Archive: Browsers

In this talk at The Future of Web Apps London, Aza Raskin talks about the future of browsers. He discusses …

1. YOU-Centric browsing
2. How browsers will manage your identity
3. Browsers with native natural language processing
4. Built-in payments in browsers

By the way, hope you can join us at …

(more…)

A Microsoft browser plug-in might seem an odd target for the PHP developer, more used to working with open source platforms such as Linux, Apache and the MySQL database server. However there is much about Microsoft Silverlight that makes it a good match to such technologies. For a start, it is a free download and there are versions that run not only on Microsoft Windows XP and Vista but also on Intel-based Apple Macs running OS X 10. It is designed to work not only with Microsoft Internet Explorer but with all major Web browsers, and Microsoft is taking particular care to ensure compatibility with Firefox and Safari. There is even a version for Linux called Moonlight which is being developed as part of the open source Mono Project.

Silverlight is a powerful tool for creating Internet applications that go considerably beyond the capabilities of standard HTML and CSS. It supports a wide range of visual effects and has more than 30 user interface controls built-in, including not only buttons, list boxes and sliders but also a data grid and a calendar. It can display PNG and JPEG image files, and play back WMV, WMA and MP3 media with support for 720p HDTV display modes. Silverlight 1.0 was released in April 2007. The current version is Silverlight 2.0 (originally referred to as Silverlight 1.1) which is fully compatible with the original while offering many enhancements.

Inside a Silverlight application
You define the application that you want Silverlight to present using XAML (eXtensible Application Markup Language). This is based on the XML specification and was designed by Microsoft for initialising structured values and objects. The following XAML document declares a Canvas object containing a TextBlock, which is a lightweight element for displaying text:

Download complete code example

The visual elements that make up a Silverlight application need to be placed within a container object, and this provides a reference in which they can be positioned. In our example we are using a Canvas object measuring 300 by 100 pixels as the container and we have set its Background property so that it displays in a light blue color. Into this we have placed a single TextBlock object which will display the traditional ‘Hello World!’ text string in a Verdana font 30 pixels in size and 10 pixels below and to the right of the top-left corner of the Canvas object. Note the dot syntax that we have employed to reference properties of the Canvas object.

Actually displaying a Silverlight application within an HTML page need involve little more than a standard Object tag. At its simplest, the following renders our example within a browser:

Download complete code example

Here we have defined a space 300 pixels wide and 100 pixels wide in which to place the Silverlight plug-in, as defined by its MIME type. We have also defined a data attribute for the plug-in. In practice this is usually ignored but it can boost performance with some browsers (and note that the trailing comma is necessary as the attribute takes two parameters, the second having a ‘null’ value in this case). Finally, in the event that the client does not have Silverlight 2.0 installed, the anchor element displays a ‘Get Silverlight’ image from the Microsoft Web site which is linked to the page from which the user can download and install the plug-in.

The Silverlight plug-in takes a number of parameters but in this context the most important is ‘source’ which tells the plug-in where to find the application. In this case we are directing it to the file ‘silverlightapp.xml’. If this was to contain the XAML of our earlier example in simple text form, and both these files were uploaded to a directory on your Web server, then opening the HTML page would result in our ‘Hello World!’ application appearing to the top-left of your browser.

The XAML that defines the Silverlight application need not reside in a separate file. It can instead be defined within the page that instantiates the plug-in using a special script block. For example, we could insert the following immediately before the ‘pluginHost’ div block in our HTML page above, which also shows off some of the special effects supported by Silverlight:

Download complete code example

We reference this XAML block by changing the ‘source’ parameter for the Silverlight1 object as follows:

Download complete code example

The hash character indicates that what follows references a script block on the current page. The other principle difference between this and our earlier XAML example is that we have placed a Rectangle object on the Canvas. This is a Shape element, as is the Line, Ellipse, Polygon and Polyline, and as such supports a wider range of display options. The RadiusX and RadiusY attributes round the corners of the Rectangle, while the Fill property allows us to specify a Brush object. In this case we have used the LinearGradientBrush to shade the Rectangle in a graduated blend of yellow and light blue.

Most of the other parameters supported by the Silverlight plug-in can be ignored at this stage. However ‘minRuntimeVersion’ can be useful if you want to ensure, for example, that version 2.0 is installed rather than version 1.0. This can be accompanied by ‘autoUpgrade’ which means that an attempt should be made to upgrade automatically in the event of too early a version being found. There is also the ‘OnLoad’ parameter which can specify a JavaScript function that should be run once the plug-in is loaded (more on that later).

