Awesome

nostr-client

This is a demo nostr client application using the nostr-java library, implemented as a java module.

Writing the Client Code

Maven setup

To use the nostr-java library in the project,

I add the following dependency to the pom.xml file:

        <dependency>
            <groupId>nostr-java</groupId>
            <artifactId>nostr-java-api</artifactId>
            <version>${nostr-java-version}</version>
        </dependency>

The library is currently hosted in the jitpack.io repository

    <repositories>
        <repository>
            <id>jitpack.io</id>
            <url>https://jitpack.io</url>
        </repository>
    </repositories>

Custom Command Handler

The client provides custom command handlers for the Ok, Notice, Error, Eose, and Event events, in replacement of the default OOTB dummy command handlers.

To register the custom command handlers:

I add the following entry to the module-info.java file:

import client.provider.EoseCustomHandler;
import client.provider.EventCustomHandler;
import client.provider.NoticeCustomHandler;
import client.provider.CustomOKCommandHandler;
import client.provider.OKCustomHandler;


module NostrClient {
    ...

    provides nostr.command.CommandHandler with EventCustomHandler, OKCustomHandler, NoticeCustomHandler, EoseCustomHandler;
}

I also need to create the file src/main/resources/META-INF/services/nostr.command.CommandHandler with the content:

client.provider.EventCustomHandler
client.provider.NoticeCustomHandler
client.provider.OKCustomHandler
client.provider.EoseCustomHandler

Compiling and Running the Code

To compile and run the nostr-client application, follow these steps:

Build the project using Maven in your preferred IDE.
Run the application using the following command:

