Get a list of global posts #180

maxbrito500 · 2024-10-15T17:53:27Z

maxbrito500
Oct 15, 2024

Hello,

I would like to get a list of the global posts being published on a few selected servers. So far I was able to write a demo program but the text is being written to console. What is needed is to output the events through a callback event.

Question: How can this code be changed so that one method is called when a new text is published?

I've looked for an answer on the examples, but I'm not yet finding how to get the new texts. I guess maybe an example for that would help other developers too.

Many thanks in advance.

package online.nostrium.apps.nostr;

import lombok.extern.java.Log;
import nostr.api.NIP01;
import nostr.base.PublicKey;
import nostr.event.impl.Filters;
import nostr.event.Kind;
import nostr.id.Identity;
import nostr.util.NostrException;

import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.logging.Level;
import nostr.api.EventNostr;
import nostr.api.Nostr;

@Log
public class NostrGlobalPostsExample {

    private static final Identity SENDER = Identity.generateRandomIdentity();
    private final static Map<String, String> RELAYS = Map.of(
            "damus", "wss://relay.damus.io", 
            "wellorder", "wss://nostr-pub.wellorder.net", 
            "snort", "wss://relay.snort.social"
    );

    public static void main(String[] args) throws Exception {
        try {
            log.log(Level.FINE, "================= Start Fetching Global Posts");

            ExecutorService executor = Executors.newFixedThreadPool(10);

            // Submit task to fetch global posts
            executor.submit(() -> {
                try {
                    filters();
                } catch (InterruptedException t) {
                    log.log(Level.SEVERE, t.getMessage(), t);
                }
            });

            stop(executor);

            if (executor.isTerminated()) {
                log.log(Level.FINE, "================== The End");
            }

        } catch (IllegalArgumentException ex) {
            log.log(Level.SEVERE, null, ex);
            throw new NostrException(ex);
        }
    }

    /**
     * Fetches global posts (text notes) from relays using filters.
     */
    public static void filters() throws InterruptedException {
        //logHeader("filters");

        // Define the kinds of events you want to fetch (Kind 1: text notes)
        var kinds = List.of(Kind.TEXT_NOTE);

        // Time filter: Get posts from now
        var date = Calendar.getInstance();
        date.add(Calendar.DAY_OF_MONTH, -0);

        // Create filters
        Filters filters = Filters.builder()
                .kinds(kinds) // Kind 1 is text note events (global posts)
                .since(date.getTimeInMillis() / 1000) // Get posts from now
                .build();

        
        // Create the NIP01 instance and set the sender identity
        var nip01 = new NIP01<>(SENDER); // Explicitly set the sender identity here
        EventNostr eventNostr = nip01.setRelays(RELAYS);
        eventNostr.send(filters, "global-posts");
        
        Nostr nostr = new Nostr();
        nostr.setRelays(RELAYS);
        
        
        // Wait for events (adjust timing as necessary)
        Thread.sleep(5000);
    }

  
    private static void stop(ExecutorService executor) {
        try {
            executor.shutdown();
            executor.awaitTermination(60, TimeUnit.SECONDS);
        } catch (InterruptedException e) {
            log.log(Level.SEVERE, "termination interrupted");
        } finally {
            if (!executor.isTerminated()) {
                log.log(Level.SEVERE, "killing non-finished tasks");
            }
            executor.shutdownNow();
        }
    }
}

tcheeric · 2024-10-15T20:10:32Z

tcheeric
Oct 15, 2024
Maintainer

I'm away on vacation this week. I'll look as soon as I can. -- Sent with Tuta; enjoy secure & ad-free emails: https://tuta.com 15 Oct 2024, 19:53 by ***@***.***:

