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36/WAKU2-BINDINGS-API

Introduction​

Native applications that wish to integrate Waku may not be able to use nwaku and its JSON RPC API due to constraints on packaging, performance or executables.

An alternative is to link existing Waku implementation as a static or dynamic library in their application.

This specification describes the C API that SHOULD be implemented by native Waku library and that SHOULD be used to consume them.

Design requirements​

The API should be generic enough, so:

  • it can be implemented by both nwaku and go-waku C-Bindings,
  • it can be consumed from a variety of languages such as C#, Kotlin, Swift, Rust, C++, etc.

The selected format to pass data to and from the API is JSON.

It has been selected due to its widespread usage and easiness of use. Other alternatives MAY replace it in the future (C structure, protobuf) if it brings limitations that need to be lifted.

The API​

General​

WakuCallBack type​

All the API functions require passing callbacks which will be executed depending on the result of the execution result. These callbacks are defined as

typedef void (*WakuCallBack) (const char* msg, size_t len_0);

With msg containing a \0 terminated string, and len_0 the length of this string. The format of the data sent to these callbacks will depend on the function being executed. The data can be characters, numeric or json.

Status Codes​

The API functions return an integer with status codes depending on the execution result. The following status codes are defined:

  • 0 - Success
  • 1 - Error
  • 2 - Missing callback

JsonMessage type​

A Waku Message in JSON Format:

{
    payload: string;
    contentTopic: string;
    version: number;
    timestamp: number;
}

Fields:

  • payload: base64 encoded payload, waku_utils_base64_encode can be used for this.
  • contentTopic: The content topic to be set on the message.
  • version: The Waku Message version number.
  • timestamp: Unix timestamp in nanoseconds.

DecodedPayload type​

A payload once decoded, used when a received Waku Message is encrypted:

interface DecodedPayload {
    pubkey?: string;
    signature?: string;
    data: string;
    padding: string;
  }

Fields:

  • pubkey: Public key that signed the message (optional), hex encoded with 0x prefix,
  • signature: Message signature (optional), hex encoded with 0x prefix,
  • data: Decrypted message payload base64 encoded,
  • padding: Padding base64 encoded.

FilterSubscription type​

The criteria to create subscription to a light node in JSON Format:

{
    contentFilters: ContentFilter[];
    pubsubTopic: string?;
}

Fields:

  • contentFilters: Array of ContentFilter being subscribed to / unsubscribed from.
  • topic: Optional pubsub topic.

ContentFilter type​

{
    contentTopic: string;
}

Fields:

  • contentTopic: The content topic of a Waku message.

StoreQuery type​

Criteria used to retrieve historical messages

interface StoreQuery {
    pubsubTopic?: string;
    contentFilters?: ContentFilter[];
    startTime?: number;
    endTime?: number;
    pagingOptions?: PagingOptions
  }

Fields:

  • pubsubTopic: The pubsub topic on which messages are published.
  • contentFilters: Array of ContentFilter to query for historical messages,
  • startTime: The inclusive lower bound on the timestamp of queried messages. This field holds the Unix epoch time in nanoseconds.
  • endTime: The inclusive upper bound on the timestamp of queried messages. This field holds the Unix epoch time in nanoseconds.
  • pagingOptions: Paging information in PagingOptions format.

StoreResponse type​

The response received after doing a query to a store node:

interface StoreResponse {
    messages: JsonMessage[];
    pagingOptions?: PagingOptions;
  }

Fields:

  • messages: Array of retrieved historical messages in JsonMessage format.
  • pagingOption: Paging information in PagingOptions format from which to resume further historical queries

PagingOptions type​

interface PagingOptions {
    pageSize: number;
    cursor?: Index;
    forward: bool;
  }

Fields:

  • pageSize: Number of messages to retrieve per page.
  • cursor: Message Index from which to perform pagination. If not included and forward is set to true, paging will be performed from the beginning of the list. If not included and forward is set to false, paging will be performed from the end of the list.
  • forward: true if paging forward, false if paging backward

Index type​

interface Index {
    digest: string;
    receiverTime: number;
    senderTime: number;
    pubsubTopic: string;
  }

Fields:

  • digest: Hash of the message at this Index.
  • receiverTime: UNIX timestamp in nanoseconds at which the message at this Index was received.
  • senderTime: UNIX timestamp in nanoseconds at which the message is generated by its sender.
  • pubsubTopic: The pubsub topic of the message at this Index.

Events​

Asynchronous events require a callback to be registered. An example of an asynchronous event that might be emitted is receiving a message. When an event is emitted, this callback will be triggered receiving a JSON string of type JsonSignal.

