Marcelo's WebLog

New WCF Data Services Release

2012-04-09T21:00:00Z

WCF Data Services 5.0 for OData v3 is out today. Read all about it here, and get it while it's hot. Actions, geospatial support, and an assortment of other goodies, not the least of which is support for Any and All operators. This restriction has been around for a long time, and it's great to see that workaround are no longer required.

Enjoy!

Performance for Metro style app

2012-04-04T21:00:00Z

The Windows 8 app developer blog recently published How to improve performance in your Metro style app. A lot of the content might be familiar, including the always-handy Interaction class table, but there are additional considerations to play nice with the rest of the system, particularly with regards to how expectations change for different app states, so I recommend reading the full thing.

And if this whets your appetite, you can always learn more at the Windows Performance Analysis Developer Center.

Enjoy!

datajs version 1.0.2 released

2011-11-10T10:00:00Z

A new release of datajs with a minor update is available today, version 1.0.2. The most significant change is support for high-precision DateTime values, which incidentally means that Azure Table Storage feeds are now better supported.

Get it while it's hot and enjoy!

Server-side paging in OData with datajs

2011-09-08T21:00:00Z

I haven't posted for a while and it seems to be an effective method to get others to do so. :)

Today, I'm happy to point you to Client side paging of Server Paged OData Entity Sets using datajs. Lohith does a good and detailed job at explaining what server-side pagination looks and how to handle it from a client, and ends with a handy summary. Don't miss it!

Enjoy!

datajs at DevCon5

2011-07-25T21:00:00Z

Later this week I'll be speaking at DevCon5 in New York. We'll look at how the browser landscape is evolving and where it's going, and present some of the work we've done in layering conventions over REST in producing OData, as well as the work we've been doing in datajs to leverage the increase in capabilities.

Hope to see any readers of this blog at the conference - drop me a comment if you want to meet up during/after the conference, or catch me on Twitter at @mlrdev.

SkyDrive - HTML5 improving performance, again

2011-07-18T21:00:00Z

Continuing in the spirit of my last post, I wanted to make sure that folks are aware of the How we used HTML5 to make SkyDrive fast for millions of people post on the Inside Windows Live blog.

It's an accessible read that walks you through a number of important improvements that are powering the new SkyDrive experience. Definitely worth the read.

Enjoy!

Thoughts on radically improving web performance

2011-07-06T21:00:00Z

If you're a web developer, you definitely owe it to yourself to read the Instant email: how we made Hotmail 10x faster post on the Inside Windows Live blog. Go ahead and read it - I can wait.

You see, with the right techniques, it's possible to provide a very, very compelling and performant experience for users. That translates into happier, more productive users.

I found it reassuring to read the post because although Hotmail doesn't use datajs, it still leverages some of the same techniques we used when we set out to develop a APIs to help improve web performance:

Caching. datajs provides a store API suitable for caching different kinds of data by the application, and a cache API that is suitable for large, slowly changing collections.
Pre-loading. The cache API support prefetching out of the box, which makes the typical use case much faster for end users.
Asynchronous operations. datajs was built from the ground up on purely asynchronous operations. The store, cache, networking and OData components are all asynchronous, and so the user interface is never blocked.

Enjoy!

datajs samples

2011-07-05T21:00:00Z

One of the things that we care about a lot in datajs is in being practical and enabling better productivity. As such, we don't think you should spend a lot of time pouring over the library documentation to figure out how to put it to use.

Instead, we build some high-level pages with important information, and put together a set of samples that you can use to get up and running quickly. The samples cover using OData, the storage API, and the cache API. They try to show some good best practices, like how to organize UI, in-memory objects and server-data representations so you have cleaner, more maintainable code.

But of course you don't have to rebuild things from the ground up to use datajs to make your site better. You can add a cache on a page to make some lookups faser. You can add preferences locally so the user doesn't have to round-trip to the server to keep them around. You can have input on the side send structured data to your server, or query from it, without having to start from scratch - there is no "page model" associated with datajs, so you can simply pick and choose what you want to get started with and then take it from there.