If you want to know more about the options available when instantiating Silverlight, then the article ‘Instantiating a Silverlight Plug-in’ from Microsoft’s MSDN Library is a good place to start.

Using PHP with Silverlight
For the PHP developer, the important point is that the source for the Silverlight object can be anything that returns XAML, and that includes a PHP script. This opens up many possibilities. For example, the following PHP page uses Silverlight to display data extracted from a MySQL database:

Download complete code example

Assuming this is part of the page ‘customers.php’ on our PHP server, then calling it with the following URL would cause Silverlight to display the name, city and postcode of the 134th customer in the database:

http://myserver.com/customers.php?ID=134

Having extracted the ID value from the query string, the code opens a connection to the database and then runs a query which gets the data for the customer specified and places it in the object $result. The function mysqli_fetch_array() extracts the data from $result into the array $row, from where it can be read and inserted into the XAML using the echo command.
This is far from production code, with little in the way of error checking, but it does serve to demonstrate how PHP can be used to generate a Silverlight application. For the sake of simplicity our example embeds the XAML within the page that instantiates the Silverlight control, but you could equally specify a PHP page as the source for the Silverlight control itself, as in the following snippet:

Download complete code example

All that is required here is that the page clients.php return valid XAML code that can be rendered by Silverlight.

Adding user interaction with JavaScript
The Silverlight plug-in exposes a JavaScript API that allows any XAML element can be manipulated by JavaScript, in much the same way that you would program against the HTML Document Object Model (DOM) exposed by the page. Furthermore, Silverlight boasts a wide range of programmable events which opens up many possibilities for user interaction.

For example, in the following we have added an ‘x:Name’ attribute to the TextBlock element. This allows JavaScript to access and manipulate the element using the findName function. We have also attached an event handler stating that the JavaScript function changeText should be executed if the user depresses the left mouse button while the pointer is over the Canvas element:

Download complete code example

We can now define the changeText function by adding the following to the page that instantiates the Silverlight object:

Download complete code example

This script locates the element we want to manipulate using the findName function, and then sets its Text attribute to change from ‘Hello World!’ to ‘Goodbye!’ when the Canvas is clicked. One important point to note here is that the JavaScript is interpreted by the browser and not by the Silverlight plug-in. The x:Name attribute provides a handle that allows the findName function to reach into Silverlight for objects declared within the XAML code.

You can use these techniques to respond to a wide range of events. The API allows you to respond to simple movements of the mouse, or when the mouse pointer enters or leaves an object. You can respond to the depression of the left mouse button, and when it is released. Most objects respond to key up and key down events as well, and there are facilities for determining the key combination. The TextBox control supports a TextChanged event, while the PasswordBox control supports a PasswordChanged event and the Button control supports a Click event

One of Silverlight’s great strengths is this ability to manipulate anything you declare in your XAML code through a coherent object model. Check out the Silverlight Developer Center in the MSDN Library for a comprehensive reference to the whole API.

Interacting with a PHP Web Service
Most of the techniques discussed so far work with both versions of Silverlight. However Silverlight 2.0 opens up new possibilities for client-side processing as it includes a version of the .NET Framework and the Common Language Runtime (CLR) which allows it to run client-side code written in C#, Visual Basic and many other languages. The code for such programs is compressed into a single ZIP file together with the XAML definition and a manifest (also written in XML). The result is given the file extension XAP and referenced through the plug-in’s source parameter in the same way as we referenced our XAML file in the example above. When the page containing the plug-in is opened by the client, the XAP file is downloaded and unpacked, and then the code is compiled and executed.

This opens up further opportunities for the PHP programmer as such applications can make calls to Web services, and those Web services can be defined in PHP. For such an application to work the service has to be SOAP 1.1 compliant, and you will need to define a clientaccesspolicy.xml file if the service comes from a different domain to the application. This is to prevent cross-site forgery (see the article Making a Service Available Across Domain Boundaries for more on this).

It is also worth noting that Silverlight 2.0 also includes the Dynamic Language Runtime (DLR) which supports IronPython, IronRuby and Managed JScript. These languages are being developed at Microsoft’s open source project hosting site Codeplex. For further details see Silverlight Dynamic Languages SDK.

