Implement web browser socket

8 files changed, 190 insertions, 26 deletions

diff --git a/packages/connect/src/browser_ws_orderbook_channel.ts b/packages/connect/src/browser_ws_orderbook_channel.ts
new file mode 100644
index 000000000..b97a82ec9
--- /dev/null
+++ b/packages/connect/src/browser_ws_orderbook_channel.ts
@@ -0,0 +1,140 @@
+import * as _ from 'lodash';
+import * as WebSocket from 'websocket';
+
+import {
+    OrderbookChannel,
+    OrderbookChannelHandler,
+    OrderbookChannelMessageTypes,
+    OrderbookChannelSubscriptionOpts,
+    WebsocketClientEventType,
+    WebsocketConnectionEventType,
+} from './types';
+import { assert } from './utils/assert';
+import { orderbookChannelMessageParser } from './utils/orderbook_channel_message_parser';
+
+interface Subscription {
+    subscriptionOpts: OrderbookChannelSubscriptionOpts;
+    handler: OrderbookChannelHandler;
+}
+
+/**
+ * This class includes all the functionality related to interacting with a websocket endpoint
+ * that implements the standard relayer API v0 in a browser environment
+ */
+export class BrowserWebSocketOrderbookChannel implements OrderbookChannel {
+    private _apiEndpointUrl: string;
+    private _clientIfExists?: WebSocket.w3cwebsocket;
+    private _subscriptions: Subscription[] = [];
+    /**
+     * Instantiates a new WebSocketOrderbookChannel instance
+     * @param   url                 The relayer API base WS url you would like to interact with
+     * @return  An instance of WebSocketOrderbookChannel
+     */
+    constructor(url: string) {
+        assert.isUri('url', url);
+        this._apiEndpointUrl = url;
+    }
+    /**
+     * Subscribe to orderbook snapshots and updates from the websocket
+     * @param   subscriptionOpts     An OrderbookChannelSubscriptionOpts instance describing which
+     *                               token pair to subscribe to
+     * @param   handler              An OrderbookChannelHandler instance that responds to various
+     *                               channel updates
+     */
+    public subscribe(subscriptionOpts: OrderbookChannelSubscriptionOpts, handler: OrderbookChannelHandler): void {
+        assert.isOrderbookChannelSubscriptionOpts('subscriptionOpts', subscriptionOpts);
+        assert.isOrderbookChannelHandler('handler', handler);
+        const newSubscription: Subscription = {
+            subscriptionOpts,
+            handler,
+        };
+        this._subscriptions.push(newSubscription);
+        const subscribeMessage = {
+            type: 'subscribe',
+            channel: 'orderbook',
+            requestId: this._subscriptions.length - 1,
+            payload: subscriptionOpts,
+        };
+        if (_.isUndefined(this._clientIfExists)) {
+            this._clientIfExists = new WebSocket.w3cwebsocket(this._apiEndpointUrl);
+            this._clientIfExists.onopen = () => {
+                this._sendMessage(subscribeMessage);
+            };
+            this._clientIfExists.onerror = error => {
+                this._alertAllHandlersToError(error);
+            };
+            this._clientIfExists.onclose = () => {
+                _.forEach(this._subscriptions, subscription => {
+                    subscription.handler.onClose(this, subscription.subscriptionOpts);
+                });
+            };
+            this._clientIfExists.onmessage = message => {
+                this._handleWebSocketMessage(message);
+            };
+        } else {
+            this._sendMessage(subscribeMessage);
+        }
+    }
+    /**
+     * Close the websocket and stop receiving updates
+     */
+    public close(): void {
+        if (!_.isUndefined(this._clientIfExists)) {
+            this._clientIfExists.close();
+        }
+    }
+    /**
+     * Send a message to the client if it has been instantiated and it is open
+     */
+    private _sendMessage(message: any): void {
+        if (!_.isUndefined(this._clientIfExists) && this._clientIfExists.readyState === WebSocket.w3cwebsocket.OPEN) {
+            this._clientIfExists.send(JSON.stringify(message));
+        }
+    }
+    /**
+     * For use in cases where we need to alert all handlers of an error
+     */
+    private _alertAllHandlersToError(error: Error): void {
+        _.forEach(this._subscriptions, subscription => {
+            subscription.handler.onError(this, subscription.subscriptionOpts, error);
+        });
+    }
+    private _handleWebSocketMessage(message: any): void {
+        // if we get a message with no data, alert all handlers and return
+        if (_.isUndefined(message.data)) {
+            this._alertAllHandlersToError(new Error(`Message does not contain utf8Data`));
+            return;
+        }
+        // try to parse the message data and route it to the correct handler
+        try {
+            const utf8Data = message.data;
+            const parserResult = orderbookChannelMessageParser.parse(utf8Data);
+            const subscription = this._subscriptions[parserResult.requestId];
+            if (_.isUndefined(subscription)) {
+                this._alertAllHandlersToError(new Error(`Message has unknown requestId: ${utf8Data}`));
+                return;
+            }
+            const handler = subscription.handler;
+            const subscriptionOpts = subscription.subscriptionOpts;
+            switch (parserResult.type) {
+                case OrderbookChannelMessageTypes.Snapshot: {
+                    handler.onSnapshot(this, subscriptionOpts, parserResult.payload);
+                    break;
+                }
+                case OrderbookChannelMessageTypes.Update: {
+                    handler.onUpdate(this, subscriptionOpts, parserResult.payload);
+                    break;
+                }
+                default: {
+                    handler.onError(
+                        this,
+                        subscriptionOpts,
+                        new Error(`Message has unknown type parameter: ${utf8Data}`),
+                    );
+                }
+            }
+        } catch (error) {
+            this._alertAllHandlersToError(error);
+        }
+    }
+}
diff --git a/packages/connect/src/index.ts b/packages/connect/src/index.ts
index ef5d8683e..88b09506c 100644
--- a/packages/connect/src/index.ts
+++ b/packages/connect/src/index.ts
@@ -1,9 +1,11 @@
 export { HttpClient } from './http_client';
-export { WebSocketOrderbookChannel } from './ws_orderbook_channel';
+export { BrowserWebSocketOrderbookChannel } from './browser_ws_orderbook_channel';
+export { NodeWebSocketOrderbookChannel } from './node_ws_orderbook_channel';
 export {
     Client,
     FeesRequest,
     FeesResponse,
+    NodeWebSocketOrderbookChannelConfig,
     OrderbookChannel,
     OrderbookChannelHandler,
     OrderbookChannelSubscriptionOpts,
@@ -14,7 +16,6 @@ export {
     TokenPairsItem,
     TokenPairsRequestOpts,
     TokenTradeInfo,
-    WebSocketOrderbookChannelConfig,
 } from './types';
 
