Sagar Ganatra's Blog

I've been looking into ways in which a web application can be made more user friendly and HTML5 does include some powerful features such as PageVisibility, Navigation Timing, etc,. that can be used to provide good user experience. Today I was looking into FullScreen API that allows you show any of the elements in the DOM in Full-Screen mode. Suppose you have a HTML5 video embedded in a page and would like to play that video in full-screen mode then it is now possible with the FullScreen API. Similarly say if you have an image element, it can also be shown in full screen mode.

I’ve always liked the Virtual File System (VFS) implementation in ColdFusion, but I always griped about one thing. The files written to the VFS are available at the Server level and are not specific to an application. However, ColdFusion 10 now includes support for Application specific in-memory file system. This means that, if you write a file to the virtual file system, only those files in the same application can access it. If an attempt is made by another application to access this file, the server would happily throw an error.

I’ve been playing with the WebSocket feature introduced in ColdFusion 10 for some time now. I was trying out pushing images over a ColdFusion WebSocket channel and it worked just fine. But this time I wanted to put WebSockets to test and wanted to push large data at regular intervals. I thought maybe I can push video data over WebSockets and it turned out that there is no direct way to stream video data to many clients. I came across the function - drawImage that can be used to draw an Image or Video on a HTML5 Canvas. Once an image is drawn on the Canvas, it’s base64 encoded data can be obtained by calling the toDataURL function on the Canvas object.  This data can then be transferred over a ColdFusion WebSocket to all subscribers who can then use this  data to draw the image(video frame) on a Canvas.

This week I started to learn jQueryMobile and was going through the online documentation that explained the basics. While I was trying out the sample examples, I came across an issue that I thought I’ll share with you. I had posted this on the jQueryMobile forum but I didn’t receive any solution to this. The issue here is when you have two anchor elements with its ‘href’ attribute pointing to the same div (#child data-role=”page”) with one marked as a button and the other marked as a popup dialog, then which ever button you choose first its action will be applied to the other button as well. Say if you click the second button that shows the dialog box containing the page it works fine, but now when you click the first button it shows the dialog box instead of showing it as a page. This is how it works the other way too i.e. if you click the first button the page is shown (as expected), but on clicking the second button it shows the page instead of displaying it as a dialog box.

Today I was reading about CSS3 and I stumbled upon CSS3 regions . I was completely flabbergasted with what I saw and learnt today. Imagine that you’re trying to build a website for a magazine containing multiple columns (say 3). It would be arduous to fix the textual content on a particular column and then move the rest of the text to other columns. Now with Content Flow mechanism, the extra content can be moved to other columns in the layout with ease. There are just a couple of properties that you need to define in the styling sheet and you’re done. But this is not it. When you resize the browser window, the content automatically flows to other regions depending on the browser size.

The for-in loop construct in ColdFusion is generally used to loop over a structure variable. In ColdFusion 10, one can use the same for-in construct to loop over Query and List variables. Here is an example in which the for-in construct is used to loop over Query and List variables.

Yesterday Ben Nadel asked me a question on Twitter, on using filterCriteria when publishing a message on a web socket channel from server side. The method ‘wspublish’ allows you to perform a server side push to a client who has subscribed to a channel. It takes three parameters – channelName, message and filterCriteria. I always assumed that the values present in subscriberInfo and publisherInfo can be compared in Channel Listener functions (canSendMessage, beforePublish etc) before the message can be received by the client. Although this technique is available, what I found after having a discussion with a fellow developer ( Awdhesh ), is that I can specify simple conditions when subscribing or publishing.