我正在尝试从boost :: asio服务器（嵌入式系统）发送编码和压缩的图像数据（~300kB），并通过python套接字客户端（笔记本电脑）接收它。当客户端发送大约350000字节时，客户端似乎每次只接收65532个字节。
我的想法是，可能有些东西将TCP数据包大小（boost :: asio或python socket或其他）限制在65535字节左右。
READY（长度为5的字符串）发送到服务器。READY。length，一个4字节uint（长度仅为消息;即排除length本身）。< / LI>
length和消息。服务器将在建立新连接时创建新的img_session对象。发生读取事件时，将调用handle_read()函数。 img_stream是zlib压缩和base64编码std::string，它是同步的＆＃39;通过img_lock。
客户端在线程中调用run_image()一次。该方法将首先发送READY信号并等待服务器响应。服务器的第一个响应将是消息其余部分的长度。然后它将不断接收消息的其余部分并将其保存在变量message中。同时，并发线程将对消息进行解码和解压缩，并将图像保留在变量frame中。
服务器代码（img_session.h）
#ifndef _IMG_SESSION_H_
#define _IMG_SESSION_H_
#include <session.h>
#include <boost/bind.hpp>
#include <boost/asio.hpp>
#include <iostream>
#include <utility.h>
#include <boost/thread.hpp>
class img_session : public session
{
public:
img_session(boost::asio::io_service& io_service, std::string * img_stream, int* img_lock);
~img_session();
/* Starts the session. This is called in the constructor.*/
void start();
private:
void handle_read(const boost::system::error_code& error, size_t bytes_transferred);
void handle_write(const boost::system::error_code& error);
std::string * img_stream;
int * img_lock;
};
#endif /* _IMG_SESSION_H */
服务器代码（img_session.cpp）
#include "img_session.h"
#include <session.h>
/* Public Methods */
img_session:: img_session(boost::asio::io_service& io_service, std::string * img_stream, int * img_lock) : session(io_service), img_stream(img_stream), img_lock(img_lock){
}
img_session::~img_session() { }
void img_session::start()
{
std::cout << "connection from " << _socket.remote_endpoint() << "\n";
std::cout << "img_session waiting for READY signal..." << std::endl;
_socket.async_read_some(boost::asio::buffer(_data, max_length),
boost::bind(&img_session::handle_read, this,
boost::asio::placeholders::error,
boost::asio::placeholders::bytes_transferred));
}
/* Private Methods */
void img_session::handle_read(const boost::system::error_code& error, size_t bytes_transferred)
{
if (!error)
{
char otherString[6];
std::cout << "[INFO ] IMG READ" << std::endl;
if (strncmp(_data, "READY", 5) == 0) {
std::cout << "[INFO ] READY signal received..." << std::endl;
while (*img_lock == 1) boost::this_thread::yield();
*img_lock = 1;
std::string message = std::string(*img_stream);
unsigned int len = message.length();
std::cout << "len = " << len << std::endl;
unsigned char bytes[4];
bytes[0] = (len >> 24) & 0xFF;
bytes[1] = (len >> 16) & 0xFF;
bytes[2] = (len >> 8) & 0xFF;
bytes[3] = len & 0xFF;
message = std::string((char* ) bytes, 4) + message;
std::cout << "img_session.cpp: bytes[] = " << (int) bytes[0] << " " << (int)bytes[1] << " " << (int)bytes[2] << " " << (int)bytes[3] << std::endl;
std::cout << "img_session.cpp: message.length() = " << message.length() << std::endl;
std::cout << "img_session.cpp: HEAD: " << message.substr(0, 1024) << std::endl;
std::cout << "img_session.cpp: TAIL: " << message.substr(message.length() - 1024, message.length() - 1);
boost::asio::async_write(_socket,
boost::asio::buffer(message.c_str(), message.length()),
boost::bind(&img_session::handle_write, this,
boost::asio::placeholders::error));
*img_lock = 0;
}
else {
std::cout << "[INFO ] READY signal not received..." << std::endl;
boost::asio::async_write(_socket,
boost::asio::buffer("", 1),
boost::bind(&img_session::handle_write, this,
boost::asio::placeholders::error));
}
clean();
}
else
{
delete this;
}
}
void img_session::handle_write(const boost::system::error_code& error)
{
if (!error)
{
std::cout << "img_session waiting for READY signal..." << std::endl;
_socket.async_read_some(boost::asio::buffer(_data, max_length),
boost::bind(&img_session::handle_read, this,
boost::asio::placeholders::error,
boost::asio::placeholders::bytes_transferred));
}
else
{
delete this;
}
}
客户代码（controller.py）
...
