Handle comma-separated query parameters in API requests (#9102)

* return empty array when no peers found

* add missing query params to endpoint factory

* fix validator endpoints in endpoint factory

* peers test

* Move API param handling to separate file

* Handle comma-separated query parameters

shared/gateway/param_handling.go

@@ -3,6 +3,7 @@ package gateway
 import (
 	"encoding/base64"
 	"net/http"
+	"net/url"
 	"strings"
 
 	"github.com/gorilla/mux"
@@ -54,6 +55,8 @@ segmentsLoop:
 func HandleQueryParameters(req *http.Request, params []QueryParam) ErrorJson {
 	queryParams := req.URL.Query()
 
+	normalizeQueryValues(queryParams)
+
 	for key, vals := range queryParams {
 		for _, p := range params {
 			if key == p.Name {
@@ -93,3 +96,14 @@ func HandleQueryParameters(req *http.Request, params []QueryParam) ErrorJson {
 func isRequestParam(s string) bool {
 	return len(s) > 2 && s[0] == '{' && s[len(s)-1] == '}'
 }
+
+func normalizeQueryValues(queryParams url.Values) {
+	// Replace comma-separated values with individual values.
+	for key, vals := range queryParams {
+		splitVals := make([]string, 0)
+		for _, v := range vals {
+			splitVals = append(splitVals, strings.Split(v, ",")...)
+		}
+		queryParams[key] = splitVals
+	}
+}

shared/gateway/param_handling_test.go

@@ -109,3 +109,16 @@ func TestIsRequestParam(t *testing.T) {
 		assert.Equal(t, tt.b, b)
 	}
 }
+
+func TestNormalizeQueryValues(t *testing.T) {
+	input := make(map[string][]string)
+	input["key"] = []string{"value1", "value2,value3,value4", "value5"}
+
+	normalizeQueryValues(input)
+	require.Equal(t, 5, len(input["key"]))
+	assert.Equal(t, "value1", input["key"][0])
+	assert.Equal(t, "value2", input["key"][1])
+	assert.Equal(t, "value3", input["key"][2])
+	assert.Equal(t, "value4", input["key"][3])
+	assert.Equal(t, "value5", input["key"][4])
+}