 export { Order, SignedOrder } from '@0xproject/types';
diff --git a/packages/connect/src/ws_orderbook_channel.ts b/packages/connect/src/node_ws_orderbook_channel.ts
index bdcc8a75d..5f61ac4c8 100644
--- a/packages/connect/src/ws_orderbook_channel.ts
+++ b/packages/connect/src/node_ws_orderbook_channel.ts
@@ -1,18 +1,17 @@
-import { assert } from '@0xproject/assert';
-import { schemas } from '@0xproject/json-schemas';
 import * as _ from 'lodash';
 import * as WebSocket from 'websocket';
 
 import { schemas as clientSchemas } from './schemas/schemas';
 import {
+    NodeWebSocketOrderbookChannelConfig,
     OrderbookChannel,
     OrderbookChannelHandler,
     OrderbookChannelMessageTypes,
     OrderbookChannelSubscriptionOpts,
     WebsocketClientEventType,
     WebsocketConnectionEventType,
-    WebSocketOrderbookChannelConfig,
 } from './types';
+import { assert } from './utils/assert';
 import { orderbookChannelMessageParser } from './utils/orderbook_channel_message_parser';
 
 const DEFAULT_HEARTBEAT_INTERVAL_MS = 15000;
@@ -20,9 +19,9 @@ const MINIMUM_HEARTBEAT_INTERVAL_MS = 10;
 
