options -> Preferences -> Options -> Compress 256x256 images for Windows Vista. Of course the consequence is that the icon is a couple of hundred kilobytes larger.

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(Published to the Fediverse as: XamlParseException and 256x256 icons #code #xaml #wpf #wtf You can't use a compressed 256x256 icon with WPF but you can include an uncompressed version. )

I've spent the last day learning how to use OAuth and XAuth to post to Twitter. There are rumblings that Twitter will start to phase out basic authentication later this year, and more importantly you can only get the nice “via...” attribution if you use OAuth (for new apps, old ones are grandfathered in).

I coded up my own OAuth implementation, referring to Twitter Development: The OAuth Specification on Wrox and the OAuthBase.cs class from the oauth project on Google Code. Both are great references, but both fail with multibyte characters. The problem is that each byte needs to be separately escaped. OAuthBase.cs encodes characters as ints rather than breaking out the bytes and the Wrox article incorrectly suggests using Uri.EscapeDataString().

Here's a method to correctly encode parameters for OAuth:

NoEncode chars is a list of the permitted characters:

An impact of this encoding is that spaces must be encoded as %20 rather than plus. I was worried that each space would end up counting as three characters towards the 140 character limit. I tested this and it isn't true, so use HttpUtility.UrlEncode() to calculate the number of characters in the post OAuthUrlEncode() or similar to actually encode post parameter.

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If you send email to customers it's important that you let them know where the email will come from and then use then use this address consistently. Using different email addresses is a recipe for getting trapped in spam filters. This is equally important for marketing and other messaging like bills and canceled flights.

I bring up flights because I'm flying to the UK later today and was planning to return on Sunday. British Airways' Cabin Crew is going on strike this weekend and my return flight has been canceled. Instead of sending a text message BA tried to notify me by email. This would have been fine if they used the address they've used for years, but instead they used a new address and a new domain. In fact in the process of canceling and re-booking I (eventually) got email from britishairways.com, my.ba.com, email.ba.com and pop3.amadeus.net.

Since I've had the same email address for twelve years now I get a fair amount of spam. I use SpamArrest to keep myself sane:

94.9% of my email is spam. Since I started using the service SpamArrest has eaten 482,494 messages for me. I'm far from alone in using white list based email filtering so if you want your message to get through transparency and consistency are the way to go.

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(Published to the Fediverse as: Email marketing - don't shoot yourself in the foot #etc #britishairways #spamarrest #spam #email Transparency and consistency are important when sending email. Let the customer know where the email comes from and always use the same address. )

Yes.

Some more color. I use Intuit's assisted payroll service, which is fantastic. You run payroll straight out of QuickBooks and Intuit handles all the tax disbursement and filing for you.

I got an email today with an attachment called securedoc.html claiming to be a message from Intuit. The idea is that you open the attachment and then login to view the message.

It really couldn't look any more like a phishing email, however I called Intuit and remarkably it's a real message. They seriously expect me to open an email attachment and provide account information. The support person at Intuit was able to read the message to me and it was just a routine acknowledgment that some tax rates had been updated.

Intuit is seriously training its customers to fall victim to phishing attacks. The right approach would be to say that a message is available and to log in to your account to retrieve it, or better still to send a message through the existing system in QuickBooks. Securedoc.htm is just begging customers to provide their account information to the bad guys.

Intuit's payroll service stores bank account information, employee Social Security numbers and other data that you really don't want to expose. If you're an Intuit Payroll customer please call and complain. If you've received one of these messages I'd also recommend forwarding it to [email protected], their address for reporting phishing attacks. 

 

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(Published to the Fediverse as: Is Intuit Insane? #etc #spoof #phishing #intuit #quickbooks Intuit is training its customers to fall victim to phishing attacks by sending messages using securedoc.html )