JsonSignal type​

{
    type: string;
    event: any;
}

Fields:

  • type: Type of signal being emitted. Currently, only message is available.
  • event: Format depends on the type of signal.

For example:

{
  "type": "message",
  "event": {
    "pubsubTopic": "/waku/2/default-waku/proto",
    "messageId": "0x6496491e40dbe0b6c3a2198c2426b16301688a2daebc4f57ad7706115eac3ad1",
    "wakuMessage": {
      "payload": "TODO",
      "contentTopic": "/my-app/1/notification/proto",
      "version": 1,
      "timestamp": 1647826358000000000
    }
  }
}
typeevent Type
messageJsonMessageEvent

JsonMessageEvent type​

Type of event field for a message event:

{
    pubsubTopic: string;
    messageId: string;
    wakuMessage: JsonMessage;
}
  • pubsubTopic: The pubsub topic on which the message was received.
  • messageId: The message id.
  • wakuMessage: The message in JsonMessage format.

waku_set_event_callback​

extern void waku_set_event_callback(WakuCallBack cb){}

Register callback to act as event handler and receive application signals, which are used to react to asynchronous events in Waku.

Parameters

  1. WakuCallBack cb: callback that will be executed when an async event is emitted.

Node management​

JsonConfig type​

Type holding a node configuration:

interface JsonConfig {
    host?: string;
    port?: number;
    advertiseAddr?: string;
    nodeKey?: string;
    keepAliveInterval?: number;
    relay?: boolean;
    relayTopics?: Array<string>;
    gossipsubParameters?: GossipSubParameters;
    minPeersToPublish?: number
    legacyFilter?: boolean;
    discV5?: boolean;
    discV5BootstrapNodes?: Array<string>;
    discV5UDPPort?: number;
    store?: boolean;
    databaseURL?: string;
    storeRetentionMaxMessages?: number;
    storeRetentionTimeSeconds?: number;
    websocket?: Websocket;
    dns4DomainName?: string;
}

Fields:

All fields are optional. If a key is undefined, or null, a default value will be set.

  • host: Listening IP address. Default 0.0.0.0.
  • port: Libp2p TCP listening port. Default 60000. Use 0 for random.
  • advertiseAddr: External address to advertise to other nodes. Can be ip4, ip6 or dns4, dns6. If null, the multiaddress(es) generated from the ip and port specified in the config (or default ones) will be used. Default: null.
  • nodeKey: Secp256k1 private key in Hex format (0x123...abc). Default random.
  • keepAliveInterval: Interval in seconds for pinging peers to keep the connection alive. Default 20.
  • relay: Enable relay protocol. Default true.
  • relayTopics: Array of pubsub topics that WakuRelay will automatically subscribe to when the node starts Default []
  • gossipSubParameters: custom gossipsub parameters. See GossipSubParameters section for defaults
  • minPeersToPublish: The minimum number of peers required on a topic to allow broadcasting a message. Default 0.
  • legacyFilter: Enable Legacy Filter protocol. Default false.
  • discV5: Enable DiscoveryV5. Default false
  • discV5BootstrapNodes: Array of bootstrap nodes ENR
  • discV5UDPPort: UDP port for DiscoveryV5 Default 9000
  • store: Enable store protocol to persist message history Default false
  • databaseURL: url connection string. Accepts SQLite and PostgreSQL connection strings Default: sqlite3://store.db
  • storeRetentionMaxMessages: max number of messages to store in the database. Default 10000
  • storeRetentionTimeSeconds: max number of seconds that a message will be persisted in the database. Default 2592000 (30d)
  • websocket: custom websocket support parameters. See Websocket section for defaults
  • dns4DomainName: the domain name resolving to the node's public IPv4 address.

For example:

{
  "host": "0.0.0.0",
  "port": 60000,
  "advertiseAddr": "1.2.3.4",
  "nodeKey": "0x123...567",
  "keepAliveInterval": 20,
  "relay": true,
  "minPeersToPublish": 0
}

GossipsubParameters type​

Type holding custom gossipsub configuration:

interface GossipSubParameters {
    D?: number;
    D_low?: number;
    D_high?: number;
    D_score?: number;
    D_out?: number;
    HistoryLength?: number;
    HistoryGossip?: number;
    D_lazy?: number;
    GossipFactor?: number;
    GossipRetransmission?: number;
    HeartbeatInitialDelayMs?: number;
    HeartbeatIntervalSeconds?: number;
    SlowHeartbeatWarning?: number;
    FanoutTTLSeconds?: number;
    PrunePeers?: number;
    PruneBackoffSeconds?: number;
    UnsubscribeBackoffSeconds?: number;
    Connectors?: number;
    MaxPendingConnections?: number;
    ConnectionTimeoutSeconds?: number;
    DirectConnectTicks?: number;
    DirectConnectInitialDelaySeconds?: number;
    OpportunisticGraftTicks?: number;
    OpportunisticGraftPeers?: number;
    GraftFloodThresholdSeconds?: number;
    MaxIHaveLength?: number;
    MaxIHaveMessages?: number;
    IWantFollowupTimeSeconds?: number;
}

Fields:

All fields are optional. If a key is undefined, or null, a default value will be set.