java -jar nostr-client.jar 

Oct 20, 2024 10:24:36 PM nostr.connection.impl.ConnectionPool connect
INFO: Connecting to relays
Oct 20, 2024 10:24:36 PM nostr.connection.impl.ConnectionImpl connect
INFO: Connecting to Relay(scheme=ws, host=localhost:3333)... httpUrl = http://localhost:3333/
Oct 20, 2024 10:24:36 PM nostr.connection.impl.ConnectionImpl connect
INFO: Connected to Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:36 PM nostr.connection.impl.listeners.OpenListener onOpen
INFO: WebSocket opened to Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:36 PM nostr.connection.impl.ConnectionImpl send
INFO: Sending message: ["EVENT",{"id":"86aa0dc2a82078b41548597470e1c6ab9f5c41a3d2d6763cabd3e0b3cf8b11be","kind":1,"content":"Hello Nostr World!","pubkey":"b178aa906ad89352d82da90ec5a732093aa7331100bfc6dfaca9b3642bb20295","created_at":1729459475,"tags":[],"sig":"4ff2d22b8d7cde7a39a172b48b0d139158311f3a92d2e2e85625b9b230bf6dae66d6dcf2ce2c96e5b07f88668e6ae706e93e7a16d829873358e77822b45b182b"}] - Relay: Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:36 PM nostr.connection.impl.listeners.TextListener onMessage
INFO: WebSocket received: ["OK","86aa0dc2a82078b41548597470e1c6ab9f5c41a3d2d6763cabd3e0b3cf8b11be",true,""] - Relay: Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:36 PM nostr.connection.impl.listeners.TextListener handleReceivedText
INFO: Received message ["OK","86aa0dc2a82078b41548597470e1c6ab9f5c41a3d2d6763cabd3e0b3cf8b11be",true,""] from Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:36 PM client.provider.OKCustomHandler onCommand
INFO: <<< Received OK message: eventId=86aa0dc2a82078b41548597470e1c6ab9f5c41a3d2d6763cabd3e0b3cf8b11be, message=, flag=true
Oct 20, 2024 10:24:36 PM nostr.connection.impl.ConnectionPool connect
INFO: Connecting to relays
Oct 20, 2024 10:24:37 PM nostr.connection.impl.ConnectionImpl send
INFO: Sending message: ["EVENT",{"id":"cefc7ec402312f8a9e6cfc063b5ca939236e91a189b213218419e088d00581bf","kind":1,"content":"Bonjour Nostr Monde!","pubkey":"287bef38850f805ee37e1a4241517cef91e684b7602708eff08dcebfff546afc","created_at":1729459476,"tags":[["e","86aa0dc2a82078b41548597470e1c6ab9f5c41a3d2d6763cabd3e0b3cf8b11be"]],"sig":"148945be91aa410de5acb83fc4e3bf52cee2fb9e064b96c7d83e2eaa506b636659c11676151dbbb0ff056335752afdfcd0c71667dd7456f3d1e1edcdc0be253b"}] - Relay: Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:37 PM nostr.connection.impl.listeners.TextListener onMessage
INFO: WebSocket received: ["OK","cefc7ec402312f8a9e6cfc063b5ca939236e91a189b213218419e088d00581bf",true,""] - Relay: Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:37 PM nostr.connection.impl.listeners.TextListener handleReceivedText
INFO: Received message ["OK","cefc7ec402312f8a9e6cfc063b5ca939236e91a189b213218419e088d00581bf",true,""] from Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:37 PM client.provider.OKCustomHandler onCommand
INFO: <<< Received OK message: eventId=cefc7ec402312f8a9e6cfc063b5ca939236e91a189b213218419e088d00581bf, message=, flag=true
Oct 20, 2024 10:24:37 PM nostr.connection.impl.ConnectionPool connect
INFO: Connecting to relays
Oct 20, 2024 10:24:37 PM nostr.connection.impl.ConnectionImpl send
INFO: Sending message: ["EVENT",{"id":"232bfbc5dae2ee3ad09554f37eb58632f8f518fdf5af4f26eea63b896e417c80","kind":1,"content":"Hola Nostr Mundo!","pubkey":"b178aa906ad89352d82da90ec5a732093aa7331100bfc6dfaca9b3642bb20295","created_at":1729459477,"tags":[],"sig":"e5b117d49c537083c615d9fda24f57034ef3fb73ff7f4c4b1e953ad6ddf30b82713fa8afe50363e4c05da8f0c2a6f5dec2e47d2813015e07031c0abc2bc3cb5c"}] - Relay: Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:37 PM nostr.connection.impl.listeners.TextListener onMessage
INFO: WebSocket received: ["OK","232bfbc5dae2ee3ad09554f37eb58632f8f518fdf5af4f26eea63b896e417c80",false,"invalid: bad signature"] - Relay: Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:37 PM nostr.connection.impl.listeners.TextListener handleReceivedText
