XHTTPCREQ GET request download file in chunks

RE: XHTTPCREQ GET request download file in chunks

yesheng — Tue, 12 Dec 2023 06:40:36 GMT

Bryan,

I revisited this recently, and the following AT command does the job.

AT#XHTTPCREQ="GET","your_file","Range: bytes=167936-172031\r\n"

hope this helps.

RE: XHTTPCREQ GET request download file in chunks

yesheng — Tue, 18 Jul 2023 01:04:51 GMT

Hi Bryan,

Thanks for the suggestion. I was using the SLM FW w/o any modification, and I didn't see the "overflow" issue. I use a double-buffer to store the streaming data in one buffer while writing the data from another buffer to the flash. So far it works.

RE: XHTTPCREQ GET request download file in chunks

Bryan Mills — Mon, 17 Jul 2023 20:05:58 GMT

Did you get it working? I am downloading a 300kB file using HTTP with SLM through a UART to my secondary processor. The trick was making the HTTP download to UART functions "blocking". They are set to non-blocking by default so once the incoming data size exceeds the buffer size in SLM, it starts overwriting the data before you can read it out of the UART. If you have a 2K file you want to download, set your buffer size to 2K and you have no problem. However, you can't set it to 300k so large files need to have the UART sending routines be set to blocking.

RE: XHTTPCREQ GET request download file in chunks

yesheng — Wed, 01 Mar 2023 05:41:17 GMT

Hi Amanda,

Thanks, I guess it supports only HTTPS at the moment.

RE: XHTTPCREQ GET request download file in chunks

Amanda Hsieh — Mon, 27 Feb 2023 13:53:18 GMT

Hi,

Our expert thinks HTTP chunked transfer is for streaming, not for splittd downloading. In order to download by segments, HTTP range request is the proper solution.
https://developer.mozilla.org/en-US/docs/Web/HTTP/Range_requests

Check how it is used in NCS download_client library.
https://github.com/nrfconnect/sdk-nrf/blob/main/subsys/net/lib/download_client/src/http.c#L36
MCU will need to calculate offset and do the same in the request header.

-Amanda H.

RE: XHTTPCREQ GET request download file in chunks

yesheng — Thu, 23 Feb 2023 01:55:29 GMT

Hi Amanda,

Thanks for your reply. However, I'm not entirely sure how to use this flag. Could you show me the proper syntax if I want to download a file from "example.com/test.txt", and split it into multiple chunks?

Thanks,

RE: XHTTPCREQ GET request download file in chunks

Amanda Hsieh — Mon, 20 Feb 2023 17:01:42 GMT

Hi,

Check out HTTP request #XHTTPCREQ with <chunked_transfer> flag

Regards,
Amanda H.