v10 driver - empty 200 response throws protocol error (#313)

Co-authored-by: Paul Paterson <[email protected]>

__tests__/unit/query.test.ts

@@ -5,6 +5,7 @@ import {
   AuthorizationError,
   FetchClient,
   fql,
+  ProtocolError,
   QueryTimeoutError,
   ServiceError,
   ServiceInternalError,
@@ -123,6 +124,25 @@ describe("query", () => {
     expect(actual.summary).toEqual("the summary");
   });
 
+  it("Throws ProtocolError on an empty 200 response", async () => {
+    expect.assertions(2);
+    fetchMock.mockResponse("", {
+      status: 200,
+      headers: [["content-length", "0"]],
+    });
+    try {
+      const result = await client.query(fql`'foo'.length`);
+      console.log("result", result);
+    } catch (e) {
+      if (e instanceof ProtocolError) {
+        expect(e.message).toEqual(
+          "There was an issue communicating with Fauna. Response is empty. Please try again.",
+        );
+        expect(e.httpStatus).toEqual(500);
+      }
+    }
+  });
+
   // it("throws an NetworkError on a timeout", async () => {
   //   expect.assertions(2);
   //   // axios mock adapater currently has a bug that cannot match

src/client.ts

@@ -639,6 +639,19 @@ in an environmental variable named FAUNA_SECRET or pass it to the Client\
         JSON.stringify(response.headers),
       );
 
+      // Receiving a 200 with no body/content indicates an issue with core router
+      if (
+        response.status === 200 &&
+        (response.body.length === 0 ||
+          response.headers["content-length"] === "0")
+      ) {
+        throw new ProtocolError({
+          message:
+            "There was an issue communicating with Fauna. Response is empty. Please try again.",
+          httpStatus: 500,
+        });
+      }
+
       let parsedResponse;
       try {
         parsedResponse = {