Missing scopes error handler (#17)

README.md

@@ -136,7 +136,8 @@ Currently following middlewares are available:
 - removing unspecified query parameters,
 - content type validation,
 - routing to appropriate controller,
-- oauth scopes authorization.
+- oauth scopes authorization,
+- error handlers (`MissingRequiredScopes`).
 
 ### Validation middlewares
 

docs/CONTRIBUTING.md

@@ -23,4 +23,4 @@ Before submitting pull request, you can `$ npm run preversion`. It will:
 
 ## Fixing README.md
 
-Project's readme is generated using [docs/README.hbs](docs/README.hbs), so please modify this file.
+Project's readme is generated using [docs/docs.hbs](docs/docs.hbs), so please modify this file.

docs/docs.hbs

@@ -136,7 +136,8 @@ Currently following middlewares are available:
 - removing unspecified query parameters,
 - content type validation,
 - routing to appropriate controller,
-- oauth scopes authorization.
+- oauth scopes authorization,
+- error handlers (`MissingRequiredScopes`).
 
 ### Validation middlewares
 

middlewares/error-handlers/missing-scopes.js

@@ -0,0 +1,15 @@
+const MissingRequiredScopesError = require('../../errors/MissingRequiredScopes')
+
+/**
+ * Sends response with `403` status code and message with required scopes
+ * when `err` is an instance of `MissingRequiredScopes`
+ *
+ * @returns {function(err, req, res, next)} error handler
+ */
+module.exports = () => (err, req, res, next) => {
+    if (err instanceof MissingRequiredScopesError) {
+        res.status(403).json({message: `Missing required scopes: ${err.requiredScopes}`})
+    } else {
+        return next(err)
+    }
+}

test/middlewares/error-handlers/missing-scopes.spec.js

@@ -0,0 +1,38 @@
+const missingScopesHandler = require('../../../middlewares/error-handlers/missing-scopes')()
+const MissingRequiredScopes = require('../../../errors/MissingRequiredScopes')
+
+describe('missing scopes error handler', () => {
+
+    it('should catch MissingRequiredScopes', () => {
+        // given
+        const res = {
+            json(obj) {
+                this.message = obj.message
+                return this
+            },
+            status(status) {
+                this.statusCode = status
+                return this
+            }
+        }
+
+        // when
+        missingScopesHandler(new MissingRequiredScopes(['write']), undefined, res, undefined)
+
+        // then
+        expect(res.statusCode).to.eql(403)
+        expect(res.message).to.eql('Missing required scopes: write')
+    })
+
+    it('should not catch different errors', () => {
+        // given
+        const next = sinon.spy()
+
+        // when
+        missingScopesHandler(new Error(), undefined, undefined, next)
+
+        // then
+        sinon.assert.called(next)
+    })
+
+})