sunlabs.brazil.handler.PollHandler 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
Show all versions of sunlabs.brazil Show documentation
Extremely small footprint Java HTTP stack.
The newest version!
/*
* PollHandler.java
*
* Brazil project web application toolkit,
* export version: 2.3
* Copyright (c) 2000-2006 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: 2.5
* Created by suhler on 00/12/13
* Last modified by suhler on 06/12/11 14:48:12
*
* Version Histories:
*
* 2.5 06/12/11-14:48:12 (suhler)
* - allow relative url's
* - fix code to match the documentation
*
* 2.4 04/08/30-09:02:15 (suhler)
* "enum" became a reserved word, change to "enumer".
*
* 2.3 02/11/04-14:01:40 (suhler)
* oops
*
* 2.2 02/11/04-13:55:55 (suhler)
* Merged changes between child workspace "/home/suhler/brazil/naws" and
* parent workspace "/net/mack.eng/export/ws/brazil/naws".
*
* 1.15.1.1 02/11/04-13:55:38 (suhler)
* move check for redundant poll into the right place
*
* 2.1 02/10/01-16:36:23 (suhler)
* version change
*
* 1.15 02/07/30-16:21:22 (suhler)
* - fixed bug in then==now computation
* - code reordering
*
* 1.14 02/07/29-15:29:43 (suhler)
* make sure a "host" header is present
*
* 1.13 02/07/11-15:02:27 (suhler)
* changed interface to fillProps to take an HttpRequest object instead of
* an input stream
*
* 1.12 02/07/10-11:26:23 (suhler)
* add note to indicate future encoding option
*
* 1.11 02/06/13-17:56:13 (suhler)
* don't do interval checking at init time
*
* 1.10 02/04/18-11:09:53 (suhler)
* add ${..} evaluation of url's
*
* 1.9 02/02/26-14:24:54 (suhler)
* - made "namespace" a separate configuration parameter (it was convolved with
* "prepend")
* - added "headers" parameter to specify additional http headers added to each
* polled request
*
* 1.8 01/11/21-11:42:54 (suhler)
* doc fixes
*
* 1.7 01/08/13-16:22:55 (suhler)
* added "format" option to spedify format for "Cron" matching of date/times
*
* 1.6 01/08/01-17:14:31 (suhler)
* Allow properties to be extracted into a sessionmanager session,
* accessable via
*
* 1.5 01/07/10-17:26:48 (suhler)
* make url, post, and interval public, so they may be
* modified from python or tcl
*
* 1.4 01/06/04-11:04:11 (suhler)
* allow "post" input
*
* 1.3 01/03/06-09:05:29 (suhler)
* Add:
* - talk through proxy
* - better error diagnostics
* - more robust behavior in the face of errors
*
* 1.2 00/12/14-17:48:28 (suhler)
* added cron like capability, allowing a url fetch based on a schedule
*
* 1.2 00/12/13-12:16:37 (Codemgr)
* SunPro Code Manager data about conflicts, renames, etc...
* Name history : 1 0 handlers/PollHandler.java
*
* 1.1 00/12/13-12:16:36 (suhler)
* date and time created 00/12/13 12:16:36 by suhler
*
*/
package sunlabs.brazil.handler;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.SimpleTimeZone;
import java.util.Date;
import java.util.Enumeration;
import java.util.Locale;
import java.util.Properties;
import sunlabs.brazil.server.Handler;
import sunlabs.brazil.server.Request;
import sunlabs.brazil.server.Server;
import sunlabs.brazil.util.Format;
import sunlabs.brazil.util.http.HttpRequest;
import sunlabs.brazil.util.http.HttpUtil;
import sunlabs.brazil.util.regexp.Regexp;
import sunlabs.brazil.session.SessionManager;
/**
* Handler for periodically polling another web site, whose
* results are (optionally) added to the server's properties.
* This also includes the ability to request URL's on a cron-like schedule.
*
* The result of fetching the url is expected to be a text document in
* java Properties format.
*
* Properties:
*
* - url
- URL to fetch periodically.
* any ${...} constructs are evaluated at each poll, with
* the values in the server properties object. If the URL
* starts with "/", then the current server is used.
*
- post
- The "post" data, if any. ${...} are evaluates as per
*
url above.