…

Hello, I would like to get a list of the global posts being published on a few selected servers. So far I was able to write a demo program but the text is being written to console. What is needed is to output the events through a callback event. Question:> How can this code be changed so that one method is called when a new text is published? I've looked for an answer on the examples, but I'm not yet finding how to get the new texts. I guess maybe an example for that would help other developers too. Many thanks in advance. package> > online> .> nostrium> .> apps> .> nostr> ;> import> > lombok> .> extern> .> java> .> Log> ;> import> > nostr> .> api> .> NIP01> ;> import> > nostr> .> base> .> PublicKey> ;> import> > nostr> .> event> .> impl> .> Filters> ;> import> > nostr> .> event> .> Kind> ;> import> > nostr> .> id> .> Identity> ;> import> > nostr> .> util> .> NostrException> ;> import> > java> .> util> .> ArrayList> ;> import> > java> .> util> .> Calendar> ;> import> > java> .> util> .> List> ;> import> > java> .> util> .> Map> ;> import> > java> .> util> .> concurrent> .> ExecutorService> ;> import> > java> .> util> .> concurrent> .> Executors> ;> import> > java> .> util> .> concurrent> .> TimeUnit> ;> import> > java> .> util> .> logging> .> Level> ;> import> > nostr> .> api> .> EventNostr> ;> import> > nostr> .> api> .> Nostr> ;> @> Log> public> > class> > NostrGlobalPostsExample> { > private> > static> > final> > Identity> > SENDER> = > Identity> .> generateRandomIdentity> (); > private> > final> > static> > Map> <> String> , > String> > > RELAYS> = > Map> .> of> ( > "damus"> , > "wss://relay.damus.io"> , > "wellorder"> , > "wss://nostr-pub.wellorder.net"> , > "snort"> , > "wss://relay.snort.social"> ); > public> > static> > void> > main> (> String> [] > args> ) > throws> > Exception> { > try> { > log> .> log> (> Level> .> FINE> , > "================= Start Fetching Global Posts"> ); > ExecutorService> > executor> = > Executors> .> newFixedThreadPool> (> 10> ); > // Submit task to fetch global posts> > executor> .> submit> (() -> { > try> { > filters> (); } > catch> (> InterruptedException> > t> ) { > log> .> log> (> Level> .> SEVERE> , > t> .> getMessage> (), > t> ); } }); > stop> (> executor> ); > if> (> executor> .> isTerminated> ()) { > log> .> log> (> Level> .> FINE> , > "================== The End"> ); } } > catch> (> IllegalArgumentException> > ex> ) { > log> .> log> (> Level> .> SEVERE> , > null> , > ex> ); > throw> > new> > NostrException> (> ex> ); } } > /**> * Fetches global posts (text notes) from relays using filters.> */> > public> > static> > void> > filters> () > throws> > InterruptedException> { > //logHeader("filters");> > // Define the kinds of events you want to fetch (Kind 1: text notes)> > var> > kinds> = > List> .> of> (> Kind> .> TEXT_NOTE> ); > // Time filter: Get posts from now> > var> > date> = > Calendar> .> getInstance> (); > date> .> add> (> Calendar> .> DAY_OF_MONTH> , -> 0> ); > // Create filters> > Filters> > filters> = > Filters> .> builder> () .> kinds> (> kinds> ) > // Kind 1 is text note events (global posts)> .> since> (> date> .> getTimeInMillis> () / > 1000> ) > // Get posts from now> .> build> (); > // Create the NIP01 instance and set the sender identity> > var> > nip01> = > new> > NIP01> <>(> SENDER> ); > // Explicitly set the sender identity here> > EventNostr> > eventNostr> = > nip01> .> setRelays> (> RELAYS> ); > eventNostr> .> send> (> filters> , > "global-posts"> ); > Nostr> > nostr> = > new> > Nostr> (); > nostr> .> setRelays> (> RELAYS> ); > // Wait for events (adjust timing as necessary)> > Thread> .> sleep> (> 5000> ); } > private> > static> > void> > stop> (> ExecutorService> > executor> ) { > try> { > executor> .> shutdown> (); > executor> .> awaitTermination> (> 60> , > TimeUnit> .> SECONDS> ); } > catch> (> InterruptedException> > e> ) { > log> .> log> (> Level> .> SEVERE> , > "termination interrupted"> ); } > finally> { > if> (!> executor> .> isTerminated> ()) { > log> .> log> (> Level> .> SEVERE> , > "killing non-finished tasks"> ); } > executor> .> shutdownNow> (); } }} — Reply to this email directly, > view it on GitHub <#180>> , or > unsubscribe <https://github.com/notifications/unsubscribe-auth/ABQMG7D35YZPGKEVCSLF5RDZ3VJC3AVCNFSM6AAAAABP7WGU26VHI2DSMVQWIX3LMV43ERDJONRXK43TNFXW4OZXGMZDEOBYHA>> . You are receiving this because you are subscribed to this thread.> Message ID: > <tcheeric/nostr-java/repo-discussions/180> @> github> .> com>

