2007-08-14

erlang inet:setopts 未公开选项

关键字: erlang setopts
inet:setopt有packet设置选项：
{packet, PacketType} (TCP/IP sockets)
Defines the type of packets to use for a socket. The following values are valid:
raw | 0
No packaging is done.
1 | 2 | 4
Packets consist of a header specifying the number of bytes in the packet, followed by that number of bytes. The length of header can be one, two, or four bytes; the order of the bytes is big-endian. Each send operation will generate the header, and the header will be stripped off on each receive operation.
asn1 | cdr | sunrm | fcgi | tpkt | line
These packet types only have effect on receiving. When sending a packet, it is the responsibility of the application to supply a correct header. On receiving, however, there will be one message sent to the controlling process for each complete packet received, and, similarly, each call to gen_tcp:recv/2,3 returns one complete packet. The header is not stripped off.
The meanings of the packet types are as follows:
asn1 - ASN.1 BER,
sunrm - Sun's RPC encoding,
cdr - CORBA (GIOP 1.1),
fcgi - Fast CGI,
tpkt - TPKT format [RFC1006],
line - Line mode, a packet is a line terminated with newline, lines longer than the receive buffer are truncated.
文档中写的就这么多了 其实还有2个选项：http， httph 用于解释http的请求
实现在otp_src_R11B-5\erts\emulator\drivers\common\inet_drv.c 里面
#ifdef USE_HTTP
。。。
#endif
/*
** load http message:
**  {http_eoh, S}                          - end of headers
**  {http_header,   S, Key, Value}         - Key = atom() | string()
**  {http_request,  S, Method,Url,Version}
**  {http_response, S, Version, Status, Message}
**  {http_error,    S, Error-Line}
*/
消息以上面的方式发给process，用于gen_tcp


由于在driver层面实现的 所以效率就很高，对于编写http隧道之类的程序 很有帮助哦
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