perf: Improve processHeader (nodejs#2513)

* perf: Improve processHeader

* rewrite

* use if statement

* fixup

Author: tsctx

lib/core/request.js

@@ -7,17 +7,11 @@ const {
 const assert = require('assert')
 const { kHTTP2BuildRequest, kHTTP2CopyHeaders, kHTTP1BuildRequest } = require('./symbols')
 const util = require('./util')
+const { headerNameLowerCasedRecord } = require('./constants')
 
-// tokenRegExp and headerCharRegex have been lifted from
+// headerCharRegex have been lifted from
 // https://github.com/nodejs/node/blob/main/lib/_http_common.js
 
-/**
- * Verifies that the given val is a valid HTTP token
- * per the rules defined in RFC 7230
- * See https://tools.ietf.org/html/rfc7230#section-3.2.6
- */
-const tokenRegExp = /^[\^_`a-zA-Z\-0-9!#$%&'*+.|~]+$/
-
 /**
  * Matches if val contains an invalid field-vchar
  *  field-value    = *( field-content / obs-fold )
@@ -416,65 +410,41 @@ function processHeader (request, key, val, skipAppend = false) {
     return
   }
 
-  if (
-    request.host === null &&
-    key.length === 4 &&
-    key.toLowerCase() === 'host'
-  ) {
+  let headerName = headerNameLowerCasedRecord[key]
+
+  if (headerName === undefined) {
+    headerName = key.toLowerCase()
+    if (headerNameLowerCasedRecord[headerName] === undefined && !util.isValidHTTPToken(headerName)) {
+      throw new InvalidArgumentError('invalid header key')
+    }
+  }
+
+  if (request.host === null && headerName === 'host') {
     if (headerCharRegex.exec(val) !== null) {
       throw new InvalidArgumentError(`invalid ${key} header`)
     }
     // Consumed by Client
     request.host = val
-  } else if (
-    request.contentLength === null &&
-    key.length === 14 &&
-    key.toLowerCase() === 'content-length'
-  ) {
+  } else if (request.contentLength === null && headerName === 'content-length') {
     request.contentLength = parseInt(val, 10)
     if (!Number.isFinite(request.contentLength)) {
       throw new InvalidArgumentError('invalid content-length header')
     }
-  } else if (
-    request.contentType === null &&
-    key.length === 12 &&
-    key.toLowerCase() === 'content-type'
-  ) {
+  } else if (request.contentType === null && headerName === 'content-type') {
     request.contentType = val
     if (skipAppend) request.headers[key] = processHeaderValue(key, val, skipAppend)
     else request.headers += processHeaderValue(key, val)
-  } else if (
-    key.length === 17 &&
-    key.toLowerCase() === 'transfer-encoding'
-  ) {
-    throw new InvalidArgumentError('invalid transfer-encoding header')
-  } else if (
-    key.length === 10 &&
-    key.toLowerCase() === 'connection'
-  ) {
+  } else if (headerName === 'transfer-encoding' || headerName === 'keep-alive' || headerName === 'upgrade') {
+    throw new InvalidArgumentError(`invalid ${headerName} header`)
+  } else if (headerName === 'connection') {
     const value = typeof val === 'string' ? val.toLowerCase() : null
     if (value !== 'close' && value !== 'keep-alive') {
       throw new InvalidArgumentError('invalid connection header')
     } else if (value === 'close') {
       request.reset = true
     }
-  } else if (
-    key.length === 10 &&
-    key.toLowerCase() === 'keep-alive'
-  ) {
-    throw new InvalidArgumentError('invalid keep-alive header')
-  } else if (
-    key.length === 7 &&
-    key.toLowerCase() === 'upgrade'
-  ) {
-    throw new InvalidArgumentError('invalid upgrade header')
-  } else if (
-    key.length === 6 &&
-    key.toLowerCase() === 'expect'
-  ) {
+  } else if (headerName === 'expect') {
     throw new NotSupportedError('expect header not supported')
-  } else if (tokenRegExp.exec(key) === null) {
-    throw new InvalidArgumentError('invalid header key')
   } else {
     if (Array.isArray(val)) {
       for (let i = 0; i < val.length; i++) {