  • d: optimal degree for a GossipSub topic mesh. Default 6
  • dLow: lower bound on the number of peers we keep in a GossipSub topic mesh Default 5
  • dHigh: upper bound on the number of peers we keep in a GossipSub topic mesh. Default 12
  • dScore: affects how peers are selected when pruning a mesh due to over subscription. Default 4
  • dOut: sets the quota for the number of outbound connections to maintain in a topic mesh. Default 2
  • historyLength: controls the size of the message cache used for gossip. Default 5
  • historyGossip: controls how many cached message ids we will advertise in IHAVE gossip messages. Default 3
  • dLazy: affects how many peers we will emit gossip to at each heartbeat. Default 6
  • gossipFactor: affects how many peers we will emit gossip to at each heartbeat. Default 0.25
  • gossipRetransmission: controls how many times we will allow a peer to request the same message id through IWANT gossip before we start ignoring them. Default 3
  • heartbeatInitialDelayMs: short delay in milliseconds before the heartbeat timer begins after the router is initialized. Default 100 milliseconds
  • heartbeatIntervalSeconds: controls the time between heartbeats. Default 1 second
  • slowHeartbeatWarning: duration threshold for heartbeat processing before emitting a warning. Default 0.1
  • fanoutTTLSeconds: controls how long we keep track of the fanout state. Default 60 seconds
  • prunePeers: controls the number of peers to include in prune Peer eXchange. Default 16
  • pruneBackoffSeconds: controls the backoff time for pruned peers. Default 60 seconds
  • unsubscribeBackoffSeconds: controls the backoff time to use when unsuscribing from a topic. Default 10 seconds
  • connectors: number of active connection attempts for peers obtained through PX. Default 8
  • maxPendingConnections: maximum number of pending connections for peers attempted through px. Default 128
  • connectionTimeoutSeconds: timeout in seconds for connection attempts. Default 30 seconds
  • directConnectTicks: the number of heartbeat ticks for attempting to reconnect direct peers that are not currently connected. Default 300
  • directConnectInitialDelaySeconds: initial delay before opening connections to direct peers. Default 1 second
  • opportunisticGraftTicks: number of heartbeat ticks for attempting to improve the mesh with opportunistic grafting. Default 60
  • opportunisticGraftPeers: the number of peers to opportunistically graft. Default 2
  • graftFloodThresholdSeconds: If a GRAFT comes before GraftFloodThresholdSeconds has elapsed since the last PRUNE, then there is an extra score penalty applied to the peer through P7. Default 10 seconds
  • maxIHaveLength: max number of messages to include in an IHAVE message, also controls the max number of IHAVE ids we will accept and request with IWANT from a peer within a heartbeat. Default 5000
  • maxIHaveMessages: max number of IHAVE messages to accept from a peer within a heartbeat. Default 10
  • iWantFollowupTimeSeconds: Time to wait for a message requested through IWANT following an IHAVE advertisement. Default 3 seconds
  • seenMessagesTTLSeconds: configures when a previously seen message ID can be forgotten about. Default 120 seconds

Websocket type​

Type holding custom websocket support configuration:

interface Websocket {
    enabled?: bool;
    host?: string;
    port?: number;
    secure?: bool;
    certPath?: string;
    keyPath?: string;
}

Fields:

All fields are optional. If a key is undefined, or null, a default value will be set. If using secure websockets support, certPath and keyPath become mandatory attributes. Unless selfsigned certificates are used, it will probably make sense in the JsonConfiguration to specify the domain name used in the certificate in the dns4DomainName attribute.

  • enabled: indicates if websockets support will be enabled Default false
  • host: listening address for websocket connections Default 0.0.0.0
  • port: TCP listening port for websocket connection (0 for random, binding to 443 requires root access) Default 60001, if secure websockets support is enabled, the default is 6443“
  • secure: enable secure websockets support Default false
  • certPath: secure websocket certificate path
  • keyPath: secure websocket key path

waku_new​

extern int waku_new(char* jsonConfig, WakuCallBack onErrCb){}

Instantiates a Waku node.