def run_image(hostname, port, interrupt):
global frame
sck = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sck.connect((hostname, port))
sck.settimeout(100)
message = None
while(interrupt.is_set()):
buffer = message
t = threading.Thread(target=decodeImg, args=(buffer,))
t.start()
answer = b" "
message = b""
sck.send(b"READY")
print("Sent READY signal")
answer = sck.recv(4)
num = int(answer[0] << 24) + int(answer[1] << 16) + int(answer[2] << 8) + int(answer[3])
print("num:", num)
try:
for i in range(math.ceil(num/1024)):
print("Receiving... (", i,"of",math.ceil(num/1024),")")
answer = sck.recv(1024) # row size
if (i == 0):
print("#### HEAD ####")
print(answer)
message += answer
except socket.timeout:
pass
print("#### TAIL ####")
print(answer)
print("###########################################")
print("##### Received! message (len=", len(message),") #####")
print("###########################################")
t.join()
#print("Updated")
sck.close()
print("run_image exited")
decompress = zlib.decompress
decode = base64.b64decode
toframe = pygame.image.fromstring
def decodeImg(raw):
if (raw is None or raw == ""):
return
global frame
print("Message length :", len(raw))
raw = decode(raw)
print("Decoded length :", len(raw))
raw = decompress(raw)
print("Decompressed length:", len(raw))
frame = toframe(raw, image_size, 'RGB')
if (frame is None):
print("ERR None frame")
...
（完整客户端代码位于https://pastebin.com/ut6L70XM）
服务器日志
...
connection from 127.0.0.1:61616
img_session waiting for READY signal...
[DEBUG] server.h: instance of img_session found
[INFO ] IMG READ
[INFO ] READY signal received...
[INFO ] img_stream.length() = 349544
len = 349544
img_session.cpp: bytes[] = 0 5 85 104
img_session.cpp: message.length() = 349548
img_session.cpp: HEAD: UheJy0vYGZpLgSrIsJMkEmyARMwASZIBNkAiZgQpnQJowJY8Ix4ZUyI
jITqnrPnnvv62V7KBBCUP3xKyJTYtvKdv8p6Td+2u1jeR5gP/W5oaSVtVRuKh8FvhyTV7095VkDz1u+V
ZVrbR8nq79cxfbtFI/Pv5/stmcvpbDJVc0sreC8a1fZarPf7722mddXuBeNLPZTsRfFCiusqrzVdw3vO
1wqjl2rONf6VO0O1Lq1dSCqKmulbLbwp64jqhVchzaUuS3r8Lax2rLpRJWfV2MKm6fL8SuIC6z2x5CLq
VX5o58xrhTNbjjpvu4edjWW8Yt6X8Yqs5ZNK9iCu7eXWm1LteW9/X0D/ZCKG871OByLGmC3ay3vjU3F3
rsaitmdbFar3dL1VduS7nBlDWt7LXu1b8m3V9SwVvZW2/7+3Nr+/r+uXY01vy9lLVZmLdu7YFsre92Hr
b+XrRylHK0eRz1aO+p7qX2vx96wvNd7q/1o63fVeqmjvbfYxrbKj2NtGdV+71qOtKy9+9jXmUdpo+/js
OW9sar8e1dL6+O92Mpuh7dbnR1lViVt/Y6Tro39vYy9t/1drOvjKvn+2HdbWh+rGdj7bsYqbCddB2L7f
vTdVt4fsfKuoR8dy7vCVc8x5rGaus57jHasSxv9XWx9fP9+r8+DW+b7nH28D+32+73MPrE+bOO0LcOW9
8f35mOtzPf2MdZGlZ/Vtmt5l8PhOHDiqLXBtpza+F7KmPvgRhRGtUOHHKp2tyYNtootPHBdOOMx38t5j
