org.littleshoot.proxy.impl

Class ClientToProxyConnection

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

io.netty.channel.SimpleChannelInboundHandler<Object>

org.littleshoot.proxy.impl.ClientToProxyConnection

All Implemented Interfaces:

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

public class ClientToProxyConnection
extends io.netty.channel.SimpleChannelInboundHandler<Object>

Represents a connection from a client to our proxy. Each ClientToProxyConnection can have multiple ProxyToServerConnections, at most one per outbound host:port.

Once a ProxyToServerConnection has been created for a given server, it is continually reused. The ProxyToServerConnection goes through its own lifecycle of connects and disconnects, with different underlying Channels, but only a single ProxyToServerConnection object is used per server. The one exception to this is CONNECT tunneling - if a connection has been used for CONNECT tunneling, that connection will never be reused.

As the ProxyToServerConnections receive responses from their servers, they feed these back to the client by calling respond(ProxyToServerConnection, HttpFilters, HttpRequest, HttpResponse, HttpObject) .

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

Methods

Modifier and Type	Method and Description
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() When the ClientToProxyConnection becomes saturated, stop reading on all associated ProxyToServerConnections.
protected void	becameWritable() When the ClientToProxyConnection becomes writable, resume reading on all associated ProxyToServerConnections.
protected void	become(org.littleshoot.proxy.impl.ConnectionState state) Udpates the current state to the given value.
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() On connect of the client, start waiting for an initial HttpRequest.
protected void	disconnected() On disconnect of the client, disconnect all server connections.
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.
InetSocketAddress	getClientAddress()
protected org.littleshoot.proxy.impl.ConnectionState	getCurrentState()
SSLEngine	getSslEngine()
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.
boolean	isMitming()
protected boolean	isSaturated() Indicates whether or not this connection is saturated (i.e.
boolean	isTunneling()
protected void	read(Object msg) Read is invoked automatically by Netty as messages arrive on the socket.
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.HttpRequest httpRequest) Reading
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	serverBecameSaturated(ProxyToServerConnection serverConnection) When a server becomes saturated, we stop reading from the client.
protected void	serverBecameWriteable(ProxyToServerConnection serverConnection) When a server becomes writeable, we check to see if all servers are writeable and if they are, we resume reading.
protected boolean	serverConnectionFailed(ProxyToServerConnection serverConnection, org.littleshoot.proxy.impl.ConnectionState lastStateBeforeFailure, Throwable cause) If the ProxyToServerConnection fails to complete its connection lifecycle successfully, this method is called to let us know about it.
protected void	serverConnectionFlowStarted(ProxyToServerConnection serverConnection) Called when ProxyToServerConnection starts its connection flow.
protected void	serverConnectionSucceeded(ProxyToServerConnection serverConnection, boolean shouldForwardInitialRequest) If the ProxyToServerConnection completes its connection lifecycle successfully, this method is called to let us know about it.
protected void	serverDisconnected(ProxyToServerConnection serverConnection) On disconnect of the server, track that we have one fewer connected servers and then disconnect the client if necessary.
protected void	setMitming(boolean isMitming)
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

readHTTPInitial

protected org.littleshoot.proxy.impl.ConnectionState readHTTPInitial(io.netty.handler.codec.http.HttpRequest httpRequest)

Reading

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.

connected

protected void connected()

On connect of the client, start waiting for an initial HttpRequest.

timedOut

protected void timedOut()

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

disconnected

protected void disconnected()

On disconnect of the client, disconnect all server connections.

serverConnectionFlowStarted

protected void serverConnectionFlowStarted(ProxyToServerConnection serverConnection)

Called when ProxyToServerConnection starts its connection flow.

Parameters:

serverConnection -

serverConnectionSucceeded

protected void serverConnectionSucceeded(ProxyToServerConnection serverConnection,
                             boolean shouldForwardInitialRequest)

If the ProxyToServerConnection completes its connection lifecycle successfully, this method is called to let us know about it.

Parameters:

serverConnection -

shouldForwardInitialRequest -

serverConnectionFailed

protected boolean serverConnectionFailed(ProxyToServerConnection serverConnection,
                             org.littleshoot.proxy.impl.ConnectionState lastStateBeforeFailure,
                             Throwable cause)

If the ProxyToServerConnection fails to complete its connection lifecycle successfully, this method is called to let us know about it.

After failing to connect to the server, one of two things can happen:

1. If the server was a chained proxy, we fall back to connecting to the ultimate endpoint directly.
2. If the server was the ultimate endpoint, we return a 502 Bad Gateway to the client.

Parameters:

serverConnection -

lastStateBeforeFailure -

cause - what caused the failure

Returns:

true if we're falling back to a another chained proxy (or direct connection) and trying again

serverDisconnected

protected void serverDisconnected(ProxyToServerConnection serverConnection)

On disconnect of the server, track that we have one fewer connected servers and then disconnect the client if necessary.

Parameters:

serverConnection -

becameSaturated

protected void becameSaturated()

When the ClientToProxyConnection becomes saturated, stop reading on all associated ProxyToServerConnections.

becameWritable

protected void becameWritable()

When the ClientToProxyConnection becomes writable, resume reading on all associated ProxyToServerConnections.

serverBecameSaturated

protected void serverBecameSaturated(ProxyToServerConnection serverConnection)

When a server becomes saturated, we stop reading from the client.

Parameters:

serverConnection -

serverBecameWriteable

protected void serverBecameWriteable(ProxyToServerConnection serverConnection)

When a server becomes writeable, we check to see if all servers are writeable and if they are, we resume reading.

Parameters:

serverConnection -

exceptionCaught

protected void exceptionCaught(Throwable cause)

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

isMitming

public boolean isMitming()

setMitming

protected void setMitming(boolean isMitming)

getClientAddress

public InetSocketAddress getClientAddress()

read

protected void read(Object msg)

Read is invoked automatically by Netty as messages arrive on the socket.

Parameters:

msg -

writeHttp

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

Writes HttpObjects to the connection asynchronously.

Parameters:

httpObject -

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)

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:

become

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

Udpates the current state to the given value.

Parameters:

state -

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