Develop Reference

How to use java with Braid framework example: pigtail?

I try to define Braid server in java like this repo. And the following is my BootstrapBraidService class:
#CordaService
public class BootstrapBraidService extends SingletonSerializeAsToken{
private AppServiceHub appServiceHub;
private BraidConfig braidConfig;
public BootstrapBraidService(AppServiceHub appServiceHub){
this.appServiceHub = appServiceHub;
this.braidConfig = new BraidConfig();
// Include a flow on the Braid server.
braidConfig.withFlow(ExtendedStatusFlow.IssueFlow.class);
// Include a service on the Braid server.
braidConfig.withService("myService", new BraidService(appServiceHub));
// The port the Braid server listens on.
braidConfig.withPort(3001);
// Using http instead of https.
braidConfig.withHttpServerOptions(new HttpServerOptions().setSsl(false));
// Start the Braid server.
braidConfig.bootstrapBraid(this.appServiceHub,Object::notify);
}
}
However node startup without my setting, like port use default(8080) instead of my setting(3001).
And NodeJS server fails to get services descriptor:
{ Error: failed to get services descriptor from
http://localhost:8080/api/
at createHangUpError (_http_client.js:331:15)
at Socket.socketOnEnd (_http_client.js:423:23)
at emitNone (events.js:111:20)
at Socket.emit (events.js:208:7)
at endReadableNT (_stream_readable.js:1064:12)
at _combinedTickCallback (internal/process/next_tick.js:138:11)
at process._tickCallback (internal/process/next_tick.js:180:9) code: 'ECONNRESET', url: 'http://localhost:8080/api/' }
Can somebody tell me how to fix this problem? Thanks.
Update:
the node shell screenshot

The reason why this isn't working is because BraidConfig is an immutable class with a fluent API, but your code is using it as a classic mutable POJO which means none of your changes are being applied to the BraidConfig.
The following should work fine:
#CordaService
public class BootstrapBraidService extends SingletonSerializeAsToken{
private AppServiceHub appServiceHub;
private BraidConfig braidConfig;
public BootstrapBraidService(AppServiceHub appServiceHub){
this.appServiceHub = appServiceHub;
this.braidConfig = new BraidConfig()
// Include a flow on the Braid server.
.withFlow(ExtendedStatusFlow.IssueFlow.class)
// Include a service on the Braid server.
braidConfig.withService(new BraidService(appServiceHub))
// The port the Braid server listens on.
braidConfig.withPort(3001)
// Using http instead of https.
braidConfig.withHttpServerOptions(new HttpServerOptions().setSsl(false));
// Start the Braid server.
braidConfig.bootstrapBraid(this.appServiceHub,null);
}
}
regards,
Fuzz

How to get the source ip address of DDP call by a Java client in Meteor

I call a meteor server function from a java client via ddp, how to get the ip of the java server in meteor in order to restrict the access ?

Inside a Meteor method, you could access client information through this.connection object. The detail of this object is specified here. To get IP of client you could do:
Meteor.methods({
test() {
const ip = this.connection.clientAddress;
}
});
Note that if your server is run behind proxies, you will need to set the HTTP_FORWARDED_COUNT environment variable to the number of proxies in front of your server.

Java websocket with proxy

I have been trying all day and night for couple of days trying to make websocket to work using proxy in Java. I tried different library like
https://github.com/TooTallNate/Java-WebSocket
https://github.com/AsyncHttpClient/async-http-client
But sadly these library doesn't support proxy with credentials. If you guys have known any other library that supports proxy then I would be appreciated.
Thanks in advance

Try nv-websocket-client library. It supports authentication at a proxy server. Note that, however, the current implementation supports Basic Authentication only.
// 1. Create a WebSocketFactory instance.
WebSocketFactory factory = new WebSocketFactory();
// 2. Set up information about a proxy server.
// Credentials can be set here.
ProxySettings settings = factory.getProxySettings();
settings.setServer("http://proxy.example.com");
settings.setCredentials("id", "password");
// 3. Connect to a WebSocket endpoint via the proxy.
WebSocket ws = factory.createSocket("ws://websocket.example.com");
// 4. Add a listener to receive WebSocket events.
ws.addListener(new WebSocketAdapter() {
#Override
public void onTextMessage(WebSocket ws, String message) {
// Received a text message.
......
}
});
// 5. Perform a WebSocket opening handshake.
ws.connect();
// 6. Send frames.
// 6-1. Text
ws.sendText("Hello.");
// 6-2. Binary
byte[] binary = ......;
ws.sendBinary(binary);
// 6-3. Ping
ws.sendPing("Are you there?");
// 6-4. Pong (unsolicited pong; RFC 6455, 5.5.3. Pong)
ws.sendPong("I'm OK.");
// 6-5. Fragmented Frames
ws.sendText("How ", false)
.sendContinuation("are ")
.sendContinuation("you?", true);
// 6-6. Periodical Ping
ws.setPingInterval(60 * 1000);
// 6-7. Periodical Pong (unsolicited pong; RFC 6455, 5.5.3. Pong)
ws.setPongInterval(60 * 1000);
// 6-8. Close (if you want to send one manually).
ws.sendClose(WebSocketCloseCode.NORMAL, "Bye.");
// 7. Disconnect
ws.disconnect();
Blog
WebSocket client library (Java SE 1.5+, Android)
http://darutk-oboegaki.blogspot.jp/2015/05/websocket-client-library-java-se-15.html
GitHub
https://github.com/TakahikoKawasaki/nv-websocket-client
JavaDoc
http://takahikokawasaki.github.io/nv-websocket-client/
Maven
<dependency>
<groupId>com.neovisionaries</groupId>
<artifactId>nv-websocket-client</artifactId>
<version>1.3</version>
</dependency>
The size of nv-websocket-client-1.3.jar is 62,854 bytes and it does not require any external dependencies.

