refactor(h1): track HEAD keep-alive override as boolean

lib/dispatcher/client-h1.js

@@ -232,7 +232,7 @@ class Parser {
 
     this.keepAlive = ''
     this.contentLength = ''
-    this.connection = ''
+    this.connectionKeepAlive = false
     this.maxResponseSize = client[kMaxResponseSize]
   }
 
@@ -447,7 +447,9 @@ class Parser {
       if (headerName === 'keep-alive') {
         this.keepAlive += buf.toString()
       } else if (headerName === 'connection') {
-        this.connection += buf.toString()
+        this.connectionKeepAlive =
+          this.headers[len - 1].length === 10 &&
+          util.bufferToLowerCasedHeaderName(this.headers[len - 1]) === 'keep-alive'
       }
     } else if (key.length === 14 && util.bufferToLowerCasedHeaderName(key) === 'content-length') {
       this.contentLength += buf.toString()
@@ -554,7 +556,7 @@ class Parser {
     this.shouldKeepAlive = (
       shouldKeepAlive ||
       // Override llhttp value which does not allow keepAlive for HEAD.
-      (request.method === 'HEAD' && !socket[kReset] && this.connection.toLowerCase() === 'keep-alive')
+      (request.method === 'HEAD' && !socket[kReset] && this.connectionKeepAlive)
     )
 
     if (this.statusCode >= 200) {
@@ -689,7 +691,7 @@ class Parser {
     this.bytesRead = 0
     this.contentLength = ''
     this.keepAlive = ''
-    this.connection = ''
+    this.connectionKeepAlive = false
 
     this.headers = []
     this.headersSize = 0

test/client-keep-alive.js

@@ -113,6 +113,67 @@ test('keep-alive header 1', async (t) => {
   await t.completed
 })
 
+test('HEAD keep-alive header reuses socket when connection header is fragmented', async (t) => {
+  t = tspl(t, { plan: 4 })
+
+  let connections = 0
+  let requests = 0
+
+  const server = createServer((socket) => {
+    connections++
+
+    let request = ''
+    socket.on('data', (chunk) => {
+      request += chunk.toString()
+
+      while (request.includes('\r\n\r\n')) {
+        const endOfHeaders = request.indexOf('\r\n\r\n') + 4
+        request = request.slice(endOfHeaders)
+        requests++
+
+        socket.write('HTTP/1.1 200 OK\r\n')
+        socket.write('Content-Length: 0\r\n')
+        socket.write('Connection: keep-')
+        socket.write('alive\r\n')
+        socket.write('\r\n')
+
+        if (requests === 2) {
+          socket.end()
+        }
+      }
+    })
+  })
+  after(() => server.close())
+  await once(server.listen(0), 'listening')
+
+  const client = new Client(`http://localhost:${server.address().port}`)
+  after(() => client.destroy())
+
+  const disconnect = once(client, 'disconnect')
+
+  const first = await client.request({
+    path: '/',
+    method: 'HEAD',
+    reset: false
+  })
+  t.strictEqual(first.statusCode, 200)
+  await first.body.text()
+
+  const second = await client.request({
+    path: '/',
+    method: 'HEAD',
+    reset: false
+  })
+  t.strictEqual(second.statusCode, 200)
+  await second.body.text()
+
+  await disconnect
+  t.strictEqual(connections, 1)
+  t.strictEqual(requests, 2)
+
+  await t.completed
+})
+
 test('keep-alive header no postfix', async (t) => {
   t = tspl(t, { plan: 2 })