 /**
  * This class includes all the functionality related to interacting with a websocket endpoint
- * that implements the standard relayer API v0
+ * that implements the standard relayer API v0 in a node environment
  */
-export class WebSocketOrderbookChannel implements OrderbookChannel {
+export class NodeWebSocketOrderbookChannel implements OrderbookChannel {
     private _apiEndpointUrl: string;
     private _client: WebSocket.client;
     private _connectionIfExists?: WebSocket.connection;
@@ -30,15 +29,15 @@ export class WebSocketOrderbookChannel implements OrderbookChannel {
     private _subscriptionCounter = 0;
     private _heartbeatIntervalMs: number;
     /**
-     * Instantiates a new WebSocketOrderbookChannel instance
+     * Instantiates a new NodeWebSocketOrderbookChannelConfig instance
      * @param   url                 The relayer API base WS url you would like to interact with
      * @param   config              The configuration object. Look up the type for the description.
-     * @return  An instance of WebSocketOrderbookChannel
+     * @return  An instance of NodeWebSocketOrderbookChannelConfig
      */
-    constructor(url: string, config?: WebSocketOrderbookChannelConfig) {
+    constructor(url: string, config?: NodeWebSocketOrderbookChannelConfig) {
         assert.isUri('url', url);
         if (!_.isUndefined(config)) {
-            assert.doesConformToSchema('config', config, clientSchemas.webSocketOrderbookChannelConfigSchema);
+            assert.doesConformToSchema('config', config, clientSchemas.nodeWebSocketOrderbookChannelConfigSchema);
         }
         this._apiEndpointUrl = url;
         this._heartbeatIntervalMs =
@@ -55,15 +54,8 @@ export class WebSocketOrderbookChannel implements OrderbookChannel {
      *                               channel updates
      */
     public subscribe(subscriptionOpts: OrderbookChannelSubscriptionOpts, handler: OrderbookChannelHandler): void {
-        assert.doesConformToSchema(
-            'subscriptionOpts',
-            subscriptionOpts,
-            schemas.relayerApiOrderbookChannelSubscribePayload,
-        );
-        assert.isFunction('handler.onSnapshot', _.get(handler, 'onSnapshot'));
-        assert.isFunction('handler.onUpdate', _.get(handler, 'onUpdate'));
-        assert.isFunction('handler.onError', _.get(handler, 'onError'));
-        assert.isFunction('handler.onClose', _.get(handler, 'onClose'));
+        assert.isOrderbookChannelSubscriptionOpts('subscriptionOpts', subscriptionOpts);
+        assert.isOrderbookChannelHandler('handler', handler);
         this._subscriptionCounter += 1;
         const subscribeMessage = {
             type: 'subscribe',
diff --git a/packages/connect/src/schemas/websocket_orderbook_channel_config_schema.ts b/packages/connect/src/schemas/node_websocket_orderbook_channel_config_schema.ts
index 81c0cac9c..c745d0b82 100644
--- a/packages/connect/src/schemas/websocket_orderbook_channel_config_schema.ts
+++ b/packages/connect/src/schemas/node_websocket_orderbook_channel_config_schema.ts
@@ -1,5 +1,5 @@
-export const webSocketOrderbookChannelConfigSchema = {
-    id: '/WebSocketOrderbookChannelConfig',
+export const nodeWebSocketOrderbookChannelConfigSchema = {
+    id: '/NodeWebSocketOrderbookChannelConfig',
     type: 'object',
     properties: {
         heartbeatIntervalMs: {
diff --git a/packages/connect/src/schemas/schemas.ts b/packages/connect/src/schemas/schemas.ts
index b9a8472fb..835fc7b4f 100644
--- a/packages/connect/src/schemas/schemas.ts
+++ b/packages/connect/src/schemas/schemas.ts
@@ -1,15 +1,15 @@
 import { feesRequestSchema } from './fees_request_schema';
+import { nodeWebSocketOrderbookChannelConfigSchema } from './node_websocket_orderbook_channel_config_schema';
 import { orderBookRequestSchema } from './orderbook_request_schema';
 import { ordersRequestOptsSchema } from './orders_request_opts_schema';
 import { pagedRequestOptsSchema } from './paged_request_opts_schema';
 import { tokenPairsRequestOptsSchema } from './token_pairs_request_opts_schema';
-import { webSocketOrderbookChannelConfigSchema } from './websocket_orderbook_channel_config_schema';
 
