Upload files using QNetworkManager is not woking - php

Question

So I'm trying to upload a simple text file using Qt Network Mangager to a php script that I'm serving. But it's not working. I tried examples with QHttpMultiPart and with Setting raw data headers in request but none work.
Here is my Qt Code:
#include <QCoreApplication>
#include <QNetworkReply>
#include <QNetworkRequest>
#include <QDebug>
#include <QEventLoop>
#include <QObject>
#include <QVariantMap>
#include <QJsonDocument>
#include <QFile>
#include <QHttpMultiPart>
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QString address = "http://localhost/api_test/";
//address = "https://dashboard.viewmind.ai/dashboard/api_test/welcome.php";
QUrl api_url = QUrl(address);
QVariantMap postDatamap;
postDatamap.insert("Name","Ariel Ñoño");
postDatamap.insert("Age",37);
QJsonDocument json = QJsonDocument::fromVariant(postDatamap);
qDebug() << "Sending the request";
QNetworkAccessManager *networkManager = new QNetworkAccessManager();
QNetworkRequest request(api_url);
QString bound = "<<<<<boundary>>>>>";
request.setRawHeader(QString("Content-Type").toUtf8(),QString("multipart/form-postData; boundary=" + bound).toUtf8());
//QByteArray postData;
QByteArray postData(QString("--" + bound + "\r\n").toUtf8());
postData.append("Content-Disposition: form-postData; name=\"action\"\r\n\r\n");
postData.append("welcome.php\r\n");
postData.append(QString("--" + bound + "\r\n").toUtf8());
postData.append("Content-Disposition: form-postData; name=\"uploaded\"; filename=\"");
postData.append("test.json");
postData.append("\"\r\n");
postData.append("Content-Type: text/xml\r\n\r\n"); //postData type
QFile file("test.json");
if (!file.open(QIODevice::ReadOnly)){
qDebug() << "QFile Error: File not found!";
delete networkManager;
return 0;
} else { qDebug() << "File found, proceed as planned"; }
postData.append(file.readAll());
postData.append("\r\n");
postData.append(QString("--" + bound + "\r\n").toUtf8());
request.setRawHeader(QString("Content-Length").toUtf8(), QString::number(postData.length()).toUtf8());
//request.setHeader(QNetworkRequest::ContentTypeHeader,"application/json; charset=utf-8");
//request.setHeader(QNetworkRequest::ContentDispositionHeader, QVariant("form-postData; name=\"text\""));
//qDebug() << QString(json.toJson());
//QHttpMultiPart multipart(QHttpMultiPart::FormDataType);
//QHttpPart textPart;
// QFile file("test.json");
// if (!file.open(QIODevice::ReadOnly)){
// qDebug() << "Could not open file for reading";
// delete networkManager;
// return 0;
// }
//textPart.setBodyDevice(&file);
//multipart.append(textPart);
//file.setParent(&multipart);
//QNetworkReply *reply = networkManager->post(request,json.toJson());
//QNetworkReply *reply = networkManager->post(request,file.readAll());
//QNetworkReply *reply = networkManager->post(request,&multipart);
QNetworkReply *reply = networkManager->post(request,postData);
//file.setParent(reply);
//multipart.setParent(reply);
// Using the loop to wait for the reply to finish.
QEventLoop loop;
QObject::connect(reply, &QNetworkReply::finished, &loop, &QEventLoop::quit);
loop.exec();
qDebug() << "Reply is finished";
//file.close();
if (reply->error() != QNetworkReply::NoError){
qDebug() << "The following error ocurred";
qDebug() << reply->errorString();
return 0;
}
QString postData_returned = QString::fromUtf8(reply->readAll());
qDebug() << "DATA RETURNED";
qDebug() << postData_returned;
return 0;
}
My php code looks like this
<?php
header("Access-Control-Allow-Origin: *"); // Anyone can access
header("Content-Type: application/json; charset=UTF-8"); // Will return json data.
error_log("FILES iS");
vardump_toerror($_FILES);
?>
It is my understanding that the $_FILES super global should get filled with the file information. Am I mistaken? But the print out shows it's empty.

Answer 1

I am not an expert in PHP but I find it unnecessary to use the content-type application/json since multipart (submit forms) is not part of that protocol. On the other hand I can't find a reference of the vardump_toerror function so I change with var_dump so my test php is:
<?php
var_dump($_FILES);
?>
In a previous question for PyQt5 I implemented a similar logic for django that also applies in this case so I will show a translation.
#include <QCoreApplication>
#include <QFile>
#include <QHttpMultiPart>
#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QTextCodec>
QHttpMultiPart *buildMultpart(const QVariantMap & data, const QMap<QString, QString> filenames){
QHttpMultiPart *multipart = new QHttpMultiPart(QHttpMultiPart::FormDataType);
QVariantMap::const_iterator i_data = data.constBegin();
while (i_data != data.constEnd()) {
QHttpPart postpart;
postpart.setHeader(QNetworkRequest::ContentDispositionHeader, QString("form-data; name=\"%1\"").arg(i_data.key()));
postpart.setBody(i_data.value().toByteArray());
multipart->append(postpart);
++i_data;
}
QMap<QString, QString>::const_iterator i_filenames = filenames.constBegin();
while (i_filenames != filenames.constEnd()) {
QFile *file = new QFile(i_filenames.value());
if(!file->open(QIODevice::ReadOnly)){
delete file;
continue;
}
QHttpPart postpart;
postpart.setHeader(QNetworkRequest::ContentDispositionHeader,
QString("form-data; name=\"%1\"; filename=\"%2\"")
.arg(i_filenames.key(), file->fileName()));
postpart.setBodyDevice(file);
multipart->append(postpart);
file->setParent(multipart);
++i_filenames;
}
return multipart;
}
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QUrl url("http://localhost:4000/upload.php");
QNetworkAccessManager manager;
QMap<QString, QString> filenames;
filenames["fileToUpload"] = "/path/of/data.txt";
QHttpMultiPart *multipart = buildMultpart({}, filenames);
QNetworkRequest request(url);
QNetworkReply *reply = manager.post(request, multipart);
multipart->setParent(reply);
QObject::connect(reply, &QNetworkReply::finished, QCoreApplication::quit);
a.exec();
if(reply->error() == QNetworkReply::NoError){
qDebug() << reply->readAll();
}
else{
qDebug() << reply->error() << reply->errorString();
}
delete reply;
return 0;
}
Output:
"array(1) {\n [\"fileToUpload\"]=>\n array(5) {\n [\"name\"]=>\n string(8) \"data.txt\"\n [\"type\"]=>\n string(0) \"\"\n [\"tmp_name\"]=>\n string(14) \"/tmp/phpVmOAhO\"\n [\"error\"]=>\n int(0)\n [\"size\"]=>\n int(6)\n }\n}\n"