I'm developping a Qt5 application on MacOS.
I would like to test my application serial port communication.
I'd like to use socat but I'm unable to open the port created with socat: QSerialPortInfo::availablePorts() lists only the /dev/cu-XXXXXX ports...
Socat port creation example:
socat pty,link=/dev/mytty,raw tcp:192.168.254.254:2001&
After this you get your pseudo port /dev/mytty
Now you can reference this port via QSerialPort
serial = new QSerialPort("/dev/mytty");
You might be having troubles because of the symlink.
You could try something like this:
QFileInfo file_info("/dev/mytty");
QSerialPort* serial = nullptr;
if (file_info.isSymLink()) {
serial = new QSerialPort(file_info.symLinkTarget());
} else {
serial = new QSerialPort(file_info.path());
}
serial->open(QIODevice::ReadWrite);
You could also construct a QSerialPortInfo class with those paths instead of creating a port directly.
Maybe it's just a permission issue.
Make sure the user running your application has permition to access the virtual port.
Related
Quick question...
Can the ESP32 AsyncWebServer port be set/reset AFTER the server has been declared?
The server is declared after the global variables, but before any functions, with the line:
AsyncWebServer server(PortNumber);
Usually, the port number is 80 (the default HTTP port).
However, I have the need to use a different port and the port will be chosen by the user from a WiFi credentials page and then stored in NVS.
So, I need to retrieve the port number from the NVS before I execute the AsyncWebServer command, or be able to change the port number on the fly.
How can I achieve this?
Looking at the ESPAsyncWebserver declaration there doesn't seem to be a way to change or set the port after creating an instance of it. But isn't the solution to your problem as simple as creating the server later, after your configuration settings have been read? Something to this tune:
uint16_t port = config.read("server_port");
ESPAsyncWebserver* server = new ESPAsyncWebserver(port);
The answer to this is here: Answer
Hi there,
I will search and tried lots of solution for our problem but none of works. This will be a long post so be ready.
Our System:
We have an arduino uno r3 clone and ethernet shield wiznet w5100,
This Arduino makes a http post request to a windows web service.
According to response arduino will make something that is not revelant to question.
So in our test environment, we will install a windows webservice to our windows machine and plug this machine to our local network. Then plug arduino to our local network too. than with our server ip ,arduino made an dhcp request get ip from our modem-router and can call webservices from our server.
From now on everything works fine.
Here is some sample code from our arduino.(I only use this extra library for arduino:"RestClient.h"
#include <Ethernet.h>
#include <SPI.h>
#include "RestClient.h"
RestClient client = RestClient("192.168.100.17",51200);
String response;
String PostData;
void setup()
{
Serial.begin(9600);
byte mac[] = { 0x04, 0xD6, 0x2E, 0x81, 0x01, 0xB0 };
if ( Ethernet.begin(mac) == 0) {
Serial.println("Failed to configure Ethernet using DHCP");
}
delay(1000);
Serial.println(Ethernet.localIP());
}
void postDataToServer(long rfidnumber,int rfidsource){
String postedRFIDNumber=String(rfidnumber);
postedRFIDNumber="000"+postedRFIDNumber;
response = "";
PostData="RFID="+postedRFIDNumber+"&SOURCE="+rfidsource;
const char * myPost = PostData.c_str();
int statusCode =
client.post("/sqlpublish/TTSWebService.asmx/INSERT_INDEXRFID",myPost,&response);
}
We need to install our system to a company. This Company has its own local network. they have very restricted local network. You can connect their network but can not go to the "www" without their permissions. But that is not problem. We will use only local connection for our web services because we will also use an windows server which will inside local network.
This is a picture of their network system schema:
In this picture switches is missing but you can simply guess they uses lots of swtiches .Because company is very wide and have lots of device.
So if I connect any device to their local network , this device first call dhcp protocals get ip from Windows DHCP Server and then can communicate in the local network with other devices. But can not get through the internet modem because of the firewall in the router.
Then We will setup our system like this:
In this setup switch models are : "AVAYA".
VSP7000 XLS
ERS4826 GTS-PWR+
ERS3549 GTS-PWR+
Firewall is: Watchguard Firebox M300
When we setup the system something weird is going on. First of all when I connect my PC(My Device) to local network I can call webservices in the windows server. But Arduino cannot get IP from DHCP Server, and naturaly cannot connect to web services. So we think that "ok we can give IP static". Than we will give IP to our Arduino manually. After that weird things started to begin. When Arduino try to conenct our Windows webservices it only get response some times. Roughly 1 of 20 has got response from server anything else get time out connection.And also succeded response time also too long.
If we ping our static arduino IP From another Device(For example Device_1), It get response sometimes again. (Same Amount)
So then we try to narrow down our problem.
First Of All We Change the setup like this for once to make sure problem in local network.
And Normaly all systems works perfectly. So our Modem's DHCP server make it works perfectly.(Also in this setup If I give Ip static it worked too).
So there is these possibilties for connection error.
1-Firewall
2-Switch problem
3-Arduino Clon Problem.