HqM4te789rfy/sGHrxXuF3vjb2tjbh16+69b/tm6/sqj9u4bjWL2eGo7X2WceC8645V+43t3bbbxzn89
rK221XUdRPsRg0rOXiXum3B3XivzHHyhhxz1dPfV3mui8WucU5bxvsujmvYlvf6NVeBc66P/b1MFFjHv
rfs65avwnNOHD77+yzn+irnuXcWu/p52oroVjLmHjR5bKm3YjcA/bKdp/hCKVX4laoJrL9C7yuUP8vc1
1lz/Ydj
img_session.cpp: TAIL: sC5fp569IQ/fnp9NsY4EfMdjx8cR77ftC8426c2vPM27KFV/q+Crrf1tH
/fnYt+KoafkL+S9PaSs96I4qAmH7fHK/p2qcY6IFrOdR14uAs87ssSvGTw+rx/ib0ci+kXMpRGd2D2Sx
cHWl4rCb42a3MHfFyUzlPUTwhm5rA+DWF1Z6JPUtpwUqX90KiWpYMzOer1mRRv5K1yOUPHB36F/H6PjY
Hw4NkqwQb0WHrJn2ws85PB3owhbaZ4iECNkp2D0aylzFBMLVOK4USwzpKFWQZpFXd2lOm8eicRyLAuKL
y3Gou2FvyGELfezceNR8I31QOXroJiuOOH9OMhSpxVgmPGlQ4XMXw5by49xfWOSrSIlVVOoBlUxAnp9u
xwSTPras50W+LMZAE6iSe26qbDbAPcyfeyQpIQ+91BTfkKdYbcaJBWH35RQ8qVLKKuoMaAvQlnIBms4l
XNeiFJesperkO000isv5NQ48FkQZ1Ua/w7AqRI6M1EEGuc4sSw7GdFmibbpNMGUnyjCxtkGQzjnaouUr
2o+ajPq3JSM2pt03zroAyzDs1axEu05eHWd5WDo5ZC0rvEd8RR496IsuxuzWCyeNszWWM9lQOGMAmtI4
Dm1I/egQrD6knzxq3sY2oXHNbJk1i5At0YpbLrOntb1AgHKcuyxZ/pXBvIAMpDac/LVXtNhXvA6Hel2Z
PvwOBj2GaXgpt7Evaj/Vm6WeePzRrQ+nQfzYDPUHkr5/B0rGvgQKrgi/Hz+ehT4zLPgu9GCHvmNIYStZ
fC7L7luR1NVhtBwKmSuQNip9DjfAe9/0a0k2fkx0Vko4HKijDkh62YmXF5YTBgG3jSgmRv/qvbeIZwP/
NsG+HIdYWGoqmxX0C5PamF936VxCd0bYz8rtjnf1v35pj8soTpHasDdfTFsvGuuRdMtFLycccHIVgK3I
gX9UnpZIjQnaeD2HpK2vubAyVc8CrIXAzdemYjOXHTo3EeI3/7RCR3yDA7qDsZIkNWj7vKl84XsQeH/A
X1TLNQ=
...
客户的日志
Sent READY signal
num: 349544
Receiving... ( 0 of 342 )
#### HEAD ####
b'eJy0vYGZpLgSrIsJMkEmyARMwASZIBNkAiZgQpnQJowJY8Ix4ZUyIjITqnrPnnvv62V7KBBCUP3xKyJTYtvKdv8p6Td+2u1jeR5gP/W5oaSVtVRuKh8FvhyTV7095VkDz1u+VZVrbR8nq79cxfbtFI/Pv5/stmcvpbDJVc0sreC8a1fZarPf7722mddXuBeNLPZTsRfFCiusqrzVdw3vO1wqjl2rONf6VO0O1Lq1dSCqKmulbLbwp64jqhVchzaUuS3r8Lax2rLpRJWfV2MKm6fL8SuIC6z2x5CLqVX5o58xrhTNbjjpvu4edjWW8Yt6X8Yqs5ZNK9iCu7eXWm1LteW9/X0D/ZCKG871OByLGmC3ay3vjU3F3rsaitmdbFar3dL1VduS7nBlDWt7LXu1b8m3V9SwVvZW2/7+3Nr+/r+uXY01vy9lLVZmLdu7YFsre92Hrb+XrRylHK0eRz1aO+p7qX2vx96wvNd7q/1o63fVeqmjvbfYxrbKj2NtGdV+71qOtKy9+9jXmUdpo+/jsOW9sar8e1dL6+O92Mpuh7dbnR1lViVt/Y6Tro39vYy9t/1drOvjKvn+2HdbWh+rGdj7bsYqbCddB2L7fvTdVt4fsfKuoR8dy7vCVc8x5rGaus57jHasSxv9XWx9fP9+r8+DW+b7nH28D+32+73MPrE+bOO0LcOW98f35mOtzPf2MdZGlZ/Vtmt5l8PhOHDiqLXBtpza+F7KmPvgRhRGtUOHHKp2tyYNtootPHBdOOMx38t5jHqM4te789rfy/sGHrxXuF3vjb2tjbh16+69b/tm6/sqj9u4bjWL2eGo7X2WceC8645V+43t3bbbxzn89rK221XUdRPsRg0rOXiXum3B3XivzHHyhhxz1dPfV3mui8WucU5bxvsujmvYlvf6NVeBc66P/b1MFFjHvrfs65avwnNOHD77+yzn+irnuXcWu/p52oroVjLmHjR5bKm3YjcA/bKdp/hCKVX4laoJrL9C7yuUP8vc11lz/Ydjfr/M'
...
Receiving... ( 63 of 342 )
b'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'
Receiving... ( 64 of 342 )
b''
Receiving... ( 65 of 342 )
b''
...
