Incorporate @spolti's review

Signed-off-by: Ricardo Zanini <ricardozanini@gmail.com>

Author: ricardozanini

README.md

@@ -41,7 +41,7 @@ The current status of features implemented in the SDK is listed below:
 | [v1.0.0](https://github.com/serverlessworkflow/sdk-go/releases/tag/v1.0.0) |  [v0.5](https://github.com/serverlessworkflow/specification/tree/0.5.x)  |
 | [v2.0.1](https://github.com/serverlessworkflow/sdk-go/releases/tag/v2.0.1) |  [v0.6](https://github.com/serverlessworkflow/specification/tree/0.6.x)  |
 | [v2.1.2](https://github.com/serverlessworkflow/sdk-go/releases/tag/v2.1.2) |  [v0.7](https://github.com/serverlessworkflow/specification/tree/0.7.x)  |
-| [v2.4.1](https://github.com/serverlessworkflow/sdk-go/releases/tag/v2.4.1) |  [v0.8](https://github.com/serverlessworkflow/specification/tree/0.8.x)  |
+| [v2.4.3](https://github.com/serverlessworkflow/sdk-go/releases/tag/v2.4.1) |  [v0.8](https://github.com/serverlessworkflow/specification/tree/0.8.x)  |
 | [v3.0.0](https://github.com/serverlessworkflow/sdk-go/releases/tag/v3.0.0) | [v1.0.0](https://github.com/serverlessworkflow/specification/releases/tag/v1.0.0-alpha5) |
 
 ---
@@ -67,7 +67,30 @@ import "github.com/serverlessworkflow/sdk-go/v3/model"
 You can now use the SDK types and functions, for example:
 
 ```go
-myHttpTask := model.CallHTTP{}
+package main
+
+import (
+	"github.com/serverlessworkflow/sdk-go/v3/builder"
+    "github.com/serverlessworkflow/sdk-go/v3/model"
+)
+
+func main() {
+  workflowBuilder := New().
+    SetDocument("1.0.0", "examples", "example-workflow", "1.0.0").
+          AddTask("task1", &model.CallHTTP{
+            TaskBase: model.TaskBase{
+              If: &model.RuntimeExpression{Value: "${condition}"},
+            },
+            Call: "http",
+            With: model.HTTPArguments{
+              Method:   "GET",
+              Endpoint: model.NewEndpoint("http://example.com"),
+            },
+          })
+    workflow, _ := builder.Object(workflowBuilder)
+    // use your models
+}
+
 ```
 
 ### Parsing Workflow Files

model/validator.go

@@ -17,15 +17,15 @@ package model
 import (
 	"errors"
 	"fmt"
-	"regexp"
-
 	"github.com/go-playground/validator/v10"
+	"regexp"
+	"strings"
 )
 
 var (
-	iso8601DurationPattern = regexp.MustCompile(`^P(\d+Y)?(\d+M)?(\d+W)?(\d+D)?(T(\d+H)?(\d+M)?(\d+S)?)?$`)
+	iso8601DurationPattern = regexp.MustCompile(`^P(\d+Y)?(\d+M)?(\d+D)?(T(\d+H)?(\d+M)?(\d+S)?)?$`)
 	semanticVersionPattern = regexp.MustCompile(`^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-((?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)(?:\.(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*))?(?:\+([0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?$`)
-	hostnameRFC1123Pattern = regexp.MustCompile(`^[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?$`)
+	hostnameRFC1123Pattern = regexp.MustCompile(`^(([a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)*[a-zA-Z]{2,63}|[a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)$`)
 )
 
 var validate *validator.Validate
@@ -47,11 +47,8 @@ func init() {
 	registerValidator("client_auth_type", validateOptionalOAuthClientAuthentication)
 	registerValidator("encoding_type", validateOptionalOAuth2TokenRequestEncoding)
 
-	registerValidator("semver_pattern", func(fl validator.FieldLevel) bool {
-		return semanticVersionPattern.MatchString(fl.Field().String())
-	})
 	registerValidator("hostname_rfc1123", func(fl validator.FieldLevel) bool {
-		return hostnameRFC1123Pattern.MatchString(fl.Field().String())
+		return isHostnameValid(fl.Field().String())
 	})
 	registerValidator("uri_pattern", func(fl validator.FieldLevel) bool {
 		value, ok := fl.Field().Interface().(string)
@@ -67,6 +64,7 @@ func init() {
 		}
 		return LiteralUriTemplatePattern.MatchString(value)
 	})
+	registerValidator("semver_pattern", validateSemanticVersion)
 	registerValidator("iso8601_duration", validateISO8601Duration)
 
