From 906ddc39a03c1505972099bc9967f8fdb3e7f34c Mon Sep 17 00:00:00 2001
From: Jon Williams <jon.williams@thetalake.com>
Date: Thu, 19 Dec 2024 14:12:17 -0500
Subject: [PATCH] Changed ExtractContentType to use mime.ParseMediaType. Fixes
 #91.

---
 helpers/operation_utilities.go      | 25 +++++--------------------
 helpers/operation_utilities_test.go | 22 ++++++++++++++++++++++
 2 files changed, 27 insertions(+), 20 deletions(-)

diff --git a/helpers/operation_utilities.go b/helpers/operation_utilities.go
index 1347093..a4ceadd 100644
--- a/helpers/operation_utilities.go
+++ b/helpers/operation_utilities.go
@@ -4,8 +4,8 @@
 package helpers
 
 import (
+	"mime"
 	"net/http"
-	"strings"
 
 	"github.com/pb33f/libopenapi/datamodel/high/v3"
 )
@@ -38,23 +38,8 @@ func ExtractOperation(request *http.Request, item *v3.PathItem) *v3.Operation {
 // of the request.The second (optional) argument is the charset of the request. The third (optional)
 // argument is the boundary of the type (only used with forms really).
 func ExtractContentType(contentType string) (string, string, string) {
-	var charset, boundary string
-	if strings.ContainsRune(contentType, ';') {
-		segs := strings.Split(contentType, SemiColon)
-		contentType = strings.TrimSpace(segs[0])
-		for _, v := range segs[1:] {
-			kv := strings.Split(v, Equals)
-			if len(kv) == 2 {
-				if strings.TrimSpace(strings.ToLower(kv[0])) == Charset {
-					charset = strings.TrimSpace(kv[1])
-				}
-				if strings.TrimSpace(strings.ToLower(kv[0])) == Boundary {
-					boundary = strings.TrimSpace(kv[1])
-				}
-			}
-		}
-	} else {
-		contentType = strings.TrimSpace(contentType)
-	}
-	return contentType, charset, boundary
+	// mime.ParseMediaType: "If there is an error parsing the optional parameter,
+	// the media type will be returned along with the error ErrInvalidMediaParameter."
+	ct, params, _ := mime.ParseMediaType(contentType)
+	return ct, params["charset"], params["boundary"]
 }
diff --git a/helpers/operation_utilities_test.go b/helpers/operation_utilities_test.go
index 2a3ef53..9d1f01f 100644
--- a/helpers/operation_utilities_test.go
+++ b/helpers/operation_utilities_test.go
@@ -4,6 +4,7 @@
 package helpers
 
 import (
+	"mime"
 	"net/http"
 	"testing"
 
@@ -89,4 +90,25 @@ func TestExtractContentType(t *testing.T) {
 	require.Equal(t, "application/xml", contentType)
 	require.Empty(t, charset)
 	require.Empty(t, boundary)
+
+	// Content type with custom parameter
+	contentType, charset, boundary = ExtractContentType("text/html; version=2")
+	require.Equal(t, "text/html", contentType)
+	require.Empty(t, charset)
+	require.Empty(t, boundary)
+
+	// Content type with custom parameter, charset, and boundary
+	contentType, charset, boundary = ExtractContentType("text/html; charset=UTF-8; version=2; boundary=myBoundary")
+	require.Equal(t, "text/html", contentType)
+	require.Equal(t, "UTF-8", charset)
+	require.Equal(t, "myBoundary", boundary)
+
+	// mime.ParseMediaType returns an error, but ExtractContentType still returns the content type.
+	const ct = "text/plain;;"
+	_, _, err := mime.ParseMediaType(ct)
+	require.ErrorIs(t, err, mime.ErrInvalidMediaParameter)
+	contentType, charset, boundary = ExtractContentType(ct)
+	require.Equal(t, "text/plain", contentType)
+	require.Empty(t, charset)
+	require.Empty(t, boundary)
 }