sunlabs.brazil.groovy.GroovyServerTemplate Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of sunlabs.brazil Show documentation
Extremely small footprint Java HTTP stack.
The newest version!
/*
 * GroovyServerTemplate.java
 *
 * Brazil project web application toolkit,
 * export version: 2.3 
 * Copyright (c) 2004 Sun Microsystems, Inc.
 *
 * Sun Public License Notice
 *
 * The contents of this file are subject to the Sun Public License Version 
 * 1.0 (the "License"). You may not use this file except in compliance with 
 * the License. A copy of the License is included as the file "license.terms",
 * and also available at http://www.sun.com/
 * 
 * The Original Code is from:
 *    Brazil project web application toolkit release 2.3.
 * The Initial Developer of the Original Code is: suhler.
 * Portions created by suhler are Copyright (C) Sun Microsystems, Inc.
 * All Rights Reserved.
 * 
 * Contributor(s): suhler.
 *
 * Version:  1.3
 * Created by suhler on 04/12/16
 * Last modified by suhler on 04/12/30 13:44:32
 *
 * Version Histories:
 *
 * 1.3 04/12/30-13:44:32 (suhler)
 *   minor doc fixes
 *
 * 1.2 04/12/17-14:28:22 (suhler)
 *   Defer starting the groovy intepreter until the first time it's needed
 *
 * 1.2 04/12/16-20:44:08 (Codemgr)
 *   SunPro Code Manager data about conflicts, renames, etc...
 *   Name history : 1 0 groovy/GroovyServerTemplate.java
 *
 * 1.1 04/12/16-20:44:07 (suhler)
 *   date and time created 04/12/16 20:44:07 by suhler
 *
 */

package sunlabs.brazil.groovy;

import java.io.IOException;

import sunlabs.brazil.server.Server;
import sunlabs.brazil.template.RewriteContext;
import sunlabs.brazil.template.Template;
import sunlabs.brazil.handler.ResourceHandler;

import groovy.lang.Binding;
import groovy.lang.GroovyShell;
import org.codehaus.groovy.control.CompilationFailedException;

/**
 * The GroovyServerTemplate looks for each
 * <groovy>
 * tag in an HTML page and treats the following data up to the next
 * </groovy>)
 * tag as a groovy script to evaluate.
 * 
 * All Groovy fragments within a given page are evaluated in the same Groovy
 * interpreter.  The Groovy interpreter actually lives for the entire duration
 * of this Template object, so the user can implement
 * persistence across requests:  Each session gets its own interpreter.
 * 

 * The following configuration parameters are used to initialize this
 * template. 

 *  script
 *	
 The name of the Groovy script to evaluate when the interpreter is
 *	created.  This script only evaluated when the interp is created,
 *	not on every request. The variables prefix and
 *	server are set before this file is evaluated, and
 *	are references to the parameters passed to a handler
 *	init method.
 * 
 root
 *	
 The document root, if the script is a relative file name.
 *	If the "root" property under the template prefix is not found, the
 *	global "root" property is used.  If the global "root" property is
 *	not found, the current directory is used.
 * 
 debug
 *	
 If this configuration parameter is present, this class
 *	replaces the <groovy> and
 *	</groovy> tags with comments, so the user
 *	can keep track of where the dynamically generated content is coming
 *	from by examining the comments in the resultant HTML document.
 *	By default, the <groovy> and
 *	</groovy> are completely eliminated from the
 *	HTML document rather than changed into comments.
 * 
 * 
 * Before evaluating each HTML document, this class sets variables
 * in the Groovy interpreter, which can be used to interact back with Java to
 * do things like set the response headers: 

 *  request
 *	
 Exposes the {@link sunlabs.brazil.server.Request} Java object.  
 *	It is set anew at each request.
 * 
 prefix
 *	
 Exposes the handler prefix String.
 * 
 server
 *	
 Exposes the handler {@link sunlabs.brazil.server.Server} object.
 * 
 *
 * @author	Stephen Uhler
 * @version		GroovyServerTemplate.java
 */

public class GroovyServerTemplate extends Template {
    private static final String SCRIPT = "script";

    GroovyShell interp=null;		// our groovy interpreter
    Binding binding=null;		// Brazil - groovy interactionv
    boolean bad=false;			// bad init, don't retry

    /**
     * Initialize the groovy interperter (1st time only) and set the
     * current request object.
     */

    public boolean
    init(RewriteContext hr) {
	hr.addClosingTag("groovy");
	return super.init(hr);
    }

    /**
     * Set up the interp and run the init script (if any).
     */

    boolean
    setup(RewriteContext hr) {
	if (interp == null) {
	    try {
		binding = new Binding();
		interp = new GroovyShell(binding);
	    } catch (NoClassDefFoundError e) {
		hr.request.log(Server.LOG_ERROR, hr.prefix,
			"Missing Groovy libraries" + e);
		return false;
	    }
	    binding.setVariable("prefix", hr.prefix);
	    binding.setVariable("server", hr.server);

	    String script = hr.request.props.getProperty(hr.prefix + SCRIPT);
	    if (script != null) {
		try {
		    String body = ResourceHandler.getResourceString(
			    hr.request.props, hr.prefix, script);
		hr.request.log(Server.LOG_DIAGNOSTIC, hr.prefix, body);
			interp.evaluate(body);
		} catch (IOException e) {
		    hr.request.log(Server.LOG_DIAGNOSTIC, hr.prefix,
			"Can't read groovy script: " + e);
		    return false;
		} catch (CompilationFailedException e) {
		    hr.request.log(Server.LOG_DIAGNOSTIC, hr.prefix,
			"Can't compile groovy script: " + e);
		    return false;
		} catch (groovy.lang.GroovyRuntimeException e) {
		    debug(hr, "Groovy Runtime error: " + e.getMessage());
		    return false;
		}
	    }
	}
	binding.setVariable("request", hr.request);
	return true;
    }

    public void
    tag_groovy(RewriteContext hr) {
	debug(hr);
	hr.accumulate(false);
	hr.nextToken();
	String script = hr.getBody();
	hr.request.log(Server.LOG_DIAGNOSTIC, hr.prefix, script);
	debug(hr, script);
	if (!bad && setup(hr)) {
	    try {
		Object result = interp.evaluate(script);
		hr.append(result.toString());
	    } catch (CompilationFailedException e) {
		debug(hr, "Bad Script: " + e.getMessage());
	    } catch (IOException e) {
		debug(hr, "I/O problem: " + e.getMessage());
	    } catch (groovy.lang.GroovyRuntimeException e) {
		debug(hr, "Groovy error: " + e.getMessage());
	    }
	} else {
	    bad = true;
	}
	hr.nextToken();
	hr.accumulate(true);
    }
}