io.continual.http.service.framework.routing.playish.CHttpPlayishRoutingFileSource Maven / Gradle / Ivy

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/*
 *	Copyright 2019, Continual.io
 *
 *	Licensed under the Apache License, Version 2.0 (the "License");
 *	you may not use this file except in compliance with the License.
 *	You may obtain a copy of the License at
 *	
 *	http://www.apache.org/licenses/LICENSE-2.0
 *	
 *	Unless required by applicable law or agreed to in writing, software
 *	distributed under the License is distributed on an "AS IS" BASIS,
 *	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *	See the License for the specific language governing permissions and
 *	limitations under the License.
 */

package io.continual.http.service.framework.routing.playish;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;
import java.util.NoSuchElementException;
import java.util.StringTokenizer;

import org.slf4j.LoggerFactory;

import io.continual.resources.ResourceLoader;

public class CHttpPlayishRoutingFileSource extends CHttpPlayishStaticEntryPointRoutingSource
{
	public CHttpPlayishRoutingFileSource ( File f ) throws IOException
	{
		this ( f, true );
	}

	public CHttpPlayishRoutingFileSource ( File f, boolean withAutoRefresh ) throws IOException
	{
		super ();

		loadRoutes ( f );
		createRefreshThread ( f, withAutoRefresh );
	}

	public CHttpPlayishRoutingFileSource ( URL u ) throws IOException
	{
		super ();

		if ( u == null )
		{
			throw new IOException ( "URL for routing file is null in CHttpPlayishRoutingFileSource ( URL )" );
		}
		loadRoutes ( u );
	}

	public CHttpPlayishRoutingFileSource ( ResourceLoader rl ) throws IOException
	{
		super ();

		loadRoutes ( rl );
	}

	private static final org.slf4j.Logger log = LoggerFactory.getLogger ( CHttpPlayishRoutingFileSource.class );

	private synchronized void loadRoutes ( URL u ) throws IOException
	{
		loadRoutes ( new InputStreamReader ( u.openStream () ) );
	}

	private synchronized void loadRoutes ( File f ) throws IOException
	{
		loadRoutes ( new FileReader ( f ) );
	}

	private synchronized void loadRoutes ( ResourceLoader rl ) throws IOException
	{
		final InputStream is = rl.load ();
		if ( is == null ) throw new IOException ( "Unable to load " + rl.toString () );
		loadRoutes ( new InputStreamReader ( is ) );
	}

	private synchronized void loadRoutes ( Reader r ) throws IOException
	{
		clearRoutes ();

		final BufferedReader fr = new BufferedReader ( r );
		
		String line;
		while ( ( line = fr.readLine () ) != null )
		{
			line = line.trim ();
			if ( line.length () > 0 && !line.startsWith ( "#" ) )
			{
				processLine ( line );
			}
		}
	}

	private void processLine ( String line )
	{
		try
		{
			final StringTokenizer st = new StringTokenizer ( line );
			final String verb = st.nextToken ();
			if ( verb.toLowerCase ().equals ( "package" ) )
			{
				final String pkg = st.nextToken ();
				addPackage ( pkg );
			}
			else
			{
				final String path = st.nextToken ();
				final String action = st.nextToken ();
				addRoute ( verb, path, action );
			}
		}
		catch ( NoSuchElementException e )
		{
			log.warn ( "There was an error processing route config line: \"" + line + "\"" );
		}
		catch ( IllegalArgumentException e )
		{
			log.warn ( "There was an error processing route config line: \"" + line + "\": " + e.getMessage () );
		}
	}

	private Thread createRefreshThread ( final File f, boolean routeRefresh )
	{
		Thread result = null;
		if ( routeRefresh )
		{
			result = new Thread ()
			{
				private long fLastMod = f.lastModified ();
	
				@Override
				public void run ()
				{
					try
					{
						sleep ( 2000 );
					}
					catch ( InterruptedException e1 )
					{
						// ignore
					}
	
					final long lastMod = f.lastModified (); 
					if ( lastMod > fLastMod )
					{
						log.info ( "Reloading routes from " + f.getAbsolutePath () );
						try
						{
							fLastMod = lastMod;
							loadRoutes ( f );
						}
						catch ( IOException e )
						{
							log.error ( "Unable to load route file", e );
						}
					}
				}					
			};
			result.setName ( "Route file update watcher for " + f.getName () + "." );
			result.setDaemon ( true );
			result.start ();
		}
		return result;
	}
}