* - headers
- A list of white space delimited tokens that refer to
* additional HTTP headers that are added onto the polled
* request. For each token the server properties
*
[token].name and [token].value
* define a new http header.
* - interval
- The interval (in seconds) to fetch the url. Defaults
* to 10 seconds. If match is specified, this is the
* interval used to check for a time/date match.
* At each "interval", the current time format is computed, based
* on "format", below. If the computed format has not
* changed since the previous poll, then no poll is done.
* The interval is recalculated after each poll.
*
- fast
- If set, don't wait "interval" before 1st poll.
*
- prepend
- The string to prepend to the properties.
* If not supplied no properties are loaded.
*
- namespace
- The namespace to use to store the properties to.
* If the
sessionTable (see below)parameter is
* identical to the sessionTable parameter of
* the SetTemplate, then this specifies the
* namespace parameter that may be used with
* the SetTemplate "namespace" parameter to
* obtain the extracted data. Defaults to the "prepend" parameter.
* - match
- If specified, a regular expression that must match
* the current time for this URL to run. The format to match is
* specified by the "format" parameter, below.
* "EEE-dd-HH-mm" (eg: Thu-Dec, 14, 14:12 pm).
*
- format
- a {@link java.text.SimpleDateFormat date format specifier}
* to use for matching "match"
* patterns. Defaults to "EE-MM-dd-HH-mm".
*
- proxy
- If specified, connect through a proxy. This should be
* in the form
host:port, or host
* it the desired port is 80.
* - sessionTable
*
- The name of the SessionManager table to use for
* storing values. By default, properties are stored in
* server.props. The value should match the
sessionTable
* used by the {@link sunlabs.brazil.template.SetTemplate} to allow
* values obtained by this handler to be accessable from within
* templates.
*
* If the sessionTable is set, the namespace
* value is used to name the table (e.g. the namespace
* specified by {@link sunlabs.brazil.template.SetTemplate}. If no
* namespace parameter is given, then prepend is used
* as the namespace parameter.
*
*
* If prepend is specified, the following additional
* properties are
* created, and added to the properties with the specified prefix.
*
* - count.attempts
- The total number of polls attemped.
*
- count.errors
- The total number of poll failures.
*
- error.at
- The poll attempt # for the last failure.
*
- error.msg
- The message describing the last failure.
*
- error.time
- The timestamp of the last failure.
*
- timestamp
- The timestamp for the last successful poll.
*
*
* @author Stephen Uhler
* @version %V% PollHandler.java 2.5
*/
public class PollHandler extends Thread implements Handler {
public String url; // url to fetch
public String post; // post data to send
public int interval; // how often to fetch it (ms)
long pollCount = 0; // # of times polled
long errorCount = 0; // # of times polls failed
Server server; // our server.
String prefix; // our prefix
String prepend; // our prefix in the props table
String namespace; // our namespace in the session manager
Regexp re; // the re to match the date/time expression
String then; // Last time we processed this url
String proxyHost=null; // The proxyhost to use (if any)
String sessionTable; // the "other" session key
SimpleDateFormat date; // date format for "cron" matching
int proxyPort = 80; // The proxyport
String tokens; // our tokens in server.props
String match;
boolean fast; // make first poll withoug waiting
/**
* Set up the initial configuration, and kick off a thread
* to periodically fetch the url.
*/
public boolean
init(Server server, String prefix) {
this.server = server;
this.prefix = prefix;
prepend = server.props.getProperty(prefix + "prepend");
namespace = server.props.getProperty(prefix + "namespace", prepend);
url = server.props.getProperty(prefix + "url");
post = server.props.getProperty(prefix + "post");
tokens = server.props.getProperty(prefix + "headers");
fast= (server.props.getProperty(prefix + "fast") != null);
sessionTable = server.props.getProperty(prefix + "sessionTable");
String proxy = server.props.getProperty(prefix + "proxy");
if (proxy != null) {
int index = proxy.indexOf(":");
if (index < 0) {
proxyHost = proxy;
} else {
proxyHost = proxy.substring(0,index);
try {
proxyPort =
Integer.decode(proxy.substring(index+1)).intValue();
} catch (Exception e) {}
}
server.log(Server.LOG_DIAGNOSTIC, prefix, "Proxy to: " +
proxyHost + ":" + proxyPort);
}
server.log(Server.LOG_DIAGNOSTIC, prefix, "Polling: " + url);
String format = server.props.getProperty(prefix + "format",
"EE-MM-dd-HH-mm");
date = new SimpleDateFormat(format, Locale.US);
date.setTimeZone(SimpleTimeZone.getDefault());
if (url == null) {
server.log(Server.LOG_WARNING, prefix, "Invalid url");
return false;
}
/*
* work on the match stuff
*/
match = server.props.getProperty(prefix + "match");
re = null;
if (match != null) {
try {
re = new Regexp(match, true);
} catch (Exception e) {
server.log(Server.LOG_WARNING, prefix, "Bad expression:" + e);
}
}
Thread poller = (Thread) this;
poller.setDaemon(true);
poller.start();
return true;
}
/**
* This might allow control over the polling via requests at a later date.