Enjoy!

datajs V1 Now Available

2011-06-30T18:45:00Z

Check out the official announcement. The library is out there in all its glory. The datajs team will be writing a couple more samples as well as listening to the post-release feedback, then enjoying the long weekend (4th of July is a holiday in the US).

If you're near a browser during the weekend, why not challenge yourself to learn how to use datajs to be more productive?

Enjoy!

Microsoft Office 365 is now available!

2011-06-28T21:00:00Z

Personally, I think that having some storage and Office Web Apps is a great combination on its own. The fact that you also get mail & calendar (including Outlook Web Access), SharePoint Online, Lync Online, and Forefront protection, makes this an unbelievably awesome package. I think this is delivering on the "help realize potential" mission in a major way, particularly for small businesses who perhaps never had access to these capabilities in the past.

If you haven't already, check it out at http://www.microsoft.com/en-us/office365/online-software.aspx.

Enjoy!

datajs 0.0.4 is out - very important release!

2011-06-21T21:00:00Z

So, as per yesterday's announcement, datajs 0.0.4 is out. Go get it while it's fresh!

An important thing that's worth remarking is this is the last planned release before version 1.0.0. We don't have plans to add any new features or change the API for the next release. Right now we're considering whether there's anything else that needs to be fixed, testing across various browsers & devices, building samples, spiffing up the docs, and generally giving people a few more days to give us feedback on whether things are looking the way they should be.

So if you've got any issues or additional feedback that you think should be considered for the first release, this is a great time to let us know - we're listening more attentively than ever.

Enjoy!

Network capture with Internet Explorer

2011-06-15T21:00:00Z

Here is a handy video showing how you can quickly try something out with datajs and get a network capture (even if you don't have a functioning website!).

Of course it's easier if you do, simply enable capturing and run your repro steps through your app. You can download the video here.

Enjoy!

View Video
Format: wmv
Duration: 04:27

Populating a combo box from the cache with datajs

2011-06-08T21:00:00Z

A new documentation topic is up on CodePlex with a sample page demonstrating how to populate a combo box from a datajs cache.

If the browser doesn't support any storage API or if the user's storage quota is full, it still works as intended.

There is also some very simple code to disable and re-enable the control, always a good thing. Note that the error handler leaves the combo box disabled on purpose and removes any partial progress made, which is often better than letting the user work with incomplete data.

Enjoy!

Latest datajs changes - changeset 8334

2011-06-07T21:00:00Z

Yesterday we uploaded the changeset 8334 to datajs, which includes a pretty extensive list of improvements. These haven't made it into a release yet, but you can build and play with the sources - here's what's new.

Adds support for configuring cache sizes. The options argument to datajs.cacheSize can include a cache size in (estimated) bytes - this helps allocate storage across different stores, and make sure you leave room for the most important ones.
Adds support for RxJs to caches. If you include the Reactive Extensions for JavaScript library, you can get an observable source by simply invoking ToObservable on a cache.
Adds support for options in cache constructor. This includes things like user and password.
Adds support for filtering forward/backwards to caches. You don't have to wait for data to be local - after all, the cache can't index on an opaque callback. So we're simplifying this, and you can simply call filter at any point.
Supports JSON options on a per-request basis. In the OData.request object (and the cache options), you can specify values that would otherwise have been set on default objects, including whether to enable JSONP, the callback handler name, whether dates should be handled, etc.
Supports user and password in requests. In addition to the JSON/JSONP flags, you can also specify user and password for basic authentication scenarios.
Improves default success handler. Now we stringify the response data, so if you're just playing with the API to get a sense of the response data it's super-easy to get started.
And a bunch of bug fixes, internal changes and test improvements...

Enjoy!

Cool tricks with Internet Explorer Developer Tools and datajs

2011-06-06T21:00:00Z

Today I want to show you how the Internet Explorer Developer Tools and datajs make it easy for developers to experiment with code and data. Just follow along in another Internet Explorer window and enjoy.

First, we'll want to start with a page, let's say http://www.bing.com/. As always, we're greeted with a nice background picture.

Next, we'll bring up the developer tools. Simply press F12 in your browser and the window will come up. Pin it by pressing Ctrl+P (or clicking the rightmost button on the menu area).