Parameters

  1. char* jsonConfig: JSON string containing the options used to initialize a waku node. Type JsonConfig. It can be NULL to use defaults.
  2. WakuCallBack onErrCb: WakuCallBack. Callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onErrCb callback

waku_start​

extern int waku_start(WakuCallBack onErrCb){}

Starts a Waku node mounting all the protocols that were enabled during the Waku node instantiation.

Parameters

  1. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onErrCb callback

waku_stop​

extern int waku_stop(WakuCallBack onErrCb){}

Stops a Waku node.

Parameters

  1. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onErrCb callback

waku_peerid​

extern int waku_peerid(WakuCallBack onOkCb, WakuCallBack onErrCb){}

Get the peer ID of the waku node.

Parameters

  1. WakuCallBack onOkCb: callback to be executed if the function is succesful
  2. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive the base58 encoded peer ID, for example QmWjHKUrXDHPCwoWXpUZ77E8o6UbAoTTZwf1AD1tDC4KNP
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

waku_listen_addresses​

extern int waku_listen_addresses(WakuCallBack onOkCb, WakuCallBack onErrCb){}

Get the multiaddresses the Waku node is listening to.

Parameters

  1. WakuCallBack onOkCb: callback to be executed if the function is succesful
  2. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive a json array of multiaddresses. The multiaddresses are strings. For example:
[
    "/ip4/127.0.0.1/tcp/30303",
    "/ip4/1.2.3.4/tcp/30303",
    "/dns4/waku.node.example/tcp/8000/wss"
]
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb and onErrCb callback

Connecting to peers​

waku_add_peer​

extern int waku_add_peer(char* address, char* protocolId, WakuCallBack onOkCb, WakuCallBack onErrCb){}

Add a node multiaddress and protocol to the waku node's peerstore.

Parameters

  1. char* address: A multiaddress (with peer id) to reach the peer being added.
  2. char* protocolId: A protocol we expect the peer to support.
  3. WakuCallBack onOkCb: callback to be executed if the function is succesful
  4. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive the base 58 peer ID of the peer that was added.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

waku_connect​

extern int waku_connect(char* address, int timeoutMs, WakuCallBack onErrCb){}

Dial peer using a multiaddress.

Parameters

  1. char* address: A multiaddress to reach the peer being dialed.
  2. int timeoutMs: Timeout value in milliseconds to execute the call. If the function execution takes longer than this value, the execution will be canceled and an error returned. Use 0 for no timeout.
  3. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onErrCb callback

waku_connect_peerid​

extern int waku_connect_peerid(char* peerId, int timeoutMs, WakuCallBack onErrCb){}

Dial peer using its peer ID.

Parameters

  1. char* peerID: Peer ID to dial. The peer must be already known. It must have been added before with waku_add_peer or previously dialed with waku_connect.
  2. int timeoutMs: Timeout value in milliseconds to execute the call. If the function execution takes longer than this value, the execution will be canceled and an error returned. Use 0 for no timeout.
  3. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onErrCb callback

waku_disconnect​

extern int waku_disconnect(char* peerId, WakuCallBack onErrCb){}

Disconnect a peer using its peerID

Parameters

  1. char* peerID: Peer ID to disconnect.
  2. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onErrCb callback

waku_peer_cnt​

extern int waku_peer_cnt(WakuCallBack onOkCb, WakuCallBack onErrCb){}

Get number of connected peers.

Parameters

  1. WakuCallBack onOkCb: callback to be executed if the function is succesful
  2. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive the number of connected peers.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

waku_peers​

extern int waku_peers(WakuCallBack onOkCb, WakuCallBack onErrCb){}

Retrieve the list of peers known by the Waku node.

Parameters

  1. WakuCallBack onOkCb: callback to be executed if the function is succesful
  2. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive a json array with the list of peers. This list has this format:
[
  {
    "peerID": "16Uiu2HAmJb2e28qLXxT5kZxVUUoJt72EMzNGXB47RedcBafeDCBA",
    "protocols": [
      "/ipfs/id/1.0.0",
      "/vac/waku/relay/2.0.0",
      "/ipfs/ping/1.0.0"
    ],
    "addrs": [
      "/ip4/1.2.3.4/tcp/30303"
    ],
    "connected": true
  }
]
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

Waku Relay​

waku_content_topic​

extern int waku_content_topic(char* applicationName, unsigned int applicationVersion, char* contentTopicName, char* encoding, WakuCallBack onOkCb){}

Create a content topic string according to RFC 23.

Parameters

  1. char* applicationName
  2. unsigned int applicationVersion
  3. char* contentTopicName
  4. char* encoding: depending on the payload, use proto, rlp or rfc26
  5. WakuCallBack onOkCb: callback to be executed if the function is succesful

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive the content topic formatted according to RFC 23: /{application-name}/{version-of-the-application}/{content-topic-name}/{encoding}
  • 1 - The operation failed for any reason.
  • 2 - The function is missing the onOkCb callback

waku_pubsub_topic​

extern int waku_pubsub_topic(char* name, char* encoding, WakuCallBack onOkCb){}

Create a pubsub topic string according to RFC 23.