* For now, it always returns false.
*/
public boolean
respond(Request request) {
return false;
}
/**
* Periodically poll the url, and copy the results into the server
* properties.
*/
public void
run() {
Properties props;
if (sessionTable != null) {
props = (Properties) SessionManager.getSession(namespace,
sessionTable, Properties.class);
props.list(System.out);
} else {
props = new Properties();
}
boolean first = fast;
while(true) {
interval=10;
try {
String str = server.props.getProperty(prefix + "interval");
interval = Integer.decode(str).intValue();
} catch (Exception e) {}
if (interval < 1) {
interval=10;
}
server.log(Server.LOG_DIAGNOSTIC, prefix, "Sleeping: " +
interval);
try {
Thread.sleep(first ? 2 : interval * 1000);
} catch (InterruptedException e) {
break;
}
first = false;
if (re != null) {
String now = date.format(new Date(System.currentTimeMillis()));
server.log(Server.LOG_DIAGNOSTIC, prefix, "Checking: " +
now + " matches " + match);
if (now.equals(then)) {
server.log(Server.LOG_DIAGNOSTIC, prefix,
" Already polled at: " + now);
continue;
}
if (re.match(now) == null) {
server.log(Server.LOG_DIAGNOSTIC, prefix, now +
" match failed");
continue;
}
then = now;
}
url = Format.subst(server.props, url);
if (url.startsWith("/")) {
int port = server.listen.getLocalPort();
url = server.protocol + "://" + server.hostName +
(port != 80 ? ":" + port : "") + url;
}
server.log(Server.LOG_DIAGNOSTIC, prefix, "Polling: " + url);
pollCount++;
if (sessionTable == null) {
props.clear();
}
HttpRequest target = new HttpRequest(url);
if (proxyHost != null) {
target.setProxy(proxyHost, proxyPort);
}
if (tokens != null) {
target.addHeaders(tokens, server.props);
}
target.requestHeaders.putIfNotPresent("Host",
HttpUtil.extractUrlHost(url));
try {
if (post != null) {
OutputStream out = target.getOutputStream();
String data = Format.subst(server.props, post);
out.write(data.getBytes()); // XXX choose encoding here
out.close();
}
target.connect();
if (prepend != null) {
int code = target.getResponseCode();
if (code == 200) {
fillProps(props, target);
} else {
throw new Exception("Request failed, code: " + code);
}
}
} catch (Exception e) {
server.log(Server.LOG_DIAGNOSTIC, prefix, "target error: " + e);
errorCount++;
if (prepend != null) {
props.put(prepend + "error.msg", e.getMessage());
props.put(prepend + "error.time",
"" + System.currentTimeMillis());
props.put(prepend + "error.at", "" + pollCount);
}
} finally {
target.close();
}
server.log(Server.LOG_DIAGNOSTIC, prefix, " found " + props.size() +
" items");
if (prepend != null) {
props.put("timestamp", "" + System.currentTimeMillis());
props.put("count.attempts", "" + pollCount);
props.put("count.errors", "" + errorCount);
}
/*
* Copy the properties into the server.
*/
if (prepend != null && sessionTable == null) {
Enumeration enumer = props.propertyNames();
while(enumer.hasMoreElements()) {
String key = (String) enumer.nextElement();
server.props.put(prepend + key, props.getProperty(key));
}
}
}
}
/**
* Fill the properties from the input stream
*/
public void
fillProps(Properties props, HttpRequest target) throws IOException {
InputStream in = target.getInputStream();
props.load(in);
in.close();
}
}