Hi Karsten,
don't stop the feedback!
Karsten Ohme wrote:
> Hi,
>
> I want to program a proxy (actually tunnel). All connections are made to the proxy, the proxy
> makes some decisions and forwards them to the server. For my situation many clients connect to
> the proxy on port 80, the proxy forwards the requests to a Tomcat server on port 8080 and
> writes the response back to the client.
Stupid question: can the client connect directly to Tomcat or does all
connection must go to the proxy? I suspect all connections have to pass
through the proxy, but in case not, the proxy can always send a redirect
to the client (using the location: header).
>
> How can I acieve this with Grizzly? I though I had to extend the TCPSelectorHandler, overwrite
> the onAcceptInterest method, establish there a new TCPConnectorHandler for the path client-proxy
> and one for proxy-server and register CallbackHandlers wo propagate the read and write
> operations.
I would not override the onAcceptInterest but instead let the default
workflow happen. On of the reason is onAcceptInterest is executed on the
same thread as the Selector.select(), which is a performance bottleneck.
I would instead implement two ProtocolFilters that uses the newly added
ConnectionPool/Cache. My recommendation is to do:
1. Use the default ReadFilter to execute the first read to make sure the
connection hasn't been closed between the accept() and the first read.
2. Add a new ProxyProtocolFilter:
+ When initializing, create a pool of connection your remote server
(Tomcat). I recommend you take a look at the new ConnectionPool/Cache
Alexey demonstrated yesterday at the Grizzly meeting.
+ When execute() is invoked, use a StreamAlgorithm implementation to
make sure you can read the complete HTTP request (note: you gonna need
to buffer the body as well). The module/http sub module have a
StreamAlgorithm implementations called
ContentLengthAlgorithm|StateMachineAlgoruithm that can be reused. Mainly
those classes will make sure the entire headers + body are read.
+ Once you have read all the bytes, get a connection from the connection
pool and flush the bytes to Tomcat. Make the
TCPConnectionHandler.write(bb,TRUE) so the temporary Selector trick can
be reused.
+ Then read back the response and flush it back to the client.
Would that make sense? You might also want to create two ProtocolFilter,
one for reading the request, and one for writing the response to the
active connection to Tomcat.
>
> But I don't know how the ProtocolFilter fits into the picture. How do I use it? I also
> want to use TLS connections. How can I get the data which is decoded?
>
> Is there any documentation or tutorial for the new Grizzly API?
Take a look at the following talks:
https://grizzly.dev.java.net/presentations/FISL-2007.pdf
http://weblogs.java.net/blog/jfarcand/archive/BOF-4989-Grizzly.pdf
We don't have yet tutorials but I'm working on one right now.
Hope that help.
-- Jeanfrancois
>
> Regards,
> Karsten
>
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