fix(lambda) File uploads

CHANGELOG.md

@@ -16,7 +16,7 @@ The version headers in this history reflect the versions of Apollo Server itself
 
 - `apollo-server-testing`: types: Allow generic `variables` usage of `query` and `mutate` functions. [PR #4383](https://github.com/apollograpqh/apollo-server/pull/4383)
 - `apollo-server-express`: Export the `GetMiddlewareOptions` type. [PR #4599](https://github.com/apollograpqh/apollo-server/pull/4599)
-
+- `apollo-server-lambda`: Fix file uploads - ignore base64 decoding for multipart queries. [PR #4506](https://github.com/apollographql/apollo-server/pull/4506)
 ## v2.18.2
 
 - `apollo-server-core`: Explicitly include `lru-cache` dependency in `apollo-server-core`'s dependencies. [PR #4600](https://github.com/apollographql/apollo-server/pull/4600)

packages/apollo-server-lambda/src/ApolloServer.ts

@@ -242,15 +242,16 @@ export class ApolloServer extends ApolloServerBase {
       };
 
       const fileUploadHandler = (next: Function) => {
-        const contentType =
-          event.headers["content-type"] || event.headers["Content-Type"];
-        if (contentType && contentType.startsWith("multipart/form-data")
-          && typeof processFileUploads === "function") {
+        const contentType = (
+          event.headers['content-type'] || event.headers['Content-Type'] || ''
+        ).toLowerCase();
+        if (contentType.startsWith('multipart/form-data')
+          && typeof processFileUploads === 'function') {
           const request = new FileUploadRequest() as IncomingMessage;
           request.push(
             Buffer.from(
               <any>event.body,
-              event.isBase64Encoded ? "base64" : "ascii"
+              event.isBase64Encoded ? 'base64' : 'ascii'
             )
           );
           request.push(null);

packages/apollo-server-lambda/src/lambdaApollo.ts

@@ -32,9 +32,14 @@ export function graphqlLambda(
     callback,
   ): void => {
     context.callbackWaitsForEmptyEventLoop = false;
-    let { body, isBase64Encoded } = event;
+    let { body, headers, isBase64Encoded } = event;
+    let query: Record<string, any> | Record<string, any>[];
+    const contentType = (
+      headers['content-type'] || headers['Content-Type'] || ''
+    ).toLowerCase();
+    const isMultipart = contentType.startsWith('multipart/form-data');
 
-    if (body && isBase64Encoded) {
+    if (body && isBase64Encoded && !isMultipart) {
       body = Buffer.from(body, 'base64').toString();
     }
 
@@ -45,12 +50,7 @@ export function graphqlLambda(
       });
     }
 
-    const contentType = event.headers["content-type"] || event.headers["Content-Type"];
-    let query: Record<string, any> | Record<string, any>[];
-
-    if (body && event.httpMethod === 'POST' &&
-      contentType && contentType.startsWith("multipart/form-data")
-    ) {
+    if (body && event.httpMethod === 'POST' && isMultipart) {
       query = body as any;
     } else if (body && event.httpMethod === 'POST') {
       query = JSON.parse(body);