org.littleshoot.proxy.impl

Class ProxyToServerConnection

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

io.netty.channel.SimpleChannelInboundHandler<Object>

org.littleshoot.proxy.impl.ProxyToServerConnection

All Implemented Interfaces:

io.netty.channel.ChannelHandler, io.netty.channel.ChannelInboundHandler

@ChannelHandler.Sharable
public class ProxyToServerConnection
extends io.netty.channel.SimpleChannelInboundHandler<Object>

Represents a connection from our proxy to a server on the web. ProxyConnections are reused fairly liberally, and can go from disconnected to connected, back to disconnected and so on.

Connecting a ProxyToServerConnection can involve more than just connecting the underlying Channel. In particular, the connection may use encryption (i.e. TLS) and it may also establish an HTTP CONNECT tunnel. The various steps involved in fully establishing a connection are encapsulated in the property connectionFlow, which is initialized in initializeConnectionFlow().

Nested Class Summary

Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler

io.netty.channel.ChannelHandler.Sharable

Field Summary

Fields

Modifier and Type	Field and Description
protected io.netty.channel.Channel	channel
protected io.netty.channel.ChannelHandlerContext	ctx
protected long	lastReadTime
protected org.littleshoot.proxy.impl.ProxyConnectionLogger	LOG
protected DefaultHttpProxyServer	proxyServer
protected boolean	runsAsSslClient
protected SSLEngine	sslEngine If using encryption, this holds our SSLEngine.
protected org.littleshoot.proxy.impl.ConnectionFlowStep	StartTunneling Enables tunneling on this connection by dropping the HTTP related encoders and decoders, as well as idle timers.

Method Summary

Modifier and Type	Method and Description
static InetSocketAddress	addressFor(String hostAndPort, DefaultHttpProxyServer proxyServer) Build an InetSocketAddress for the given hostAndPort.
protected void	aggregateContentForFiltering(io.netty.channel.ChannelPipeline pipeline, int numberOfBytesToBuffer) Enables decompression and aggregation of content, which is useful for certain types of filtering activity.
protected void	becameSaturated() Callback that's invoked if this connection becomes saturated.
protected void	becameWritable() Callback that's invoked when this connection becomes writeable again.
protected void	become(org.littleshoot.proxy.impl.ConnectionState newState) Lifecycle
void	channelActive(io.netty.channel.ChannelHandlerContext ctx) Only once the Netty Channel is active to we recognize the ProxyConnection as connected.
void	channelInactive(io.netty.channel.ChannelHandlerContext ctx) As soon as the Netty Channel is inactive, we recognize the ProxyConnection as disconnected.
protected void	channelRead0(io.netty.channel.ChannelHandlerContext ctx, Object msg) Adapting the Netty API
void	channelRegistered(io.netty.channel.ChannelHandlerContext ctx)
void	channelWritabilityChanged(io.netty.channel.ChannelHandlerContext ctx)
protected void	connected() This method is called as soon as the underlying Channel is connected.
protected boolean	connectionFailed(Throwable cause) Called when the connection to the server or upstream chained proxy fails.
protected void	disconnected() This method is called as soon as the underlying Channel becomes disconnected.
protected io.netty.util.concurrent.Future<io.netty.channel.Channel>	encrypt(io.netty.channel.ChannelPipeline pipeline, SSLEngine sslEngine, boolean authenticateClients) Encrypts traffic on this connection with SSL/TLS.
protected io.netty.util.concurrent.Future<io.netty.channel.Channel>	encrypt(SSLEngine sslEngine, boolean authenticateClients) Encrypts traffic on this connection with SSL/TLS.
protected org.littleshoot.proxy.impl.ConnectionFlowStep	EncryptChannel(SSLEngine sslEngine) Encrypts the channel using the provided SSLEngine.
void	exceptionCaught(io.netty.channel.ChannelHandlerContext ctx, Throwable cause)
protected void	exceptionCaught(Throwable cause) Override this to handle exceptions that occurred during asynchronous processing on the Channel.
ChainedProxy	getChainedProxy()
InetSocketAddress	getChainedProxyAddress()
protected org.littleshoot.proxy.impl.ConnectionState	getCurrentState()
protected HttpFilters	getHttpFiltersFromProxyServer(io.netty.handler.codec.http.HttpRequest httpRequest) Request the ProxyServer for Filters.
io.netty.handler.codec.http.HttpRequest	getInitialRequest()
InetSocketAddress	getRemoteAddress()
String	getServerHostAndPort()
SSLEngine	getSslEngine()
TransportProtocol	getTransportProtocol() State Management
boolean	hasUpstreamChainedProxy()
protected boolean	is(org.littleshoot.proxy.impl.ConnectionState state) Utility for checking current state.
protected boolean	isConnecting() If this connection is currently in the process of going through a ConnectionFlow, this will return true.
protected boolean	isSaturated() Indicates whether or not this connection is saturated (i.e.
boolean	isTunneling()
protected void	read(Object msg) Reading
protected void	readHTTPChunk(io.netty.handler.codec.http.HttpContent chunk) Implement this to handle reading a chunk in a chunked transfer.
protected org.littleshoot.proxy.impl.ConnectionState	readHTTPInitial(io.netty.handler.codec.http.HttpResponse httpResponse) Implement this to handle reading the initial object (e.g.
protected void	readRaw(io.netty.buffer.ByteBuf buf) Implement this to handle reading a raw buffer as they are used in HTTP tunneling.
protected void	resumeReading() Call this to resume reading.
protected void	stopReading() Call this to stop reading.
protected void	timedOut() This method is called when the underlying Channel times out due to an idle timeout.
void	userEventTriggered(io.netty.channel.ChannelHandlerContext ctx, Object evt) We're looking for IdleStateEvents to see if we need to disconnect.
protected void	writeHttp(io.netty.handler.codec.http.HttpObject httpObject) Writes HttpObjects to the connection asynchronously.
protected void	writeRaw(io.netty.buffer.ByteBuf buf) Writes raw buffers to the connection.
protected io.netty.channel.ChannelFuture	writeToChannel(Object msg)

