Use Json compacter in the bidders/params endpoint

endpoints/openrtb2/auction_test.go

@@ -18,6 +18,7 @@ import (
 	"time"
 
 	"github.com/buger/jsonparser"
+	jsoniter "github.com/json-iterator/go"
 	"github.com/julienschmidt/httprouter"
 	"github.com/prebid/openrtb/v20/native1"
 	nativeRequests "github.com/prebid/openrtb/v20/native1/request"
@@ -43,6 +44,11 @@ import (
 
 const jsonFileExtension string = ".json"
 
+func TestMain(m *testing.M) {
+	jsoniter.RegisterExtension(&jsonutil.RawMessageExtension{})
+	os.Exit(m.Run())
+}
+
 func TestJsonSampleRequests(t *testing.T) {
 	testSuites := []struct {
 		description          string

main.go

@@ -8,11 +8,13 @@ import (
 	"runtime"
 	"time"
 
+	jsoniter "github.com/json-iterator/go"
 	"github.com/prebid/prebid-server/v2/config"
 	"github.com/prebid/prebid-server/v2/currency"
 	"github.com/prebid/prebid-server/v2/openrtb_ext"
 	"github.com/prebid/prebid-server/v2/router"
 	"github.com/prebid/prebid-server/v2/server"
+	"github.com/prebid/prebid-server/v2/util/jsonutil"
 	"github.com/prebid/prebid-server/v2/util/task"
 
 	"github.com/golang/glog"
@@ -21,6 +23,7 @@ import (
 
 func init() {
 	rand.Seed(time.Now().UnixNano())
+	jsoniter.RegisterExtension(&jsonutil.RawMessageExtension{})
 }
 
 func main() {

openrtb_ext/bidders.go

@@ -612,6 +612,7 @@ func NewBidderParamsValidator(schemaDirectory string) (BidderParamValidator, err
 		if _, ok := bidderMap[bidderName]; !ok {
 			return nil, fmt.Errorf("File %s/%s does not match a valid BidderName.", schemaDirectory, fileInfo.Name())
 		}
+
 		toOpen, err := paramsValidator.abs(filepath.Join(schemaDirectory, fileInfo.Name()))
 		if err != nil {
 			return nil, fmt.Errorf("Failed to get an absolute representation of the path: %s, %v", toOpen, err)

router/bidder_params_tests/appnexus.json

@@ -0,0 +1,27 @@
+{
+    "$schema": "http://json-schema.org/draft-04/schema#",
+    "title": "Sample schema",
+    "description": "A sample schema to test the bidder/params endpoint",
+    "type": "object",
+    "properties": {
+        "integer_param": {
+            "type": "integer",
+            "minimum": 1,
+            "description": "A customer id"
+        },
+        "string_param_1": {
+            "type": "string",
+            "minLength": 1,
+            "description": "Text with blanks in between"
+        },
+        "string_param_2": {
+            "type": "string",
+            "minLength": 1,
+            "description": "Text_with_no_blanks_in_between"
+        }
+    },
+    "required": [
+        "integer_param",
+        "string_param_2"
+    ]
+}

router/router.go

@@ -93,7 +93,7 @@ func newJsonDirectoryServer(schemaDirectory string, validator openrtb_ext.Bidder
 		data[aliasName] = bidderData
 	}
 
-	response, err := json.Marshal(data)
+	response, err := jsonutil.Marshal(data)
 	if err != nil {
 		glog.Fatalf("Failed to marshal bidder param JSON-schema: %v", err)
 	}

router/router_test.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"testing"
 
+	jsoniter "github.com/json-iterator/go"
 	"github.com/prebid/prebid-server/v2/config"
 	"github.com/prebid/prebid-server/v2/openrtb_ext"
 	"github.com/prebid/prebid-server/v2/util/jsonutil"
@@ -18,6 +19,11 @@ const adapterDirectory = "../adapters"
 
 type testValidator struct{}
 
+func TestMain(m *testing.M) {
+	jsoniter.RegisterExtension(&jsonutil.RawMessageExtension{})
+	os.Exit(m.Run())
+}
+
 func (validator *testValidator) Validate(name openrtb_ext.BidderName, ext json.RawMessage) error {
 	return nil
 }
@@ -275,3 +281,23 @@ func TestValidateDefaultAliases(t *testing.T) {
 		}
 	}
 }
+
+func TestBidderParamsCompactedOutput(t *testing.T) {
+	expectedFormattedResponse := `{"appnexus":{"$schema":"http://json-schema.org/draft-04/schema#","title":"Sample schema","description":"A sample schema to test the bidder/params endpoint","type":"object","properties":{"integer_param":{"type":"integer","minimum":1,"description":"A customer id"},"string_param_1":{"type":"string","minLength":1,"description":"Text with blanks in between"},"string_param_2":{"type":"string","minLength":1,"description":"Text_with_no_blanks_in_between"}},"required":["integer_param","string_param_2"]}}`
+
+	// Setup
+	inSchemaDirectory := "bidder_params_tests"
+	paramsValidator, err := openrtb_ext.NewBidderParamsValidator(inSchemaDirectory)
+	assert.NoError(t, err, "Error initialing validator")
+
+	handler := newJsonDirectoryServer(inSchemaDirectory, paramsValidator, nil, nil)
+	recorder := httptest.NewRecorder()
+	request, err := http.NewRequest("GET", "/bidder/params", nil)
+	assert.NoError(t, err, "Error creating request")
+
+	// Run
+	handler(recorder, request, nil)
+
+	// Assertions
+	assert.Equal(t, expectedFormattedResponse, recorder.Body.String())
+}

util/jsonutil/jsonutil.go

@@ -5,8 +5,10 @@ import (
 	"encoding/json"
 	"io"
 	"strings"
+	"unsafe"
 
 	jsoniter "github.com/json-iterator/go"
+	"github.com/modern-go/reflect2"
 	"github.com/prebid/prebid-server/v2/errortypes"
 )
 
