Hi, Im playing around with the /boost_asio/example/http/server3 and using POST method. The bytes_transferred is 231, but thats only the header and ends with \r\n\r\n, need to read the rest. Sometimes i get bytes_transferred to 1032, the right amount of data, sometimes i get bytes_transferred = 231, but if i print the buffer_ i have all the 1032 bytes. Is it right that the bytes in the buffer_ and the bytes_transferred is not the same? appreciate any help. /christer void connection::handle_read(const boost::system::error_code& e, std::size_t bytes_transferred) { if (!e) { boost::tribool result; boost::tie(result, boost::tuples::ignore) = request_parser_.parse( request_, buffer_.data(), buffer_.data() + bytes_transferred); if (result) { request_handler_.handle_request(request_, reply_); boost::asio::async_write(socket_, reply_.to_buffers(), strand_.wrap( boost::bind(&connection::handle_write, shared_from_this(), boost::asio::placeholders::error))); } else if (!result) { reply_ = reply::stock_reply(reply::bad_request); boost::asio::async_write(socket_, reply_.to_buffers(), strand_.wrap( boost::bind(&connection::handle_write, shared_from_this(), boost::asio::placeholders::error))); } else { socket_.async_read_some(boost::asio::buffer(buffer_), strand_.wrap( boost::bind(&connection::handle_read, shared_from_this(), boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred))); } }
On Saturday, April 28, 2012 4:57 AM, Christer Borgqvist wrote:
Im playing around with the /boost_asio/example/http/server3 and using POST method. The bytes_transferred is 231, but thats only the header and ends with \r\n\r\n, need to read the rest. Sometimes i get bytes_transferred to 1032, the right amount of data, sometimes i get bytes_transferred = 231, but if i print the buffer_ i have all the 1032 bytes. Is it right that the bytes in the buffer_ and the bytes_transferred is not the same?
appreciate any help. /christer
It is normal for async_read_some to read less than the size requested. Think of it as a request to read whatever is available up to a maximum size. If you wish to read the whole buffer, then check out ::boost::asio::async_read at http://www.boost.org/doc/libs/1_49_0/doc/html/boost_asio/reference/async _read.html Depending on your needs, you might also use ::boost::asio::async_read_until http://www.boost.org/doc/libs/1_49_0/doc/html/boost_asio/reference/async _read_until.html
On Sat, Apr 28, 2012 at 10:56:49AM +0200, Christer Borgqvist wrote:
Hi, Im playing around with the /boost_asio/example/http/server3 and using POST method. The bytes_transferred is 231, but thats only the header and ends with \r\n\r\n, need to read the rest. Sometimes i get bytes_transferred to 1032, the right amount of data, sometimes i get bytes_transferred = 231, but if i print the buffer_ i have all the 1032 bytes. Is it right that the bytes in the buffer_ and the bytes_transferred is not the same?
Only the first 'bytes_transferred' octets are the ones you asked for, the rest are indeterminate (or well, likely whatever they were before you made the read). The language doesn't know how many of the elements you consider "valid" or "real", it just knows about the size of the storage. If you've got a container that fits 1032 bytes, it stays so after the call, as the read/read_some functions only work with existing dumb storage. read_some is a low-level function that doesn't give that many promises in number of bytes read. The reason it's used here is because the length of a HTTP message or header is unknown and it's happy enough just reading repeatedly in arbitrary chunks until it has enough to parse the request. Last, but not least, TCP is a stream protocol. The chunks you write data to the connection are not preserved in any way across the stream. When the data arrives at the recieving end, it's just a boundary-less sequence of bytes, which your underlying platform tends to give you in chunks of uncorrelated size. -- Lars Viklund | zao@acc.umu.se
participants (3)
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Andrew Holden -
Christer Borgqvist -
Lars Viklund