0 replies

avlo · 2024-10-15T22:07:03Z

avlo
Oct 15, 2024
Collaborator

@maxbrito500, if functionality you require is standalone, many web socket clients exist (both chrome and postman, for example) without the need to write one.

otherwise if you're looking for a programmatic java client, since nostr-java currently does not support callbacks, you can:

write your own (for which i would suggest using spring web socket client api)
use a forked branch of nostr-java (jdk22) which supports both reactive and standard web socket client

0 replies

maxbrito500 · 2024-10-15T22:55:55Z

maxbrito500
Oct 15, 2024
Author

Thank you for the reply, but it would be expected from a nostr library to get a list of texts published on relays.

If you look carefully, the listener/callback functionality is already available.
It is just outputting the results to console instead of permitting developers to overwrite the method here:

nostr-java/nostr-java-connection/src/main/java/nostr/connection/impl/listeners/TextListener.java

Line 28 in 20f0986

public class TextListener extends WebSocketListener {

I will avoid using a forked version for a basic necessary feature from the library. Would prefer that other developers can use this library without scattered forks.

In fact, I don't even understand the logic of pushing JDK 22 as version for handling simple JSON communication. The aim should be compatibility with Java 8 ideally so this library can be used across as many JDK versions as possible including Android.

Nope, sorry. These are just awful engineering decisions like the previous difficulties to setup the library to run. My apologies for the harsh statements, but these things do end up impacting nostr adoption and need to be improved.

0 replies

avlo · 2024-10-15T23:36:57Z

avlo
Oct 15, 2024
Collaborator

current android api (v14) uses java 17 not 8
jdk22 is required for virtual threads (used by superconductor, a nostr relay utilizing many nostr-java classes) but an android client application developer is not forced to use any jdk22 features beyond what they wish to support in their application.
if you're inclined to implement remaining callback (& other necessary websocket considerations) into TextListener (uses okttp3, which is not a web socket client)- instead of leveraging spring websocketclient (jdk 17+), good luck to you.

0 replies

tcheeric · 2024-10-17T00:37:27Z

tcheeric
Oct 17, 2024
Maintainer

Britto, You will have to customise the command handlers (ok, eose, notice etc) by _providing_ your own custom module (it will be loaded automatically here https://github.com/tcheeric/nostr-java/blob/main/nostr-java-controller%2Fsrc%2Fmain%2Fjava%2Fnostr%2Fcontroller%2Fimpl%2FApplicationControllerImpl.java#L61), then add your logic in your custom ok command handler. Alternatively, you may consider Nick's fork, which he has customised for his specific needs with superconductor. (It's also probably a much cleaner nostr-java library tbh) Please note that this project was started, and is maintained by many volunteers for _selfish_ reasons only. If you decide to implement the feature to customise the listeners, I will happily merge it.

