Mahjayar's WebLog. : Silverlight

Upgrading Silverlight Samples to Beta2

Mahjayar — Fri, 20 Jun 2008 21:53:00 GMT

Cross posting from http://maheshwar.net/Blog

Now that Silverlight Beta2 has been released I have upgraded the SL samples on this site to the new build. I have moved the current beta1 samples to a subdirectory under the current sample. Source code for the new Beta2 sample is also updated at http://code.msdn.microsoft.com/silverlightws

Beta1 Pox Proxy Sample: http://maheshwar.net/Projects/SLPoxSample/Beta1/SLPoxSample.aspx

Beta2 Pox Proxy Sample: http://maheshwar.net/Projects/SLPoxSample/SLPoxSample.aspx

Source Code for POX Proxy: https://code.msdn.microsoft.com/Release/ProjectReleases.aspx?ProjectName=silverlightws&ReleaseId=601

Maheshwar

Silverlight 2.0 - Rundown of WebServices related functionality in Beta1

Mahjayar — Wed, 12 Mar 2008 06:50:01 GMT

Technorati Tags: Silverlight,WebServices

Hope everyone had a chance to download and play with the Silverlight 2.0 Beta1 bits. I wanted to put up a quick post detailing the features we have shipped in this Beta. We have shipped total of 5 features split across 5 assemblies.

Core Assembly:

System.Runtime.Serialization.dll - Data Contract OM and Data Contract Serializer
System.ServiceModel.Web.dll - Data Contract JSON Serializer
System.ServiceModel.dll - WCF Client side proxy OM and runtime.

Extension/SDK Assembly:

System.ServiceModel.Syndication.dll - RSS/ATOM OM
System.Xml.Serialization.dll - Xml Serializer

Core assemblies are the assemblies that gets installed on to your box when you install Silverlight 2.0 and SDK assemblies are installed with the SDK. When your app uses SDK assemblies its treated like any other third party dll and gets bundled with user app in the XAP file. All references to core assemblies are loaded from the users Silverlight installation directory. All WebServices components have API/wire parity with recently released Orcas version. We have strived very hard to ensure that the wire representation of Silverlight serialized types are compatible with Orcas serializer.

System.Runtime.Serialization.dll

This contains the DataContract public OM and the DataContractSerializer (DCS) class. The Silverlight DCS serializer supports the following public properties:

Supports DataContractAttributes, CollectionDataContractAttribute, EnumMemberAttribute, DataMemberAttribute and KnownTypeAttributes on types.
XmlDictionaryReader and XmlDictionaryWriters
Ability to serialize Plain Old Clr Objects (POCO or non data contract types)

We are waiting to hear from users to decide on supporting features like IExtensibleDataObject, IDataContractSurrogate and PreserveObjectReferences. Type ISerializable is no longer available in Silverlight and so DCS can no longer serialize pure ISerializable types (it was fallback to serializing it as a POCO type provided the type has a public no argument constructor).

System.ServiceModel.Web.dll

We have completely rewritten DataContractJsonSerializer (DCJS) to ensure that the assembly fits in the reduced size requirements of Silverlight. This type is semi-compatible with the Orcas runtime. It maintains a subset of the public method but no longer derives from XmlObjectSerializer. Its a stand alone type and supports serializing any DataContract/POCO type to JSON. JSON produced by the Silverlight serializer is wire compatible with Orcas and so Orcas serializer should be able to deserialize that JSON just fine. Support for working with JXML (XmlJsonReader and XmlJsonWriter classes) is not available in the core and we have shipped it as a standalone sample. We believe the scenarios for JXML on the client is very limited but are open to feedback.

System.Xml.Serialization.dll

We have shipped an almost full featured port of the desktop XmlSerializer. Again we have strived very hard to ensure wire compat with existing Orcas serializer. One big implementation difference is the fact that the Silverlight Xml Serializer uses Lightweight Code Gen (LCG) to generate (de)serialize types on the fly. The Orcas serializer used Code Dom to generate the code required to read/write types. This implies that users will not be able to see the generate code. This behavior is actually pretty good as executing IL is way faster than executing raw code. Silverlight doesnt support features like XElement/XNode yet and hence the XmlSerializer doesnt support serializing them yet.

