From 91ca5d0b0e93afeb5c68a48fef461bbcc095fcbe Mon Sep 17 00:00:00 2001
From: Justin Wind <justin.wind+git@gmail.com>
Date: Sat, 26 Aug 2023 12:39:54 -0700
Subject: [PATCH] minor refactor of router to use explicit exceptions

---
 lib/dingus.js       | 21 ++++++++-------------
 lib/errors.js       | 16 ++++++++++++++++
 lib/router/index.js |  6 +++---
 test/lib/router.js  | 11 ++++-------
 4 files changed, 31 insertions(+), 23 deletions(-)

diff --git a/lib/dingus.js b/lib/dingus.js
index 5b4643c..484debc 100644
--- a/lib/dingus.js
+++ b/lib/dingus.js
@@ -13,7 +13,7 @@ const querystring = require('querystring');
 const common = require('./common');
 const ContentNegotiation = require('./content-negotiation');
 const Enum = require('./enum');
-const { DingusError, ResponseError } = require('./errors');
+const { DingusError, ResponseError, RouterNoMethodError, RouterNoPathError } = require('./errors');
 const { extensionToMime } = require('./mime-helper');
 const Router = require('./router');
 const Template = require('./template');
@@ -268,18 +268,13 @@ class Dingus {
     try {
       ({ handler, handlerArgs } = this.router.lookup(req.method, pathPart, ctx));
     } catch (e) {
-      if (e instanceof DingusError) {
-        switch (e.message) {
-          case 'NoPath':
-            handler = this.handlerNotFound.bind(this);
-            break;
-          case 'NoMethod':
-            handler = this.handlerMethodNotAllowed.bind(this);
-            break;
-          default:
-            this.logger.error(_scope, 'unknown dingus error', { error: e });
-            handler = this.handlerInternalServerError.bind(this);
-        }
+      if (e instanceof RouterNoPathError) {
+        handler = this.handlerNotFound.bind(this);
+      } else if (e instanceof RouterNoMethodError) {
+        handler = this.handlerMethodNotAllowed.bind(this);
+      } else if (e instanceof DingusError) {
+        this.logger.error(_scope, 'unknown dingus error', { error: e });
+        handler = this.handlerInternalServerError.bind(this);
       } else if (e instanceof URIError) {
         handler = this.handlerBadRequest.bind(this);
       } else {
diff --git a/lib/errors.js b/lib/errors.js
index ed5b151..942ecc0 100644
--- a/lib/errors.js
+++ b/lib/errors.js
@@ -22,7 +22,23 @@ class ResponseError extends DingusError {
   }
 }
 
+class RouterError extends DingusError {
+  constructor(...args) {
+    super(...args);
+    delete this.stack;
+  }
+}
+
+class RouterNoPathError extends RouterError {
+}
+
+class RouterNoMethodError extends RouterError {
+}
+
 module.exports = {
   DingusError,
   ResponseError,
+  RouterError,
+  RouterNoPathError,
+  RouterNoMethodError,
 };
diff --git a/lib/router/index.js b/lib/router/index.js
index 1585065..fd19bdf 100644
--- a/lib/router/index.js
+++ b/lib/router/index.js
@@ -7,7 +7,7 @@
 
 const { METHODS: httpMethods } = require('http');
 const common = require('../common');
-const { DingusError } = require('../errors');
+const { DingusError, RouterNoPathError, RouterNoMethodError } = require('../errors');
 const PathParameter = require('./path-parameter');
 
 // Internal identifiers for route entries.
@@ -266,10 +266,10 @@ class Router {
       if ('*' in matchedPath[kPathMethods]) {
         return matchedPath[kPathMethods]['*'];
       }
-      throw new DingusError('NoMethod');
+      throw new RouterNoMethodError();
     }
     ctx.unmatchedPath = pathParts;
-    throw new DingusError('NoPath');
+    throw new RouterNoPathError();
   }
 
 
diff --git a/test/lib/router.js b/test/lib/router.js
index 8a9d1e2..bcb45f2 100644
--- a/test/lib/router.js
+++ b/test/lib/router.js
@@ -6,7 +6,7 @@ const assert = require('assert');
 const sinon = require('sinon'); // eslint-disable-line node/no-unpublished-require
 const Router = require('../../lib/router');
 const PathParameter = require('../../lib/router/path-parameter');
-const { DingusError } = require('../../lib/errors');
+const { DingusError, RouterNoPathError, RouterNoMethodError } = require('../../lib/errors');
 
 const noExpectedException = 'did not get expected exception';
 
@@ -311,8 +311,7 @@ describe('Router', function () {
         router.lookup(method, path, ctx);
         assert.fail(noExpectedException);
       } catch (e) {
-        assert(e instanceof DingusError);
-        assert.strictEqual(e.message, 'NoPath');
+        assert(e instanceof RouterNoPathError);
       }
     });
     it('finds handler', function () {
@@ -353,8 +352,7 @@ describe('Router', function () {
         router.lookup(method, path, ctx);
         assert.fail(noExpectedException);
       } catch (e) {
-        assert(e instanceof DingusError);
-        assert.strictEqual(e.message, 'NoMethod');
+        assert(e instanceof RouterNoMethodError);
       }
     });
     it('does not lookup non-existent path', async function () {
@@ -365,8 +363,7 @@ describe('Router', function () {
         router.lookup(method, path, ctx);
         assert.fail(noExpectedException);
       } catch (e) {
-        assert(e instanceof DingusError);
-        assert.strictEqual(e.message, 'NoPath');
+        assert(e instanceof RouterNoPathError);
       }
     });
 
-- 
2.45.2