You can try Tyrus (reference implementation of WebSocket API in Java EE); client side does not require any Java EE server to be running and if you are using Java 7, the client could be minimized to ~500kb.
Client behing proxy and Dependencies should provide enough info to try.

How to get client's Proxy IP address in CometD?

Using fiddler as a HTTP proxy, i connect to a local CometD server.
I inherit the class DefaultSecurityPolicy, and got the client's IP address with server.getContext().getRemoteAddress().getAddress().getHostAddress() in canHandshake Method.
However, it returns the client's real IP (original IP), but what i want is the one directly communicates with the server. Any help?
If the client using WebSocket to communicate with CometD server, The HTTP proxy doesn't take effect at all, So what i got is the original addr, am i right?

public function getlocationFromIp()
{
if (!empty($_SERVER['HTTP_CLIENT_IP'])) {
// Check if using Shared Internet Environment
$ipAddress = $_SERVER['HTTP_CLIENT_IP'];
}elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])){
// Check if using Proxy User
$ipAddress = $_SERVER['HTTP_X_FORWARDED_FOR'];
}else{
$ipAddress = $_SERVER['REMOTE_ADDR'];
}
$ip_geo_url = 'http://freegeoip.net/json/'.$ipAddress;
$ip_json = file_get_contents($ip_geo_url);
$ip_json = json_decode($ip_json);
return $ip_json;
}
it will get the location whit ip if it help you ...
it will be get the proxy location too

How to discover the IP address of a Tomcat server on a network?

I have a Android application which consumes a webservice on a local network. There's a config screen where the user inform the server IP address, which is running Apache Tomcat.
I'm looking for a way to auto-detect the server based on the current connected wi-fi network.
i.e: The smartphone's IP is 10.1.1.90 and the server IP is 10.1.1.254.
Is there a way to achieve this? I'm thinking on using ping, but I don't know if is a good ideia.

The way I understand it, you need to discover IP of your tomcat server and connect it using your client.
I am assuming , both the server and client is in your control.
One simple way can be to use jGroups Cluster.
You can make your tomcat discoverable
Client can discover it using the name of the cluster you have provided .Refer the JChannel API that Jgroups uses
I simulated it making following server class
public class TomcatServer {
JChannel channel;
private void start() throws Exception {
channel = new JChannel(); // use the default config, udp.xml
channel.connect("TomcatCluster");
}
public static void main(String[] args) throws Exception {
new TomcatServer().start();
}
}
The simulated client class
public class MobileApp extends ReceiverAdapter {
JChannel channel;
private void start() throws Exception {
channel = new JChannel(); // use the default config, udp.xml
channel.setReceiver(this);
channel.connect("TomcatCluster");
channel.close();
}
public static void main(String args[]) throws Exception {
new MobileApp().start();
}
The client will provide you following information
GMS: address=MACHINENAME-47879, cluster=TomcatCluster, physical address=xxxxx:0:xxx:xxxx:xxxx:xxxx:xxx:xxxx:xxxx
** view: [MACHINENAME-31239|1] [MACHINENAME-31239, MACHINENAME-47879]
Where MACHINENAME-47879 is the client machine and port & MACHINENAME-31239 is the tomcat server name and port

Do you want to detect "a tomcat server" or "your tomcat server" ?
I mean, do you have any way to custom your server ? If it's the case, then you could create a very simple test page on your server (say a "Hello" JSP page), which your Android application could look for.
If your Android gets a "Hello" result with a GET request on http://<tomcat_ip>/hello.jsp, then you may assume that the tomcat is online.
If you can't add this test page, then you can test any page which the server is supposed to serve. (even a 404 page which sometimes is not configured well, and shows the tomcat version...)

Tomcat response headers can contain the xpoweredBy field that would advertise Tomcat if enabled. However it is most often disabled due security considerations, and even disabled by default. You however could re-enable it if you need to auto-detect exactly your Tomcat servers. From the other side, indeed, if you can place a web page on your server, you can simply place a marking page with the agreed signature.
If the server IP is unknown, I would propose the following ways to detect the server on the network:
The most straightforward way is to do the breadcast ping (ping -b broadcast_address where breadcast address can be computed here, for instance). All network devices that are configured so would reply, then verify as explained above which one is the server. However pinging broadcast address requires a rooted phone. Also the router may not support.
Your DHCP service (most likely your router) can often be configured to issue always the same IP address for the same MAC address of your server network card.
If the server is a desktop computer or laptop, it could show its address as QR code on display. It is possible for a smartphone to scan the code from the screen, and this is way easier than to enter IP address through the touchscreen. QR code can also include auto-generated password for extra security.
If there is wireless router with the possible login where both server and client are connected, the internal pages of that router often contain the relevant IP addresses. You would need to implement logging into the router and doing some screen scrapping.

I made an Android app which used a local server in the WLAN. I made the terminal (the phone) broadcast it's own IP address, which the server then picked up.
I used MultiCast class on the phone, which added the ip-address of itself to the payload. The server always has a thread in multicast read class that obains the payload of the packet (which is the terminals ip-address). Set the terminal in datagram read state and send the servers ip-address to terminal.
Maybe are better ways, but a great way to get the ip-addresses of unknown terminals in the network.

The way i had resolved this problem is with the use of enumerations.
public String getLocalIpAddress()
{
try {
for (Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces(); en.hasMoreElements();) {
NetworkInterface intf = en.nextElement();
for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); enumIpAddr.hasMoreElements();) {
InetAddress inetAddress = enumIpAddr.nextElement();
if (!inetAddress.isLoopbackAddress()) {
return inetAddress.getHostAddress().toString();
}
}
}
} catch (Exception ex) {
}
return null;
}
}