Choosing the Right Tools
While not a requirement, Microsoft has released a number of tools that would be useful to the PHP developer looking to work with Silverlight. Microsoft Visual Web Developer 2008 Express Edition is a useful Web page designer with full support for CSS, JavaScript and AJAX. It can also be used with Silverlight Tools for Visual Studio 2008 to automate production of much of the infrastructure behind a Silverlight application. Both can be downloaded from the Microsoft Web site free of charge.

Microsoft Expression Blend 2 is a professional graphic design tool that outputs XAML, allowing designers to create attractive user interfaces and to automatically generate the code required by Silverlight for its display. Alternatively increased support from the community means there are a growing number of third party XAML editors out there as well.

Sitting alongside Blend 2 is Microsoft Expression Web 2. Aimed at the professional Web designer, this latest release introducing many features that have been designed specifically for the PHP developer. There are menu options for inserting common PHP snippets, including pre-defined form, URL and session variables, server side includes and other structures. Furthermore, Expression Web 2 will render the page in Design View as though all the code, including server side includes, were in a single file, allowing you to see your code in action without leaving the editor.

Expression Web 2 understands PHP which means it will colour code language constructs intelligently, and there is full support for auto-completion so that you can see what functions and parameters are available to you as you write the code. Expression Web 2 also includes the PHP 5.2.5 runtime which you can use locally as a development server.

So Silverlight has a great deal to offer the PHP developer – something that Microsoft is clearly recognising with its support for PHP in Expression Web 2. Trial versions of Microsoft’s Expression range are available for download.

[Main image by Pathfinder Linden]

The internet would never have become the phenomenon it is today without the web browser; the simplicity of the browser concept allowed the Web to grow rapidly. Developers just had to write basic text documents using a simple markup language (HTML) and the browser took care of everything. As websites became web applications developers still did not have to deal with the complex task of building client applications in the traditional sense: make it work in a browser and anyone can access it without having to install any new software, no matter what device (or OS) they are using.

While the browser makes life easy in many ways for developers it also throws up certain challenges. Major software companies such as Microsoft, Adobe and Google are now trying to address these challenges, albeit in different ways. This article will focus primarily on the option of building desktop applications, what the key drivers and considerations are, and how this may affect the future of the web browser.

What are the Challenges?

The recent launch of Google’s web browser is the latest shakeup in the browser wars that have raged for over a decade. Of course, competition has been good for the evolution of the Web, by bringing us new technologies such as CSS and Ajax and driving adoption of web standards, but there has been some negatives.

The inconsistencies between browsers have always been a major headache for developers. What works in one browser doesn’t always work in another or, worse yet, works differently. Many of the latest web applications now utilise Ajax for a superior user experience, but unfortunately Ajax libraries are so bloated to handle cross-browser quirks that they can cause performance problems. Even with the latest “standards compliant” browsers a lot of time has to be invested in making web apps work and look the same across IE, Firefox, Safari, Opera, and so on.

Today’s web apps are complex and, perhaps, pushing the browser to its limit. Other technologies are emerging to try and help developers build the next generation of Rich Internet Applications (RIAs): Flash has been around for many years, but now Adobe offers Flex and Microsoft have given us Silverlight. In the context of the web browser these are great options and will certainly challenge the traditional mix of HTML, JavaScript and CSS as the standard way of building web apps.

These new technologies are still running up against one of the age-old challenges: the more browsers do to protect the user from viruses, spyware and the like the more these security barriers limit a web app’s interaction with the user’s PC. Uploading your latest holiday snaps to Flickr is a painful process, primarily because anything running inside a browser is abstracted from the user’s desktop.

In addition, a number of social networks and services have run into the other major challenge with browsers: if the user does not have the browser open with the site loaded and are looking at it they have no idea what’s going on in their network. This creates a level of separation between the app and the user which is problematic if part of the application’s benefit is live data.

What’s the answer?

The problem of keeping users up-to-date when the browser is not running (or the app is not loaded in the browser) has seen a raft of third party desktop applications pop-up. For example, just look at the array of desktop applicationss for Twitter (Twhirl, Twitterific, Snitter, Tweetr, Twitteroo), FriendFeed (AlertThingy, Sobees, Feedalizr) or Facebook (FizzBoost, Facebook Desktop Client). These are just a small selection from the vast number out there.

These have been made possible by, firstly, the growth in web apps providing developers access to their functionality via APIs and, secondly, by the increased ease of building desktop applications. While developers have been focused on the Web (browser) as the main app platform the major vendors have been working on ways to make traditional desktop application development faster and more accessible. The latest and most popular of these is Adobe’s AIR technology which allows developers to use the knowledge and skills acquired from building web apps to develop cross-platform desktop applications. Using HTML, JavaScript, and CSS you can now build a fully-functional desktop application with AIR that runs on PC, Mac and Linux.

