Optimise regexp usage (#1502)

* Optimise regexp usage

* Revert regexp removal

* Atleast use the semioptimised version

core/chat/events/events.go

@@ -124,6 +124,11 @@ func RenderMarkdown(raw string) string {
 	return buf.String()
 }
 
+var (
+	_sanitizeReSrcMatch      = regexp.MustCompile(`(?i)^/img/emoji`)
+	_sanitizeReAltTitleMatch = regexp.MustCompile(`:\S+:`)
+)
+
 func sanitize(raw string) string {
 	p := bluemonday.StrictPolicy()
 
@@ -146,8 +151,8 @@ func sanitize(raw string) string {
 	p.AllowElementsContent("p")
 
 	// Allow img tags from the the local emoji directory only
-	p.AllowAttrs("src").Matching(regexp.MustCompile(`(?i)^/img/emoji`)).OnElements("img")
+	p.AllowAttrs("src").Matching(_sanitizeReSrcMatch).OnElements("img")
-	p.AllowAttrs("alt", "title").Matching(regexp.MustCompile(`:\S+:`)).OnElements("img")
+	p.AllowAttrs("alt", "title").Matching(_sanitizeReAltTitleMatch).OnElements("img")
 	p.AllowAttrs("class").OnElements("img")
 
 	// Allow bold

core/rtmp/utils.go

@@ -14,13 +14,15 @@ import (
 
 const unknownString = "Unknown"
 
+var _getInboundDetailsFromMetadataRE = regexp.MustCompile(`\{(.*?)\}`)
+
 func getInboundDetailsFromMetadata(metadata []interface{}) (models.RTMPStreamMetadata, error) {
 	metadataComponentsString := fmt.Sprintf("%+v", metadata)
 	if !strings.Contains(metadataComponentsString, "onMetaData") {
 		return models.RTMPStreamMetadata{}, errors.New("Not a onMetaData message")
 	}
-	re := regexp.MustCompile(`\{(.*?)\}`)
+
-	submatchall := re.FindAllString(metadataComponentsString, 1)
+	submatchall := _getInboundDetailsFromMetadataRE.FindAllString(metadataComponentsString, 1)
 
 	if len(submatchall) == 0 {
 		return models.RTMPStreamMetadata{}, errors.New("unable to parse inbound metadata")