I am using a React client and a node js server (MERN Stack). The server runs good on my pc but when i try to connect from my mobile phone to the ipv4 of my pc with the correct port I am unable to send requests to the server. I tried to change the proxy of the React app but it doesn't seem to work.
Do you know what the problem might be?
Thanks.
That could be a network issue if your are trying to access your PC from an external IP (Phone not connected to local network, wifi), for example the PC connected to a router that does not forward external traffic to it.
If you can, try connecting your phone to the same network via wifi and access the local IP:PORT instead of ipv4.
I currently own a website, which will be used for global access and a database. I am also building devices that run a local node.js server, that forms a connection to this website.
So I guess this would be a reverse websocket? I don't own the webserver, it's hosted, so I'd assume I would use php.
I'm needing a 2 way connection that can push or request updates from both ends... Maybe websockets isn't the answer in this case?
TL;DR
In Javascript, how do you to find the IP of all servers running a specified program on a specified port in the LAN?
Background
I'm writing a server in node.js that is supposed to connect users browsers as controllers to a common device on which a game is running. The browsers are running a web app based on html and Javascript. The connection is based on socket.io.
I'd like for the web app to be able to find all available instances of this server in the LAN in order to create a server list for the user to choose from.
Is there a way to make the server discoverable by the web app on the local network in Javascript, and in that case: how?
Ideas
Have the server broadcast its IP to all devices on the LAN and have the web app listen for these messages (No idea how to do this without node on the client)
Connect to every IP on the network and see if the connection is successful. (Does not seem feasible)
Scan every IP on the network and connect only to those where the port is open. (Once again, no idea how to do this without node on the client and does not seeem feasible either.)
EDIT
The server is supposed to be portable and work independently, without any central system backing it up or providing matchmaking for clients. It is a LAN only server and should work even without internet access.
There is no way for you do this. Sorry. Since there is no exposure to UDP on client-side JavaScript, broadcasting is out of question. Any attempt on massive scanning will quickly raise flags on network monitoring software. You have to use a known address.
I'm working on a project which uses HTML5 WebSockets to connect with an iOS App. I need to display a list of near by (within the same local WiFi network) iPhones/iPads inside the webpage.
Is it possible to use any discovery mechanism like Bonjour to achieve this?
Is there any way to detect the local IP address from the website (using Javascript or from server side script) so that I can scan the local IP range?
If you're only looking to match devices on the same network, you could just check the public IP, since everyone connected to the same router will likely share one. That said, while a native iOS app should be able to detect a local IP address, I don't know of any way to do so using Javascript.
The one exception is if you have a server running inside the local network (or a custom binary running on their machine). It doesn't sound from your description like this is an option for you, but in case it is, a server within the user's LAN will see their local IP rather than their public IP. It could then relay that to a public server if needed.
I'd love to be proven wrong though, because I could think of some really cool things to do if it were possible.
Recently received a request to add communication to a device connected via serialport on the client's machine through my webpage.
I'd done some googling and found that node.js with node-serialport seems to be the javascript way of doing it. However, in my case, the device is actually connected to the client's machine, and not the server.
My question would be how do i implement node.js in this sense? Since the code is run at the client browser, is it possible for me to 'embed' node.js on my webpage?
Or is there any other alternative for doing this? Applet and ActiveX are out of the picture though.
Thanks
UPDATES:
Had managed to convince the client to have applet loaded from the web, so we'll be going through the applet route. Thanks all for your great info! =)
JavaScript in the browser only has access to the APIs provided by the browser: it lives in the browser sandbox where it (rightly) has no access to the client file system or other hardware.
This is different from node.js, which is a server implementation that has access to all sorts of other file system APIs.
To "break out" of the browser you must use some sort of browser extension.
You will have to create a plugin, an applet, or a client side application to get the data into the client's web browser before being sent off to your server.
You could make a small app that reads the serial port of the clients machine that creates a .js file, and then your web page includes that src of that "dynamically" created js file on the client's machine and presto your webpage gets access to the serial port in a roundabout way.
This is how GPSGate works: http://gpsgate.com/developer/gps_in_browser/
See also here: How to read from Serial port in a webpage
And a java applet based solution:
http://code.google.com/p/java-simple-serial-connector/
http://code.google.com/p/java-simple-serial-connector/wiki/jSSC_Terminal
Try app.js if you want to access node.js functions from browser.
This can only be done via Active X or a plugin like Java or Flash. Code in JavaScript is only as powerful as the APIs provided to it from the browser.
Want to sent an HTTP request to a server? JavaScript can do that (subject to the same-origin policy), because the browser has the XMLHttpRequest API. Want to query what processes are running on the operating system right now? JavaScript cannot do that, because no browser provides an API for querying the OS about what processes it is running.
No browser that I know of implements any kind of JavaScript API for performing serial port operations, so there is no way to do it without using a plugin.
However, this does not preclude the possibility of such an API existing someday: the getUserMedia function can grab data from a camera or microphone, and it could theoretically be expanded to get data from other devices as well.
Another option (other than ActiveX or Java applet with security permissions) might be Google Native Client and the Pepper API, though whether this would be sufficient to access a serial port, I do not know.
A Firefox extension can include a native XPCOM component that could access the serial port, and you might find there is already a way to access the serial port from browser chrome (which extensions are) because the security token and smartcard system supports serial readers. A Firefox extension could also be used to deliver the next solution, which requires placing a native component or application on the system.
Can you tell us what browser(s) and OS('s) are targetted here, and why ActiveX and Java are ruled out?
Others have suggested a native running proxy exposing the serial port through some protocol. You could use node for this, or python, or any other language that can create both a serial connection and a socket. To access the proxy from a browser application you would need special security permissions to be granted to the page, and then you can make your proxy an HTTP or WebSocket server. You can also serve javascript from the proxy which would grant the script HTTP and WebSocket access to it's origin server which is the proxy. Google Chrome extensions can access any destination and port with their socket client. Also, I believe a config can be set in Google Chrome to allow this for certain or every page, the same with allowing native client to be used by a webpage.
Without knowing more about your goal, I can't determine what the best solution would be.
Another option to read the serial port data is using sockjs and sockjs-client-node at the server side and sockjs-0.3.js at the client side.