Parameters

  1. char* name
  2. char* encoding: depending on the payload, use proto, rlp or rfc26
  3. WakuCallBack onOkCb: callback to be executed if the function is succesful

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will get populated with a pubsub topic formatted according to RFC 23: /waku/2/{topic-name}/{encoding}
  • 1 - The operation failed for any reason.
  • 2 - The function is missing the onOkCb callback

waku_default_pubsub_topic​

extern int waku_default_pubsub_topic(WakuCallBack onOkCb){}

Returns the default pubsub topic used for exchanging waku messages defined in RFC 10.

Parameters

  1. WakuCallBack onOkCb: callback to be executed if the function is succesful

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will get populated with /waku/2/default-waku/proto
  • 1 - The operation failed for any reason.
  • 2 - The function is missing the onOkCb callback

waku_relay_publish​

extern int waku_relay_publish(char* messageJson, char* pubsubTopic, int timeoutMs, WakuCallBack onOkCb, WakuCallBack onErrCb){}

Publish a message using Waku Relay.

Parameters

  1. char* messageJson: JSON string containing the Waku Message as JsonMessage.
  2. char* pubsubTopic: pubsub topic on which to publish the message. If NULL, it uses the default pubsub topic.
  3. int timeoutMs: Timeout value in milliseconds to execute the call. If the function execution takes longer than this value, the execution will be canceled and an error returned. Use 0 for no timeout.
  4. WakuCallBack onOkCb: callback to be executed if the function is succesful
  5. WakuCallBack onErrCb: callback to be executed if the function fails

If the execution is successful, the result field contains the message ID.

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will get populated with the message ID
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

waku_relay_enough_peers​

extern int waku_relay_enough_peers(char* pubsubTopic, WakuCallBack onOkCb, WakuCallBack onErrCb){}

Determine if there are enough peers to publish a message on a given pubsub topic.

Parameters

  1. char* pubsubTopic: Pubsub topic to verify. If NULL, it verifies the number of peers in the default pubsub topic.
  2. WakuCallBack onOkCb: callback to be executed if the function is succesful
  3. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive a string boolean indicating whether there are enough peers, i.e. true or false
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

waku_relay_subscribe​

extern int waku_relay_subscribe(char* topic, WakuCallBack onErrCb){}

Subscribe to a Waku Relay pubsub topic to receive messages.

Parameters

  1. char* topic: Pubsub topic to subscribe to. If NULL, it subscribes to the default pubsub topic.
  2. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onErrCb callback

Events

When a message is received, a "message" event is emitted containing the message, pubsub topic, and node ID in which the message was received.

The event type is JsonMessageEvent.

For Example:

{
  "type": "message",
  "event": {
    "pubsubTopic": "/waku/2/default-waku/proto",
    "messageId": "0x6496491e40dbe0b6c3a2198c2426b16301688a2daebc4f57ad7706115eac3ad1",
    "wakuMessage": {
      "payload": "TODO",
      "contentTopic": "/my-app/1/notification/proto",
      "version": 1,
      "timestamp": 1647826358000000000
    }
  }
}

waku_relay_unsubscribe​

extern int waku_relay_unsubscribe(char* topic, WakuCallBack onErrCb)

Closes the pubsub subscription to a pubsub topic. No more messages will be received from this pubsub topic.

Parameters

  1. char* pusubTopic: Pubsub topic to unsubscribe from. If NULL, unsubscribes from the default pubsub topic.
  2. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly.
  • 1 - The operation failed for any reason.
  • 2 - The function is missing the onErrCb callback

waku_relay_topics​

extern int waku_relay_topics(WakuCallBack onOkCb, WakuCallBack onErrCb)

Get the list of subscribed pubsub topics in Waku Relay.

Parameters

  1. WakuCallBack onOkCb: callback to be executed if the function is succesful
  2. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive a json array of pubsub topics i.e ["pubsubTopic1", "pubsubTopic2"]
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

Waku Filter​

waku_filter_subscribe​

extern int waku_filter_subscribe(char* filterJSON, char* peerID, int timeoutMs, WakuCallBack onOkCb, WakuCallBack onErrCb)

Creates a subscription to a filter full node matching a content filter..