Now we'll check whether we have datajs loaded. Click on the Script tab, and type datajs at the prompt. A red message will be shown, "'datajs' is undefined". OK then, let's load it by pasting the following code at the prompt.

(function() {
var url = "http://download.codeplex.com/Project/Download/FileDownload.aspx?ProjectName=datajs&DownloadId=227462&FileTime=129470492005570000&Build=17889";
var scriptTag = document.createElement("SCRIPT");
scriptTag.setAttribute("type", "text/javascript");
scriptTag.setAttribute("src", url);
var h = document.getElementsByTagName("HEAD")[0];
h.appendChild(scriptTag);
})();

This pulls in datajs 0.0.3 from CodePlex. You'll note that the tool went into multi-line mode after pasting; you can go back to the single line by clicking on the 'Single line mode' button. 'Single line' is more convenient in that you can execute everything by pressing Enter, but of course it doesn't work well for multi-line snippets like the one above. If you run OData now, you'll get a few of the members displayed, and we're ready to go.

Next, if we check whether jQuery is loaded like before, we'll see that it's not, so the following snippet will do the trick (we're really just changing the url value).

(function() {
var url = "http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.6.1.min.js";
var scriptTag = document.createElement("SCRIPT");
scriptTag.setAttribute("type", "text/javascript");
scriptTag.setAttribute("src", url);
var h = document.getElementsByTagName("HEAD")[0];
h.appendChild(scriptTag);
})();

Now we're ready to rock and roll. Let's get some sample data from the web and display it on the page.

Of course, you can also use the developer tools to craft more interesting queries, submit changes, test / tweak scripts, extract and reshape some interesting page... There are lots of scenarios and uses for this very useful tool for web developers.

Enjoy!

Netflix + OData + datajs sample released

2011-05-25T21:00:00Z

Check out the sample and code walkthrough at http://kashyapas.com/2011/05/releasing-netflix-catalog-using-htmlodatadatajsjquery/.

Some highlights:

All the app components run in the browser!
Clever use of the datajs cache - those values aren't changing anytime soon, and it definitely speeds things up to avoid round-trips. Nice way of reducing the page startup time.
Templates are stored as plain text files on the server, then retrieved at runtime when the page needs them - again, clever!
A server that opens up its data for cross-domain access enables some very, very powerful scenarios.

The code is available on CodePlex and is short & sweet. Enjoy!

More datajs on Twitter

2011-05-19T21:00:00Z

These days, I'm using #datajs when I tweet about small updates like minor code fixes or improvements to the CodePlex site.

Enjoy!

Windows Azure Storage Emulator returning 503 - Service Unavailable

2011-05-06T21:00:00Z

Today's post is the result of about four hours of tracking down a tricky problem, so hopefully this will help others.

My problem began when I was testing an Azure project with the storage emulator. The code that was supposed to work with the blob service would fail any request with a "503 - Service Unavailable" error. All other services seemed to be working correctly.

Looking at the headers in the Response object of the exception, I could see that this was produced by the HTTP Server library by the telling Server header (Microsoft-HTTPAPI/2.0 in my case). So this wasn't really a problem with the storage emulator - something was failing earlier on.

Looking at the error log at %SystemRoot%\System32\LogFiles\HTTPERR\httperr1.log in an Administrator command prompt, there almost no details, so I had to look around more to figure out what was wrong.

Turns out that some time ago I had configure port 10000 on my machine to self-host WCF services according to the instructions on Configuring HTTP and HTTPS, using http://+:10000. The storage emulator currently sets itself up as http://127.0.0.1:10000/. According to the precedence rules, "+" trumps an explicit host name, so that was routed to first, but there was no service registered for "+" at the moment, so http.sys was correctly returning 503 - Service Unavailable.

To verify, I can simply run this command from an Aministrator command prompt:

C:\Windows\system32>netsh http show urlacl

URL Reservations:
-----------------

    Reserved URL            : http://*:2869/
        User: NT AUTHORITY\LOCAL SERVICE
            Listen: Yes
            Delegate: No
            SDDL: D:(A;;GX;;;LS)

    Reserved URL            : http://+:80/Temporary_Listen_Addresses/
        User: \Everyone
            Listen: Yes
            Delegate: No
            SDDL: D:(A;;GX;;;WD)

... (an entry for http://+:10000/ was among these!) ...

