Microsoft Silverlight 2.0 and the Last.FM webservices

- sinistrad said...
- User
- 10 Mar 2008, 15:15
Microsoft Silverlight 2.0 and the Last.FM webservices

Hi All,

After the release of Silverlight 2.0 last week i tried to make a nice Silverlight banner that reads the Last.FM webservices. A great new feature (WebClient Class) is introduced in Silverlight that enable you to read data from the internet. Too bad MS included a new security method on webservice calls:
The WebClient class does not currently support cross-domain calls. The current release of WebClient requires that the Silverlight-based application be hosted on the same server as the target Web service. Alternatively, if the Web service and Silverlight-based application are hosted in separate domains, the Web service hosting the service must have an XML policy file that indicates that clients can make these cross-domain calls.
from this page: Sending and Receiving Plain XML Messages with Silverlight
a sample app on Scott Guthrie's sample.

According to MS the webservice provider has to explicitly opt-in to allow cross-domain access. By opting-in, a service states that the operations it exposes can safely be invoked by a Silverlight control, without potentially damaging consequences to the data the service stores.

The solution is to add a XML to http://ws.audioscrobbler.com:

Silverlight supports two different mechanisms for services to opt-in to cross-domain access:

Place a clientaccesspolicy.xml file at the root of the domain where the service is hosted to configure the service to allow cross-domain-access.

Place a valid crossdomain.xml file at the root of the domain where the service is hosted. The file must mark the entire domain public. Silverlight supports a subset of the crossdomain.xml schema.

For more info see the microsoft page How to: Make a Service Available Across Domain Boundaries and a post about this issue on My blog

Is it possible for Last.FM to create one of these XML files on the audioscrobbler website ?

Sincerly,
Kasper

[quote][b][user]sinistrad[/user][/b] said: Hi All, After the release of Silverlight 2.0 last week i tried to make a nice Silverlight banner that reads the Last.FM webservices. A great new feature (WebClient Class) is introduced in Silverlight that enable you to read data from the internet. Too bad MS included a new security method on webservice calls: [quote]The WebClient class does not currently support cross-domain calls. The current release of WebClient requires that the Silverlight-based application be hosted on the same server as the target Web service. Alternatively, if the Web service and Silverlight-based application are hosted in separate domains, the Web service hosting the service must have an XML policy file that indicates that clients can make these cross-domain calls.[/quote] from this page: [url=http://silverlight.net/Quickstarts/Remote/UsingREST.aspx]Sending and Receiving Plain XML Messages with Silverlight[/url] a sample app on [url=http://weblogs.asp.net/scottgu/pages/silverlight-tutorial-part-3-using-networking-to-retrieve-data-and-populate-a-datagrid.aspx]Scott Guthrie's sample[/url]. According to MS the webservice provider has to explicitly opt-in to allow cross-domain access. By opting-in, a service states that the operations it exposes can safely be invoked by a Silverlight control, without potentially damaging consequences to the data the service stores. The solution is to add a XML to http://ws.audioscrobbler.com: [quote] Silverlight supports two different mechanisms for services to opt-in to cross-domain access: Place a clientaccesspolicy.xml file at the root of the domain where the service is hosted to configure the service to allow cross-domain-access. Place a valid crossdomain.xml file at the root of the domain where the service is hosted. The file must mark the entire domain public. Silverlight supports a subset of the crossdomain.xml schema. [/quote] For more info see the microsoft page [url=http://msdn2.microsoft.com/en-us/library/cc197955(VS.95).aspx]How to: Make a Service Available Across Domain Boundaries[/url] and a post about this issue on [url=http://community.ada-ict.nl/blogs/kjonge/archive/2008/03/10/silverlight-2-0-and-network-cross-domain-calls.aspx]My blog[/url] Is it possible for Last.FM to create one of these XML files on the audioscrobbler website ? Sincerly, Kasper [/quote]

Permalink Quote
- Noin said...
- User
- 22 Mar 2008, 12:18
I got hit by the same problem just yesterday as well.
Would be nice to have a crossdomain.xml file in the domain root.

More info:
http://www.crossdomainxml.org/

[quote][b][user]Noin[/user][/b] said: I got hit by the same problem just yesterday as well. Would be nice to have a crossdomain.xml file in the domain root. More info: http://www.crossdomainxml.org/[/quote]

Permalink Quote
- sanakan said...
- User
- 22 Apr 2008, 04:28
how about bugging Microsoft to fix this (i.e. to properly allow to access web services), instead of thousands of WS-providers?

[quote][b][user]sanakan[/user][/b] said: how about bugging Microsoft to fix this (i.e. to properly allow to access [b]web[/b] services), instead of thousands of WS-providers?[/quote]

Permalink Quote

Anonymous users may not post messages. Please log in or create an account to post in the forums.