From 8820ed89f4b1538ae6bbee63db60a521c98868df Mon Sep 17 00:00:00 2001
From: Benji Encalada Mora <benjifs@users.noreply.github.com>
Date: Thu, 21 May 2020 13:58:51 -0500
Subject: [PATCH] feat: parse array from multipart form data

---
 .../__tests__/index.js                        | 20 +++++++++++++++++++
 packages/http-multipart-body-parser/index.js  | 12 ++++++++++-
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/packages/http-multipart-body-parser/__tests__/index.js b/packages/http-multipart-body-parser/__tests__/index.js
index de9b1a9fa..af3005682 100644
--- a/packages/http-multipart-body-parser/__tests__/index.js
+++ b/packages/http-multipart-body-parser/__tests__/index.js
@@ -164,4 +164,24 @@ describe('📦  Middleware Multipart Form Data Body Parser', () => {
     const response = await invoke(handler, event)
     expect(response).toEqual('LS0tLS0tV2ViS2l0Rm9ybUJvdW5kYXJ5cHBzUUV3ZjJCVkplQ2UwTQpDb250ZW50LURpc3Bvc2l0aW9uOiBmb3JtLWRhdGE7IG5hbWU9ImZvbyIKCmJhcgotLS0tLS1XZWJLaXRGb3JtQm91bmRhcnlwcHNRRXdmMkJWSmVDZTBNLS0=')
   })
+
+  test('It should parse an array from a multipart/form-data request', async () => {
+    const handler = middy((event, context, cb) => {
+      cb(null, event.body) // propagates the body as a response
+    })
+
+    handler.use(httpMultipartBodyParser())
+
+    const event = {
+      headers: {
+        'content-type': 'multipart/form-data; boundary=----WebKitFormBoundaryppsQEwf2BVJeCe0M'
+      },
+      body: 'LS0tLS0tV2ViS2l0Rm9ybUJvdW5kYXJ5cHBzUUV3ZjJCVkplQ2UwTQ0KQ29udGVudC1EaXNwb3NpdGlvbjogZm9ybS1kYXRhOyBuYW1lPSJmb29bXSINCg0Kb25lDQotLS0tLS1XZWJLaXRGb3JtQm91bmRhcnlwcHNRRXdmMkJWSmVDZTBNDQpDb250ZW50LURpc3Bvc2l0aW9uOiBmb3JtLWRhdGE7IG5hbWU9ImZvb1tdIg0KDQp0d28NCi0tLS0tLVdlYktpdEZvcm1Cb3VuZGFyeXBwc1FFd2YyQlZKZUNlME0tLQ==',
+      isBase64Encoded: true
+    }
+    const response = await invoke(handler, event)
+
+    expect(Object.keys(response)).toContain('foo')
+    expect(response.foo.length).toEqual(2)
+  })
 })
diff --git a/packages/http-multipart-body-parser/index.js b/packages/http-multipart-body-parser/index.js
index 5eae22699..522fe3307 100644
--- a/packages/http-multipart-body-parser/index.js
+++ b/packages/http-multipart-body-parser/index.js
@@ -59,7 +59,17 @@ const parseMultipartData = (event, options) => {
           multipartData[fieldname] = attachment
         })
       })
-      .on('field', (fieldname, value) => { multipartData[fieldname] = value })
+      .on('field', (fieldname, value) => {
+        const matches = fieldname.match(/(.+)\[(.*)]$/)
+        if (!matches) {
+          multipartData[fieldname] = value
+        } else {
+          if (!multipartData[matches[1]]) {
+            multipartData[matches[1]] = []
+          }
+          multipartData[matches[1]].push(value)
+        }
+      })
       .on('finish', () => resolve(multipartData))
       .on('error', err => reject(err))