Programmatically check whether my machine has internet access or not
If you work on Windows, just try this
#include <iostream>
#include <windows.h>
#include <wininet.h>
using namespace std;
int main(){
if(InternetCheckConnection(L"http://www.google.com",FLAG_ICC_FORCE_CONNECTION,0))
{
cout << "connected to internet";
}
return 0;
}
What is the best way to check for Internet connectivity using .NET?
public static bool CheckForInternetConnection(int timeoutMs = 10000, string url = null)
{
try
{
url ??= CultureInfo.InstalledUICulture switch
{
{ Name: var n } when n.StartsWith("fa") => // Iran
"http://www.aparat.com",
{ Name: var n } when n.StartsWith("zh") => // China
"http://www.baidu.com",
_ =>
"http://www.gstatic.com/generate_204",
};
var request = (HttpWebRequest)WebRequest.Create(url);
request.KeepAlive = false;
request.Timeout = timeoutMs;
using (var response = (HttpWebResponse)request.GetResponse())
return true;
}
catch
{
return false;
}
}
How to check if internet connection is present in Java?
You should connect to the place that your actual application needs. Otherwise you're testing whether you have a connection to somewhere irrelevant (Google in this case).
In particular, if you're trying to talk to a web service, and if you're in control of the web service, it would be a good idea to have some sort of cheap "get the status" web method. That way you have a much better idea of whether your "real" call is likely to work.
In other cases, just opening a connection to a port that should be open may be enough - or sending a ping. InetAddress.isReachable
may well be an appropriate API for your needs here.
Test if an internet connection is present in python
My approach would be something like this:
import socket
REMOTE_SERVER = "one.one.one.one"
def is_connected(hostname):
try:
# see if we can resolve the host name -- tells us if there is
# a DNS listening
host = socket.gethostbyname(hostname)
# connect to the host -- tells us if the host is actually reachable
s = socket.create_connection((host, 80), 2)
s.close()
return True
except Exception:
pass # we ignore any errors, returning False
return False
%timeit is_connected(REMOTE_SERVER)
> 31.9 ms ± 627 µs per loop (mean ± std. dev. of 7 runs, 10 loops each)
This will return within less than a second if there is no connection (Linux, Python 3.8).
Note: This test can return false positives -- e.g. the DNS lookup may return a server within the local network. To be really sure you are connected to the internet, and talking to a valid host, be sure to use more sophisticated methods (e.g. SSL).
How do I check for a network connection?
You can check for a network connection in .NET 2.0 using GetIsNetworkAvailable()
:
System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable()
To monitor changes in IP address or changes in network availability use the events from the NetworkChange class:
System.Net.NetworkInformation.NetworkChange.NetworkAvailabilityChanged
System.Net.NetworkInformation.NetworkChange.NetworkAddressChanged
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