Methods inherited from class io.netty.channel.SimpleChannelInboundHandler

acceptInboundMessage, channelRead

Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

channelReadComplete, channelUnregistered

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

handlerAdded, handlerRemoved, isSharable

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface io.netty.channel.ChannelHandler

handlerAdded, handlerRemoved

Field Detail

LOG

protected final org.littleshoot.proxy.impl.ProxyConnectionLogger LOG

proxyServer

protected final DefaultHttpProxyServer proxyServer

runsAsSslClient

protected final boolean runsAsSslClient

ctx

protected volatile io.netty.channel.ChannelHandlerContext ctx

channel

protected volatile io.netty.channel.Channel channel

lastReadTime

protected volatile long lastReadTime

sslEngine

protected volatile SSLEngine sslEngine

If using encryption, this holds our SSLEngine.

StartTunneling

protected org.littleshoot.proxy.impl.ConnectionFlowStep StartTunneling

Enables tunneling on this connection by dropping the HTTP related encoders and decoders, as well as idle timers.

Note - the work is done on the ChannelHandlerContext's executor because ChannelPipeline.remove(String) can deadlock if called directly.

Method Detail

read

protected void read(Object msg)

Reading

readHTTPInitial

protected org.littleshoot.proxy.impl.ConnectionState readHTTPInitial(io.netty.handler.codec.http.HttpResponse httpResponse)

Implement this to handle reading the initial object (e.g. HttpRequest or HttpResponse).