…

-- Sent with Tuta; enjoy secure & ad-free emails: https://tuta.com 16 Oct 2024, 01:37 by ***@***.***:

current android api (v14) uses > java 17 <https://developer.android.com/build/jdks#compileSdk>> not 8 jdk22 is required for virtual threads (used by > superconductor <https://github.com/avlo/superconductor>> , a nostr relay utilizing many nostr-java classes) but an android client application developer is not forced to use any jdk22 features beyond what they wish to support in their application. if you're inclined to implement remaining callback (& other websocket considerations) into TextListener (uses okttp3, which is not a web socket client)- instead of leveraging spring > websocketclient <https://spring.io/guides/gs/messaging-stomp-websocket>> (jdk 17+), good luck to you. — Reply to this email directly, > view it on GitHub <#180 (comment)>> , or > unsubscribe <https://github.com/notifications/unsubscribe-auth/ABQMG7CW6WQOEIKNNVHOIHLZ3WRK7AVCNFSM6AAAAABP7WGU26VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTAOJVGMZTEMQ>> . You are receiving this because you commented.> Message ID: > <tcheeric/nostr-java/repo-discussions/180/comments/10953322> @> github> .> com>

0 replies

maxbrito500 · 2024-10-17T15:40:40Z

maxbrito500
Oct 17, 2024
Author

Thanks, I will see which approach to follow. Ideally would prefer to submit code to improve this library.

Today I've wrote some code to get the global posts and it is really easy:

/*
 * Get the global posts from a specific relay
 *
 * Copyright (c) Nostrium contributors
 * License: Apache-2.0
 */

package online.nostrium.apps.nostr;

import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import okhttp3.WebSocket;
import okhttp3.WebSocketListener;
import okio.ByteString;

import java.time.Instant;

/**
 * @author Brito
 * @date: 2024-10-17
 * @location: Portugal
 */
public class NostrGlobalPosts {

    // Static method to query Nostr relay
    public static void queryNostrRelay(String relayUrl, long sinceTimestamp) {
        OkHttpClient client = new OkHttpClient();

        Request request = new Request.Builder().url(relayUrl).build();
        WebSocketListener listener = new WebSocketListener() {
            @Override
            public void onOpen(WebSocket webSocket, Response response) {
                // Send subscription request with the since filter
                String subscriptionRequest = "[\"REQ\", \"subscription\", {"
                        + "\"kinds\": [1],"            // Kind 1 for text messages
                        + "\"since\": " + sinceTimestamp
                        + "}]";
                webSocket.send(subscriptionRequest);
                System.out.println("Subscription sent: " + subscriptionRequest);
            }

            @Override
            public void onMessage(WebSocket webSocket, String text) {
                // Handle incoming message
                System.out.println("Received message: " + text);
            }

            @Override
            public void onMessage(WebSocket webSocket, ByteString bytes) {
                // Handle incoming binary message
                System.out.println("Received binary message: " + bytes.hex());
            }

            @Override
            public void onClosing(WebSocket webSocket, int code, String reason) {
                webSocket.close(1000, null);
                System.out.println("Closing WebSocket: " + reason);
            }

            @Override
            public void onFailure(WebSocket webSocket, Throwable t, Response response) {
                t.printStackTrace();
            }
        };

        // Create WebSocket connection
        WebSocket webSocket = client.newWebSocket(request, listener);

        // Trigger shutdown of the dispatcher's executor to clean up resources.
        client.dispatcher().executorService().shutdown();
    }

    // Utility to convert a date string to a Unix timestamp
    public static long getUnixTimestamp(String date) {
        Instant instant = Instant.parse(date + "T00:00:00Z");
        return instant.getEpochSecond();
    }

    public static void main(String[] args) {
        // Example usage
        String relayUrl = "wss://relay.damus.io"; 
        long sinceTimestamp = getUnixTimestamp("2024-10-17"); // Replace with desired date
        queryNostrRelay(relayUrl, sinceTimestamp);
    }

    
}

0 replies

tcheeric · 2024-10-20T21:46:44Z

tcheeric
Oct 20, 2024
Maintainer

@maxbrito500 , have a look at this nostr client where I implement the custom command handlers.
In the EVENT handler (client.provider.EventCustomHandler), I retrieve the published events from relays:
https://github.com/tcheeric/nostr-client/tree/0.6.2-SNAPSHOT

I hope it helps.

PS: I had to make some minor adjustments to nostr-java to get it to work, and these changes have not yet been deployed to the jitpack repository.

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