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Problems with Live JSON API in C# RRS feed

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    I have the following Code, which works fine with the flickrUrl, but actually I don't want to access Flickr, but Live. When I change the url in the following line: "wc.DownloadStringAsync(new Uri(flickrUrl + SearchBox.Text));" VS2008 throws an error:

    Message: Unhandled Error in Silverlight 2 Application 
Code: 4004    
Category: ManagedRuntimeError       
Message: System.Reflection.TargetInvocationException: An exception occurred during the operation, making the result invalid.  Check InnerException for exception details. ---> System.Security.SecurityException ---> System.Security.SecurityException: Security error.
   at System.Net.BrowserHttpWebRequest.InternalEndGetResponse(IAsyncResult asyncResult)
   at System.Net.BrowserHttpWebRequest.<>c__DisplayClass5.<EndGetResponse>b__4(Object sendState)
   at System.Net.AsyncHelper.<>c__DisplayClass2.<BeginOnUI>b__0(Object sendState)
   --- End of inner exception stack trace ---
   at System.Net.AsyncHelper.BeginOnUI(SendOrPostCallback beginMethod, Object state)
   at System.Net.BrowserHttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
   at System.Net.WebClient.GetWebResponse(WebRequest request, IAsyncResult result)
   at System.Net.WebClient.DownloadBitsResponseCallback(IAsyncResult result)
   --- End of inner exception stack trace ---
   at System.ComponentModel.AsyncCompletedEventArgs.RaiseExceptionIfNecessary()
   at System.Net.DownloadStringCompletedEventArgs.get_Result()
   at WebServices.Page.wc_DownloadFlickrCompleted(Object sender, DownloadStringCompletedEventArgs e)
   at System.Net.WebClient.OnDownloadStringCompleted(DownloadStringCompletedEventArgs e)
   at System.Net.WebClient.DownloadStringOperationCompleted(Object arg)

    It works with Google API too, but actually I don't want to access Google either. Can someone help me?

    public string flickrUrl = "http://api.flickr.com/services/rest/?method=flickr.photos.search&format=json&nojsoncallback=1&api_key=" + flickrKey + "&tags=";

public string liveUrl = "http://api.search.live.net/json.aspx?AppId=" + liveSearchKey + "&JsonType=raw&Market=de-DE&sources=image&query=";

private void ButtonFlickr_Click(object sender, RoutedEventArgs e)
{
	var wc = new WebClient();
	if (!String.IsNullOrEmpty(SearchBox.Text))
        {
        	wc.DownloadStringAsync(new Uri(flickrUrl + SearchBox.Text));
        }
}

void wc_DownloadFlickrCompleted(object sender, DownloadStringCompletedEventArgs e)
{
        MessageBox.Show(e.Result, "Debug Info", MessageBoxButton.OK);
}


    Monday, April 6, 2009 6:56 AM

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    Hi Sascha,

    I am guessing that you are trying to run the silverlight application using the dynamically generated test page in VS 2008 ( option 2 - "Automatically generate a test page to host silverlight at build time" when you try to create the Silverlight application in VS 2008 ). Due to a bug in Silverlight 2 where if you try to do just this AND there is a clientccesspolicy.xml available ( compared to no clientaccesspolicy.xml and a crossdomain.xml file being available) , the securityexception is generated. The reason you are not hitting this exception while using the the flickr Url is because there is no clientaccesspolicy.xml file for flickr.

    As a workaround, please use option 1 - "Add a new ASP.NET Web project to the solution to host silverlight" while creating the silverlight application.

    HTH
    Roopali
    Wednesday, April 15, 2009 11:32 PM

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    If you want to access Live Search API 2.0 then the DownloadStringAsync line should be:

    wc.DownloadStringAsync(new Uri(liveUrl + SearchBox.Text));

    However, you should know that building URLs in this fashion is not secure. A user could easily inject any parameters he/she wishes into the query string, which could cause your application to crash. A better way to write the line is like this:
    wc.DownloadStringAsync(new Uri(liveUrl + Uri.EscapeDataString(SearchBox.Text));
    Also you should check the value of e.Error to determine if the asynchronous call was successful. Use this MSDN example as reference:
    private static void DownloadStringCallback (Object sender, DownloadStringCompletedEventArgs e)
{
    // If the request was not canceled and did not throw
    // an exception, display the resource.
    if (!e.Cancelled && e.Error == null)
    {
        string textString = (string)e.Result;

        Console.WriteLine (textString);
    }
}
    Eric Carter - SDET - Webmaster Tools Team
    Tuesday, April 14, 2009 6:09 PM
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    Hi Sascha,

    I am guessing that you are trying to run the silverlight application using the dynamically generated test page in VS 2008 ( option 2 - "Automatically generate a test page to host silverlight at build time" when you try to create the Silverlight application in VS 2008 ). Due to a bug in Silverlight 2 where if you try to do just this AND there is a clientccesspolicy.xml available ( compared to no clientaccesspolicy.xml and a crossdomain.xml file being available) , the securityexception is generated. The reason you are not hitting this exception while using the the flickr Url is because there is no clientaccesspolicy.xml file for flickr.

    As a workaround, please use option 1 - "Add a new ASP.NET Web project to the solution to host silverlight" while creating the silverlight application.

    HTH
    Roopali
    Wednesday, April 15, 2009 11:32 PM