1、 Introduction to TCP Protocol

TCP is a reliable connection oriented transmission protocol. During TCP transmission, data is divided into TCP packets and transmitted to the destination address. TCP ensures the reliability of data transmission through the following three methods:

Confirmation and retransmission mechanism: After receiving data, the receiver will return a confirmation message, and if the sender does not receive confirmation, the data will be retransmitted.

Congestion control: TCP avoids network congestion by dynamically adjusting the sending rate.

Flow control: There is a buffer between the sender and receiver to control the sending rate of data and avoid data loss.

2、 TCP data reception mechanism

When using Python for TCP data reception, we need to use the recv method in the socket library. The function of this method is to receive data sent by the client (or server) and return a string.

In the above code, connection represents the connection with the client, address represents the client address, the recv method receives data sent by the client, and parameter 1024 represents a maximum of 1024 bytes received each time.

3、 Reasons for incomplete TCP data reception

However, in practical use, we often encounter situations where TCP data reception is incomplete. This is because the TCP protocol is based on data flow, where data is divided into multiple TCP packets for transmission, and multiple packets are merged into a complete data flow. The data received by the recv method may not be transmitted in full at once, but rather divided into multiple transmissions, resulting in incomplete data reception.

4、 Solution

1. Set the receive buffer size

We can avoid incomplete data reception by setting the buffer size for each data reception. for example

In the above code, a loop iteration is used to receive 1024 bytes of data each time, and it is added to the data buffer until all data is received.

2. Manually adding delimiters

Manually add a delimiter when sending data, and then the receiving end specifies the same delimiter for data reception. for example

In the above code, each time the data is received, it is converted into a string and incomplete data is separated. Determine whether the received data contains line breaks, and if so, extract the complete data for processing.

Incomplete data reception in Python TCP is a common issue that can be resolved by setting the receive buffer size or manually adding delimiters. I hope this article is helpful to readers.