aer/Default to headers for client identity in

lolwut

Revert "lolwut"

This reverts commit 03a2e10.

packages/apollo-engine-reporting/src/extension.ts

@@ -19,6 +19,10 @@ import { EngineReportingOptions, GenerateClientInfo } from './agent';
 import { defaultSignature } from './signature';
 import { GraphQLRequestContext } from 'apollo-server-core/dist/requestPipelineAPI';
 
+const clientNameHeaderKey = 'apollographql-client-name';
+const clientReferenceIdHeaderKey = 'apollographql-client-reference-id';
+const clientVersionHeaderKey = 'apollographql-client-version';
+
 // EngineReportingExtension is the per-request GraphQLExtension which creates a
 // trace (in protobuf Trace format) for a single request. When the request is
 // done, it passes the Trace back to its associated EngineReportingAgent via the
@@ -55,10 +59,32 @@ export class EngineReportingExtension<TContext = any>
     this.nodes.set(responsePathAsString(undefined), root);
     this.generateClientInfo =
       options.generateClientInfo ||
-      // Default to using the clientInfo field of the request's extensions, when
-      // the ClientInfo fields are undefined, we send the empty string
-      (({ request }) =>
-        (request.extensions && request.extensions.clientInfo) || {});
+      // Default to using the `apollo-client-x` header fields if present.
+      // If none are present, fallback on the `clientInfo` query extension
+      // for backwards compatibility.
+      // The default value if neither header values nor query extension is
+      // set is the empty String for all fields (as per protobuf defaults)
+      (({ request }) => {
+        if (
+          request.http &&
+          request.http.headers &&
+          (request.http.headers.get(clientNameHeaderKey) ||
+            request.http.headers.get(clientVersionHeaderKey) ||
+            request.http.headers.get(clientReferenceIdHeaderKey))
+        ) {
+          return {
+            clientName: request.http.headers.get(clientNameHeaderKey),
+            clientVersion: request.http.headers.get(clientVersionHeaderKey),
+            clientReferenceId: request.http.headers.get(
+              clientReferenceIdHeaderKey,
+            ),
+          };
+        } else if (request.extensions && request.extensions.clientInfo) {
+          return request.extensions.clientInfo;
+        } else {
+          return {};
+        }
+      });
   }
 
   public requestDidStart(o: {