1- import type { paths } from "./types" ;
2- import createClient , { ClientOptions } from "openapi-fetch" ;
1+ import type { paths , components } from "./types" ;
2+ import createClient , {
3+ ClientOptions as FetchClientOptions ,
4+ } from "openapi-fetch" ;
35import {
46 Address ,
57 encodeAbiParameters ,
@@ -10,7 +12,7 @@ import {
1012 keccak256 ,
1113} from "viem" ;
1214import { privateKeyToAccount , sign , signatureToHex } from "viem/accounts" ;
13-
15+ import WebSocket from "isomorphic-ws" ;
1416/**
1517 * ERC20 token with contract address and amount
1618 */
@@ -118,11 +120,172 @@ function checkTokenQty(token: { contract: string; amount: string }): TokenQty {
118120 } ;
119121}
120122
123+ type ClientOptions = FetchClientOptions & { baseUrl : string } ;
124+
125+ export interface WsOptions {
126+ /**
127+ * Max time to wait for a response from the server in milliseconds
128+ */
129+ response_timeout : number ;
130+ }
131+
132+ const DEFAULT_WS_OPTIONS : WsOptions = {
133+ response_timeout : 5000 ,
134+ } ;
135+
121136export class Client {
122- private clientOptions ?: ClientOptions ;
137+ public clientOptions : ClientOptions ;
138+ public wsOptions : WsOptions ;
139+ public websocket ?: WebSocket ;
140+ public idCounter = 0 ;
141+ public callbackRouter : Record <
142+ string ,
143+ ( response : components [ "schemas" ] [ "ServerResultMessage" ] ) => void
144+ > = { } ;
145+ private websocketOpportunityCallback ?: (
146+ opportunity : Opportunity
147+ ) => Promise < void > ;
123148
124- constructor ( clientOptions ? : ClientOptions ) {
149+ constructor ( clientOptions : ClientOptions , wsOptions ?: WsOptions ) {
125150 this . clientOptions = clientOptions ;
151+ this . wsOptions = { ...DEFAULT_WS_OPTIONS , ...wsOptions } ;
152+ }
153+
154+ private connectWebsocket ( ) {
155+ const websocketEndpoint = new URL ( this . clientOptions . baseUrl ) ;
156+ websocketEndpoint . protocol =
157+ websocketEndpoint . protocol === "https:" ? "wss:" : "ws:" ;
158+ websocketEndpoint . pathname = "/v1/ws" ;
159+
160+ this . websocket = new WebSocket ( websocketEndpoint . toString ( ) ) ;
161+ this . websocket . on ( "message" , async ( data ) => {
162+ const message :
163+ | components [ "schemas" ] [ "ServerResultResponse" ]
164+ | components [ "schemas" ] [ "ServerUpdateResponse" ] = JSON . parse (
165+ data . toString ( )
166+ ) ;
167+ if ( "id" in message && message . id ) {
168+ const callback = this . callbackRouter [ message . id ] ;
169+ if ( callback !== undefined ) {
170+ callback ( message ) ;
171+ delete this . callbackRouter [ message . id ] ;
172+ }
173+ } else if ( "type" in message && message . type === "new_opportunity" ) {
174+ if ( this . websocketOpportunityCallback !== undefined ) {
175+ const convertedOpportunity = this . convertOpportunity (
176+ message . opportunity
177+ ) ;
178+ if ( convertedOpportunity !== undefined ) {
179+ await this . websocketOpportunityCallback ( convertedOpportunity ) ;
180+ }
181+ }
182+ } else if ( "error" in message ) {
183+ // Can not route error messages to the callback router as they don't have an id
184+ console . error ( message . error ) ;
185+ }
186+ } ) ;
187+ }
188+
189+ /**
190+ * Converts an opportunity from the server to the client format
191+ * Returns undefined if the opportunity version is not supported
192+ * @param opportunity
193+ */
194+ private convertOpportunity (
195+ opportunity : components [ "schemas" ] [ "OpportunityParamsWithMetadata" ]
196+ ) : Opportunity | undefined {
197+ if ( opportunity . version != "v1" ) {
198+ console . warn (
199+ `Can not handle opportunity version: ${ opportunity . version }
200+ ) ;
201+ return undefined ;
202+ }
203+ return {
204+ chainId : opportunity . chain_id ,
205+ opportunityId : opportunity . opportunity_id ,
206+ permissionKey : checkHex ( opportunity . permission_key ) ,
