Transferring files

Upon receiving a QueryHit message a servent may initiate a HTTP connection with the host holding the file. The GET command issued by the servent contains the index of the requested file, as specified in the result set of the QueryHit message. Following the index is the name of the file. Next follows a small example.

Assume that a QueryHit message contained at least the entry shown in table tbl:examplequeryhitresult.

Table 3.10: Example of a QueryHit result

Index	Size	Name
1342	78835	gnutella_0.6_draft.txt

A download request for the file gnutella_0.6_draft.txt would be initiated as follows:

    GET /get/1342/gnutella_0.6_draft.txt HTTP/1.1\r\n
    User-Agent: Gnutella\r\n
    Host: 123.456.789.012:6346\r\n
    Connection: Keep-Alive\r\n
    Range: bytes=0-\r\n
    \r\n
   

The servent receiving this request responds with HTTP compliant headers such as:

    HTTP/1.1 200 OK\r\n
    Server: Gnutella\r\n
    Content-type: text/plain\r\n
    Content-length: 78835\r\n
    \r\n
   

The Range header can be used to request a file segment, if this header contains a range other than the whole file. This allows a Gnutella client to download different parts of the same file from different hosts, which can reduce the download time substantially. This technique is called swarm downloading. If a segment is requested the HTTP response headers could look as follows:

    HTTP/1.1 206 Partial Content\r\n
    Server: Gnutella\r\n
    Content-Type: text/plain\r\n
    Content-Length: 24761\r\n
    Content-Range: bytes 32104-56864/78835\r\n
    \r\n