Parameters

  1. char* filterJSON: JSON string containing the FilterSubscription to subscribe to.
  2. char* peerID: Peer ID to subscribe to. The peer must be already known. It must have been added before with waku_add_peer or previously dialed with waku_connect_peer. Use NULL to automatically select a node.
  3. int timeoutMs: Timeout value in milliseconds to execute the call. If the function execution takes longer than this value, the execution will be canceled and an error returned. Use 0 for no timeout.
  4. WakuCallBack onOkCb: callback to be executed if the function is succesful
  5. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive the subscription details, for example:
{
  "peerID": "....",
  "pubsubTopic": "...",
  "contentTopics": [...]
}
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

Events

When a message is received, a "message" event is emitted containing the message, pubsub topic, and node ID in which the message was received.

The event type is JsonMessageEvent.

For Example:

{
  "type": "message",
  "event": {
    "pubsubTopic": "/waku/2/default-waku/proto",
    "messageId": "0x6496491e40dbe0b6c3a2198c2426b16301688a2daebc4f57ad7706115eac3ad1",
    "wakuMessage": {
      "payload": "TODO",
      "contentTopic": "/my-app/1/notification/proto",
      "version": 1,
      "timestamp": 1647826358000000000
    }
  }
}

waku_filter_ping​

extern int waku_filter_ping(char* peerID, int timeoutMs, WakuCallBack onErrCb){}

Used to know if a service node has an active subscription for this client

Parameters

  1. char* peerID: Peer ID to check for an active subscription The peer must be already known. It must have been added before with waku_add_peer or previously dialed with waku_connect_peer.
  2. int timeoutMs: Timeout value in milliseconds to execute the call. If the function execution takes longer than this value, the execution will be canceled and an error returned. Use 0 for no timeout.
  3. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onErrCb callback

waku_filter_unsubscribe​

extern int waku_filter_unsubscribe(filterJSON *C.char, char* peerID, int timeoutMs, WakuCallBack onErrCb){}

Sends a requests to a service node to stop pushing messages matching this filter to this client. It might be used to modify an existing subscription by providing a subset of the original filter criteria

Parameters

  1. char* filterJSON: JSON string containing the FilterSubscription criteria to unsubscribe from
  2. char* peerID: Peer ID to unsubscribe from The peer must be already known. It must have been added before with waku_add_peer or previously dialed with waku_connect_peer.
  3. int timeoutMs: Timeout value in milliseconds to execute the call. If the function execution takes longer than this value, the execution will be canceled and an error returned. Use 0 for no timeout.
  4. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

waku_filter_unsubscribe_all​

extern int waku_filter_unsubscribe_all(char* peerID, int timeoutMs, WakuCallBack onOkCb, WakuCallBack onErrCb){}

Sends a requests to a service node (or all service nodes) to stop pushing messages

Parameters

  1. char* peerID: Peer ID to unsubscribe from The peer must be already known. It must have been added before with waku_add_peer or previously dialed with waku_connect_peer. Use NULL to unsubscribe from all peers with active subscriptions
  2. int timeoutMs: Timeout value in milliseconds to execute the call. If the function execution takes longer than this value, the execution will be canceled and an error returned. Use 0 for no timeout.
  3. WakuCallBack onOkCb: callback to be executed if the function is succesful
  4. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive an array with information about the state of each unsubscription attempt (one per peer)
[
  {
    "peerID": ....,
    "error": "" // Empty if succesful
  },
  ...
]
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

Waku Legacy Filter​

waku_legacy_filter_subscribe​

extern int waku_legacy_filter_subscribe(char* filterJSON, char* peerID, int timeoutMs, WakuCallBack onErrCb){}

Creates a subscription in a lightnode for messages that matches a content filter and optionally a PubSub topic.

Parameters

  1. char* filterJSON: JSON string containing the LegacyFilterSubscription to subscribe to.
  2. char* peerID: Peer ID to subscribe to. The peer must be already known. It must have been added before with waku_add_peer or previously dialed with waku_connect_peer. Use NULL to automatically select a node.
  3. int timeoutMs: Timeout value in milliseconds to execute the call. If the function execution takes longer than this value, the execution will be canceled and an error returned. Use 0 for no timeout.
  4. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onErrCb callback

Events

When a message is received, a "message" event is emitted containing the message, pubsub topic, and node ID in which the message was received.

The event type is JsonMessageEvent.

For Example:

{
  "type": "message",
  "event": {
    "pubsubTopic": "/waku/2/default-waku/proto",
    "messageId": "0x6496491e40dbe0b6c3a2198c2426b16301688a2daebc4f57ad7706115eac3ad1",
    "wakuMessage": {
      "payload": "TODO",
      "contentTopic": "/my-app/1/notification/proto",
      "version": 1,
      "timestamp": 1647826358000000000
    }
  }
}

waku_legacy_filter_unsubscribe​

extern int waku_legacy_filter_unsubscribe(char* filterJSON, int timeoutMs, WakuCallBack onErrCb){}

Removes subscriptions in a light node matching a content filter and, optionally, a PubSub topic.

