feat: add optional charset option to multipart body parser

packages/http-multipart-body-parser/README.md

@@ -59,6 +59,7 @@ npm install --save @middy/http-multipart-body-parser
 ## Options
 
 - `busboy` (object) (default `{}`): it can be used to pass extraparameters to the internal `busboy` instance at creation time. Checkout [the official documentation](https://www.npmjs.com/package/busboy#busboy-methods) for more information on the supported options.
+- `charset` (string) (default `utf-8`): it can be used to change default charset.
 
 **Note**: this middleware will buffer all the data as it is processed internally by `busboy`, so, if you are using this approach to parse significantly big volumes of data, keep in mind that all the data will be allocated in memory. This is somewhat inevitable with Lambdas (as the data is already encoded into the JSON in memory as Base64), but it's good to keep this in mind and evaluate the impact on you application.  
 If you really have to deal with big files, then you might also want to consider to allowing your users to [directly upload files to S3](https://docs.aws.amazon.com/AmazonS3/latest/API/sigv4-UsingHTTPPOST.html)

packages/http-multipart-body-parser/index.d.ts

@@ -18,7 +18,8 @@ interface Options {
       parts?: number
       headerPairs?: number
     }
-  }
+  },
+  charset?: string
 }
 
 export type Event = Omit<APIGatewayEvent, 'body'> & {

packages/http-multipart-body-parser/index.js

@@ -6,7 +6,8 @@ const fieldnamePattern = /(.+)\[(.*)]$/
 
 const defaults = {
   // busboy options as per documentation: https://www.npmjs.com/package/busboy#busboy-methods
-  busboy: {}
+  busboy: {},
+  charset: 'utf8'
 }
 
 const httpMultipartBodyParserMiddleware = (opts = {}) => {
@@ -19,7 +20,7 @@ const httpMultipartBodyParserMiddleware = (opts = {}) => {
 
     if (!mimePattern.test(contentType)) return
 
-    return parseMultipartData(request.event, options.busboy)
+    return parseMultipartData(request.event, options)
       .then((multipartData) => {
         // request.event.rawBody = body
         request.event.body = multipartData
@@ -41,9 +42,10 @@ const httpMultipartBodyParserMiddleware = (opts = {}) => {
 
 const parseMultipartData = (event, options) => {
   const multipartData = {}
+  const charset = event.isBase64Encoded ? 'base64' : options.charset
   // header must be lowercase (content-type)
   const busboy = BusBoy({
-    ...options,
+    ...options.busboy,
     headers: {
       'content-type':
         event.headers['Content-Type'] ?? event.headers['content-type']
@@ -90,7 +92,7 @@ const parseMultipartData = (event, options) => {
       .on('close', () => resolve(multipartData))
       .on('error', (e) => reject(e))
 
-    busboy.write(event.body, event.isBase64Encoded ? 'base64' : 'utf8')
+    busboy.write(event.body, charset)
     busboy.end()
   })
 }

packages/http-multipart-body-parser/index.test-d.ts

@@ -23,6 +23,7 @@ middleware = multipartBodyParser({
       parts: 100,
       headerPairs: 100
     }
-  }
+  },
+  charset: 'utf-8'
 })
 expectType<middy.MiddlewareObj<Event>>(middleware)

website/docs/middlewares/http-multipart-body-parser.md

@@ -24,6 +24,7 @@ npm install --save @middy/http-multipart-body-parser
 ## Options
 
 - `busboy` (`object`) (optional): defaults to `{}` and it can be used to pass extraparameters to the internal `busboy` instance at creation time. Checkout [the official documentation](https://www.npmjs.com/package/busboy#busboy-methods) for more information on the supported options.
+- `charset` (string) (default `utf-8`): it can be used to change default charset.
 
 **Note**: this middleware will buffer all the data as it is processed internally by `busboy`, so, if you are using this approach to parse significantly big volumes of data, keep in mind that all the data will be allocated in memory. This is somewhat inevitable with Lambdas (as the data is already encoded into the JSON in memory as Base64), but it's good to keep this in mind and evaluate the impact on you application.  
 If you really have to deal with big files, then you might also want to consider to allowing your users to [directly upload files to S3](https://docs.aws.amazon.com/AmazonS3/latest/API/sigv4-UsingHTTPPOST.html)