The first was a simple one-liner, again from an Administrator command prompt, to delete that bit of configuration I didn't need anymore, and the storage server is up and running again.

netsh http delete urlacl url=http://+:10000/

Enjoy!

Must-have resource for Azure developers

2011-05-05T21:00:00Z

Lately I've been looking into writing Azure applications. I already know the .NET platform, so it's a very familiar development experience for me: all the libraries I know and love are there.

There are two aspects however that are new to me.

The first is how to build systems that can scale up and be always on. There is a lot of support from Windows Azure in terms of runtime environment, libraries and services, and I think I've got a fair grip on them, but I'm still building the muscle of thinking about building highly scalable, highly reliable systems.
The second is how to engineer the development environment and runtime operations. In other words, how to set up my environment correctly, design things to be able to run unit tests quickly and with flexibility, and how to maintain enough information flowing and stored in the system to be able to keep the thing going when it's deployed. It turns out that building in flexiblity and diagnostics can help in both cases.

If you're in a similar situation as I am, I can't recomment the Windows Azure How-To Index enough. It's a densely packed page with lots of information to get you going with practical tasks, and it's refreshed quite frequently.

Enjoy!

Anecdotally, datajs delivers quiet success

2011-05-04T21:00:00Z

Most of the people I've discussed datajs describe their experience as simply getting the code, using it and having it work on the first go. "It just works", and people get on with building the rest of their web app.

So far it seems that the simple API resonates well with developers, and we're hitting the right level of simplicity with control, but I'm interested in hearing more of course. If you've tried datajs, what was your experience like? Good things, bad things, difficult things? If you haven't, is there something that's getting in your way or something that could change that would make the library more appealing to you?

If you want to be heard, just comment on this post or drop me a message - thanks in advance for your time!

What we're up to with datajs

2011-05-03T21:00:00Z

It's been a while since I last blogged about datajs, so in the interest of transparency I thought I'd give a quick update on what we're up to.

There are three things that we're working on.

Cache implementation. Alex is doing some awesome work here, but the changes are pretty deep, which is why we haven't uploaded code for a while; we want to make sure that the codebase gets more stable over time at this moment.
Bug fixes. A few minor things here and there, nothing too serious has come up so far.
Responding to feedback. There are a couple of tweaks in design that we're considering to help with some scenarios. This is a great time to contribute ideas, so if you're interested, just go over to the Discussions page and post - we're listening.

Enjoy!

Supporting JSONP callbacks in WCF Data Services

2011-04-19T21:00:00Z

By default, WCF Data Services does not support the $format and $callback options to support JSONP.

If you're using datajs to access a service and have set the enableJsonpCallback flag to true but you're seeing an error on the response that looks like "The query parameter '$callback' begins with a system-reserved '$' character but is not recognized." (you'll need a network capture to see this), then the server doesn't support JSONP. Thanks to Marco Bettiolo for the problem report and network diagnostics!

A very common way to add support is described by Pablo Castro in this blog post, or if you prefer to get up and running faster, the sample is here.

Enjoy!

datajs intro video now online

2011-04-18T17:00:00Z

The MIX11 session on datajs is now online - enjoy!

datajs release announcement

2011-04-13T23:30:00Z

I'm excited about the announcement of the datajs 0.0.3 release. This new release comes out within two months of the previous one, and as you can see from the changelists, there are a few very interesting changes.

Basic key/value storage API over various mechanisms.
Caching component with prefetching and durable data.
Support for OData $link and plain-text content.
Compatibility with more browsers.
Various bug fixes.

If you're attending MIX11, you can see the library in action at the Data in an HTML5 World session this Thursday.

Enjoy!

OData and TFS and yes, CodePlex

2011-04-08T21:49:55Z

The beta of the OData Service for Team Foundation Service 2010 was announced yesterday, and of course as a TFS user I find this tremendously exciting. TFS ends up having a lot of data about my day-to-day work, and now thanks to OData it's easily unlocked and programmable!

For extra awesome points, there is a preview of the CodePlex OData API as well.

Enjoy!