@@ -211,3 +213,38 @@ func tryExtractErrorMessage(err error) string {
 func isLikelyDetailedErrorMessage(msg string) bool {
 	return !strings.HasPrefix(msg, "request.")
 }
+
+// RawMessageExtension will call json.Compact() on every json.RawMessage field when getting marshalled.
+type RawMessageExtension struct {
+	jsoniter.DummyExtension
+}
+
+// CreateEncoder substitutes the default jsoniter encoder of the json.RawMessage type with ours, that
+// calls json.Compact() before writting to the stream
+func (e *RawMessageExtension) CreateEncoder(typ reflect2.Type) jsoniter.ValEncoder {
+	if typ == jsonRawMessageType {
+		return &rawMessageCodec{}
+	}
+	return nil
+}
+
+var jsonRawMessageType = reflect2.TypeOfPtr(&json.RawMessage{}).Elem()
+
+// rawMessageCodec implements jsoniter.ValEncoder interface so we can override the default json.RawMessage Encode()
+// function with our implementation
+type rawMessageCodec struct{}
+
+func (codec *rawMessageCodec) Encode(ptr unsafe.Pointer, stream *jsoniter.Stream) {
+	if ptr != nil {
+		jsonRawMsg := *(*[]byte)(ptr)
+
+		dst := bytes.NewBuffer(make([]byte, 0, len(jsonRawMsg)))
+		if err := json.Compact(dst, jsonRawMsg); err == nil {
+			stream.Write(dst.Bytes())
+		}
+	}
+}
+
+func (codec *rawMessageCodec) IsEmpty(ptr unsafe.Pointer) bool {
+	return ptr == nil || len(*((*json.RawMessage)(ptr))) == 0
+}

util/jsonutil/jsonutil_test.go

@@ -1,10 +1,15 @@
 package jsonutil
 
 import (
+	"bytes"
+	"encoding/json"
 	"errors"
 	"strings"
 	"testing"
+	"unsafe"
 
+	jsoniter "github.com/json-iterator/go"
+	"github.com/modern-go/reflect2"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -240,3 +245,80 @@ func TestTryExtractErrorMessage(t *testing.T) {
 		})
 	}
 }
+
+func TestCreateEncoder(t *testing.T) {
+	testCases := []struct {
+		desc               string
+		inType             reflect2.Type
+		expectedValEncoder jsoniter.ValEncoder
+	}{
+		{
+			desc:               "With_extension",
+			inType:             reflect2.TypeOfPtr((*jsoniter.Any)(nil)).Elem(),
+			expectedValEncoder: nil,
+		},
+		{
+			desc:               "No_extension",
+			inType:             reflect2.TypeOfPtr(&json.RawMessage{}).Elem(),
+			expectedValEncoder: &rawMessageCodec{},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.desc, func(t *testing.T) {
+			extension := &RawMessageExtension{}
+			encoder := extension.CreateEncoder(tc.inType)
+			assert.IsType(t, encoder, tc.expectedValEncoder)
+		})
+	}
+}
+
+func TestEncode(t *testing.T) {
+	jsonBlob := json.RawMessage(`{
+  "properties": {
+    "string": "Blanks spaces in between words to not be removed if compacted",
+    "integer": 5,
+    "string_array": [
+      "string array elem one",
+      "string array elem two"
+    ]
+  }
+}`)
+
+	t.Run(
+		"Nil_pointer",
+		func(t *testing.T) {
+			// set test
+			encoder := &rawMessageCodec{}
+			output := bytes.NewBuffer([]byte{})
+			stream := jsoniter.NewStream(jsonConfigValidationOn, output, len(jsonBlob))
+
+			// run
+			encoder.Encode(nil, stream)
+
+			// assertions
+			assert.Equal(t, "", output.String())
+			assert.Equal(t, true, encoder.IsEmpty(nil))
+		},
+	)
+	t.Run(
+		"json.RawMessage_compact_JSON",
+		func(t *testing.T) {
+			// set test
+			encoder := &rawMessageCodec{}
+			output := bytes.NewBuffer([]byte{})
+			stream := jsoniter.NewStream(jsonConfigValidationOn, output, len(jsonBlob))
+
+			// run
+			encoder.Encode(unsafe.Pointer(&jsonBlob), stream)
+
+			// assertions
+			assert.Equal(
+				t,
+				`{"properties":{"string":"Blanks spaces in between words to not be removed if compacted","integer":5,"string_array":["string array elem one","string array elem two"]}}`,
+				output.String(),
+			)
+			assert.Equal(t, false, encoder.IsEmpty(unsafe.Pointer(&jsonBlob)))
+		},
+	)
+}