GOAL
The application needs to constantly read from a socket - and when it receives a line that is not empty it needs to do an appropriate action.
Issue
From what I researched you can't do services in Xamarin Forms, since each service is platform dependent. (IOS, Andoird, Windows). So what I am looking for as a way to constantly monitor inputs from a Bluetooth port in this case, simply by calling a already defined function.
Tried
I tried using a Refresh view. But there were issues with that from a code point of view and a visual point of view.
Current Code
This is what I have tried, but unfortuntately it has mixed results. The socket seems to connect when first pairing but then closed if I try to read:
Device.StartTimer(TimeSpan.FromMilliseconds(miliseconds), () =>
{
command.Execute(null);
return true;
});
Related
I can not find how to start WPS client in Windows 10 from command prompt or powershell. When I used Linux, everything was really ease with wla_supplicant (wpa_cli wps_pbc). Is there something similar in Windows?
Does anyone know how to set up Wi-Fi network (over WPS) key without human input in Windows?
I also tried WCN (Windows Connect Now) from Microsoft as it implements WPS features. I got also samples from Windows SDK on WCN, but they could not get key by WPS (it faild). But if I use Windows user interface to connect wiothout PIN, everyting seems to be pretty fine.
I am sure that there is possibility to do that, it is very important to perform Wifi Protected Setup by button start from the command prompt or app (C++/C#) without human intrusion or input (once WPS is on air, Windows should automatically get the network key and connect then).
I don't know if it's too late to answer, just put what I know in here and hope it can help.
First, if your system has updated to 16299(Fall Creator Update), you can just simply use new wifi api from UWP.
Install newest Windows SDK, create a C# console project, target C# version to at least 7.1, then add two reference to the project.
C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETCore\v4.5\System.Runtime.WindowsRuntime.dll
C:\Program Files (x86)\Windows Kits\10\UnionMetadata\10.0.16299.0\Windows.winmd
After all of that , code in below should work.
using System;
using System.Threading.Tasks;
using Windows.Devices.Enumeration;
using Windows.Devices.WiFi;
class Program
{
static async Task Main(string[] args)
{
var dic = await DeviceInformation.FindAllAsync(WiFiAdapter.GetDeviceSelector());
if (dic.Count > 0)
{
var adapter = await WiFiAdapter.FromIdAsync(dic[0].Id);
foreach (var an in adapter.NetworkReport.AvailableNetworks)
{
if (an.Ssid == "Ssid which you want to connect to.")
{
// Fouth parameter which is ssid can not be set to null even if we provided
// first one, or an exception will be thrown.
await adapter.ConnectAsync(an, WiFiReconnectionKind.Manual, null, "",
WiFiConnectionMethod.WpsPushButton);
}
}
}
}
}
Build and run the exe, then push your router's button, your pc will be connect to the router.
But if you can not update to 16299, WCN will be your only choice. You may already notice that if call IWCNDevic::Connect frist with push-button method, the WSC(Wifi Simple Configuration) session will fail. That's because WNC would not start a push-button session as a enrollee, but only as a registrar. That means you have to ensure that router's button has been pushed before you call IWCNDevic::Connect. The way to do that is using Native Wifi api to scan your router repeatedly, analyse the newest WSC information element from the scan result, confirm that Selected Registrar attribute has been set to true and Device Password Id attribute has been set to 4. After that, query the IWCNDevice and call Connect function will succeed. Then you can call IWCNDevice::GetNetworkProfile to get a profile that can use to connect to the router. Because it's too much of code, I will only list the main wifi api that will be used.
WlanEnuminterfaces: Use to get a available wifi interface.
WlanRegisterNotification: Use to register a callback to handle scan an connect results.
WlanScan: Use to scan a specified wifi BSS.
WlanGetNetworkBsslist: Use to get newest BSS information after scan.
WlanSetProfile: Use to save profile for a BSS.
WlanConnect: Use to connect to a BSS.
And about the WSC information element and it's attributes, you can find all the information from Wi-Fi Simple Configuration Technical Specification v2.0.5.
