Unable to retrieve message body for a GET method on MSP430F5529LP/CC3100 (Http_Client example)

Hi Mahendra,

There are a total of 4 posts of this topic in the forum. We shall continue the discussion in this thread.

Thanks.

Sincerely,
Bryan Kahler

Hi Mahendra,

When the server uses Transfer-encoding: chunked, as in your example response above, the Content-Length header is not utilized because the length is unknown at the time of initial transmission.

What version of SDK are you using?

What modifications have your made to the http_client example?

What does your error output look like?

Are you receiving a retVal of -118?

Sincerely,

Bryan Kahler

Hello Bryan,

Thank you for responding.

---

What version of SDK are you using?

CC3100 1.2 SDK version, CC3100 service pack version 1.0.1.6-2.7.0.0

---

What modifications have your made to the http_client example?

I have made changes to implement TLS/Security

I also have made the following changes to readResponse(HTTPCli_Handle httpClient) function for debugging and code understanding purposes 

switch(id)
	{
		case 0: /* HTTPCli_FIELD_NAME_CONTENT_LENGTH */
		{
			len = strtoul((char *)g_buff, NULL, 0);
		}
		break;
		case 1: /* HTTPCli_FIELD_NAME_CONNECTION */
		{
		}
		break;
		case 2: /* HTTPCli_FIELD_NAME_CONTENT_TYPE */
		{
			if(!strncmp((const char *)g_buff, "application/json",sizeof("application/json")))
			{
				json = 1;
				xml = 0;
				CLI_Write(" ");
				CLI_Write(HTTPCli_FIELD_NAME_CONTENT_TYPE);
				CLI_Write(" : ");
				CLI_Write("application/json\n\r");
			}
			else if (!strncmp((const char *)g_buff, "application/xml",sizeof("application/xml")))
			{
				json = 0;
				xml=1;
				CLI_Write(" ");
				CLI_Write(HTTPCli_FIELD_NAME_CONTENT_TYPE);
				CLI_Write(" : ");
				CLI_Write("application/xml\n\r");
			}
			else
			{
				/* Note:
                                Developers are advised to use appropriate
                                content handler. In this example all content
                                type other than json are treated as plain text.
				 */
				json = 0;
				xml = 0;

				CLI_Write(" ");
				CLI_Write(HTTPCli_FIELD_NAME_CONTENT_TYPE);
				CLI_Write(" : ");
				CLI_Write("Not determined \n\r");
			}
		}
		break;
		case 3: /* HTTPCli_FIELD_NAME_VARY */
		{
				CLI_Write(" Wrong filter id\n\r");
		}
		break;
		case 4: /* HTTPCli_FIELD_NAME_DATE */
		{
				CLI_Write(" Wrong filter id\n\r");
		}
		break;
		case 5: /* HTTPCli_FIELD_NAME_CACHE_CONTROL */
		{
				CLI_Write(" Wrong filter id\n\r");
		}
		break;
		case 6: /* HTTPCli_FIELD_NAME_TRANSFER_ENCODING */
		{
			CLI_Write(" HTTPCli_FIELD_NAME_TRANSFER_ENCODING\n\r");
		}
		break;
                default:
		{
				CLI_Write(" Wrong filter id\n\r");
				retVal = -1;
				goto end;
		}
	}

---

What does your error output look like?

I don't get any errors? The body of the message variable is empty

bytesRead = HTTPCli_readResponseBody(httpClient, (char *)dataBuffer, len, &moreFlags);

The dataBuffer variable is empty after executing the above line of code in readResponse(HTTPCli_Handle httpClient) function 

Also I have observed that state variable from cli data structure is 4 and flag variable is 4. 

As a result the following code inside HTTPCli_readResponseBody(HTTPCli_Handle cli, char *body, int len, bool *moreFlag) function gets executed. But I think since len=0, the content in body variable is empty.

    if (getCliState(cli, CHUNKED_FLAG)) {
        ret = getChunkedData(cli, body, len, moreFlag);
    }

Based on my research (Chunked transfer encoding) and your comment "Transfer-encoding: chunked" might have some relevance.

---

I also believe that getChunkedData function from httpcli.c might have some relevance too.  

/*
 *  ======== getChunkedData ========
 *  Get chunked transfer encoded data
 */
static int getChunkedData(HTTPCli_Handle cli, char *body, int len, bool *moreFlag)

Thank you

Mahendra

Hi Mahendra,

Is the request being properly received and processed at the server? Please try your request against a server under your control and record the response sent from the server to the device.

Sincerely,
Bryan Kahler