Implement getOrdersForPageAsync for browsers

browser/go/main.go

@@ -240,6 +240,17 @@ func (cw *MeshWrapper) GetStats() (js.Value, error) {
 	return js.ValueOf(stats), nil
 }
 
+// GetOrders converts raw JavaScript parameters into the appropriate type, calls
+// core.App.GetOrders, converts the result into basic JavaScript types (string,
+// int, etc.) and returns it.
+func (cw *MeshWrapper) GetOrders(page int, perPage int, snapshotID string) (js.Value, error) {
+	ordersResponse, err := cw.app.GetOrders(page, perPage, snapshotID)
+	if err != nil {
+		return js.Undefined(), err
+	}
+	return js.ValueOf(ordersResponse), nil
+}
+
 // JSValue satisfies the js.Wrapper interface. The return value is a JavaScript
 // object consisting of named functions. They act like methods by capturing the
 // MeshWrapper through a closure.
@@ -269,6 +280,18 @@ func (cw *MeshWrapper) JSValue() js.Value {
 				return cw.GetStats()
 			})
 		}),
+		// getOrdersForPageAsync(page: number, perPage: number, snapshotID?: string): Promise<GetOrdersResponse>
+		"getOrdersForPageAsync": js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+			return wrapInPromise(func() (interface{}, error) {
+				// snapshotID is optional in the JavaScript function. Check if it is
+				// null or undefined.
+				snapshotID := ""
+				if !isNullOrUndefined(args[2]) {
+					snapshotID = args[2].String()
+				}
+				return cw.GetOrders(args[0].Int(), args[1].Int(), snapshotID)
+			})
+		}),
 		// addOrdersAsync(orders: Array<SignedOrder>): Promise<ValidationResults>
 		"addOrdersAsync": js.FuncOf(func(this js.Value, args []js.Value) interface{} {
 			return wrapInPromise(func() (interface{}, error) {

browser/ts/index.ts

@@ -252,6 +252,30 @@ export interface Stats {
     ethRPCRateLimitExpiredRequests: number;
 }
 
+interface WrapperOrderInfo {
+    orderHash: string;
+    signedOrder: WrapperSignedOrder;
+    fillableTakerAssetAmount: string;
+}
+
+export interface OrderInfo {
+    orderHash: string;
+    signedOrder: SignedOrder;
+    fillableTakerAssetAmount: BigNumber;
+}
+
+interface WrapperGetOrdersResponse {
+    snapshotID: string;
+    snapshotTimestamp: number;
+    ordersInfos: WrapperOrderInfo[];
+}
+
+export interface GetOrdersResponse {
+    snapshotID: string;
+    snapshotTimestamp: number;
+    ordersInfos: OrderInfo[];
+}
+
 export enum Verbosity {
     Panic = 0,
     Fatal = 1,
@@ -275,6 +299,7 @@ interface MeshWrapper {
     onError(handler: (err: Error) => void): void;
     onOrderEvents(handler: (events: WrapperOrderEvent[]) => void): void;
     getStatsAsync(): Promise<WrapperStats>;
+    getOrdersForPageAsync(page: number, perPage: number, snapshotID?: string): Promise<WrapperGetOrdersResponse>;
     addOrdersAsync(orders: WrapperSignedOrder[], pinned: boolean): Promise<WrapperValidationResults>;
 }
 
@@ -761,6 +786,25 @@ export class Mesh {
         return wrapperStatsToStats(wrapperStats);
     }
 
+    /**
+     * Get page of 0x signed orders stored on the Mesh node at the specified snapshot
+     * @param page Page index at which to retrieve orders
+     * @param perPage Number of signedOrders to fetch per paginated request
+     * @param snapshotID The DB snapshot at which to fetch orders. If omitted, a new snapshot is created
+     * @returns the snapshotID, snapshotTimestamp and all orders, their hashes and fillableTakerAssetAmounts
+     */
+    public async getOrdersForPageAsync(page: number, perPage: number, snapshotID?: string): Promise<GetOrdersResponse> {
+        await waitForLoadAsync();
+        if (this._wrapper === undefined) {
+            // If this is called after startAsync, this._wrapper is always
+            // defined. This check is here just in case and satisfies the
+            // compiler.
+            return Promise.reject(new Error('Mesh is still loading. Try again soon.'));
+        }
+        const wrapperOrderResponse = await this._wrapper.getOrdersForPageAsync(page, perPage, snapshotID);
+        return wrapperGetOrdersResponseToGetOrdersResponse(wrapperOrderResponse);
+    }
+
     /**
      * Validates and adds the given orders to Mesh. If an order is successfully
      * added, Mesh will share it with any peers in the network and start
@@ -1003,6 +1047,23 @@ function wrapperStatsToStats(wrapperStats: WrapperStats): Stats {
     };
 }
 
+function wrapperGetOrdersResponseToGetOrdersResponse(
+    wrapperGetOrdersResponse: WrapperGetOrdersResponse,
+): GetOrdersResponse {
+    return {
+        ...wrapperGetOrdersResponse,
+        ordersInfos: wrapperGetOrdersResponse.ordersInfos.map(wrapperOrderInfoToOrderInfo),
+    };
+}
+
+function wrapperOrderInfoToOrderInfo(wrapperOrderInfo: WrapperOrderInfo): OrderInfo {
+    return {
+        ...wrapperOrderInfo,
+        fillableTakerAssetAmount: new BigNumber(wrapperOrderInfo.fillableTakerAssetAmount),
+        signedOrder: wrapperSignedOrderToSignedOrder(wrapperOrderInfo.signedOrder),
+    };
+}
+
 function wrapperValidationResultsToValidationResults(
     wrapperValidationResults: WrapperValidationResults,
 ): ValidationResults {

common/types/types_js.go

@@ -17,3 +17,14 @@ func (s *Stats) JSValue() js.Value {
 	statsJS := js.Global().Get("JSON").Call("parse", string(encodedStats))
 	return statsJS
 }
+
+func (r *GetOrdersResponse) JSValue() js.Value {
+	// TODO(albrow): Optimize this. Remove other uses of the JSON
+	// encoding/decoding hack.
+	encodedResponse, err := json.Marshal(r)
+	if err != nil {
+		panic(err)
+	}
+	responseJS := js.Global().Get("JSON").Call("parse", string(encodedResponse))
+	return responseJS
+}

integration-tests/browser/src/index.ts

@@ -63,9 +63,20 @@ provider.start();
     // canceled, or filled. We will check for certain events to be logged in the
     // integration tests.
     mesh.onOrderEvents((events: Array<OrderEvent>) => {
-        for (let event of events) {
-            console.log(JSON.stringify(event));
-        }
+        (async () => {
+            for (let event of events) {
+                // Check the happy path for getOrdersForPageAsync. There should
+                // be two orders.
+                const firstOrdersResponse = await mesh.getOrdersForPageAsync(0, 1, '');
+                console.log(JSON.stringify(firstOrdersResponse));
+                const secondOrdersResponse = await mesh.getOrdersForPageAsync(1, 1, firstOrdersResponse.snapshotID);
+                console.log(JSON.stringify(secondOrdersResponse));
+
+                // Log the event. The Go code will be watching the logs for
+                // this.
+                console.log(JSON.stringify(event));
+            }
+        })().catch(err => console.error(err));
     });
 
     // Start Mesh *after* we set up the handlers.