For Krisz. About timeout.
You can't cast IAsyncOperation to Task directly. The right way to do that is using AsTask method. And also, you should cancel ConnectAsync after timeout.
Sample code:
var t = adapter.ConnectAsync(an, WiFiReconnectionKind.Manual, null, "",
WiFiConnectionMethod.WpsPushButton).AsTask();
if (!t.Wait(10000))
t.AsAsyncOperation().Cancel();
This may well be a duplicate question, but no answer from an existing question has solved my problem.
I have a WebAPI end point running on my dev machine. I've configured it to run on
.UseUrls("http://localhost:57971", "http://10.0.2.2:57971", "http://192.168.44.1:57971", "http://192.168.1.48:57971", "http://*:57971")
where:
192.168.44.1 is Desktop Adapter #2 on the emulator Networks settings tab
10.0.2.2 is the special address for the Android emulator, as set out in Google's doco (possibly not relevant to Xamarin) and
192.168.1.48 is my local IP address for my dev machine.
I have created a firewall rule permitting connections on TCP port 57971.
I researched this pretty heavily and heeded instructions such as those set out here http://briannoyesblog.azurewebsites.net/2016/03/06/calling-localhost-web-apis-from-visual-studio-android-emulator/
I'm kinda out of ideas. The annoying thing is, it fails silently. There is no exception and the output just basically shows the different threads exiting with code 0. And the application keeps running i.e. the debugging session is not returning the IDE to a "code entry" state. This may suggest that something else its at play here.
The code looks pretty innocuous to me:
protected async Task<T> GetAsync<T>(string url)
where T : new()
{
HttpClient httpClient = CreateHttpClient();
T result;
try
{
var response = await httpClient.GetStringAsync(url);
result = await Task.Run(() => JsonConvert.DeserializeObject<T>(response));
}
catch
{
result = new T();
}
return result;
}
I'm using Visual Studio 2015.
I'm using the Visual Studio emulator https://www.visualstudio.com/vs/msft-android-emulator/
Any idea how I can get wheels on the ground on this thing?
Is there a way to Ping my machine from the emulator?
Thanks
I got this working by using 169.254.80.80 i.e. I added it to the list of urls which the API serves and called that ip address from the Xamarin app.
So, in Program.cs became simple:
.UseUrls("http://localhost:57971", "http://169.254.80.80:57971")
I also had to add it to the bindings element ApplicationConfig file in the hidden .vs folder of the ASP.NET API solution. Not sure why it had to be 169.254.80.80, as that was Desktop Adapter #4.
That got it working.
I have a SignalR hub and two clients (Windows and PCL for Android and iOS). Neither of the clients is able to call some methods on the server. This behaviour is quite odd, since the methods look very similar. Moreover, a colleague of mine is able to call methods I cannot call, and vice versa, does not invoke methods that I invoke with no problems.
Here is an example of a method, which works for me and does not work for my colleague:
public override async Task<bool> RefreshArray(User user, int waitMilis)
{
var cts = new CancellationTokenSource();
try
{
cts.CancelAfter(waitMilis);
await Proxy.Invoke("RefreshArray", user);
return true;
}
catch (Exception ex)
{
OnExceptionOccured(ex);
return false;
}
}
And a method which does not work for me, but works for my colleague:
public override async Task<bool> RequestInformation(User user, Product product, int waitMilis)
{
var cts = new CancellationTokenSource();
try
{
cts.CancelAfter(waitMilis);
await Proxy.Invoke("RequestInformation", user, product);
return true;
}
catch (Exception ex)
{
OnExceptionOccured(ex);
return false;
}
}
Yes, me and my colleague have exactly the same code. And no, there are no typos or different arguments. I have tried to get as much data from the client connection as possible, by setting _connection.TraceLevel = TraceLevels.All; However, I did not get any information on the invoked methods, just on the replies from the hub. When calling RefreshArray, I got exactly the data I requested. When calling RequestInformation, the debugger never even hit the breakpoint in the hub method and the _connection.Trace displayed only this: 11:22:45.6169660 - 7bc57897-489b-49a2-8459-3fcdb8fcf974 - SSE: OnMessage(Data: {})
Has anybody solved a similar issue? Is there a solution?
