apiaddicts · rafael-goterris · Aug 4, 2026 · Jul 27, 2026 · Aug 4, 2026
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -5,6 +5,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+
 ## [1.5.1-beta-1] - 2026-08-04
 
 ### Fixed
@@ -15,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - OAR082 - BinaryOrByteFormat - Issue message now shows the configured `fields-to-apply`.
 - OAR085 - OpenAPIVersion - Issue message now shows the configured `valid-versions`.
 - OAR037 - StringFormat - Issue message now interpolates the configured `formats-allowed`.
+- OAR044 - MediaTypeCheck - Media type parameters now follow RFC 9110 (charset without space, other parameter names, multiple parameters); type/subtype can no longer start with `.`.
 
 
 ## [1.5.0] - 2026-07-28

diff --git a/src/main/java/apiaddicts/sonar/openapi/checks/format/OAR044MediaTypeCheck.java b/src/main/java/apiaddicts/sonar/openapi/checks/format/OAR044MediaTypeCheck.java
@@ -44,19 +44,20 @@ public class OAR044MediaTypeCheck extends BaseCheck {
   protected static final String MESSAGE_V3 = "OAR044.error.v3";
   private final ExternalRefHandler handleExternalRef = new ExternalRefHandler();
 
+  private static final String RESTRICTED_NAME = "[a-zA-Z0-9][a-zA-Z0-9.!#$&^_+\\-]*";
+  private static final String OWS = "[ \\t]*";
+  private static final String TOKEN = "[a-zA-Z0-9!#$%&'*+\\-.^_`|~]+";
+  private static final String QUOTED_STRING = "\"(?:[^\"\\\\]|\\\\.)*\"";
+  private static final String PARAMETERS =
+      "(?:" + OWS + ";" + OWS + TOKEN + "=(?:" + TOKEN + "|" + QUOTED_STRING + "))*";
+
   @VisibleForTesting
   static final Pattern MIME_TYPE_PATTERN = Pattern.compile(
-      "[a-zA-Z0-9.][a-zA-Z0-9.!#$&_^+\\-]+/" +
-      "[a-zA-Z0-9.][a-zA-Z0-9.!#$&_^+\\-]+" +
-      "(; charset=[a-zA-Z0-9_\\-]+)?"
+      RESTRICTED_NAME + "/" + RESTRICTED_NAME + PARAMETERS
   );
   @VisibleForTesting
   static final Pattern MEDIA_RANGE_PATTERN = Pattern.compile(
-      "(\\*|[a-zA-Z0-9.][a-zA-Z0-9.!#$&_^+\\-]+)/" +
-      "(\\*|" +
-      "[a-zA-Z0-9.][a-zA-Z0-9.!#$&_^+\\-]+" +
-      "(; charset=[a-zA-Z0-9_\\-]+)?" +
-      ")"
+      "(\\*|" + RESTRICTED_NAME + ")/(\\*|" + RESTRICTED_NAME + ")" + PARAMETERS
   );
 
   @Override
@@ -114,8 +115,8 @@ private void verifyParameterContent(JsonNode node) {
     for (JsonNode property : properties.values()) {
       JsonNode keyNode = property.key();
       String key = keyNode.getTokenValue();
-      if (!MIME_TYPE_PATTERN.matcher(key).matches()) {
-        addIssue(CHECK_KEY, translate(MESSAGE_V2), keyNode);
+      if (!MEDIA_RANGE_PATTERN.matcher(key).matches()) {
+        addIssue(CHECK_KEY, translate(MESSAGE_V3), keyNode);
       }
     }
   }

diff --git a/src/test/resources/checks/v2/format/OAR044/media-type.json b/src/test/resources/checks/v2/format/OAR044/media-type.json
@@ -18,8 +18,8 @@
         }
       },
       "post" : {
-        "produces" : [ "application/vnd.ms-excel", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", "application/ld+json", "text/csv", "image/png" ],
-        "consumes" : [ "application/vnd.ms-excel", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", "application/ld+json" ],
+        "produces" : [ "application/vnd.ms-excel", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", "application/ld+json", "text/csv", "image/png", "text/plain;charset=utf-8", "multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxk" ],
+        "consumes" : [ "application/vnd.ms-excel", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", "application/ld+json", "application/json; charset=utf-8; boundary=xyz" ],
         "responses" : {
           "200" : {
             "description" : "some operation"

diff --git a/src/test/resources/checks/v2/format/OAR044/media-type.yaml b/src/test/resources/checks/v2/format/OAR044/media-type.yaml
@@ -27,10 +27,13 @@ paths:
         - application/ld+json
         - text/csv
         - image/png
+        - text/plain;charset=utf-8
+        - multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxk
       consumes:
         - application/vnd.ms-excel
         - application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
         - application/ld+json
+        - application/json; charset=utf-8; boundary=xyz
       responses:
         '200':
           description: some operation
diff --git a/src/test/resources/checks/v3/format/OAR044/media-type.json b/src/test/resources/checks/v3/format/OAR044/media-type.json
@@ -19,10 +19,11 @@
           "name" : "someParam",
           "in" : "query",
           "content" : {
-            "application" : { }, # Noncompliant {{OAR044: Declared mime type should conform to RFC6838}}
+            "application" : { }, # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
+            "text/*" : { },
             "text/plain" : { }
           }
-        }, 
+        },
         {
           "name" : "otherParam",
           "in" : "path"
@@ -32,12 +33,17 @@
       "requestBody" : {
         "content" : {
           "application" : { }, # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
+          ".text/plain" : { }, # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
           "text/*" : { },
           "application/vnd.ms-excel" : { },
           "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" : { },
           "application/ld+json" : { },
           "image/*" : { },
-          "*/*" : { }
+          "*/*" : { },
+          "text/plain;charset=utf-8" : { },
+          "multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxk" : { },
+          "multipart/form-data; boundary=\"----abc 123\"" : { },
+          "application/json; charset=utf-8; boundary=xyz" : { }
           }
         },
         "responses" : {

