JavascriptClientFilter.java

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package org.atmosphere.client;

import org.atmosphere.cpr.BroadcastFilter;
import org.atmosphere.cpr.PerRequestBroadcastFilter;

import javax.servlet.http.HttpServletRequest;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * Filter that inject Javascript code to a broadcast so it can be used with the Atmosphere JQuery Plugin.
 *
 * @author Jeanfrancois Arcand
 */
public class JavascriptClientFilter implements BroadcastFilter, PerRequestBroadcastFilter {

    private final AtomicInteger uniqueScriptToken = new AtomicInteger();

    @Override
    public BroadcastAction filter(Object originalMessage, Object message) {

        if (message instanceof String) {
            StringBuilder sb = new StringBuilder("<script id=\"atmosphere_")
                    .append(uniqueScriptToken.getAndIncrement())
                    .append("\">")
                    .append("parent.callback")
                    .append("('")
                    .append(message.toString())
                    .append("');</script>");
            message = sb.toString();
        }
        return new BroadcastAction(BroadcastAction.ACTION.CONTINUE, message);
    }

    @Override
    public BroadcastAction filter(HttpServletRequest request, Object message) {
        
        String userAgent = request.getHeader("User-Agent").toLowerCase();
        if (userAgent != null && userAgent.startsWith("opera") && message instanceof String) {
            StringBuilder sb = new StringBuilder("<script id=\"atmosphere_")
                    .append(uniqueScriptToken.getAndIncrement())
                    .append("\">")
                    .append("window.parent.$.atmosphere.streamingCallback")
                    .append("('")
                    .append(message.toString())
                    .append("');</script>");
            message = sb.toString();
        }
        return new BroadcastAction(BroadcastAction.ACTION.CONTINUE, message);
    }
}