UPDATE 1
I just realized that I have encountered almost the same issue about a year ago (Possible SignalR bug in Xamarin Android). StackOverflow has also pointed me to a question with almost the same issue (SignalR on Xamarin.iOS - randomly not able to call Hub method), just related to iOS and Azure. However, I got the same proble even outside Xamarin, on Windows Phone 8.1 and and Windows 10 Universal App. Moreover, I am running the server just locally, so it is not an issue od Azure. Is it really possible, that a 2 years old bug has no solution?
UPDATE 2
I have just created a simple console application with SignalR.Client. In the console application every method worked just fine. Amazingly, also the Windows 10 Universal Application started to behave as expected - every hub method was invoked correctly. Windows Phone 8.1 also improved its behaviour (all hub methods invoked). However, every now and then the connection tried to reconnect periodically (for no apparent reason), leading to Connection started reconnecting before invocation result was received. error. The Android application still behaved as before.
So I tried to replicate my previous steps and created another console application, but this time with SignalR.Client.Portable library. To my dissapointment, there was no change in the Android application behaviour.
Next week we will start to test our application on iOS, so I really wonder what new oddities will we encounter.
I have managed to solve the problem (at least so it seems). As it turned out, there is some weird stuff going around, when an application receives an answer from SignalR hub. It seems as if the HubProxy was blocked for a certain period of time on Android, while it drops the connection and starts to reconnect periodically on Windows Phone, not waiting for an asnwer from the hub.
The implementation of RefreshArray on the hub was something like this:
public async Task RefreshArray(User user)
{
await Clients.Caller.SendArray(_globalArray);
await Clients.Caller.SendMoreInformation(_additionalInfo);
}
Because the method sent two methods as an answer, the client Proxy got stuck and each platform handled it in its own unexpected way. The reason why some methods were called on my computer and not on colleagues was, simply, because we had different position of breakpoints, which enabled the application to resolve at least some requests and responses.
The ultimate solution was to add some synchronization into the invokation of methods. Now my hub calls only await Clients.Caller.SendArray(_globalArray);. This is then handled on the client with a ArraySent(string[] array) event, which then subsequently invokes the SendMoreInformation() method on the hub.
How can you detect the url that I am browsing in chrome/safari/firefox via cocoa (desktop app)?
As a side but related note, are there any security restrictions when developing a desktop app that the user will be alerted and asked if they want to allow? e.g. if the app accesses their contact information etc.
Looking for a cocoa based solution, not javascript.
I would do this as an extension, and because you would like to target Chrome, Safari, and Firefox, I'd use a cross-browser extension framework like Crossrider.
So go to crossrider.com, set up an account and create a new extension. Then open the background.js file and paste in code like this:
appAPI.ready(function($) {
appAPI.message.addListener({channel: "notifyPageUrl"}, function(msg) {
//Do something, like send an xhr post somewhere
// notifying you of the pageUrl that the user visited.
// The url is contained within msg.pageUrl
});
var opts = { listen: true};
// Note: When defining the callback function, the first parameter is an object that
// contains the page URL, and the second parameter contains the data passed
// to the context of the callback function.
appAPI.webRequest.onBeforeNavigate.addListener(function(details, opaqueData) {
// Where:
// * details.pageUrl is the URL of the tab requesting the page
// * opaqueData is the data passed to the context of the callback function
if(opaqueData.listen){
appAPI.message.toBackground({
msg: details.pageUrl
}, {channel: "notifyPageUrl"});
}
}, opts ); // opts is the opaque parameter that is passed to the callback function
});
Then install the extension! In the example above, nothing is being done with the detected pageUrl that the user is visiting, but you can do whatever you like here - you could send a message to the user, you could restrict access utilizing the cancel or redirectTo return parameters, you could log it locally utilizing the crossrider appAPI.db API or you could send the notification elsewhere, cross-domain, to wherever you like utilizing an XHR request from the background directly.