diff --git a/src/test/resources/checks/v3/format/OAR044/media-type.yaml b/src/test/resources/checks/v3/format/OAR044/media-type.yaml
@@ -14,20 +14,26 @@ paths:
         - name: someParam
           in: query
           content:
-            'application': {} # Noncompliant {{OAR044: Declared mime type should conform to RFC6838}}
+            'application': {} # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
+            'text/*': {}
             'text/plain': {}  # invalid (only 1 content allowed by spec), but should not be caught by this rule
         - name: otherParam
           in: path
     post:
       requestBody:
         content:
           'application': { } # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
+          '.text/plain': { } # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
           'text/*': { }
           'application/vnd.ms-excel': {}
           'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet': {}
           'application/ld+json': {}
           'image/*': {}
           '*/*': {}
+          'text/plain;charset=utf-8': {}
+          'multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxk': {}
+          'multipart/form-data; boundary="----abc 123"': {}
+          'application/json; charset=utf-8; boundary=xyz': {}
       responses:
         '200':
           description: some operation

diff --git a/src/test/resources/checks/v31/format/OAR044/media-type.json b/src/test/resources/checks/v31/format/OAR044/media-type.json
@@ -19,10 +19,11 @@
           "name" : "someParam",
           "in" : "query",
           "content" : {
-            "application" : { }, # Noncompliant {{OAR044: Declared mime type should conform to RFC6838}}
+            "application" : { }, # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
+            "text/*" : { },
             "text/plain" : { }
           }
-        }, 
+        },
         {
           "name" : "otherParam",
           "in" : "path"
@@ -32,12 +33,17 @@
       "requestBody" : {
         "content" : {
           "application" : { }, # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
+          ".text/plain" : { }, # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
           "text/*" : { },
           "application/vnd.ms-excel" : { },
           "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" : { },
           "application/ld+json" : { },
           "image/*" : { },
-          "*/*" : { }
+          "*/*" : { },
+          "text/plain;charset=utf-8" : { },
+          "multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxk" : { },
+          "multipart/form-data; boundary=\"----abc 123\"" : { },
+          "application/json; charset=utf-8; boundary=xyz" : { }
           }
         },
         "responses" : {

diff --git a/src/test/resources/checks/v31/format/OAR044/media-type.yaml b/src/test/resources/checks/v31/format/OAR044/media-type.yaml
@@ -14,20 +14,26 @@ paths:
         - name: someParam
           in: query
           content:
-            'application': {} # Noncompliant {{OAR044: Declared mime type should conform to RFC6838}}
+            'application': {} # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
+            'text/*': {}
             'text/plain': {}  # invalid (only 1 content allowed by spec), but should not be caught by this rule
         - name: otherParam
           in: path
     post:
       requestBody:
         content:
           'application': { } # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
+          '.text/plain': { } # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
           'text/*': { }
           'application/vnd.ms-excel': {}
           'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet': {}
           'application/ld+json': {}
           'image/*': {}
           '*/*': {}
+          'text/plain;charset=utf-8': {}
+          'multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxk': {}
+          'multipart/form-data; boundary="----abc 123"': {}
+          'application/json; charset=utf-8; boundary=xyz': {}
       responses:
         '200':
           description: some operation

diff --git a/src/test/resources/checks/v32/format/OAR044/media-type.json b/src/test/resources/checks/v32/format/OAR044/media-type.json
@@ -19,10 +19,11 @@
           "name" : "someParam",
           "in" : "query",
           "content" : {
-            "application" : { }, # Noncompliant {{OAR044: Declared mime type should conform to RFC6838}}
+            "application" : { }, # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
+            "text/*" : { },
             "text/plain" : { }
           }
-        }, 
+        },
         {
           "name" : "otherParam",
           "in" : "path"
@@ -32,12 +33,17 @@
       "requestBody" : {
         "content" : {
           "application" : { }, # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
+          ".text/plain" : { }, # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
           "text/*" : { },
           "application/vnd.ms-excel" : { },
           "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" : { },
           "application/ld+json" : { },
           "image/*" : { },
-          "*/*" : { }
+          "*/*" : { },
+          "text/plain;charset=utf-8" : { },
+          "multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxk" : { },
+          "multipart/form-data; boundary=\"----abc 123\"" : { },
+          "application/json; charset=utf-8; boundary=xyz" : { }
           }
         },
         "responses" : {

diff --git a/src/test/resources/checks/v32/format/OAR044/media-type.yaml b/src/test/resources/checks/v32/format/OAR044/media-type.yaml
@@ -14,20 +14,26 @@ paths:
         - name: someParam
           in: query
           content:
-            'application': {} # Noncompliant {{OAR044: Declared mime type should conform to RFC6838}}
+            'application': {} # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
+            'text/*': {}
             'text/plain': {}  # invalid (only 1 content allowed by spec), but should not be caught by this rule
         - name: otherParam
           in: path
     post:
       requestBody:
         content:
           'application': { } # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
+          '.text/plain': { } # Noncompliant {{OAR044: Declared media type range should conform to RFC7231}}
           'text/*': { }
           'application/vnd.ms-excel': {}
           'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet': {}
           'application/ld+json': {}
           'image/*': {}
           '*/*': {}
+          'text/plain;charset=utf-8': {}
+          'multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxk': {}
+          'multipart/form-data; boundary="----abc 123"': {}
+          'application/json; charset=utf-8; boundary=xyz': {}
       responses:
         '200':
           description: some operation