go-waku/library/c

This specification describes the API for consuming go-waku when built as a dynamic or static library

libgowaku.h

Introduction

Native applications that wish to integrate Waku may not be able to use go-waku/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.

The API

General

WakuMessageCallback 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) (int ret_code, const char* msg, void * user_data);

With ret_code containing a status code indicating the execution result, msg containing a \0 terminated string. The format of the data sent to these callbacks will depend on the function being executed. The data for succesful results can be characters, numeric or json. If the function being invoked returns an error, msg will contain the error string.

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.

ContentFilter type

The criteria to create subscription in relay protocol or to a filter full node in JSON Format:

{
    contentTopics: string[];
    pubsubTopic?: string;
}

Fields:

• contentTopics: Array of content topics.
• pubsubTopic: Optional pubsub topic when using contentTopics as per Autosharding. In case of named or static-sharding, pubSub topic is mandatory.

LegacyFilterSubscription type

The criteria to create subscription to a filter full node in JSON Format:

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

Fields:

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

LegacyContentFilter type

{
    contentTopic: string;
}

Fields:

• contentTopic: The content topic of a Waku message.

StoreQuery type

Criteria used to retrieve historical messages

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

Fields:

• pubsubTopic: The pubsub topic on which messages are published.
• contentTOpics: Array of content topics 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
    }
  }
}

type	event Type
message	JsonMessageEvent

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.

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. The function signature for the callback should be void myCallback(char* signal, void * user_data)

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

extern int waku_new(char* jsonConfig, WakuCallBack onErrCb void* userData)

Instantiates a Waku node.

Parameters

1. char* jsonConfig: JSON string containing the options used to initialize a go-waku node. Type JsonConfig. It can be NULL to use defaults.
2. WakuCallBack onErrCb: callback to be executed if the function fails
3. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values.

extern int waku_start(WakuCallBack onErrCb void* userData)

Start 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
2. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values.

extern int waku_stop(WakuCallBack onErrCb void* userData)

Stops a Waku node.

Parameters

1. WakuCallBack onErrCb: callback to be executed if the function fails
2. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values.

extern int waku_peerid(WakuCallBack cb, void* userData)

Get the peer ID of the waku node.

Parameters

1. WakuCallBack cb: callback to be executed.
2. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, cb will receive the base58 encoded peer ID, for example QmWjHKUrXDHPCwoWXpUZ77E8o6UbAoTTZwf1AD1tDC4KNP.

extern int waku_listen_addresses(WakuCallBack cb, void* userData)

Get the multiaddresses the Waku node is listening to.

Parameters

1. WakuCallBack cb: callback to be executed
2. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, cb 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"
]

Connecting to peers

extern int waku_add_peer(char* address, char* protocolId, WakuCallBack cb, void* userData)

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 cb: callback to be executed
4. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, cb will receive the base 58 peer ID of the peer that was added. For example: QmWjHKUrXDHPCwoWXpUZ77E8o6UbAoTTZwf1AD1tDC4KNP

extern int waku_connect(char* address, int timeoutMs, WakuCallBack onErrCb void* userData)

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
4. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values.

extern int waku_connect_peerid(char* peerId, int timeoutMs, WakuCallBack onErrCb void* userData)

Dial peer using its peer ID.

Parameters

1char* 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 4. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values.

extern int waku_disconnect(char* peerId, WakuCallBack onErrCb void* userData)

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
3. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values.

extern int waku_peer_cnt(WakuCallBack cb, void* userData)

Get number of connected peers.

Parameters

1. WakuCallBack cb: callback to be executed
2. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, cb will receive the number of connected peers.

extern int waku_peers(WakuCallBack cb, void* userData)

Retrieve the list of peers known by the Waku node.

Parameters

1. WakuCallBack cb: callback to be executed if the function is succesful
2. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, cb will receive a json array with the list of peers. The list of peers 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
  }
]

Waku Relay

extern int waku_content_topic(char* applicationName, unsigned int applicationVersion, char* contentTopicName, char* encoding, WakuCallBack onOkCb void* userData)

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
6. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values.

If the function is executed succesfully, onOkCb will receive the content topic formatted according to RFC 23.

/{application-name}/{version-of-the-application}/{content-topic-name}/{encoding}

extern int waku_pubsub_topic(char* name, char* encoding, WakuCallBack onOkCb, void* userData)

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
4. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values.

If the function is executed succesfully, onOkCb will receive the pubsub topic formatted according to RFC 23.

/waku/2/{topic-name}/{encoding}

extern int waku_default_pubsub_topic(WakuCallBack onOkCb void* userData)

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

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
4. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values.

If the function is executed succesfully, onOkCb will receive the default pubsub topic: /waku/2/default-waku/proto

extern int waku_relay_publish(char* messageJson, char* pubsubTopic, int timeoutMs, WakuCallBack cb, void* userData)

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 derives the pubsub topic from content-topic based on autosharding.
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 cb: callback to be executed
5. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, onOkCb will receive the message ID.

extern int waku_relay_enough_peers(char* pubsubTopic, WakuCallBack cb, void* userData)

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 cb: callback to be executed
3. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, onOkCb will receive a string boolean indicating whether there are enough peers, i.e. true or false

extern int waku_relay_subscribe(char* filterJSON, WakuCallBack onErrCb, void* userData)

Subscribe to a Waku Relay pubsub topic to receive messages.