 export const schemas = {
     feesRequestSchema,
+    nodeWebSocketOrderbookChannelConfigSchema,
     orderBookRequestSchema,
     ordersRequestOptsSchema,
     pagedRequestOptsSchema,
     tokenPairsRequestOptsSchema,
-    webSocketOrderbookChannelConfigSchema,
 };
diff --git a/packages/connect/src/types.ts b/packages/connect/src/types.ts
index f5e52f50d..5657942ee 100644
--- a/packages/connect/src/types.ts
+++ b/packages/connect/src/types.ts
@@ -18,7 +18,7 @@ export interface OrderbookChannel {
 /**
  * heartbeatInterval: Interval in milliseconds that the orderbook channel should ping the underlying websocket. Default: 15000
  */
-export interface WebSocketOrderbookChannelConfig {
+export interface NodeWebSocketOrderbookChannelConfig {
     heartbeatIntervalMs?: number;
 }
 
diff --git a/packages/connect/src/utils/assert.ts b/packages/connect/src/utils/assert.ts
new file mode 100644
index 000000000..f8241aacb
--- /dev/null
+++ b/packages/connect/src/utils/assert.ts
@@ -0,0 +1,25 @@
+import { assert as sharedAssert } from '@0xproject/assert';
+// We need those two unused imports because they're actually used by sharedAssert which gets injected here
+// tslint:disable-next-line:no-unused-variable
+import { Schema, schemas } from '@0xproject/json-schemas';
+// tslint:disable-next-line:no-unused-variable
+import { ECSignature } from '@0xproject/types';
+import { BigNumber } from '@0xproject/utils';
+import * as _ from 'lodash';
+
+export const assert = {
+    ...sharedAssert,
+    isOrderbookChannelSubscriptionOpts(variableName: string, subscriptionOpts: any): void {
+        sharedAssert.doesConformToSchema(
+            'subscriptionOpts',
+            subscriptionOpts,
+            schemas.relayerApiOrderbookChannelSubscribePayload,
+        );
+    },
+    isOrderbookChannelHandler(variableName: string, handler: any): void {
+        sharedAssert.isFunction(`${variableName}.onSnapshot`, _.get(handler, 'onSnapshot'));
+        sharedAssert.isFunction(`${variableName}.onUpdate`, _.get(handler, 'onUpdate'));
+        sharedAssert.isFunction(`${variableName}.onError`, _.get(handler, 'onError'));
+        sharedAssert.isFunction(`${variableName}.onClose`, _.get(handler, 'onClose'));
+    },
+};
diff --git a/packages/connect/src/utils/orderbook_channel_message_parser.ts b/packages/connect/src/utils/orderbook_channel_message_parser.ts
index 9a9ca8901..593288078 100644
--- a/packages/connect/src/utils/orderbook_channel_message_parser.ts
+++ b/packages/connect/src/utils/orderbook_channel_message_parser.ts
@@ -8,10 +8,16 @@ import { relayerResponseJsonParsers } from './relayer_response_json_parsers';
 
 export const orderbookChannelMessageParser = {
     parse(utf8Data: string): OrderbookChannelMessage {
+        // parse the message
         const messageObj = JSON.parse(utf8Data);
+        // ensure we have a type parameter to switch on
         const type: string = _.get(messageObj, 'type');
         assert.assert(!_.isUndefined(type), `Message is missing a type parameter: ${utf8Data}`);
         assert.isString('type', type);
+        // ensure we have a request id for the resulting message
+        const requestId: number = _.get(messageObj, 'requestId');
+        assert.assert(!_.isUndefined(requestId), `Message is missing a requestId parameter: ${utf8Data}`);
+        assert.isNumber('requestId', requestId);
         switch (type) {
             case OrderbookChannelMessageTypes.Snapshot: {
                 assert.doesConformToSchema('message', messageObj, schemas.relayerApiOrderbookChannelSnapshotSchema);
@@ -28,7 +34,7 @@ export const orderbookChannelMessageParser = {
             default: {
                 return {
                     type: OrderbookChannelMessageTypes.Unknown,
-                    requestId: 0,
+                    requestId,
                     payload: undefined,
                 };
             }