Hope that helps!
And to answer the question on security issues desktop-side, just note that desktop applications will have the permissions of the user under which they run. So if you are thinking of providing a desktop app that your users will run locally, say something that will detect urls they access by tapping into the network stream using something like winpcap on windows or libpcap on *nix varieties, then just be aware of that - and also that libpcap and friends would have to have access to a network card that can be placed in promiscuous mode in the first place, by the user in question.
the pcap / installed desktop app solutions are pretty invasive - most folks don't want you listening in on literally everything and may actually violate some security policies depending on where your users work - their network administrators may not appreciate you "sniffing", whether that is the actual purpose or not. Security guys can get real spooky so-to-speak on these kinds of topics.
The extension via Crossrider is probably the easiest and least intrusive way of accomplishing your goal if I understand the goal correctly.
One last note, you can get the current tab urls for all tabs using Crossrider's tabs API:
// retrieves the array of tabs
appAPI.tabs.getAllTabs(function(allTabInfo) {
// Display the array
for (var i=0; i<allTabInfo.length; i++) {
console.log(
'tabId: ' + allTabInfo[i].tabId +
' tabUrl: ' + allTabInfo[i].tabUrl
);
}
});
For the tab API, refer to:
http://docs.crossrider.com/#!/api/appAPI.tabs
For the background navigation API:
http://docs.crossrider.com/#!/api/appAPI.webRequest.onBeforeNavigate
And for the messaging:
http://docs.crossrider.com/#!/api/appAPI.message
And for the appAPI.db stuff:
http://docs.crossrider.com/#!/api/appAPI.db
Have you looked into the Scripting Bridge? You could have an app that launches, say, an Applescript which verifies if any of the well known browser is opened and ask them which documents (URL) they are viewing.
Note: It doesn't necessarily need to be an applescript; you can access the Scripting Bridge through cocoa.
It would, however, require the browser to support it. I know Safari supports it but ignore if the others do.
Just as a quick note:
There are ways to do it via AppleScript, and you can easily wrap this code into NSAppleScript calls.
Here's gist with AppleScript commands for Safari and Chrome. Firefox seems to not support AE.
Well obviously this is what I had come across on google.
chrome.tabs.
getSelected
(null,
function
(tab) {
alert
(tab.url);
}) ;
in pure javascript we can use
alert(document.URL);
alert(window.location.href)
function to get current url
I downloaded the red5-recorder (http://www.red5-recorder.com/) , which fails to allow me to start recording. After debugging I found that the netconnection, needed to record to a media server, created does not fire a NetStatusEvent event, so essentially it fails silently. I have implemented the connection with the following minimal working example:
trace("make net connection");
nc = new NetConnection();
nc.client = { onBWDone: function():void{ trace("bandwidth check done.") } };
trace("add event listener");
nc.addEventListener(NetStatusEvent.NET_STATUS, function(event:NetStatusEvent) {
trace("handle");
});
trace("connect!");
nc.connect("rtmp://localshost/oflaDemo/test/");
trace("connect done");
The output of this piece of code is:
make net connection
add event listener
connect!
connect done
The actionscript api states that the connect-call always fires such an event:
http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/net/NetConnection.html#includeExamplesSummary
Moreover, the netconnection is not 'connected' (a state of the NetConnection object) 10 seconds after the call. I also took a look at this: NetConnect fails silently in Flash when called from SilverLight But the fix suggested by the author, swapping rtmp and http in the connection uri, do not work. Also, I tested the uri and in fact the exact same code sniplet in a personal project, where it did work. I just can not seem to find why connecting to a media server fails silently in the red5-recorder project.
The awkward part is that if I pass some random string as a conenction uri, still nothing happens (no event, no exception, no crash). Also not setting nc.client becore nc.connect(), which caused exceptions in my experience, did not cause exceptions.
Any suggestions are welcome.
You are setting the address to localshost instead localhost.
nc.connect("rtmp://localshost/oflaDemo/test/");
Correct address:
nc.connect("rtmp://localhost/oflaDemo/test/");