Experimental feature: OAS Generator (#632)

agent/pkg/oas/gibberish.go

@@ -0,0 +1,108 @@
+package oas
+
+import (
+	"regexp"
+	"strings"
+	"unicode"
+)
+
+var (
+	patBase64   = regexp.MustCompile(`^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$`)
+	patUuid4    = regexp.MustCompile(`(?i)[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}`)
+	patEmail    = regexp.MustCompile(`^\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$`)
+	patHexLower = regexp.MustCompile(`(0x)?[0-9a-f]{6,}`)
+	patHexUpper = regexp.MustCompile(`(0x)?[0-9A-F]{6,}`)
+)
+
+func IsGibberish(str string) bool {
+	if patBase64.MatchString(str) && len(str) > 32 {
+		return true
+	}
+
+	if patUuid4.MatchString(str) {
+		return true
+	}
+
+	if patEmail.MatchString(str) {
+		return true
+	}
+
+	if patHexLower.MatchString(str) || patHexUpper.MatchString(str) {
+		return true
+	}
+
+	noise := noiseLevel(str)
+	if noise >= 0.2 {
+		return true
+	}
+
+	return false
+}
+
+func noiseLevel(str string) (score float64) {
+	// opinionated algo of certain char pairs marking the non-human strings
+	prev := *new(rune)
+	cnt := 0.0
+	for _, char := range str {
+		cnt += 1
+		if prev > 0 {
+			switch {
+			// continued class of upper/lower/digit adds no noise
+			case unicode.IsUpper(prev) && unicode.IsUpper(char):
+			case unicode.IsLower(prev) && unicode.IsLower(char):
+			case unicode.IsDigit(prev) && unicode.IsDigit(char):
+
+			// upper =>
+			case unicode.IsUpper(prev) && unicode.IsLower(char):
+				score += 0.25
+			case unicode.IsUpper(prev) && unicode.IsDigit(char):
+				score += 0.25
+
+			// lower =>
+			case unicode.IsLower(prev) && unicode.IsUpper(char):
+				score += 0.75
+			case unicode.IsLower(prev) && unicode.IsDigit(char):
+				score += 0.25
+
+			// digit =>
+			case unicode.IsDigit(prev) && unicode.IsUpper(char):
+				score += 0.75
+			case unicode.IsDigit(prev) && unicode.IsLower(char):
+				score += 0.75
+
+			// the rest is 100% noise
+			default:
+				score += 1
+			}
+		}
+		prev = char
+	}
+
+	score /= cnt // weigh it
+
+	return score
+}
+
+func IsVersionString(component string) bool {
+	if component == "" {
+		return false
+	}
+
+	hasV := false
+	if strings.HasPrefix(component, "v") {
+		component = component[1:]
+		hasV = true
+	}
+
+	for _, c := range component {
+		if string(c) != "." && !unicode.IsDigit(c) {
+			return false
+		}
+	}
+
+	if !hasV && strings.Contains(component, ".") {
+		return false
+	}
+
+	return true
+}