Parameters

1. char* filterJSON: JSON string containing the ContentFilter with the criteria of the messages to receive
2. WakuCallBack onErrCb: callback to be executed if the function fails
3. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values.

extern int waku_relay_topics(WakuCallBack cb, void* userData)

Get the list of subscribed pubsub topics in Waku Relay.

Parameters

1. WakuCallBack cb: callback to be executed
2. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, cb will receive a json array of pubsub topics.

For example:

["pubsubTopic1", "pubsubTopic2"]

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
    }
  }
}

extern int waku_relay_unsubscribe(char* filterJSON, WakuCallBack onErrCb, void* userData)

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

Parameters

1. char* filterJSON: JSON string containing the ContentFilter with the criteria of the messages to unsubscribe from
2. WakuCallBack onErrCb: callback to be executed if the function fails
3. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values.

Waku Filter

extern int waku_filter_subscribe(char* filterJSON, char* peerID, int timeoutMs, WakuCallBack cb, void* userData)

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

Parameters

1. char* filterJSON: JSON string containing the ContentFilter with the criteria of the messages to receive
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 cb: callback to be executed
5. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, cb will receive the following subscription details along with any partial errors.

For example:

{
  "subscriptions" : [
    {
      "ID": "<subscriptionID>",
      "peerID": "....",
      "pubsubTopic": "...",
      "contentTopics": [...]
    }
  ],
  "error" : "subscriptions failed for contentTopics:<topicA>,.." // Empty if all subscriptions are succesful
}

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
    }
  }
}

extern int waku_filter_ping(char* peerID, int timeoutMs, WakuCallBack onErrCb, void* userData)

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
4. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values.

extern int waku_filter_unsubscribe(filterJSON *C.char, char* peerID, int timeoutMs, WakuCallBack onErrCb, void* userData)

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
5. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values.

extern int waku_filter_unsubscribe_all(char* peerID, int timeoutMs, WakuCallBack cb, void* userData)

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 cb: callback to be executed
4. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, cb will receive an array with information about the state of each unsubscription attempt (one per peer)

For example:

[
  {
    "peerID": ....,
    "error": "" // Empty if succesful
  },
  ...
]

Waku Legacy Filter

extern int waku_legacy_filter_subscribe(char* filterJSON, char* peerID, int timeoutMs, WakuCallBack onErrCb, void* userData)

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
5. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values.

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
    }
  }
}

extern int waku_legacy_filter_unsubscribe(char* filterJSON, int timeoutMs, WakuCallBack onErrCb, void* userData)

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
4. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values.

Waku Lightpush

extern int waku_lightpush_publish(char* messageJSON, char* topic, char* peerID, int timeoutMs, WakuCallBack cb, void* userData)

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 derives the pubsub topic from content-topic based on autosharding.
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 cb: callback to be executed
6. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, cb will receive the message ID.

Waku Store

extern int waku_store_query(char* queryJSON, char* peerID, int timeoutMs, WakuCallBack cb, void* userData)

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 cb: callback to be executed
5. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, cb will receive a StoreResponse.

extern int waku_store_local_query(char* queryJSON, WakuCallBack cb, void* userData)

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 cb: callback to be executed
4. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, cb will receive a StoreResponse.

Encrypting messages

extern int waku_encode_symmetric(char* messageJson, char* symmetricKey, char* optionalSigningKey, WakuCallBack cb, void* userData)

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 cb: callback to be executed
5. void* userData: used to pass custom information to the callback function

Note: messageJson.version is overwritten to 1.

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, cb will receive the encrypted waku message which can be broadcasted with relay or lightpush protocol publish functions

extern int waku_encode_asymmetric(char* messageJson, char* publicKey, char* optionalSigningKey, WakuCallBack cb, void* userData)

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 cb: callback to be executed
5. void* userData: used to pass custom information to the callback function

Note: messageJson.version is overwritten to 1.

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, cb will receive the encrypted waku message which can be broadcasted with relay or lightpush protocol publish functions

Decrypting messages

extern int waku_decode_symmetric(char* messageJson, char* symmetricKey, WakuCallBack cb, void* userData)

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 cb: callback to be executed
4. void* userData: used to pass custom information to the callback function

Note: messageJson.version is expected to be 1.

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, cb will receive the decoded payload as a DecodedPayload.

{
  "pubkey": "0x......",
  "signature": "0x....",
  "data": "...",
  "padding": "..."
}

extern int waku_decode_asymmetric(char* messageJson, char* privateKey, WakuCallBack cb, void* userData)

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 cb: callback to be executed
4. void* userData: used to pass custom information to the callback function

Note: messageJson.version is expected to be 1.

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, cb will receive the decoded payload as a DecodedPayload.

{
  "pubkey": "0x......",
  "signature": "0x....",
  "data": "...",
  "padding": "..."
}

DNS Discovery

extern int waku_dns_discovery(char* url, char* nameserver, int timeoutMs, WakuCallBack cb, void* userData)

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 cb: callback to be executed
5. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values. If the function execution fails, cb will receive a string containing an error. If the function is executed succesfully, 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"
    },
    ...
]

DiscoveryV5

extern int waku_discv5_update_bootnodes(char* bootnodes, WakuCallBack onErrCb, void* userData)

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
3. void* userData: used to pass custom information to the callback function

Returns

A status code. Refer to the Status codes section for possible values

Copyright

Copyright and related rights waived via CC0.