XML Parsing in OpenSim: Example – reading RSS feeds

In OpenSim you’re not just restricted to using LSL for scripting, it’s also possible to use c#. This opens up the possiblilities for far more powerful scripts that can access c# in built libraries.

For example I’ve previously mentioned that the string processing methods in Second Life are not very flexible when it comes to reading formatted data. Thus the reason I implemented the osParseJSON method to make Web APIs easier to use.

Obviously another common data format is XML, in this case I don’t have to implement any new OpenSim script functions because the XML capabilities are available natively in c#.

Here is a simple example of reading the RSS feed for my blog, and reading out the entries in chat.


//c#
// displays the contents of an RSS 2.0 feed

string URL = “http://robsmart.co.uk/feed”;
System.Xml.XmlDocument xDoc = new System.Xml.XmlDocument();
LSL_Types.LSLString requestID;

public void default_event_state_entry()
{
llSay(0,”RSS reader current Feed is ” + URL);
getFeedContent();

}

public void getFeedContent()
{
requestID = llHTTPRequest(URL, new LSL_Types.list(), “” );
}

public void default_event_touch_start(LSL_Types.LSLInteger total_number)
{
// read out the RSS feed.
displayFeed();

}

public void displayFeed()
{
System.Xml.XmlNodeList items = xDoc.GetElementsByTagName(“item”);

for(int i=0;i < items.Count ; i++)
{
string title = items[i].SelectSingleNode(“title”).InnerXml;
string link = items[i].SelectSingleNode(“link”).InnerXml;

string description=”no description available”;

if(items[i].SelectSingleNode(“description”)!=null)
description = items[i].SelectSingleNode(“description”).InnerXml;

llSay(0,title + “\n” + description + “\n”);
}
}

public void default_event_http_response(LSL_Types.LSLString request_id, LSL_Types.LSLInteger status, LSL_Types.list metadata, LSL_Types.LSLString body)
{
if (requestID == request_id)
{
// store the xml
xDoc.LoadXml(body);

// process the xml
llOwnerSay(“loaded feed”);
}
}

6 Comments

  1. Larry

    Sorry, I am using version 0.62 and have enabled c# compiling. I pasted your script to the script window, but when it compiles it says that System doesn’t contain Xml (The type or namespace name ‘Xml’ does not exist in the namespace ‘System’ (are you missing an assembly reference?))

    Other namespaces in System seem to be ok, but I can’t get Xml working, and it is very useful!

    Where can I find the syntax to use in such scripts? For example namespace and using statements are not accepted either.

    Thanks in advance!

  2. Rob (Post author)

    Hi Larry,

    Are you using the pre-built 0.62 version for windows or linux ?

    I just tried the script again on the latest version straight from SVN and it worked fine. If you like you can email me your OpenSim.ini file and i’ll see if there is something in your settings that prevents this from working.

    my email is rob.s.smart AT gmail.com

  3. Mike

    Is OpenSim Generally reasonably straightforward to use – my boss has just asked me about it and I’m trying not to look like a nodding dog. Have just been to opensimulator.org to download a copy – hopefully I’ll get the hang of it quickly as he wants some investigations for tuesday

  4. su

    Hi Rob,
    I am also getting the same error that Larry got. were you being able to figure out the cause for that?
    Or is it ok for me to e-mail you my opensim.ini file?
    I am using 0.6.6 (I just downloaded the setup.exe, did not build it from the source code)

    Su

  5. su

    http://opensimulator.org/mantis/view.php?id=4137
    Seems like references are harcoded in the compiler. Is there a way to change that?

  6. Dimitha

    Hello everyone,

    I am also getting the the same error that Larry got (System doesn’t contain Xml (The type or namespace name ‘Xml’ does not exist in the namespace ‘System’ (are you missing an assembly reference?)).

    I am using 0.6.7. Any idea??

    Regards,
    Dimitha

Comments are closed.