fix: OPTIONS Content-Type handling (fastify#6263)

* fix: OPTIONS Content-Type handling

* remove unnecessary comment

* add more tests

* add no content-type test

* add more

* typo

* one test

* remove unnecessary test

Author: gurgunday

lib/handleRequest.js

@@ -21,38 +21,34 @@ function handleRequest (err, request, reply) {
     return
   }
 
-  const method = request.raw.method
-  const headers = request.headers
-  const context = request[kRouteContext]
+  const method = request.method
 
   if (this[kSupportedHTTPMethods].bodyless.has(method)) {
     handler(request, reply)
     return
   }
 
   if (this[kSupportedHTTPMethods].bodywith.has(method)) {
+    const headers = request.headers
     const contentType = headers['content-type']
-    const contentLength = headers['content-length']
-    const transferEncoding = headers['transfer-encoding']
 
     if (contentType === undefined) {
-      if (
-        (contentLength === undefined || contentLength === '0') &&
-        transferEncoding === undefined
-      ) {
+      const contentLength = headers['content-length']
+      const transferEncoding = headers['transfer-encoding']
+      const isEmptyBody = transferEncoding === undefined &&
+        (contentLength === undefined || contentLength === '0')
+
+      if (isEmptyBody) {
         // Request has no body to parse
         handler(request, reply)
-      } else {
-        context.contentTypeParser.run('', handler, request, reply)
-      }
-    } else {
-      if (contentLength === undefined && transferEncoding === undefined && method === 'OPTIONS') {
-        // OPTIONS can have a Content-Type header without a body
-        handler(request, reply)
         return
       }
-      context.contentTypeParser.run(contentType, handler, request, reply)
+
+      request[kRouteContext].contentTypeParser.run('', handler, request, reply)
+      return
     }
+
+    request[kRouteContext].contentTypeParser.run(contentType, handler, request, reply)
     return
   }
 

test/internals/handle-request.test.js

@@ -191,7 +191,7 @@ test('request should be defined in onSend Hook on post request with content type
 })
 
 test('request should be defined in onSend Hook on options request with content type application/x-www-form-urlencoded', async t => {
-  t.plan(5)
+  t.plan(15)
   const fastify = require('../..')()
 
   t.after(() => {
@@ -209,16 +209,40 @@ test('request should be defined in onSend Hook on options request with content t
     reply.send(200)
   })
 
-  const fastifyServer = await fastify.listen({ port: 0 })
-  const result = await fetch(fastifyServer, {
+  // Test 1: OPTIONS with body and content-type header
+  const result1 = await fastify.inject({
+    method: 'OPTIONS',
+    url: '/',
+    body: 'first-name=OPTIONS&last-name=METHOD',
+    headers: {
+      'content-type': 'application/x-www-form-urlencoded'
+    }
+  })
+
+  // Content-Type is not supported
+  t.assert.strictEqual(result1.statusCode, 415)
+
+  // Test 2: OPTIONS with content-type header only (no body)
+  const result2 = await fastify.inject({
     method: 'OPTIONS',
+    url: '/',
     headers: {
       'content-type': 'application/x-www-form-urlencoded'
     }
   })
 
-  // Body parsing skipped, so no body sent
-  t.assert.strictEqual(result.status, 200)
+  // Content-Type is not supported
+  t.assert.strictEqual(result2.statusCode, 415)
+
+  // Test 3: OPTIONS with body but no content-type header
+  const result3 = await fastify.inject({
+    method: 'OPTIONS',
+    url: '/',
+    body: 'first-name=OPTIONS&last-name=METHOD'
+  })
+
+  // No content-type with payload
+  t.assert.strictEqual(result3.statusCode, 415)
 })
 
 test('request should respond with an error if an unserialized payload is sent inside an async handler', async t => {