Implementation of Categories Http fetcher (prebid#882)

* Implementation of Categories Http fetcher

-Added code to fetch data using http
-Added previously loaded categories to run http request just at the first time

* Moved common Category struct to stored_request

* Added comments

* Minor refactoring

* Minor refactoring

-Added verification if category exist in map

* Minor refactoring

* Minor refactoring

-strings.Replace changed to strings.TrimSuffix

config/config.go

@@ -500,6 +500,7 @@ func SetupViper(v *viper.Viper, filename string) {
 	v.SetDefault("datacache.ttl_seconds", 0)
 	v.SetDefault("category_mapping.filesystem.enabled", true)
 	v.SetDefault("category_mapping.filesystem.directorypath", "./static/category-mapping")
+	v.SetDefault("category_mapping.http.endpoint", "")
 	v.SetDefault("stored_requests.filesystem", false)
 	v.SetDefault("stored_requests.directorypath", "./stored_requests/data/by_id")
 	v.SetDefault("stored_requests.postgres.connection.dbname", "")

exchange/exchange.go

@@ -139,7 +139,7 @@ func (e *exchange) HoldAuction(ctx context.Context, bidRequest *openrtb.BidReque
 	conversions := e.currencyConverter.Rates()
 
 	adapterBids, adapterExtra := e.getAllBids(auctionCtx, cleanRequests, aliases, bidAdjustmentFactors, blabels, conversions)
-	bidCategory, adapterBids, err := applyCategoryMapping(requestExt, adapterBids, *categoriesFetcher, targData)
+	bidCategory, adapterBids, err := applyCategoryMapping(ctx, requestExt, adapterBids, *categoriesFetcher, targData)
 	auc := newAuction(adapterBids, len(bidRequest.Imp))
 	if err != nil {
 		return nil, fmt.Errorf("Error in category mapping : %s", err.Error())
@@ -321,7 +321,7 @@ func (e *exchange) buildBidResponse(ctx context.Context, liveAdapters []openrtb_
 	return bidResponse, err
 }
 
-func applyCategoryMapping(requestExt openrtb_ext.ExtRequest, seatBids map[openrtb_ext.BidderName]*pbsOrtbSeatBid, categoriesFetcher stored_requests.CategoryFetcher, targData *targetData) (map[string]string, map[openrtb_ext.BidderName]*pbsOrtbSeatBid, error) {
+func applyCategoryMapping(ctx context.Context, requestExt openrtb_ext.ExtRequest, seatBids map[openrtb_ext.BidderName]*pbsOrtbSeatBid, categoriesFetcher stored_requests.CategoryFetcher, targData *targetData) (map[string]string, map[openrtb_ext.BidderName]*pbsOrtbSeatBid, error) {
 	res := make(map[string]string)
 
 	type bidDedupe struct {
@@ -375,7 +375,7 @@ func applyCategoryMapping(requestExt openrtb_ext.ExtRequest, seatBids map[openrt
 					continue
 				} else {
 					//if unique IAB category is present then translate it to the adserver category based on mapping file
-					category, err = categoriesFetcher.FetchCategories(primaryAdServer, publisher, bidIabCat[0])
+					category, err = categoriesFetcher.FetchCategories(ctx, primaryAdServer, publisher, bidIabCat[0])
 					if err != nil || category == "" {
 						//TODO: add metrics
 						//if mapping required but no mapping file is found then discard the bid

exchange/exchange_test.go

@@ -587,7 +587,7 @@ func TestCategoryMapping(t *testing.T) {
 
 	adapterBids[bidderName1] = &seatBid
 
-	bidCategory, adapterBids, err := applyCategoryMapping(requestExt, adapterBids, categoriesFetcher, targData)
+	bidCategory, adapterBids, err := applyCategoryMapping(nil, requestExt, adapterBids, categoriesFetcher, targData)
 
 	assert.Equal(t, nil, err, "Category mapping error should be empty")
 	assert.Equal(t, "10.00_Electronics_30s", bidCategory["bid_id1"], "Category mapping doesn't match")
@@ -652,7 +652,7 @@ func TestCategoryDedupe(t *testing.T) {
 
 		adapterBids[bidderName1] = &seatBid
 
-		bidCategory, adapterBids, err := applyCategoryMapping(requestExt, adapterBids, categoriesFetcher, targData)
+		bidCategory, adapterBids, err := applyCategoryMapping(nil, requestExt, adapterBids, categoriesFetcher, targData)
 
 		assert.Equal(t, nil, err, "Category mapping error should be empty")
 		assert.Equal(t, 2, len(adapterBids[bidderName1].bids), "Bidders number doesn't match")