Note:

As you can see, I have stressed the "wire" compat nature of Silverlight serializers and did not talk about "Type" compat. Type compat between the serializers would mean that a desktop DataContract/XmlSeriailzable types can be reused in Silverlight. Silverlight being a subset of Orcas, certain serialization features/classes are not available. For example, a ISerializable type in desktop will obliviously will not be serializable in Silverlight. THe only supported way of porting types to Silverlight is "Schema" based. By Schema based I mean, users would need to create type on one side, export the schema for that type and then reimport it on the other side. For Beta1, the only way for importing schema is via the "Add Service Reference" option on a Silverlight project. We will ship the silverlight verison of SvcUtil, SlSvcUtil.exe, in Beta2.

System.ServiceModel.Syndication.dll

This is the only assembly that is complete feature port from Orcas. All Orcas RSS/Atom scenarios are fully supported in Silverlight.

System.ServiceModel.dll

WCF client side proxy deserves a separate post of its own and I will post one shortly.

Maheshwar Jayaraman.

Step by Step Guide to Silverlight POX Proxy Sample.

Mahjayar — Thu, 06 Mar 2008 07:21:42 GMT

Technorati Tags: Silverlight,POX,XmlSerializer,JSON

Scott Guthrie laid out all the details regarding Silverlight 2.0 Beta1 this morning and if you haven't had a chance to see the keynote then you can view it from VisitMix site. Scott briefly mentioned the support for networking stack in Silverlight and I would like to quote him.

"We have a very robust networking stack in SL2. We have support for REST, for SOAP, for WS-* - we support calling out to anything. We support calling external services, not just back to the server-of-origin. We even have support for sockets, if you want to program at that level."

Our PM, Yavor has already kicked off the information flow by posting bunch of posts on SilverlightWS blog. Lets quickly recap all the information that has been announced so far.

Install Silverlight Beta1 Runtime- http://www.microsoft.com/silverlight/resources/installationFiles.aspx?v=2.0
Install Silverlight tools (Runtime, SDK, VS Tools) - http://www.microsoft.com/downloads/details.aspx?FamilyId=E0BAE58E-9C0B-4090-A1DB-F134D9F095FD&displaylang=en
Silverlight WebServices MSDN Samples site - http://code.msdn.microsoft.com/silverlightws/Release/ProjectReleases.aspx?ReleaseId=601

We have shipped a prototype for a generic POX Proxy client that we are hoping to get feedback on. We want to evaluate how many people care about a generic POX proxy and what specific features they look for in such a proxy. We are hoping to use all the feedback to decide whether we need to formally add it to the produce or not. This blog post is to give a step by step guide on the sample app we wrote that uses the POX proxy to invoke EBay POX services. We will use the POX proxy to invoke the FindItems call of the EBay POX service via XML and JSON payloads and display the returned results on a DataGrid. Here is the final look of the sample.

Step1: Understanding the requirements of the remote POX Service.

EBay have exposed a POX service endpoint for its shopping services and information on it can be found at http://developer.ebay.com/products/shopping/. We would be using the POX proxy API to invoke the FindItems call. FindItems takes a FindItemsRequest and returns a FindItemsResponse. To have a strongly typed programming model, we need to first create CLR types for FindItemsRequest and FindItemsResponse. EBay doesn't support a Metadata Endpoint and so I manually mapped the types information from Ebay shopping WSDL (You could do the same from the XSD as well). Silverlight's System.Xml.dll doesn't support XmlElement or XElement in Beta1 yet so all xs:any elements from the WSDL have been mapped to object. Since we want the same type to be serialized via XmlSerializer and DataContractJsonSerializer, we will decorate the types with XmlElement and DataContract attributes. Here is how the FindItemsRequest types looks (You can refer the Shopping.cs file from the code to refer the complete set of types).

System.Xml.Serialization.XmlRoot(Namespace="urn:ebay:apis:eBLBaseComponents", ElementName="FindItemsRequest")]

[DataContract]

public partial class FindItemsRequestType : AbstractRequestType

{

private string queryKeywordsField;

private SimpleItemSortCodeType itemSortField;

private bool itemSortFieldSpecified;

private SortOrderCodeType sortOrderField;

private bool sortOrderFieldSpecified;

private int maxEntriesField;

private bool maxEntriesFieldSpecified;

private string postalCodeField;

private string[] sellerIDField;

private string[] sellerIDExcludeField;

/// <remarks/>

[System.Xml.Serialization.XmlElementAttribute(Order=0)]

[DataMember(EmitDefaultValue=false)]

public string QueryKeywords

{

get

{

    return this.queryKeywordsField;

}

set

{

    this.queryKeywordsField = value;

}

}

/// <remarks/>

[System.Xml.Serialization.XmlElementAttribute(Order=1)]

[DataMember(EmitDefaultValue = false)]

public SimpleItemSortCodeType ItemSort

{

get

{

    return this.itemSortField;

}

set

{

    this.itemSortField = value;

}

}

........