Parameters

  1. char* filterJSON: JSON string containing the LegacyFilterSubscription.
  2. int timeoutMs: Timeout value in milliseconds to execute the call. If the function execution takes longer than this value, the execution will be canceled and an error returned. Use 0 for no timeout.
  3. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onErrCb callback

Waku Lightpush​

waku_lightpush_publish​

extern int waku_lightpush_publish(char* messageJSON, char* topic, char* peerID, int timeoutMs, WakuCallBack onOkCb, WakuCallBack onErrCb){}

Publish a message using Waku Lightpush.

Parameters

  1. char* messageJson: JSON string containing the Waku Message as JsonMessage.
  2. char* pubsubTopic: pubsub topic on which to publish the message. If NULL, it uses the default pubsub topic.
  3. char* peerID: Peer ID supporting the lightpush protocol. The peer must be already known. It must have been added before with waku_add_peer or previously dialed with waku_connect_peer. Use NULL to automatically select a node.
  4. int timeoutMs: Timeout value in milliseconds to execute the call. If the function execution takes longer than this value, the execution will be canceled and an error returned. Use 0 for no timeout.
  5. WakuCallBack onOkCb: callback to be executed if the function is succesful
  6. WakuCallBack onErrCb: callback to be executed if the function fails

Note: messageJson.version is overwritten to 0.

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive the message ID
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

Waku Store​

waku_store_query​

extern int waku_store_query(char* queryJSON, char* peerID, int timeoutMs, WakuCallBack onOkCb, WakuCallBack onErrCb){}

Retrieves historical messages on specific content topics. This method may be called with PagingOptions, to retrieve historical messages on a per-page basis. If the request included PagingOptions, the node must return messages on a per-page basis and include PagingOptions in the response. These PagingOptions must contain a cursor pointing to the Index from which a new page can be requested.

Parameters

  1. char* queryJSON: JSON string containing the StoreQuery.
  2. char* peerID: Peer ID supporting the store protocol. The peer must be already known. It must have been added before with waku_add_peer or previously dialed with waku_connect_peer.
  3. int timeoutMs: Timeout value in milliseconds to execute the call. If the function execution takes longer than this value, the execution will be canceled and an error returned. Use 0 for no timeout.
  4. WakuCallBack onOkCb: callback to be executed if the function is succesful
  5. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive a StoreResponse.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

waku_store_local_query​

extern int waku_store_local_query(char* queryJSON, WakuCallBack onOkCb, WakuCallBack onErrCb){}

Retrieves locally stored historical messages on specific content topics. This method may be called with PagingOptions, to retrieve historical messages on a per-page basis. If the request included PagingOptions, the node must return messages on a per-page basis and include PagingOptions in the response. These PagingOptions must contain a cursor pointing to the Index from which a new page can be requested.

Parameters

  1. char* queryJSON: JSON string containing the StoreQuery.
  2. int timeoutMs: Timeout value in milliseconds to execute the call. If the function execution takes longer than this value, the execution will be canceled and an error returned. Use 0 for no timeout.
  3. WakuCallBack onOkCb: callback to be executed if the function is succesful
  4. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive a StoreResponse.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

Encrypting messages​

waku_encode_symmetric​

extern int waku_encode_symmetric(char* messageJson, char* symmetricKey, char* optionalSigningKey, WakuCallBack onOkCb, WakuCallBack onErrCb){}

Encrypt a message using symmetric encryption and optionally sign the message

Parameters

  1. char* messageJson: JSON string containing the Waku Message as JsonMessage.
  2. char* symmetricKey: hex encoded secret key to be used for encryption.
  3. char* optionalSigningKey: hex encoded private key to be used to sign the message.
  4. WakuCallBack onOkCb: callback to be executed if the function is succesful
  5. WakuCallBack onErrCb: callback to be executed if the function fails

Note: messageJson.version is overwritten to 1.

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive the encrypted waku message which can be broadcasted with relay or lightpush protocol publish functions.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

waku_encode_asymmetric​

extern int waku_encode_asymmetric(char* messageJson, char* publicKey, char* optionalSigningKey, WakuCallBack onOkCb, WakuCallBack onErrCb){}

Encrypt a message using asymmetric encryption and optionally sign the message

Parameters

  1. char* messageJson: JSON string containing the Waku Message as JsonMessage.
  2. char* publicKey: hex encoded public key to be used for encryption.
  3. char* optionalSigningKey: hex encoded private key to be used to sign the message.
  4. WakuCallBack onOkCb: callback to be executed if the function is succesful
  5. WakuCallBack onErrCb: callback to be executed if the function fails

Note: messageJson.version is overwritten to 1.

