如何检测时已被完全接收一个协议缓冲区的消息？ [英] How to detect when a Protocol Buffer message is fully received?
问题描述
这是怎样的一个分支了我的
This is kind of a branch off of my other question. Read it if you like, but it's not necessary.
基本上，我意识到，为了有效地使用C＃的大消息BeginReceive（），我需要是（a ）先读取数据包长度，然后阅读正是许多字节或（b）使用结束分组的分隔符。我的问题是，要么这些存在于协议缓冲区？我没有用他们尚未，但去的文档在它似乎并不像有一个长头或分隔符。
Basically, I realized that in order to effectively use C#'s BeginReceive() on large messages, I need to either (a) read the packet length first, then read exactly that many bytes or (b) use an end-of-packet delimiter. My question is, are either of these present in protocol buffers? I haven't used them yet, but going over the documentation it doesn't seem like there is a length header or a delimiter.
如果不是，我应该怎么办？我应该只是建立消息的长度页眉/ EOP分隔符然后前缀/后缀呢？
If not, what should I do? Should I just build the message then prefix/suffix it with the length header/EOP delimiter?
推荐答案
您需要包括大小或结束标志在你的协议。没有内置于基于流套接字（TCP / IP），比支承八位任意分成单独的数据包的不确定流等（和数据包可以在运输过程中以及被溢出）。
You need to include the size or end marker in your protocol. Nothing is built into stream based sockets (TCP/IP) other than supporting an indefinite stream of octets arbitrarily broken up into separate packets (and packets can be spilt in transit as well).
一个简单的方法是对每一个信息有一个固定大小标头，包括一个协议版本和净荷大小和任何其它固定的数据。然后，该消息内容（负载）。
A simple approach would be for each "message" to have a fixed size header, include both a protocol version and a payload size and any other fixed data. Then the message content (payload).
可选的消息页脚（固定大小）可以用一个校验和，甚至是密码签名加入（取决于你的可靠性/安全性要求）。
Optionally a message footer (fixed size) could be added with a checksum or even a cryptographic signature (depending on your reliability/security requirements).
知道了有效载荷的大小可以让你保持读取的字节数，这将对于消息的其余部分是足够（如果读取与少，做完成另一种阅读，直到整个消息已收到剩余的字节）。
Knowing the payload size allows you to keep reading a number of bytes that will be enough for the rest of the message (and if a read completes with less, doing another read for the remaining bytes until the whole message has been received).
有一个结束消息的指标也可以，但是你需要定义如何处理包含您的留言同样的八位顺序...
Having a end message indicator also works, but you need to define how to handle your message containing that same octet sequence...
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