Returns:

readHTTPChunk

protected void readHTTPChunk(io.netty.handler.codec.http.HttpContent chunk)

Implement this to handle reading a chunk in a chunked transfer.

readRaw

protected void readRaw(io.netty.buffer.ByteBuf buf)

Implement this to handle reading a raw buffer as they are used in HTTP tunneling.

writeHttp

protected void writeHttp(io.netty.handler.codec.http.HttpObject httpObject)

Writes HttpObjects to the connection asynchronously.

become

protected void become(org.littleshoot.proxy.impl.ConnectionState newState)

Lifecycle

becameSaturated

protected void becameSaturated()

Callback that's invoked if this connection becomes saturated.

becameWritable

protected void becameWritable()

Callback that's invoked when this connection becomes writeable again.

timedOut

protected void timedOut()

This method is called when the underlying Channel times out due to an idle timeout.

disconnected

protected void disconnected()

This method is called as soon as the underlying Channel becomes disconnected.

exceptionCaught

protected void exceptionCaught(Throwable cause)

Override this to handle exceptions that occurred during asynchronous processing on the Channel.

getTransportProtocol

public TransportProtocol getTransportProtocol()

State Management

getRemoteAddress

public InetSocketAddress getRemoteAddress()

getServerHostAndPort

public String getServerHostAndPort()

hasUpstreamChainedProxy

public boolean hasUpstreamChainedProxy()

getChainedProxyAddress

public InetSocketAddress getChainedProxyAddress()

getChainedProxy

public ChainedProxy getChainedProxy()

getInitialRequest

public io.netty.handler.codec.http.HttpRequest getInitialRequest()

getHttpFiltersFromProxyServer

protected HttpFilters getHttpFiltersFromProxyServer(io.netty.handler.codec.http.HttpRequest httpRequest)

Request the ProxyServer for Filters. By default, no-op filters are returned by DefaultHttpProxyServer. Subclasses of ProxyConnection can change this behaviour.

Parameters:

httpRequest - Filter attached to the give HttpRequest (if any)

Returns:

connectionFailed

protected boolean connectionFailed(Throwable cause)
                            throws UnknownHostException

Called when the connection to the server or upstream chained proxy fails. This method may return true to indicate that the connection should be retried. If returning true, this method must set up the connection itself.

Parameters:

cause - the reason that our attempt to connect failed (can be null)

Returns:

true if we are trying to fall back to another connection

Throws:

UnknownHostException

addressFor

public static InetSocketAddress addressFor(String hostAndPort,
                                           DefaultHttpProxyServer proxyServer)
                                    throws UnknownHostException

Build an InetSocketAddress for the given hostAndPort.

Parameters:

hostAndPort - String representation of the host and port

proxyServer - the current DefaultHttpProxyServer

Returns:

a resolved InetSocketAddress for the specified hostAndPort

Throws:

UnknownHostException - if hostAndPort could not be resolved, or if the input string could not be parsed into a host and port.

writeRaw

protected void writeRaw(io.netty.buffer.ByteBuf buf)

Writes raw buffers to the connection.

Parameters:

buf -

writeToChannel

protected io.netty.channel.ChannelFuture writeToChannel(Object msg)

connected

protected void connected()

This method is called as soon as the underlying Channel is connected. Note that for proxies with complex ConnectionFlows that include SSL handshaking and other such things, just because the Channel is connected doesn't mean that our connection is fully established.

encrypt

protected io.netty.util.concurrent.Future<io.netty.channel.Channel> encrypt(SSLEngine sslEngine,
                                                                            boolean authenticateClients)

Encrypts traffic on this connection with SSL/TLS.

Parameters:

sslEngine - the SSLEngine for doing the encryption

authenticateClients - determines whether to authenticate clients or not

Returns:

a Future for when the SSL handshake has completed

encrypt

protected io.netty.util.concurrent.Future<io.netty.channel.Channel> encrypt(io.netty.channel.ChannelPipeline pipeline,
                                                                            SSLEngine sslEngine,
                                                                            boolean authenticateClients)

Encrypts traffic on this connection with SSL/TLS.

Parameters:

pipeline - the ChannelPipeline on which to enable encryption

sslEngine - the SSLEngine for doing the encryption

authenticateClients - determines whether to authenticate clients or not

Returns:

a Future for when the SSL handshake has completed

EncryptChannel

protected org.littleshoot.proxy.impl.ConnectionFlowStep EncryptChannel(SSLEngine sslEngine)

Encrypts the channel using the provided SSLEngine.

