fix: issue #661 - don't try to access a zero length body (#734)

Co-authored-by: Mike <[email protected]>

src/utils/parseWSManResponseBody.test.ts

@@ -48,7 +48,7 @@ describe('Check parseWSManResponseBody', () => {
     expect(response).toEqual(generalSettings)
   })
 
-  it('Should fail and return null when a message does not contain \r\n', async () => {
+  it('Should fail and return an empty response when a message does not contain \r\n', async () => {
     const xmlResponse: HttpZResponseModel = {
       protocolVersion: 'HTTP/1.1',
       statusCode: 200,
@@ -78,4 +78,33 @@ describe('Check parseWSManResponseBody', () => {
     const response = parseBody(xmlResponse)
     expect(response).toBe('')
   })
+
+  it('Should fail and return an empty response when there is no message body', async () => {
+    // See issue #661; this response is documented there.
+    const xmlResponse: HttpZResponseModel = {
+      protocolVersion: 'HTTP/1.1',
+      statusCode: 400,
+      statusMessage: 'Bad Request',
+      headersSize: 143,
+      bodySize: 0,
+      headers: [
+        {
+          name: 'Date',
+          value: 'Mon, 1 Aug 2022 18:54:20 GMT'
+        },
+        {
+          name: 'Server',
+          value: 'Intel(R) Active Management Technology 15.0.41.2142'
+        },
+        {
+          name: 'Content-Length',
+          value: '0'
+        }
+      ],
+      body: null
+    }
+    delete xmlResponse.body // Yes, really!  It's not there in this case.
+    const response = parseBody(xmlResponse)
+    expect(response).toBe('')
+  })
 })

src/utils/parseWSManResponseBody.ts

@@ -7,6 +7,8 @@ import { HttpZResponseModel } from 'http-z'
 
 export function parseBody (message: HttpZResponseModel): string {
   let xmlBody: string = ''
+  // 'Bad' requests to some devices return no body (issue #661) - prevent exceptions below
+  if (message.bodySize === 0) return ''
   // parse the body until its length is greater than 5, because body ends with '0\r\n\r\n'
   while (message.body.text.length > 5) {
     const chunkLength = message.body.text.indexOf('\r\n')