INFO: Received message ["OK","232bfbc5dae2ee3ad09554f37eb58632f8f518fdf5af4f26eea63b896e417c80",false,"invalid: bad signature"] from Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:37 PM client.provider.OKCustomHandler onCommand
INFO: <<< Received OK message: eventId=232bfbc5dae2ee3ad09554f37eb58632f8f518fdf5af4f26eea63b896e417c80, message=invalid: bad signature, flag=false
Oct 20, 2024 10:24:37 PM nostr.connection.impl.ConnectionPool connect
INFO: Connecting to relays
Oct 20, 2024 10:24:37 PM nostr.connection.impl.ConnectionImpl send
INFO: Sending message: ["EVENT",{"id":"40dbdefc8d47939964d9969858dd8a9e60027456cc8a5e8fed9e968f39e24afb","kind":4,"content":"PCK1/dANkWyTqgYnaoaiRzD2P12JCvBlvYwkRATXTuE=?iv=3PgEPD95xHgfWbk3N1LjSA==","pubkey":"edd898fc2817ee64f7ee1941d193d53c2daa77db4b8409240565fc9644626878","created_at":1729459477,"tags":[["p","40b1054933b5f32c567a02f4ea1c89803e1aba7936f92cb9d3c6a26e1f3d02aa"]],"sig":"57fbd20c743f5342c24535189b62e6aa50f62ce2436100e5891879b6ce195a16b8aa822ac8bbad371a2daa206c7f2f4c2f598a3e69f75c43bc20398a3e178010"}] - Relay: Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:37 PM nostr.connection.impl.listeners.TextListener onMessage
INFO: WebSocket received: ["OK","40dbdefc8d47939964d9969858dd8a9e60027456cc8a5e8fed9e968f39e24afb",true,""] - Relay: Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:37 PM nostr.connection.impl.listeners.TextListener handleReceivedText
INFO: Received message ["OK","40dbdefc8d47939964d9969858dd8a9e60027456cc8a5e8fed9e968f39e24afb",true,""] from Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:37 PM client.provider.OKCustomHandler onCommand
INFO: <<< Received OK message: eventId=40dbdefc8d47939964d9969858dd8a9e60027456cc8a5e8fed9e968f39e24afb, message=, flag=true
Oct 20, 2024 10:24:38 PM nostr.connection.impl.ConnectionPool connect
INFO: Connecting to relays
Oct 20, 2024 10:24:38 PM nostr.connection.impl.ConnectionImpl send
INFO: Sending message: ["EVENT",{"id":"aeb3a372c47c8992b9932cc3a36647b272f24136c53d92516d16eb21f2094f22","kind":44,"content":"AhLUSc6aDL7a/OIaRXrNY+jCmKipJvzupDfCKAxGLWKEetH8eJ58ACGE/m2dPiKHelKvO0Kv6ey35nlYEy+cJlxtFK66F8PSzp4zf4+nSQpyCfQl4R6r2aqY3ytA2pRsZTb+","pubkey":"edd898fc2817ee64f7ee1941d193d53c2daa77db4b8409240565fc9644626878","created_at":1729459478,"tags":[["p","40b1054933b5f32c567a02f4ea1c89803e1aba7936f92cb9d3c6a26e1f3d02aa"]],"sig":"4ec5f2ef7cd4509b7ecdb1c7d5b2b33891bf6122e58cdc1af227a09b094a947aad123b6e70f824552977146299974a6aeaf311b574aac73bd865cee671a86e8a"}] - Relay: Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:38 PM nostr.connection.impl.listeners.TextListener onMessage
INFO: WebSocket received: ["OK","aeb3a372c47c8992b9932cc3a36647b272f24136c53d92516d16eb21f2094f22",true,""] - Relay: Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:38 PM nostr.connection.impl.listeners.TextListener handleReceivedText
INFO: Received message ["OK","aeb3a372c47c8992b9932cc3a36647b272f24136c53d92516d16eb21f2094f22",true,""] from Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:38 PM client.provider.OKCustomHandler onCommand
INFO: <<< Received OK message: eventId=aeb3a372c47c8992b9932cc3a36647b272f24136c53d92516d16eb21f2094f22, message=, flag=true
Oct 20, 2024 10:24:38 PM nostr.connection.impl.ConnectionPool connect
INFO: Connecting to relays
Oct 20, 2024 10:24:38 PM nostr.connection.impl.ConnectionImpl send
INFO: Sending message: ["REQ","sub_11c9e2525da2df874123a78950590a1b1f784ce6d65b1fb9c784554b88bffb50",{"kinds":[1],"since":1729459418}] - Relay: Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:38 PM nostr.connection.impl.listeners.TextListener onMessage
INFO: WebSocket received: ["EVENT","sub_11c9e2525da2df874123a78950590a1b1f784ce6d65b1fb9c784554b88bffb50",{"content":"Bonjour Nostr Monde!","created_at":1729459476,"id":"cefc7ec402312f8a9e6cfc063b5ca939236e91a189b213218419e088d00581bf","kind":1,"pubkey":"287bef38850f805ee37e1a4241517cef91e684b7602708eff08dcebfff546afc","sig":"148945be91aa410de5acb83fc4e3bf52cee2fb9e064b96c7d83e2eaa506b636659c11676151dbbb0ff056335752afdfcd0c71667dd7456f3d1e1edcdc0be253b","tags":[["e","86aa0dc2a82078b41548597470e1c6ab9f5c41a3d2d6763cabd3e0b3cf8b11be"]]}] - Relay: {0}
