The deduplicator now accepts a query param

README.md

@@ -128,7 +128,7 @@ The `options` object has the following fields:
 | `uploads`       | [UploadOptions](/src/types.ts#L39-L43) or `false` or `undefined` | `null`          | Provides information about upload limits; the object can have any combination of the following three keys: `maxFieldSize`, `maxFileSize`, `maxFiles`; each of these have values of type Number; setting to `false` disables file uploading                                                                                   |
 | `https`         | [HttpsOptions](/src/types.ts#L62-L65) or `undefined`             | `undefined`     | Enables HTTPS support with a key/cert
 | `getEndpoint`  | String or Boolean |  `false`  | Adds a graphql HTTP GET endpoint to your server (defaults to `endpoint` if `true`).  Used for leveraging CDN level caching. |
-| `deduplicator` | Boolean | `true` | Enables [graphql-deduplicator](https://github.com/gajus/graphql-deduplicator). Once enabled sending the header `X-GraphQL-Deduplicate` will deduplicate the data.  |
+| `deduplicator` | Boolean | `true` | Enables [graphql-deduplicator](https://github.com/gajus/graphql-deduplicator). Once enabled, adding `?deduplicate` to the endpoint URL will deduplicate the data.  |
 | `bodyParserOptions` | BodyParserJSONOptions | [BodyParserJSONOptions Defaults](https://github.com/expressjs/body-parser#bodyparserjsonoptions) | Allows pass through of [body-parser options](https://github.com/expressjs/body-parser#bodyparserjsonoptions)  |
 
 Additionally, the `options` object exposes these `apollo-server` options:

src/index.test.ts

@@ -128,6 +128,14 @@ test('Response data can be deduplicated with graphql-deduplicator', async t => {
   }).promise()
 
   const deduplicated = await request({
+    uri: uri + '?deduplicate',
+    method: 'POST',
+    json: true,
+    body: { query },
+  }).promise()
+
+  // The use of a header is deprecated but should work
+  const deduplicatedWithHeader = await request({
     uri,
     method: 'POST',
     json: true,
@@ -155,10 +163,12 @@ test('Response data can be deduplicated with graphql-deduplicator', async t => {
     },
   })
 
+  t.deepEqual(deduplicated, deduplicatedWithHeader)
+
   t.deepEqual(body.data, inflate(deduplicated.data))
 })
 
-test('graphql-deduplicated can be completely disabled', async t => {
+test('graphql-deduplicator can be completely disabled', async t => {
   const {
     uri,
     data: { book },
@@ -183,13 +193,10 @@ test('graphql-deduplicated can be completely disabled', async t => {
   `
 
   const body = await request({
-    uri,
+    uri: uri + '?deduplicate',
     method: 'POST',
     json: true,
     body: { query },
-    headers: {
-      'X-GraphQL-Deduplicate': true,
-    },
   }).promise()
 
   t.deepEqual(body, {

src/index.ts

@@ -184,7 +184,8 @@ export class GraphQLServer {
       }
       return (response, ...args) => {
         if (
-          req.get('X-GraphQL-Deduplicate') &&
+          (isTrulyQueryParam(req.query.deduplicate) ||
+            req.get('X-GraphQL-Deduplicate')) &&
           response.data &&
           !response.data.__schema
         ) {
@@ -456,3 +457,12 @@ function mergeTypeDefs(typeDefs: ITypeDefinitions): string {
 function isDocumentNode(node: any): node is DocumentNode {
   return node.kind === 'Document'
 }
+
+/**
+ * Normalises GET parameter values into a boolean.
+ * Returns true in the following cases:
+ * ?value ?value= ?value=1 ?value=true
+ */
+function isTrulyQueryParam(value: string) {
+  return value === '' || value === '1' || value === 'true'
+}