Step 2: Prepare and Issue FindItemsRequestType

Next step is to use the POX proxy API to issue a call to the FindItems request. We pulled all the POX related code to EbayUtility.cs file. All requests to the Ebay service have some common fields such as appid and version and we will populate the PoxProxyRequest with those common entries. You can also subclass EbayPOXProxyRequest from POXProxyRequest and do the common stuff within that class.

//Add custom Stuff

POXProxyRequest ebayRequest = new POXProxyRequest(new Uri("http://open.api.ebay.com/shopping"));

ebayRequest.WebMethod = POXUtils.HttpVerbs.Post;

ebayRequest.QueryParameters["callName"] = "findItems";

ebayRequest.QueryParameters["appid"] = "YOUR_EBAY_APP_ID";

ebayRequest.QueryParameters["version"] = "523";

We then specify the request and response encoding (JSON or XML) as a query and also modify the content type to match the encoding.

//Set content type to either JSON or XML

ebayRequest.QueryParameters["requestencoding"] = this.parent.ebayPoxEncodingType;

ebayRequest.QueryParameters["responseencoding"] = this.parent.ebayPoxEncodingType;

ebayRequest.ContentType = this.parent.contentType;

We then create an instance of FindItemsRequestType and populate it will all required fields. The only required filed in FindItemsRequest is QueryKeywords and we will populate that field in addition to the couple of optional fields, MaxEntires and PostalCode field. Refer the EbayControl.Xaml file for the input fields.

//Prepare the request

FindItemsRequestType fir = new FindItemsRequestType();

fir.QueryKeywords = this.parent.ebayControl.searchQueryTxtBox.Text;

fir.MaxEntries = Int32.Parse(this.parent.ebayControl.maxEntriesTxtBox.Text);

fir.MaxEntriesSpecified = true;

if (!string.IsNullOrEmpty(this.parent.ebayControl.postalCodeTxtBox.Text))

{

fir.PostalCode = this.parent.ebayControl.postalCodeTxtBox.Text;

}

Subscribe to the PoxProxyResponse's GetResponseCompleted event so that we can populate our DataGrid with the search results. Also, we will subscribe to the RequestSerialized and ResponseSerialized event so we can use that to show the actual request/response payload content to the user.

//Callback to call when the POX response is received

ebayRequest.GetResponseCompleted += new EventHandler<GetResponseCompletedEventArgs>(this.parent.ebayClient_GetResponseCompleted);

//Display the Actual serialized/deserialized contents on UI

ebayRequest.RequestSerialized = this.parent.PrintStreamContents;

ebayRequest.ResponseDeSerialized = this.parent.PrintStreamContents;

Finally issue the request.

//Issue the Async request.

ebayRequest.GetResponseAsync<FindItemsRequestType>(fir);

Step 3: Receive Response and Populate DataGrid

When the response is received from the service, the POX Proxy will invoke the callback provided in the previous step. We then retrieve POXProxyResponse from the GetCompletedEventArgs object. We will use this POXProxyResponse to retrieve the FindItemsResponseType.

POXProxyResponse resp = e.Response;

FindItemsResponseType fir = resp.GetResponse<FindItemsResponseType>();

resultsListBox.ItemsSource = fir.Item;

FindItemsResponseType contains an array of SimpleItemType objects that we will assign to the DataGrid. Since we have a strongly typed object of the response we can use data binding to pull values from the object.

<ListBox x:Name="resultsListBox" Visibility="Collapsed" Width="Auto" SelectionChanged="resultsListBox_SelectionChanged">

    <ListBox.ItemTemplate>

        <DataTemplate>

            <StackPanel Orientation="Vertical">

                <Grid>

                    <Grid.ColumnDefinitions>

                        <ColumnDefinition Width="100"/>

                        <ColumnDefinition Width="60"/>

                        <ColumnDefinition Width="*"/>

                    </Grid.ColumnDefinitions>

                    <StackPanel Orientation="Horizontal" Grid.Column="0">

                        <TextBlock Text="{Binding ConvertedCurrentPrice.currencyID}" Margin="5" Foreground="Blue" VerticalAlignment="Center"/>

                        <TextBlock Text="{Binding ConvertedCurrentPrice.Value}" Foreground="Blue" VerticalAlignment="Center"/>

                    </StackPanel>

                    <Image Source="{Binding GalleryURL}" Height="55" Margin="7,7,5,5" Grid.Column="1"/>

                    <TextBlock Text="{Binding Title}" Margin="5" Foreground="Black" VerticalAlignment="Center" Grid.Column="2"/>

                </Grid>

            </StackPanel>

        </DataTemplate>

    </ListBox.ItemTemplate>

</ListBox>

Step 4: Display Request/Response Stream Data

We had subscribed to the RequestSerialized and ResponseSerialized events and on invocation we will display the Stream contents to the user. The Stream contents will contain the actual serialized/deserialized data.