Oct 20, 2024 10:24:38 PM nostr.connection.impl.listeners.TextListener handleReceivedText
INFO: Received message ["EVENT","sub_11c9e2525da2df874123a78950590a1b1f784ce6d65b1fb9c784554b88bffb50",{"content":"Bonjour Nostr Monde!","created_at":1729459476,"id":"cefc7ec402312f8a9e6cfc063b5ca939236e91a189b213218419e088d00581bf","kind":1,"pubkey":"287bef38850f805ee37e1a4241517cef91e684b7602708eff08dcebfff546afc","sig":"148945be91aa410de5acb83fc4e3bf52cee2fb9e064b96c7d83e2eaa506b636659c11676151dbbb0ff056335752afdfcd0c71667dd7456f3d1e1edcdc0be253b","tags":[["e","86aa0dc2a82078b41548597470e1c6ab9f5c41a3d2d6763cabd3e0b3cf8b11be"]]}] from Relay(scheme=ws, host=localhost:3333)
**Oct 20, 2024 10:24:38 PM client.provider.EventCustomHandler onCommand
INFO: <<< Received EVENT GenericEvent(id=cefc7ec402312f8a9e6cfc063b5ca939236e91a189b213218419e088d00581bf, pubKey=287bef38850f805ee37e1a4241517cef91e684b7602708eff08dcebfff546afc, createdAt=1729459476, kind=1, tags=[EventTag(idEvent=86aa0dc2a82078b41548597470e1c6ab9f5c41a3d2d6763cabd3e0b3cf8b11be, recommendedRelayUrl=null, marker=null)], content=Bonjour Nostr Monde!, signature=148945be91aa410de5acb83fc4e3bf52cee2fb9e064b96c7d83e2eaa506b636659c11676151dbbb0ff056335752afdfcd0c71667dd7456f3d1e1edcdc0be253b, _serializedEvent=null, nip=null, attributes=[]) from relay Relay(scheme=ws, host=localhost:3333) with subscription id sub_11c9e2525da2df874123a78950590a1b1f784ce6d65b1fb9c784554b88bffb50**
Oct 20, 2024 10:24:38 PM nostr.connection.impl.listeners.TextListener onMessage
INFO: WebSocket received: ["EVENT","sub_11c9e2525da2df874123a78950590a1b1f784ce6d65b1fb9c784554b88bffb50",{"content":"Hello Nostr World!","created_at":1729459475,"id":"86aa0dc2a82078b41548597470e1c6ab9f5c41a3d2d6763cabd3e0b3cf8b11be","kind":1,"pubkey":"b178aa906ad89352d82da90ec5a732093aa7331100bfc6dfaca9b3642bb20295","sig":"4ff2d22b8d7cde7a39a172b48b0d139158311f3a92d2e2e85625b9b230bf6dae66d6dcf2ce2c96e5b07f88668e6ae706e93e7a16d829873358e77822b45b182b","tags":[]}] - Relay: {0}
Oct 20, 2024 10:24:38 PM nostr.connection.impl.listeners.TextListener handleReceivedText
INFO: Received message ["EVENT","sub_11c9e2525da2df874123a78950590a1b1f784ce6d65b1fb9c784554b88bffb50",{"content":"Hello Nostr World!","created_at":1729459475,"id":"86aa0dc2a82078b41548597470e1c6ab9f5c41a3d2d6763cabd3e0b3cf8b11be","kind":1,"pubkey":"b178aa906ad89352d82da90ec5a732093aa7331100bfc6dfaca9b3642bb20295","sig":"4ff2d22b8d7cde7a39a172b48b0d139158311f3a92d2e2e85625b9b230bf6dae66d6dcf2ce2c96e5b07f88668e6ae706e93e7a16d829873358e77822b45b182b","tags":[]}] from Relay(scheme=ws, host=localhost:3333)
**Oct 20, 2024 10:24:38 PM client.provider.EventCustomHandler onCommand
INFO: <<< Received EVENT GenericEvent(id=86aa0dc2a82078b41548597470e1c6ab9f5c41a3d2d6763cabd3e0b3cf8b11be, pubKey=b178aa906ad89352d82da90ec5a732093aa7331100bfc6dfaca9b3642bb20295, createdAt=1729459475, kind=1, tags=[], content=Hello Nostr World!, signature=4ff2d22b8d7cde7a39a172b48b0d139158311f3a92d2e2e85625b9b230bf6dae66d6dcf2ce2c96e5b07f88668e6ae706e93e7a16d829873358e77822b45b182b, _serializedEvent=null, nip=null, attributes=[]) from relay Relay(scheme=ws, host=localhost:3333) with subscription id sub_11c9e2525da2df874123a78950590a1b1f784ce6d65b1fb9c784554b88bffb50**
Oct 20, 2024 10:24:38 PM nostr.connection.impl.listeners.TextListener onMessage
INFO: WebSocket received: ["EOSE","sub_11c9e2525da2df874123a78950590a1b1f784ce6d65b1fb9c784554b88bffb50"] - Relay: Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:38 PM nostr.connection.impl.listeners.TextListener handleReceivedText
INFO: Received message ["EOSE","sub_11c9e2525da2df874123a78950590a1b1f784ce6d65b1fb9c784554b88bffb50"] from Relay(scheme=ws, host=localhost:3333)
Oct 20, 2024 10:24:38 PM nostr.command.provider.EoseCommandHandler handle
INFO: onEose event - DefaultCommandContext(message=nostr.event.message.EoseMessage@640c572d, challenge=null, relay=Relay(scheme=ws, host=localhost:3333), privateKey=[-86, 102, -53, 60, 67, 62, 117, -78, -75, -87, 51, 88, 18, -113, 119, -57, 51, 68, 89, -51, 92, -114, -108, 41, 120, -85, 19, -48, -25, 109, 95, -65])