207+ contract : checkAddress ( opportunity . contract ) ,
208+ calldata : checkHex ( opportunity . calldata ) ,
209+ value : BigInt ( opportunity . value ) ,
210+ repayTokens : opportunity . repay_tokens . map ( checkTokenQty ) ,
211+ receiptTokens : opportunity . receipt_tokens . map ( checkTokenQty ) ,
212+ } ;
213+ }
214+
215+ public setOpportunityHandler (
216+ callback : ( opportunity : Opportunity ) => Promise < void >
217+ ) {
218+ this . websocketOpportunityCallback = callback ;
219+ }
220+
221+ /**
222+ * Subscribes to the specified chains
223+ *
224+ * The opportunity handler will be called for opportunities on the specified chains
225+ * If the opportunity handler is not set, an error will be thrown
226+ * @param chains
227+ */
228+ async subscribeChains ( chains : string [ ] ) {
229+ if ( this . websocketOpportunityCallback === undefined ) {
230+ throw new Error ( "Opportunity handler not set" ) ;
231+ }
232+ return this . sendWebsocketMessage ( {
233+ method : "subscribe" ,
234+ params : {
235+ chain_ids : chains ,
236+ } ,
237+ } ) ;
238+ }
239+
240+ /**
241+ * Unsubscribes from the specified chains
242+ *
243+ * The opportunity handler will no longer be called for opportunities on the specified chains
244+ * @param chains
245+ */
246+ async unsubscribeChains ( chains : string [ ] ) {
247+ return this . sendWebsocketMessage ( {
248+ method : "unsubscribe" ,
249+ params : {
250+ chain_ids : chains ,
251+ } ,
252+ } ) ;
253+ }
254+
255+ async sendWebsocketMessage (
256+ msg : components [ "schemas" ] [ "ClientMessage" ]
257+ ) : Promise < void > {
258+ const msg_with_id : components [ "schemas" ] [ "ClientRequest" ] = {
259+ ...msg ,
260+ id : ( this . idCounter ++ ) . toString ( ) ,
261+ } ;
262+ return new Promise ( ( resolve , reject ) => {
263+ this . callbackRouter [ msg_with_id . id ] = ( response ) => {
264+ if ( response . status === "success" ) {
265+ resolve ( ) ;
266+ } else {
267+ reject ( response . result ) ;
268+ }
269+ } ;
270+ if ( this . websocket === undefined ) {
271+ this . connectWebsocket ( ) ;
272+ }
273+ if ( this . websocket !== undefined ) {
274+ if ( this . websocket . readyState === WebSocket . CONNECTING ) {
275+ this . websocket . on ( "open" , ( ) => {
276+ this . websocket ?. send ( JSON . stringify ( msg_with_id ) ) ;
277+ } ) ;
278+ } else if ( this . websocket . readyState === WebSocket . OPEN ) {
279+ this . websocket . send ( JSON . stringify ( msg_with_id ) ) ;
280+ } else {
281+ reject ( "Websocket connection closing or already closed" ) ;
282+ }
283+ }
284+ setTimeout ( ( ) => {
285+ delete this . callbackRouter [ msg_with_id . id ] ;
286+ reject ( "Websocket response timeout" ) ;
287+ } , this . wsOptions . response_timeout ) ;
288+ } ) ;
126289 }
127290
128291 /**
@@ -138,22 +301,11 @@ export class Client {
138301 throw new Error ( "No opportunities found" ) ;
139302 }
140303 return opportunities . data . flatMap ( ( opportunity ) => {
141- if ( opportunity . version != "v1" ) {
142- console . warn (
143- `Can not handle opportunity version: ${ opportunity . version }
144- ) ;
304+ const convertedOpportunity = this . convertOpportunity ( opportunity ) ;
305+ if ( convertedOpportunity === undefined ) {
145306 return [ ] ;
146307 }
147- return {
148- chainId : opportunity . chain_id ,
149- opportunityId : opportunity . opportunity_id ,
150- permissionKey : checkHex ( opportunity . permission_key ) ,
151- contract : checkAddress ( opportunity . contract ) ,
152- calldata : checkHex ( opportunity . calldata ) ,
153- value : BigInt ( opportunity . value ) ,
154- repayTokens : opportunity . repay_tokens . map ( checkTokenQty ) ,
155- receiptTokens : opportunity . receipt_tokens . map ( checkTokenQty ) ,
156- } ;
308+ return convertedOpportunity ;
157309 } ) ;
158310 }
159311
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