Cannot receive HTTP multipart request completely with QTcpServer.

[FloatFlower.Huang]

I am going to write a HTTP server with QTcpServer, however, when I POST a form, which consist of 2 images:

#include <QDebug>
#include <QTcpSocket>
#include "server.h"

Server::Server(QObject *parent) : QObject(parent)
{
    m_server = new QTcpServer(this);
    connect(m_server, SIGNAL(newConnection()), this, SLOT(onNewConnection()));
}

void Server::start()
{
    m_server->listen(QHostAddress::LocalHost, 3000);
}

void Server::onNewConnection()
{
    qDebug() << "New Connection established!";
    if (m_server->hasPendingConnections())
    {
        QTcpSocket* socket = m_server->nextPendingConnection();
        connect(socket, SIGNAL(readyRead()), this, SLOT(onReadyRead()));
    }
}

void Server::onReadyRead()
{
    QObject *object = sender();
    QTcpSocket* socket = qobject_cast<QTcpSocket*>(object);
    qDebug() << socket->readAll().constData();
}

And I get the log:

New Connection established!
POST / HTTP/1.1
Host: localhost:3000
Connection: keep-alive
Content-Length: 72213
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.94 Safari/537.36
Cache-Control: no-cache
Origin: chrome-extension://fhbjgbiflinjbdggehcddcbncdddomop
Postman-Token: 3b55da60-6aa1-dbb3-6aab-b3203511fe3f
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary4TVn7aSuuFAV4SrU
Accept: */*
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.9,zh-TW;q=0.8,zh;q=0.7,zh-CN;q=0.6,ja;q=0.5

------WebKitFormBoundary4TVn7aSuuFAV4SrU
Content-Disposition: form-data; name="asda"; filename="whatever.png"
Content-Type: image/png

?PNG


??xkUi????[`?W???      HLH@bb"??<1??:u

however, a HTTP request which consist of two images should be in the form:

POST / HTTP/1.1
Host: localhost:3000
Cache-Control: no-cache
Postman-Token: dcae3f50-560a-7d19-a8c3-64afea5b362f
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW

------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="asda"; filename="whatever.png"
Content-Type: image/png

// body here
------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="asdaasd"; filename="whatever.png"
Content-Type: image/png

// body here
------WebKitFormBoundary7MA4YWxkTrZu0gW--

The log means that we cannot receive the request payload completely, what's wrong with this code, or is caused by Postman?

[FloatFlower.Huang]

That my fault.
I remove the function call:

// Before
qDebug() << socket->readAll().constData();
// After
qDebug() << socket->readAll();

and it works.