FOTA in nRF91 SLM gets 404 due to double `/` in file path

RE: FOTA in nRF91 SLM gets 404 due to double `/` in file path

user115230 — Tue, 10 May 2022 13:19:01 GMT

Hi Charlie,

Thanks for the follow up. This all makes sense now. I was server the firmware out of an AWS S3 bucket so it makes sense I was seeing the problem. I'm not a web guy by nature, so I wouldn't have known some servers are picky about the leading slash. Thanks for digging deep on this with me and getting that fix in!

~Matt

RE: FOTA in nRF91 SLM gets 404 due to double `/` in file path

user93921 — Tue, 10 May 2022 10:32:01 GMT

Hi Matt,

I had one deep discussion with our developer. Based on the spec of URI scheme, file <path> should include the leading"/". This is the reason why we keep it and there is no problem when we test with our R&D HTTP test server.

After your bug reporting, we did a test on AWS and another HTTP test server, then we see the same problem as you reported. It seems some servers do not like '/' in the beginning. We decided to update the PR with permanent removal of the leading '/', as it is also tested OK with R&D test server. You can find the fixing PR from application: serial_lte_modem: Handle FOTA image under WWW root by junqingzou · Pull Request #7538 · nrfconnect/sdk-nrf (github.com)

Thanks again for helping us improve our product! We really appreciate your contribution!

Best regards,

Charlie

RE: FOTA in nRF91 SLM gets 404 due to double `/` in file path

user93921 — Wed, 04 May 2022 13:32:50 GMT

Hi Matt,

Not sure by far, in fact, I set up an HTTP server yesterday in order to do the test by myself. I can confirm the problem exists and your solution works on my side now, but I still need to have further discussion with the developers in Japan which has Golden Week vacation time now. They will be back next week. I have raised an internal case to follow up on this issue and will give you an update on your concern.

This ticket will keep open until we figure out the cause. Thank you again for your patience.

Best regards,

Charlie

RE: FOTA in nRF91 SLM gets 404 due to double `/` in file path

user115230 — Wed, 04 May 2022 12:54:28 GMT

Thank you Charlie, that's great news. I have a follow on question, does this mean that FOTA update was completely broken in v1.9.1 for the SLM? If so, I'm curious on the details of how that bug slipped in to a production release. We intend to use the SLM in production, and breakage of a critical feature like FOTA update in an SDK release needs some understanding from our side.

RE: FOTA in nRF91 SLM gets 404 due to double `/` in file path

user93921 — Wed, 04 May 2022 12:39:00 GMT

Hi Matt,

Sorry for the late reply, lost your case by mistake.

I can confirm your fix is correct and this will be fixed on the next NCS release. Thanks for your contribution.

Best regards,

Charlie

RE: FOTA in nRF91 SLM gets 404 due to double `/` in file path

user115230 — Tue, 26 Apr 2022 20:24:44 GMT

Hi Charlie, is there any update from the developers? I'm eager to know if this is a bug in the SLM or an error on my side.

RE: FOTA in nRF91 SLM gets 404 due to double `/` in file path

user93921 — Wed, 13 Apr 2022 13:11:09 GMT

Hi Matt,

Thanks for reporting and sharing your solution. I will forward it to our developer for further investigation.

Have a good easter holiday!

Best regards,

Charlie

RE: FOTA in nRF91 SLM gets 404 due to double `/` in file path

user115230 — Tue, 12 Apr 2022 12:50:22 GMT

A little follow up info, I have a work around solution for now in my code that works for now. This might help shed some light on whats going on.

// File: slm_at_fota.c
// function: do_fota_start

	if (parser.field_set & (1 << UF_PATH)) {
		/* This is a hack to remove the leading '/' in the file path. The Noridc
		 * download_client library adds another implicit leading `/` which will
		 * result in a 404 due to a double `//` on the path. This looks to be a
		 * bug in Noridc code, but we're not sure at this point.
		 * See: https://devzone.nordicsemi.com/f/nordic-q-a/86861/fota-in-nrf91-slm-gets-404-due-to-double-in-file-path
		 */
		if (parser.field_data[UF_PATH].len >= 1 &&
		    file_uri[parser.field_data[UF_PATH].off] == '/') {
			parser.field_data[UF_PATH].off++;
			parser.field_data[UF_PATH].len--;
		}

		strncpy(path, file_uri + parser.field_data[UF_PATH].off,
			parser.field_data[UF_PATH].len);
	} else {
		LOG_ERR("Parse path error");
		return -EINVAL;
	}