 	registerValidator("object_or_string", validateObjectOrString)
@@ -349,9 +347,43 @@ func validateJsonPointerOrRuntimeExpr(fl validator.FieldLevel) bool {
 }
 
 func validateISO8601Duration(fl validator.FieldLevel) bool {
-	value, ok := fl.Field().Interface().(string)
+	input, ok := fl.Field().Interface().(string)
+	if !ok {
+		return false
+	}
+
+	return isISO8601DurationValid(input)
+}
+
+func validateSemanticVersion(fl validator.FieldLevel) bool {
+	input, ok := fl.Field().Interface().(string)
 	if !ok {
 		return false
 	}
-	return iso8601DurationPattern.MatchString(value)
+
+	return isSemanticVersionValid(input)
+}
+
+// isISO8601DurationValid validates if a string is a valid ISO 8601 duration.
+func isISO8601DurationValid(input string) bool {
+	if !iso8601DurationPattern.MatchString(input) {
+		return false
+	}
+
+	trimmed := strings.TrimPrefix(input, "P")
+	if trimmed == "" || trimmed == "T" {
+		return false
+	}
+
+	return true
+}
+
+// isSemanticVersionValid validates if a string is a valid semantic version.
+func isSemanticVersionValid(input string) bool {
+	return semanticVersionPattern.MatchString(input)
+}
+
+// isHostnameValid validates if a string is a valid RFC 1123 hostname.
+func isHostnameValid(input string) bool {
+	return hostnameRFC1123Pattern.MatchString(input)
 }

model/validator_test.go

@@ -0,0 +1,54 @@
+package model
+
+import (
+	"testing"
+)
+
+func TestRegexValidators(t *testing.T) {
+	testCases := []struct {
+		name     string
+		validate func(string) bool
+		input    string
+		expected bool
+	}{
+		// ISO 8601 Duration Tests
+		{"ISO 8601 Duration Valid 1", isISO8601DurationValid, "P2Y", true},
+		{"ISO 8601 Duration Valid 2", isISO8601DurationValid, "P1DT12H30M", true},
+		{"ISO 8601 Duration Valid 3", isISO8601DurationValid, "P1Y2M3D", true},
+		{"ISO 8601 Duration Valid 4", isISO8601DurationValid, "P1Y2M3D4H", false},
+		{"ISO 8601 Duration Valid 5", isISO8601DurationValid, "P1Y", true},
+		{"ISO 8601 Duration Valid 6", isISO8601DurationValid, "PT1H", true},
+		{"ISO 8601 Duration Valid 7", isISO8601DurationValid, "P1Y2M3D4H5M6S", false},
+		{"ISO 8601 Duration Invalid 1", isISO8601DurationValid, "P", false},
+		{"ISO 8601 Duration Invalid 2", isISO8601DurationValid, "P1Y2M3D4H5M6S7", false},
+		{"ISO 8601 Duration Invalid 3", isISO8601DurationValid, "1Y", false},
+
+		// Semantic Versioning Tests
+		{"Semantic Version Valid 1", isSemanticVersionValid, "1.0.0", true},
+		{"Semantic Version Valid 2", isSemanticVersionValid, "1.2.3", true},
+		{"Semantic Version Valid 3", isSemanticVersionValid, "1.2.3-beta", true},
+		{"Semantic Version Valid 4", isSemanticVersionValid, "1.2.3-beta.1", true},
+		{"Semantic Version Valid 5", isSemanticVersionValid, "1.2.3-beta.1+build.123", true},
+		{"Semantic Version Invalid 1", isSemanticVersionValid, "v1.2.3", false},
+		{"Semantic Version Invalid 2", isSemanticVersionValid, "1.2", false},
+		{"Semantic Version Invalid 3", isSemanticVersionValid, "1.2.3-beta.x", true},
+
+		// RFC 1123 Hostname Tests
+		{"RFC 1123 Hostname Valid 1", isHostnameValid, "example.com", true},
+		{"RFC 1123 Hostname Valid 2", isHostnameValid, "my-hostname", true},
+		{"RFC 1123 Hostname Valid 3", isHostnameValid, "subdomain.example.com", true},
+		{"RFC 1123 Hostname Invalid 1", isHostnameValid, "127.0.0.1", false},
+		{"RFC 1123 Hostname Invalid 2", isHostnameValid, "example.com.", false},
+		{"RFC 1123 Hostname Invalid 3", isHostnameValid, "example..com", false},
+		{"RFC 1123 Hostname Invalid 4", isHostnameValid, "example.com-", false},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			result := tc.validate(tc.input)
+			if result != tc.expected {
+				t.Errorf("Validation failed for '%s': input='%s', expected=%v, got=%v", tc.name, tc.input, tc.expected, result)
+			}
+		})
+	}
+}