fix: correctly handle empty response bodies (#239)

There are cases, such as a HEAD request, where the response body will have a JSON content type but the body will be empty (i.e. an empty string). This is technically valid JSON but is not parsable into an object, so the code throws an exception. This commit adds specific handling for this scenario, as well as a couple of test cases Signed-off-by: Dustin Popp <[email protected]>
IBM · Mar 1, 2023 · d0c9cb3 · d0c9cb3
1 parent b599735
commit d0c9cb3
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diff --git a/lib/request-wrapper.ts b/lib/request-wrapper.ts
@@ -557,7 +557,13 @@ function parseServiceErrorMessage(response: any): string | undefined {
  * @throws error - if the content is meant as JSON but is malformed
  */
 function ensureJSONResponseBodyIsObject(response: any): any | string {
-  if (typeof response.data !== 'string' || !isJsonMimeType(response.headers['content-type'])) {
+  // If axios gave us an empty string, it is because the response had an empty body
+  // which can happen for a HEAD request, etc. Return the empty string in that case
+  if (
+    typeof response.data !== 'string' ||
+    response.data === '' ||
+    !isJsonMimeType(response.headers['content-type'])
+  ) {
     return response.data;
   }
 

diff --git a/test/unit/request-wrapper.test.js b/test/unit/request-wrapper.test.js
@@ -646,6 +646,48 @@ describe('sendRequest', () => {
     expect(res.result).toEqual({ key: 'value' });
   });
 
+  it('should return empty string when body is empty and content is JSON', async () => {
+    const parameters = {
+      defaultOptions: {
+        body: 'post=body',
+        formData: '',
+        qs: {},
+        method: 'POST',
+        url: 'https://example.ibm.com/v1/environments',
+        headers: {},
+        responseType: 'json',
+      },
+    };
+
+    axiosResolveValue.data = '';
+    axiosResolveValue.headers = { 'content-type': 'application/json' };
+    mockAxiosInstance.mockResolvedValue(axiosResolveValue);
+
+    const res = await requestWrapperInstance.sendRequest(parameters);
+    expect(res.result).toBe('');
+  });
+
+  it('should return null when body is null and content is JSON', async () => {
+    const parameters = {
+      defaultOptions: {
+        body: 'post=body',
+        formData: '',
+        qs: {},
+        method: 'POST',
+        url: 'https://example.ibm.com/v1/environments',
+        headers: {},
+        responseType: 'json',
+      },
+    };
+
+    axiosResolveValue.data = null;
+    axiosResolveValue.headers = { 'content-type': 'application/json' };
+    mockAxiosInstance.mockResolvedValue(axiosResolveValue);
+
+    const res = await requestWrapperInstance.sendRequest(parameters);
+    expect(res.result).toBeNull();
+  });
+
   it('should raise exception when response body content is invalid json', async () => {
     const parameters = {
       defaultOptions: {