//Print the serialized/Deserialized stream content.

StringBuilder builder = new StringBuilder(this.payLoadTextBox.Content.ToString());

builder.Append(Environment.NewLine);

if (s != null)

{

    StreamReader reader = new StreamReader(s);

    builder.Append("=====================Stream Contents=======================").Append(Environment.NewLine);

    builder.Append(reader.ReadToEnd()).Append(Environment.NewLine);

    builder.Append("===========================================================");

}

else

{

    builder.Append("Stream was null");

}

builder.Append(Environment.NewLine);

this.payLoadTextBox.Content = builder.ToString();

You can switch between XML and JSON payload to use either XmlSerializer or DataContractJsonSerializer. As you can see we have made the process of invoking a POX service very straight forward. If you refer the Digg sample that Scott posted last week, you can see that the sample use WebClient to do the heavy lifting and had to use LINQ to get data from the response. The WebClient class in Silverlight is a subset of the desktop version and support for headers, non Get verbs and ability to get response streams is not available. Once you want to use WebClient/HttpWebRequest to call in to various POX requests you can see that it can get cumbersome. Users can easily create a type for the Digg response and use the POX Proxy to achieve the same effect.

Please download and use the Proxy and provide us with feedback on how we can improve this.

Maheshwar Jayaraman

Mix 08 and Silverlight 2

Mahjayar — Wed, 05 Mar 2008 06:25:00 GMT

Mix 2008 is just hours away and I am very excited to talk about all the work we have been doing to get the beta of Silverlight 2 ready. Scott Guthrie already kicked off the information flow with 2 wonderful posts on Silverlight 2 and Blend. We have worked hard to incorporate WCF + Orcas SP1 features in this Beta1 and I am personally very excited about the bits. Eugene, our PM, is presenting a session tomorrow on the features available for working with Data and web services..

Working with Data and Web Services in Microsoft Silverlight 2

Wednesday, March 5 1:30 PM - 2:45 PM, Delfino 4105

Speaker(s): Eugene Osovetsky

Audience(s): Technical

Session Type: Breakout

Learn how easy it is to utilize POX, REST, RSS, ATOM, JSON, and SOAP in your Microsoft Silverlight mashup applications. Also learn how to easily access and display data with Silverlight using LINQ and databinding.

Eugene will talk about the serializer, proxy support we are shipping with Beta1 and will also briefly talk about the direction we are thinking about for the next milestone of Silverlight 2. I have been working on Silverlight 2 for the past year and with Mix 08, I can finally talk about specifics and share more details.

Update: We have setup a team blog for Silverlight Web Services at http://blogs.msdn.com/silverlightws. We plan on posting a lot of services related content there in the next few weeks.

Silverlight and Connected Systems role in Silverlight

Mahjayar — Sat, 19 May 2007 06:16:00 GMT

Microsoft recently announced Silverlight at the Mix 07 conference. Now that its released I can freely talk about what I am working on. I am really excited to start working on the connected systems API's for Silverlight 1.1. If you refer to the Silverlight API Poster you can see that there are couple of API's marked "Soon".

I am in the team that will deliver the System.ServiceModel and System.Syndication apis for Silverlight. Its still too early to talk about the exact API's and functionalities we will be releasing under the namespace but the idea is to have the class complement the desktop API. You can install Silverlight 1.1 and develop apps using the API's currently shipping with the alpha. The alpha has support for HttpWebRequest (System.dll and System.Silverlight.dll) to make calls back to the originating domain. It also has XmlReader and XmlWriter support (in System.Xml.Core.dll) with which you can do Xml operations.

If you werent convinced of the possibilties of Silverlight, todays announcement of PopFly should definetly help. Popfly is built on Silverlight and aids in creating mashups using existing services very easily. Today was the first time I learnt about the Popfly project and am looking forward to adding custom basic "connectivity" blocks. Exciting times.