prevent concurrent bid requests

If an auction is running don't accept a new request for bids..
This adds a `clearAuction` function to set `auctionRunning` false and to clear `_bidsRequested` and `_bidsReceived`. This is a stopgap measure util #353

src/prebid.js

@@ -33,6 +33,7 @@ var eventValidators = {
 
 /* Public vars */
 
+pbjs._auctionRunning = false;
 pbjs._bidsRequested = [];
 pbjs._bidsReceived = [];
 
@@ -387,6 +388,13 @@ pbjs.removeAdUnit = function (adUnitCode) {
   }
 };
 
+pbjs.clearAuction = function() {
+  pbjs._bidsRequested = [];
+  pbjs._bidsReceived = [];
+  pbjs._auctionRunning = false;
+  utils.logMessage('Prebid auction cleared');
+};
+
 /**
  *
  * @param bidsBackHandler
@@ -395,6 +403,14 @@ pbjs.removeAdUnit = function (adUnitCode) {
 pbjs.requestBids = function ({ bidsBackHandler, timeout }) {
   const cbTimeout = timeout || pbjs.bidderTimeout;
 
+  if (pbjs._auctionRunning) {
+    utils.logError('Prebid Error: `pbjs.requestBids` was called while a previous auction was' +
+      ' still running. Resubmit this request.');
+    return;
+  } else {
+    pbjs._auctionRunning = true;
+  }
+
   if (typeof bidsBackHandler === objectType_function) {
     bidmanager.addOneTimeCallback(bidsBackHandler);
   }

test/spec/unit/pbjs_api_spec.js

@@ -19,6 +19,12 @@ pbjs = pbjs || {};
 pbjs._bidsRequested = getBidRequests();
 pbjs._bidsReceived = getBidResponses();
 
+function resetAuction() {
+  pbjs.clearAuction();
+  pbjs._bidsRequested = getBidRequests();
+  pbjs._bidsReceived = getBidResponses();
+}
+
 var Slot = function Slot(elementId, pathId) {
   var slot = {
     getSlotElementId: function getSlotElementId() {
@@ -282,6 +288,7 @@ describe('Unit: Prebid Module', function () {
       assert.ok(spyAddOneTimeCallBack.calledWith(requestObj.bidsBackHandler),
         'called bidmanager.addOneTimeCallback');
       bidmanager.addOneTimeCallback.restore();
+      resetAuction();
     });
 
     it('should log message when adUnits not configured', () => {
@@ -294,6 +301,7 @@ describe('Unit: Prebid Module', function () {
       assert.ok(logMessageSpy.calledWith('No adUnits configured. No bids requested.'), 'expected message was logged');
       utils.logMessage.restore();
       pbjs.adUnits = adUnitsBackup;
+      resetAuction();
     });
 
     it('should execute callback after timeout', () => {
@@ -314,13 +322,15 @@ describe('Unit: Prebid Module', function () {
 
       bidmanager.executeCallback.restore();
       clock.restore();
+      resetAuction();
     });
 
     it('should call callBids function on adaptermanager', () => {
       var spyCallBids = sinon.spy(adaptermanager, 'callBids');
       pbjs.requestBids({});
       assert.ok(spyCallBids.called, 'called adaptermanager.callBids');
       adaptermanager.callBids.restore();
+      resetAuction();
     });
   });