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive the encrypted waku message which can be broadcasted with relay or lightpush protocol publish functions.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

Decrypting messages​

waku_decode_symmetric​

extern int waku_decode_symmetric(char* messageJson, char* symmetricKey, WakuCallBack onOkCb, WakuCallBack onErrCb){}

Decrypt a message using a symmetric key

Parameters

  1. char* messageJson: JSON string containing the Waku Message as JsonMessage.
  2. char* symmetricKey: 32 byte symmetric key hex encoded.
  3. WakuCallBack onOkCb: callback to be executed if the function is succesful
  4. WakuCallBack onErrCb: callback to be executed if the function fails

Note: messageJson.version is expected to be 1.

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive the decoded payload as a DecodedPayload.
{
  "pubkey": "0x......",
  "signature": "0x....",
  "data": "...",
  "padding": "..."
}
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

waku_decode_asymmetric​

extern int waku_decode_asymmetric(char* messageJson, char* privateKey, WakuCallBack onOkCb, WakuCallBack onErrCb){}

Decrypt a message using a secp256k1 private key

Parameters

  1. char* messageJson: JSON string containing the Waku Message as JsonMessage.
  2. char* privateKey: secp256k1 private key hex encoded.
  3. WakuCallBack onOkCb: callback to be executed if the function is succesful
  4. WakuCallBack onErrCb: callback to be executed if the function fails

Note: messageJson.version is expected to be 1.

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive the decoded payload as a DecodedPayload.
{
  "pubkey": "0x......",
  "signature": "0x....",
  "data": "...",
  "padding": "..."
}
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

DNS Discovery​

waku_dns_discovery​

extern int waku_dns_discovery(char* url, char* nameserver, int timeoutMs, WakuCallBack onOkCb, WakuCallBack onErrCb){}

Returns a list of multiaddress and enrs given a url to a DNS discoverable ENR tree

Parameters

  1. char* url: URL containing a discoverable ENR tree
  2. char* nameserver: The nameserver to resolve the ENR tree url. If NULL or empty, it will automatically use the default system dns.
  3. int timeoutMs: Timeout value in milliseconds to execute the call. If the function execution takes longer than this value, the execution will be canceled and an error returned. Use 0 for no timeout.
  4. WakuCallBack onOkCb: callback to be executed if the function is succesful
  5. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly. onOkCb will receive an array objects describing the multiaddresses, enr and peerID each node found.
[
    {
        "peerID":"16Uiu2HAmPLe7Mzm8TsYUubgCAW1aJoeFScxrLj8ppHFivPo97bUZ",
        "multiaddrs":[
            "/ip4/134.209.139.210/tcp/30303/p2p/16Uiu2HAmPLe7Mzm8TsYUubgCAW1aJoeFScxrLj8ppHFivPo97bUZ",
            "/dns4/node-01.do-ams3.wakuv2.test.statusim.net/tcp/8000/wss/p2p/16Uiu2HAmPLe7Mzm8TsYUubgCAW1aJoeFScxrLj8ppHFivPo97bUZ"
        ],
        "enr":"enr:-M-4QCtJKX2WDloRYDT4yjeMGKUCRRcMlsNiZP3cnPO0HZn6IdJ035RPCqsQ5NvTyjqHzKnTM6pc2LoKliV4CeV0WrgBgmlkgnY0gmlwhIbRi9KKbXVsdGlhZGRyc7EALzYobm9kZS0wMS5kby1hbXMzLndha3V2Mi50ZXN0LnN0YXR1c2ltLm5ldAYfQN4DiXNlY3AyNTZrMaEDnr03Tuo77930a7sYLikftxnuG3BbC3gCFhA4632ooDaDdGNwgnZfg3VkcIIjKIV3YWt1Mg8"
    },
    ...
]
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onOkCb or onErrCb callback

DiscoveryV5​

waku_discv5_update_bootnodes​

extern int waku_discv5_update_bootnodes(char* bootnodes, WakuCallBack onErrCb)`

Update the bootnode list used for discovering new peers via DiscoveryV5

Parameters

  1. char* bootnodes: JSON array containing the bootnode ENRs i.e. ["enr:...", "enr:..."]
  2. WakuCallBack onErrCb: callback to be executed if the function fails

Returns

int with a status code. Possible values:

  • 0 - The operation was completed successfuly.
  • 1 - The operation failed for any reason. onErrCb will be executed with the reason the function execution failed.
  • 2 - The function is missing the onErrCb callback

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