Receiving... ( 340 of 342 )
b''
Receiving... ( 341 of 342 )
b''
#### TAIL ####
b''
###########################################
##### Received! message (len= 65532 ) #####
###########################################
Message length : 65532
Decoded length : 49149
Exception in thread Thread-4:
Traceback (most recent call last):
File "C:\Python35\lib\threading.py", line 914, in _bootstrap_inner
self.run()
File "C:\Python35\lib\threading.py", line 862, in run
self._target(*self._args, **self._kwargs)
File "C:\Python35\controller.py", line 204, in decodeImg
raw = decompress(raw)
zlib.error: Error -5 while decompressing data: incomplete or truncated stream
答案 0 :(得分：3)
您从本地变量发送，但在写完成之前它已超出范围。
使message成为会员变量。
注意：
img_lock不是线程安全的
这是一个有效的演示：
<强> Live On Coliru
#ifndef _IMG_SESSION_H_
#define _IMG_SESSION_H_
#include <boost/bind.hpp>
#include <boost/asio.hpp>
#include <iostream>
#include <boost/thread.hpp>
struct session {
session(boost::asio::io_service& svc) : svc(svc) {
}
void clean() {}
boost::asio::io_service& svc;
boost::asio::ip::tcp::socket _socket{svc};
int max_length = 1024;
//std::array<char, 1024> _data;
char _data[1024];
};
class img_session : public session
{
public:
img_session(boost::asio::io_service& io_service, std::string * img_stream, int* img_lock);
~img_session();
/* Starts the session. This is called in the constructor.*/
void start();
private:
void handle_read(const boost::system::error_code& error, size_t bytes_transferred);
void handle_write(const boost::system::error_code& error, size_t bytes_transferred);
std::string * img_stream;
int * img_lock;
std::string message;
};
#endif /* _IMG_SESSION_H */
/* Public Methods */
img_session:: img_session(boost::asio::io_service& io_service, std::string * img_stream, int * img_lock) : session(io_service), img_stream(img_stream), img_lock(img_lock){
}
img_session::~img_session() { }
void img_session::start()
{
std::cout << "connection from " << _socket.remote_endpoint() << "\n";
std::cout << "img_session waiting for READY signal..." << std::endl;
_socket.async_read_some(boost::asio::buffer(_data, max_length),
boost::bind(&img_session::handle_read, this,
boost::asio::placeholders::error,
boost::asio::placeholders::bytes_transferred));
}
/* Private Methods */
void img_session::handle_read(const boost::system::error_code& error, size_t /*bytes_transferred*/)
{
if (!error)
{
//char otherString[6];
std::cout << "[INFO ] IMG READ" << std::endl;
if (strncmp(_data, "READY", 5) == 0) {
std::cout << "[INFO ] READY signal received..." << std::endl;
while (*img_lock == 1) boost::this_thread::yield();
*img_lock = 1;
message = "0000" + *img_stream;
size_t len = message.length();
std::cout << "len = " << len << std::endl;
message[0] = (len >> 24) & 0xFF;
message[1] = (len >> 16) & 0xFF;
message[2] = (len >> 8) & 0xFF;
message[3] = len & 0xFF;
std::cout << "img_session.cpp: bytes[] = " << (int) message[0] << " " << (int)message[1] << " " << (int)message[2] << " " << (int)message[3] << std::endl;
std::cout << "img_session.cpp: message.length() = " << message.length() << std::endl;
std::cout << "img_session.cpp: HEAD: " << message.substr(4, 1024) << std::endl;
std::cout << "img_session.cpp: TAIL: " << message.substr(message.length() - 1024, message.length() - 1);
boost::asio::async_write(_socket,
boost::asio::buffer(message),
boost::bind(&img_session::handle_write, this,
boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred));
*img_lock = 0;
}
else {
std::cout << "[INFO ] READY signal not received..." << std::endl;
/*
*boost::asio::async_write(_socket,
* boost::asio::buffer("", 1),
* boost::bind(&img_session::handle_write, this,
* boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred));
*/
}
clean();
}
else
{
delete this;
}
}
void img_session::handle_write(const boost::system::error_code& error, size_t bytes_transferred)
{
if (!error)
{
std::cout << "img_session waiting for READY signal..." << std::endl;
_socket.async_read_some(boost::asio::buffer(_data, max_length),
boost::bind(&img_session::handle_read, this,
boost::asio::placeholders::error,
boost::asio::placeholders::bytes_transferred));
}
else
{
std::cout << __FUNCTION__ << ":" << error.message() << "\n";
delete this;
}
}
int main() {
boost::asio::io_service svc;
std::string img_stream(300<<10, '*');
int img_lock = 0;
auto s = new img_session(svc, &img_stream, &img_lock);
using boost::asio::ip::tcp;
tcp::acceptor a(svc);
a.open(tcp::v4());
a.set_option(tcp::acceptor::reuse_address(true));
a.bind({{}, 6767});
a.listen(1);
a.accept(s->_socket);
s->start();
svc.run();
}
这是在使用客户端时
netcat localhost 6767 | wc
READY
打印
0 1 307204