XML Parsing in OpenSim: Example – reading RSS feeds

Rob Smart | October 27, 2008

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”);
}
}

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OpenSim Web 2.0 contribution

Rob Smart | September 14, 2008

As described over on Eightbar I have made my first contribution to the OpenSim opensource project. The contribution is in the form of a new scripting function called osParseJSON. This function allows a c# script in OpenSim to consume the JSON notation provided by many of the major Web 2.0 APIs provided by services such as Flickr and Google translation.

The following example is a script that uses the Google Translate API to let an OpenSim avatar translate ther conversations between 23 different languages.

(disclaimer – please read the terms of conditions of the Google translate API and abide by them)

//c#
// This script is written as an example use of the osParseJSON method
// it uses the Google translate API
// ensure you have read the terms and conditions of the Google translate API
// http://code.google.com/apis/ajaxlanguage/documentation/

LSL_Types.key requestID;
string sourceLang = "en";
string targetLang = "fr";

public void default_event_state_entry()
{
     llSay(0,"translator running say '/1 sentence' to translate something");
     llSay(0,"translator running say '/2 source langage' to change target language e.g. '/2 fr'");
     llSay(0,"translator running say '/3 target langage' to change source language e.g. '/3 en'");
     llSay(0,"translator running say '/4 help', to list languages");
     llListen(1, "", NULL_KEY, "");
     llListen(2, "", NULL_KEY, "");
     llListen(3, "", NULL_KEY, "");
     llListen(4, "", NULL_KEY, "");
}

public void default_event_touch_start(LSL_Types.LSLInteger total_number)
{
     llSay(0,"translator running say '/1 sentence' to translate something");
     llSay(0,"translator running say '/2 source langage' to change target language e.g. '/2 fr'");
     llSay(0,"translator running say '/3 target langage' to change source language e.g. '/3 en'");
     llSay(0,"translator running say '/4 help', to list languages");
}

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)
        {
            // the Google JSON string returned wil be of the format
            //  {"responseData": {"translatedText":"Bonjour"}, "responseDetails": null, "responseStatus": 200}
            // call the osParseJSON method so we can read the contents 
            System.Collections.Hashtable response = (System.Collections.Hashtable) osParseJSON(body);
            System.Collections.Hashtable responsedata = (System.Collections.Hashtable) response["responseData"];

            llSay(0,(string)responsedata["translatedText"]);
        }
}

public void default_event_listen(LSL_Types.LSLInteger channelIn, LSL_Types.LSLString name, LSL_Types.LSLString id, LSL_Types.LSLString message)
{
    if(channelIn==1)
    {
        string toTranslate = (string) message;
        requestID = llHTTPRequest( "http://ajax.googleapis.com/ajax/services/language/translate?v=1.0&q="+toTranslate+"&langpair="+sourceLang+"%7C"+targetLang, new LSL_Types.list(), "" );  

    }
    else if(channelIn==2)
    {
        sourceLang = (string) message;
    }
    else if(channelIn==3)
    {
        targetLang = (string)message;
    }
    else if(channelIn==4)
    {
        llOwnerSay("LANGUAGE (CODE)");
        llOwnerSay("*  Arabic (ar)");
        llOwnerSay("* Bulgarian (bg)");
        llOwnerSay("* Chinese (zh)");
        llOwnerSay("* Croatian (hr)");
        llOwnerSay("* Czech (cs)");
        llOwnerSay("* Danish (da)");
        llOwnerSay("* Dutch (nl)");
        llOwnerSay("* English (en)");
        llOwnerSay("* Finnish (fi)");
        llOwnerSay("* French (fr)");
        llOwnerSay("* German (de)");
        llOwnerSay("* Greek (el)");
        llOwnerSay("* Hindi (hi)");
        llOwnerSay("* Italian (it)");
        llOwnerSay("* Japanese (ja)");
        llOwnerSay("* Korean (ko)");
        llOwnerSay("* Norwegian(no) ");
        llOwnerSay("* Polish (pl)");
        llOwnerSay("* Portuguese (pt-PT)");
        llOwnerSay("* Romanian (ro)");
        llOwnerSay("* Russian (ru)");
        llOwnerSay("* Spanish (es)");
        llOwnerSay("* Swedish (sv)"); 

    }
}
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