sunlabs.brazil.python.PythonServerTemplate Maven / Gradle / Ivy
Show all versions of sunlabs.brazil Show documentation
/*
* PythonServerTemplate.java
*
* Brazil project web application toolkit,
* export version: 2.3
* Copyright (c) 2000-2004 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): drach, suhler.
*
* Version: 2.4
* Created by suhler on 00/09/08
* Last modified by suhler on 04/11/30 15:19:40
*
* Version Histories:
*
* 2.4 04/11/30-15:19:40 (suhler)
* fixed sccs version string
*
* 2.3 03/08/01-16:19:36 (suhler)
* fixes for javadoc
*
* 2.2 03/07/07-14:45:11 (suhler)
* Merged changes between child workspace "/home/suhler/brazil/naws" and
* parent workspace "/net/mack.eng/export/ws/brazil/naws".
*
* 1.11.1.1 03/07/07-14:05:01 (suhler)
* use addClosingTag() convenience method
*
* 2.1 02/10/01-16:38:53 (suhler)
* version change
*
* 1.11 02/07/18-14:06:26 (suhler)
* don't do \
* \XXX expansions with eval
*
* 1.10 01/07/16-16:50:52 (suhler)
* use new Template convenience methods
*
* 1.6.1.1 01/06/04-11:06:58 (suhler)
* jython -vs- jpython
*
* 1.9 01/05/24-17:07:55 (drach)
* Add closing tag every time init() is called.
*
* 1.8 01/05/14-08:52:30 (drach)
* Use new debug method in super class Template.
*
* 1.7 01/05/14-08:33:31 (drach)
* Jython apparently doesn't have a classBasedException option.
*
* 1.6 01/04/06-08:51:29 (suhler)
* added "eval" attribute to perform ${...} substitutions before running script
*
* 1.5 00/12/11-13:31:45 (suhler)
* add class=props for automatic property extraction
*
* 1.4 00/10/06-16:04:19 (suhler)
* fixed initialization bug, add python tracebacks when log=5
*
* 1.3 00/09/13-14:48:41 (suhler)
* move to python package, add tag
*
* 1.2 00/09/08-19:40:11 (suhler)
* capture stdout of pyton interp
*
* 1.2 00/09/08-18:11:17 (Codemgr)
* SunPro Code Manager data about conflicts, renames, etc...
* Name history : 2 1 python/PythonServerTemplate.java
* Name history : 1 0 tcl/PythonServerTemplate.java
*
* 1.1 00/09/08-18:11:16 (suhler)
* date and time created 00/09/08 18:11:16 by suhler
*
*/
package sunlabs.brazil.python;
import sunlabs.brazil.server.Request;
import sunlabs.brazil.server.Server;
import sunlabs.brazil.handler.ResourceHandler;
import sunlabs.brazil.template.RewriteContext;
import sunlabs.brazil.template.Template;
import sunlabs.brazil.util.Format;
import org.python.core.PyException;
import org.python.core.Options;
import org.python.util.PythonInterpreter;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Properties;
/**
* The PythonServerTemplate looks for each
* <server language="python"> (or
* <python>)
* tag in an HTML page and treats the following data up to the next
* </server> (or </python>)
* tag as a python script to evaluate.
*
* The reason that python scripts are included in an HTML page is usually
* to generate dynamic, server-side content. After running this template,
* everything between and including the <server> and
* </server> (or <python> and
* </python> tags is replaced by all output written
* to the Python standard output stream (if any).
*
* All Python fragments within a given page are evaluated in the same Python
* interpreter. The Python interpreter actually lives for the entire duration
* of this Template object, so the user can implement
* persistence across requests.
*
* The following configuration parameters are used to initialize this
* template.
* - script
*
- The name of the Python 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
<server> and
* </server> 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 <server> and
* </server> are completely eliminated from the
* HTML document rather than changed into comments.
*
*
* Before evaluating each HTML document, this class sets variables
* in the Python 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.
*
* If the attribute eval is present as an attribute, all
* constructs off the form ${...} are substituted before processing the
* script.
*
* @author Stephen Uhler
* @version 2.4
*/
public class PythonServerTemplate
extends Template {
private static final String SCRIPT = "script";
PythonInterpreter interp = null;
ByteArrayOutputStream stdout;
/*
* Called at the beginning of each HTML document that this
* PythonServerTemplate is asked to process.
*
* The first time this method is called, the initialization script is
* sourced into the interpreter, based on the configuration properties
* in the Request
*
* @param hr
* The request and associated HTML document that will be
* processed.
*
* @return true interpreter was successfully initialized
* false otherwise. About the only way that the
* initialization could fail would be
* - there was an error sourcing the initialization script.
*
* If false is returned, an error message is logged.
*/
public boolean
init(RewriteContext hr) {
Properties props = hr.request.props;
if (interp == null) {
stdout = new ByteArrayOutputStream();
try {
Options.classBasedExceptions = false;
} catch (NoSuchFieldError e) {};
if (hr.server.logLevel >= Server.LOG_DIAGNOSTIC) {
Options.showJavaExceptions = true;
}
interp = new PythonInterpreter();
String script = props.getProperty(hr.prefix + SCRIPT);
// System.err.println("Creating Python interp");
try {
interp.set("prefix", hr.prefix);
interp.set("server", hr.server);
if (script != null) {
String body = ResourceHandler.getResourceString(props,
hr.prefix, script);
// System.err.println("startup: " + body);
interp.exec(body);
}
} catch (IOException e) {
hr.request.log(Server.LOG_ERROR, "reading init script", script);
return false;
} catch (PyException e) {
hr.request.log(Server.LOG_ERROR, "initializing Python",
e.toString());
return false;
}
// System.out.println("Init done");
}
hr.addClosingTag("python");
try {
hr.request.log(Server.LOG_DIAGNOSTIC, hr.prefix, "Setting request");
interp.set("request", hr.request);
} catch (PyException e) {
hr.request.log(Server.LOG_WARNING, hr.prefix,
"Setting up Python request: " + e.toString());
done(hr);
return false;
}
return super.init(hr);
}
/**
* Processes the <server> tag. Substitues the
* result of evaluating the following Python script into the resultant
* HTML document.
*
* Note: Currently, there is no mechanism for other language interpreters
* to share the same server tag.
*
* @param hr
* The request and associated HTML document that will be
* processed.
*/
public void
tag_server(RewriteContext hr) {
if ("python".equals(hr.get("language")) == false) {
return;
}
tag_python(hr);
}
/**
* Processes the <python> tag. Substitues the
* result of evaluating the following Python script into the resultant
* HTML document.
*
* @param hr
* The request and associated HTML document that will be
* processed.
*/
public void
tag_python(RewriteContext hr) {
debug(hr);
boolean eval = hr.isTrue("eval");
hr.accumulate(false);
hr.nextToken();
interp.setOut(stdout);
String script = hr.getBody();
if (eval) {
script = Format.subst(hr.request.props, script, true);
}
hr.request.log(Server.LOG_DIAGNOSTIC, hr.prefix, script);
try {
interp.exec(script);
} catch (PyException e) {
hr.append("\n\n");
hr.request.log(Server.LOG_DIAGNOSTIC, hr.prefix, e.toString());
}
interp.setOut(System.out);
hr.nextToken();
hr.append(stdout.toString());
stdout.reset();
hr.accumulate(true);
}
}