Desktop applications have a number of advantages over those that run in the web browser. They provide an “always on” method of communicating with the user. AlertThingy, for example, can hide in the system tray, but pops up an alert in the bottom right corner of the screen whenever a new notification comes in. They also have far greater access to the users’ system than anything running within a browser: uploading files suddenly becomes as easy as drag’n’drop; user data can be saved on the user’s machine; and the app can continue to work without an internet connection. These benefits can be put to incredibly powerful use in building feature-rich apps that provide a great user experience.

Providing users with a web-based interface and a desktop version with additional functionality is not a new idea, nor is it the preserve of Web 2.0 start-ups. Microsoft Outlook, with its companion web app version, Outlook Web Access, is a well-known example of this, having been around since 1997. Fortunately, the technology available to developers has come a long way since 1997: a benefit of Adobe Flex is that the exact-same app can be hosted within AIR or the browser; you just have to disable certain features in the browser. That’s both options covered with very little extra work.

The traditional difficulties associated with building desktop applications are done away with with technologies such as AIR. Not only can you use web development skills to build a desktop application, but the runtime also takes care of features like the ability to have the application automatically update to new versions. By building within a runtime, the developer does not have to worry about the awkward plumbing of desktop apps, such as minimizing to the system tray. Plus, Dreamweaver suddenly becomes a desktop development IDE!

Important considerations

There are some important questions to answer when deciding to build a desktop application. The first is whether it is really necessary. Many web apps work perfectly well within a browser and would not add any benefit for the user by having a desktop version. Building a desktop application just because you can is not a valid reason.

Next, however easy it is for a user to install an application there is still the question of whether they will. Some are put off by the idea of installing something on their machine and will choose not to. You are adding one more barrier to entry that does not exist with traditional browser-based web apps. Will the user see the benefits and that they outweigh any reservations they may have?

Finally, it is important that as an industry we do not go crazy building desktop apps. The swelling numbers of Twitter, FriendFeed, Jaiku, etc. desktop clients is already creating problems for users who do not want (or have space on their screen for) so many apps. When we released AlertThingy, we received a lot of feedback from users asking us to add certain features just so they could stop using one of their existing desktop apps and use AlertThingy instead. This takes us back to the issue above: will users want to install the app? The more apps they have the more challenging this becomes.

One area in which this can be addressed is that there are different types of desktop app. If your potential app is providing basic information requiring little user interaction or a small amount of screen space then Mac Dashboard widgets or Vista Sidebar gadgets are a great option. They are easy to develop (again utilising web technologies), lightweight and easy to install.

Is the browser a dead man walking?

I mentioned earlier Google’s latest browser, Chrome, which comes bundled with Gears. It is an attempt by Google to increase the install base of Gears and drive development of Gears-based apps. They are certainly highlighting other features of Chrome but Gears is most likely to be Google’s motivation for investing in their own browser, especially as it will benefit their own applications, such as Google Docs.

This situation is interesting because Gears attempts to overcome the issues discussed above, like Adobe AIR, but using the browser instead. This strategy could mark a new dawn for the web browser, which some believe will lead to it replacing the desktop OS (or at least rendering it redundant) but consider this: the Web is more than the browser, so much more, and with the growth of APIs and web-enabled platforms should we not look beyond the browser as the only client in future?

The first generation iPhone used the Safari browser as its application platform for third-party developers. This had limits and developers were desperate to be able to build native iPhone apps. Apple has now given developers that ability through the iPhone SDK. Many of these iPhone applications will be web apps (communicating with server-based applications) but not browser-based apps. We have seen a much more rapid growth in these types of applications compared to the previous Safari-based ones. And it’s not just the iPhone, surely a Java app on a Nokia phone is more powerful than anything running with the phone’s web browser?

As our TVs, cars and even fridge-freezers become internet-enabled the reach of the web app grows, but many of these devices will never have a browser. I have always found it strange that people think of what they see in the browser as the internet but not their email. As we move forward developers will be focusing on building internet applications, rather than browser-based apps, which can be accessed by a multitude of more powerful native clients on different platforms.

With Chrome joining IE, Firefox, Safari and others the browser war is set to rage on but the glory days of the web browser itself may be past.