1-Firewall
When We talked about the problem with system admin, He told ust every local network connection and port is open in the firewall. He is probably right because any pc connect to local network can call the web sevice.
2-Switch problem
This Question, talks about it as a solution it says use static ip, bu in our case it did not solve the problem.
In this Question jdr5ca answer make sense but ı hve no idea how can test the problem or solve the problem
In this Question answer tried but not working.
Lastly this post , but it is so general. and also what ı should use replace for "arping" in windows.
3-Arduino Clon Problem.
next week we try it with with original arduino ,
I will inform everybody.
SO, any suggestion,tool, or some diagnostic tool for the problem I'm open all the suggestion.
Apparently Our Problem is a specific switch model!
Here is the model: https://www.zyxel.com/tr/tr/products_services/es_108a.shtml?t=p (zyxel ES-108E)
When we directly connect arduino to zyxel switch, and ping arduino from another device in the network only some of pings successful.(Roughly %15 succeeded).
But if we use another switch model or don't directly connect to zyxel switch, it works fine.
I dont know why it is not working with zyxel but problem is the switch!
I'm completely new at using the QtNetwork for connecting computers.
Right now all I want is to see an attempt at a connection. So I create a GUI application and on the mainwindow.cpp I write these two functions as slots for two buttons:
void MainWindow::on_pbTalk_clicked(){
QString IP = ui->leIP->text();
ui->pteLog->appendPlainText("Now Talking to IP: " + IP);
talker = new Talker();
talker->connectToHost(IP,25000);
}
void MainWindow::on_pbListen_clicked(){
ui->pteLog->appendPlainText("Now listening on any port, I think");
listener = new Listener(this);
if (!connect(listener, SIGNAL(newConnection()), this, SLOT(on_newConnections()))){
ui->pteLog->appendPlainText("The connection of slot and signal failed!");
}
}
Now Talker is essentially a QTcpSocket there is nothing reimplemented just yet.
Listener is a QTcpServer with the following code con Listener.cpp:
Listener::Listener(QObject *parent) :
QTcpServer(parent)
{
qDebug() << "Listening on any port";
listen(QHostAddress::Any);
}
void Listener::incomingConnection(int socketDescriptor){
qDebug() << "New connection: " << socketDescriptor;
}
So I run two instances of the same program. One is in my machine. I run the program and push the Listen button (IP 10.255.255.101).
The second instance is run in a virtual machine (IP 10.255.255.215) where I run the program and push the Talk button. This, as I understand should attempt to open a connection to IP (which is 10.255.255.101) at port 25000 and I should get a "New connection" message in the console. However no such message appears. And since this is not working, I'm not moving on.
Can any one tell me what I might be doing wrong?
Check the documenation of QTcpServer::listen - it says:
Tells the server to listen for incoming connections on address address
and port port. If port is 0, a port is chosen automatically. If
address is QHostAddress::Any, the server will listen on all network
interfaces.
QHostAddress::Any means that you are listening on all network interfaces, not ports. (For example, if you want to have a local server only, you could use QHostAddress::LocalHost - check QHostAddress::SpecialAddress for more like that.
If you want to set the port manually, you have to call:
listen(QHostAddress::Any, 25000);
If not, you can get the automatically chosen port by calling
quint16 port = serverPort();
The "listening on any port" idiom isn't available for your use; it's not how UDP and TCP were meant to be used. Most likely you shouldn't be designing your communications that way. Use a dedicated port.
If you want to build a packet sniffer, you'll have to use the platform-specific mechanisms designed for that. There are libraries that help you with that task, the most notable would be WinPcap on Windows and cross-platform libpcap from the TcpDump project.
Is there a platform independent way in Qt to get an unused TCP port? I have a need to launch an existing application which must be given an open TCP port in order for it to work.
use QTcpServer is easier way.
bool QTcpServer::listen(const QHostAddress & address = QHostAddress::Any, quint16 port = 0)
If port is 0, a port is chosen automatically, then you use quint16 QTcpServer::serverPort() const to get the "idle" port
then close your Tcp Server
OR
generate a ramdom port, use QTcpSocket to connect it(local connection)
if connected, your port is QTcpSocket::localPort() and close this tcp socket
if not connected, your port is random port;
Do you mean some kind of tcp server? Then there is QTcpServer class.
If you want to start an existiong server, then you need QProcess class. Example:
QString program = "path/to/server";
QStringList arguments;
arguments << "-p" << "1234"; //or what ever you want
QProcess *myProcess = new QProcess(parent);
myProcess->start(program, arguments);
Arduino: Is it possible to communicate with Arduino through Ethernet, using a Processing (PDE) script?
I've already created a desktop application using Processing, but in this case I communicate with Arduino through the USB.
Yes you can
You could for example create an arduino chat server : http://arduino.cc/en/Tutorial/ChatServer
And create a processing client like this : http://processing.org/reference/libraries/net/Client_write_.html
ofcourse you would need to change the
myClient = new Client(this, "127.0.0.1", 10002);
to
myClient = new Client(this, "IP of Arduino", 23);
If you would then connect with a telnet session to the arduin o you would see output from the prosessing script comming back from the arduino