Parameters:

sslEngine - the SSLEngine for doing the encryption

aggregateContentForFiltering

protected void aggregateContentForFiltering(io.netty.channel.ChannelPipeline pipeline,
                                            int numberOfBytesToBuffer)

Enables decompression and aggregation of content, which is useful for certain types of filtering activity.

Parameters:

pipeline -

numberOfBytesToBuffer -

isSaturated

protected boolean isSaturated()

Indicates whether or not this connection is saturated (i.e. not writeable).

Returns:

is

protected boolean is(org.littleshoot.proxy.impl.ConnectionState state)

Utility for checking current state.

Parameters:

state -

Returns:

isConnecting

protected boolean isConnecting()

If this connection is currently in the process of going through a ConnectionFlow, this will return true.

Returns:

getCurrentState

protected org.littleshoot.proxy.impl.ConnectionState getCurrentState()

isTunneling

public boolean isTunneling()

getSslEngine

public SSLEngine getSslEngine()

stopReading

protected void stopReading()

Call this to stop reading.

resumeReading

protected void resumeReading()

Call this to resume reading.

channelRead0

protected final void channelRead0(io.netty.channel.ChannelHandlerContext ctx,
                                  Object msg)
                           throws Exception

Adapting the Netty API

Specified by:

channelRead0 in class io.netty.channel.SimpleChannelInboundHandler<Object>

Throws:

Exception

channelRegistered

public void channelRegistered(io.netty.channel.ChannelHandlerContext ctx)
                       throws Exception

Specified by:

channelRegistered in interface io.netty.channel.ChannelInboundHandler

Overrides:

channelRegistered in class io.netty.channel.ChannelInboundHandlerAdapter

Throws:

Exception

channelActive

public final void channelActive(io.netty.channel.ChannelHandlerContext ctx)
                         throws Exception

Only once the Netty Channel is active to we recognize the ProxyConnection as connected.

Specified by:

channelActive in interface io.netty.channel.ChannelInboundHandler

Overrides:

channelActive in class io.netty.channel.ChannelInboundHandlerAdapter

Throws:

Exception

channelInactive

public void channelInactive(io.netty.channel.ChannelHandlerContext ctx)
                     throws Exception

As soon as the Netty Channel is inactive, we recognize the ProxyConnection as disconnected.

Specified by:

channelInactive in interface io.netty.channel.ChannelInboundHandler

Overrides:

channelInactive in class io.netty.channel.ChannelInboundHandlerAdapter

Throws:

Exception

channelWritabilityChanged

public final void channelWritabilityChanged(io.netty.channel.ChannelHandlerContext ctx)
                                     throws Exception

Specified by:

channelWritabilityChanged in interface io.netty.channel.ChannelInboundHandler

Overrides:

channelWritabilityChanged in class io.netty.channel.ChannelInboundHandlerAdapter

Throws:

Exception

exceptionCaught

public final void exceptionCaught(io.netty.channel.ChannelHandlerContext ctx,
                                  Throwable cause)
                           throws Exception

Specified by:

exceptionCaught in interface io.netty.channel.ChannelHandler

Specified by:

exceptionCaught in interface io.netty.channel.ChannelInboundHandler

Overrides:

exceptionCaught in class io.netty.channel.ChannelInboundHandlerAdapter

Throws:

Exception

userEventTriggered

public final void userEventTriggered(io.netty.channel.ChannelHandlerContext ctx,
                                     Object evt)
                              throws Exception

We're looking for IdleStateEvents to see if we need to disconnect.

Note - we don't care what kind of IdleState we got. Thanks to qbast for pointing this out.

Specified by:

userEventTriggered in interface io.netty.channel.ChannelInboundHandler

Overrides:

userEventTriggered in class io.netty.channel.ChannelInboundHandlerAdapter

Throws:

Exception