feat(name-state): add getStatusName method

Co-authored-by: Bryan Clement <bclement@newrelic.com>
Co-authored-by: Michael Goin <mgoin@newrelic.com>

lib/transaction/index.js

@@ -310,8 +310,9 @@ function _partialNameFromUri(requestUrl, status) {
   // potentially apply the URL backstop now. Only do so if no user rules matched.
   if (!partialName) {
     // avoid polluting root path when 404
-    if (status === 404) {
-      partialName = this.nameState.getNameNotFound()
+    const statusName = this.nameState.getStatusName(status)
+    if (statusName) {
+      partialName = statusName
     } else {
       var normalized = this.agent.urlNormalizer.normalize(scrubbedUrl)
       ignore = ignore || normalized.ignore

lib/transaction/name-state.js

@@ -15,6 +15,11 @@ var LEGACY_NAMING = {
   Restify: true
 }
 
+const STATUS_CODE_NAMES = {
+  404: '(not found)',
+  501: '(not implemented)',
+  405: '(method not allowed)'
+}
 
 /**
  * Manages transaction names using a stack of paths.
@@ -41,6 +46,16 @@ NameState.prototype.setName = function setName(prefix, verb, delimiter, path) {
   logger.trace('setName called on name state, path stack now %j', this.pathStack)
 }
 
+NameState.prototype.getStatusName = function getStatusName(statusCode) {
+  const name = STATUS_CODE_NAMES[statusCode]
+  if (name) {
+    if (LEGACY_NAMING.hasOwnProperty(this.prefix)) {
+      return _getName(this, name)
+    }
+    return NAMES.WEB.FRAMEWORK_PREFIX + '/' + _getName(this, name)
+  }
+}
+
 NameState.prototype.markPath = function markPath() {
   this.markedPath = this.pathStack.slice()
 }