query question
 

1. if my computer get a query message, how can I know where it comes from? is this possible? it doesn't show in the query definition in the protocol.
2. How can I know the file names the other peers are sharing? The pong message only gives how many files are sharing, but not the names.

Thanks a lot

You don't know where it comes from, you only know which ultrapeer transmitted you the query, - and that's where to send the queryReply.

How about the second Q? how to know that?

All queries have unique GUIDs so you can associate queryHits with the corresponding queries. In addition all clients keep routing-tables mapping the GUIDs to the connections that sent the messages.

What I mean is all the files a particular peer are sharing. I can know the # of files it is sharing from the pong, but not the names. How can I know that?

You can either connect via http and request a list of shared files or you can send a query for a keyword.

How to do this, do you have any referene? any code?

It is also possible that the query comes from its leaf? then how to distinguish if it is from a ultra or a leaf?

It's all documented in the files section at http://www.yahoogroups.com/groups/the_gdf and at rfc-gnutella.sf.net

you can't, except if you would mark the GUID. Some vendors put certain information into the GUID but it's not documented.

I'm a little bit confused: HTTP use port 80 and Gnutella 6346, how can they communicate? Even if I can send "Get /HTTP/1.1" to other peers, they're not servers, how can they response with the file name list? If they can, what is the HTTP request for the file name list? Thanks.

If you read the HTTP protocol you will see, that HTTP does not have a standard port.

If I want to set up a HTTP connection, how do I know the file path on the other computer?

You always have to know the URL in advance, before making the HTTP connection. How you learned of that URL does not really matter and is not covered by the HTTP specs.

Can anybody tell me how the "Browse Host" function in many P2P software finds out the URL of the other peers? Thanks.

Read the GDF protocol documents:
http://groups.yahoo.com/group/the_gdf/files/

Or read the code:
http://www.limewire.org

Thanks
-greg