node-red-node-wemo uncaught exception on EHOSTUNREACH

[Achronite]

Which node are you reporting an issue on?

node-red-node-wemo v0.2.0

What are the steps to reproduce?

Switch off the mains power to a wemo switch, and try to use the wemo-lookup node to query the status of the device.

What happens?

Node-red crashes with:
2 Apr 19:06:08 - [red] Uncaught Exception:
2 Apr 19:06:08 - Error: connect EHOSTUNREACH 192.168.86.22:49153
at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1107:14)

What do you expect to happen?

Device should respond with output msg to say it is unreachable, node-red should not crash.

Please tell us about your environment:

• Node-RED version: v1.2.5
• node.js version: v10.19.0
• npm version: 6.13.4
• Platform/OS: rPi raspbian
• Browser: firefox

[hardillb]

There is a possible fix on my fork. I can't test it at the moment as I'm away from my WeMo Hardware for the weekend. If you want to give it a test and let me know:

https://github.com/hardillb/node-red-nodes

[Achronite]

I'm having difficulty installing locally in ~/node-red directory. I keep getting write access permissions problems despite chmod'ing the node-modules directory.
pi@pi3:~/.node-red $ npm install ~/development/node-red-nodes/hardware/wemo

npm WARN checkPermissions Missing write access to /home/pi/development/node-red-nodes/hardware/wemo/node_modules/assert-plus
npm WARN checkPermissions Missing write access to /home/pi/development/node-red-nodes/hardware/wemo/node_modules/aws-sign2
npm WARN checkPermissions Missing write access to /home/pi/development/node-red-nodes/hardware/wemo/node_modules/caseless
npm WARN checkPermissions Missing write access to /home/pi/development/node-red-nodes/hardware/wemo/node_modules/form-data
npm WARN checkPermissions Missing write access to /home/pi/development/node-red-nodes/hardware/wemo/node_modules/node-uuid
npm WARN checkPermissions Missing write access to /home/pi/development/node-red-nodes/hardware/wemo/node_modules/oauth-sign
npm WARN checkPermissions Missing write access to /home/pi/development/node-red-nodes/hardware/wemo/node_modules/process-nextick-args
npm WARN checkPermissions Missing write access to /home/pi/development/node-red-nodes/hardware/wemo/node_modules/punycode
npm WARN checkPermissions Missing write access to /home/pi/development/node-red-nodes/hardware/wemo/node_modules/qs
npm WARN checkPermissions Missing write access to /home/pi/development/node-red-nodes/hardware/wemo/node_modules/string_decoder
npm WARN checkPermissions Missing write access to /home/pi/development/node-red-nodes/hardware/wemo/node_modules/tough-cookie
npm WARN checkPermissions Missing write access to /home/pi/development/node-red-nodes/hardware/wemo/node_modules/tunnel-agent
npm WARN checkPermissions Missing write access to /home/pi/development/node-red-nodes/hardware/wemo/node_modules/readable-stream
npm WARN checkPermissions Missing write access to /home/pi/development/node-red-nodes/hardware/wemo/node_modules/bl
npm WARN checkPermissions Missing write access to /home/pi/development/node-red-nodes/hardware/wemo/node_modules/http-signature
npm WARN checkPermissions Missing write access to /home/pi/development/node-red-nodes/hardware/wemo/node_modules/har-validator
npm WARN checkPermissions Missing write access to /home/pi/development/node-red-nodes/hardware/wemo/node_modules/request
npm WARN node-red-project@0.0.1 No repository field.
npm WARN node-red-project@0.0.1 No license field.

npm ERR! code ENOENT
npm ERR! syscall access
npm ERR! path /home/pi/development/node-red-nodes/hardware/wemo/node_modules/assert-plus
npm ERR! errno -2
npm ERR! enoent ENOENT: no such file or directory, access '/home/pi/development/node-red-nodes/hardware/wemo/node_modules/assert-plus'
npm ERR! enoent This is related to npm not being able to find a file.
npm ERR! enoent

npm ERR! A complete log of this run can be found in:
npm ERR! /home/pi/.npm/_logs/2021-04-04T12_07_29_621Z-debug.log
pi@pi3:/.node-red $ ls -l /home/pi/development/node-red-nodes/hardware/wemo/
total 56
drwxr-xr-x 2 pi pi 4096 Apr 4 12:51 icons
drwxr-xr-x 2 pi pi 4096 Apr 4 12:51 lib
-rw-r--r-- 1 pi pi 627 Apr 4 12:51 LICENSE
drwxrwxrwx 2 pi pi 4096 Apr 4 13:03 node_modules
-rw-r--r-- 1 pi pi 884 Apr 4 12:51 package.json
-rw-r--r-- 1 pi pi 3910 Apr 4 12:51 README.md
-rw-r--r-- 1 pi pi 10124 Apr 4 12:51 WeMoNG.html
-rw-r--r-- 1 pi pi 18485 Apr 4 12:51 WeMoNG.js
pi@pi3:/.node-red $ ls -l /home/pi/development/node-red-nodes/hardware/wemo/node_modules
total 0

What am I doing wrong

[hardillb]

Without access to the system to have a look at all the file permissions for the whole directory tree I can't really help here.

I would suggest deleting the node_modules dir in the node-red-nodes/hardware/wemo directory then use the npm pack command to create a tgz of the and then installing from the tgz file.

[Achronite]

I've managed to get it installed via the npm pack route you suggested, but it crashed as soon as I added the wemo-in node back to my flow:

5 Apr 09:31:36 - [info] Starting modified nodes
5 Apr 09:31:36 - [info] Started modified nodes
5 Apr 09:31:37 - [red] Uncaught Exception:
5 Apr 09:31:37 - ReferenceError: request is not defined
    at SsdpClient.<anonymous> (/home/pi/.node-red/node_modules/node-red-node-wemo/lib/wemo.js:175:5)
    at SsdpClient.emit (events.js:198:13)
    at SsdpClient.parseResponse [as _parseResponse] (/home/pi/.node-red/node_modules/node-ssdp/lib/index.js:436:8)
    at SsdpClient.SSDP._parseMessage (/home/pi/.node-red/node_modules/node-ssdp/lib/index.js:279:10)
    at Socket.onSocketMessage (/home/pi/.node-red/node_modules/node-ssdp/lib/index.js:231:12)
    at Socket.emit (events.js:198:13)
    at UDP.onMessage [as onmessage] (dgram.js:628:8)

[hardillb]

Uncomment line 8 in the lib/wemo.js file.

I was trying to tidy something else up while fixing the original problem and missed something

[Achronite]

Yeah that would do it :). Running tests now

[Achronite]

Looks like there is still an uncaught exception:

5 Apr 09:41:33 - [red] Uncaught Exception:
5 Apr 09:41:33 - Error: connect EHOSTUNREACH 192.168.86.22:49153
    at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1107:14)

[hardillb]

OK, then I'm at a loss as there doesn't look to be anywhere else to try and catch that error.
The Lookup node should be calling getSocketStatus which is here:
https://github.com/node-red/node-red-nodes/blob/master/hardware/wemo/lib/wemo.js#L382

And there is a valid on('error',...) callback that should catch this.

[hardillb]

Having dug a bit deeper it looks like there is no way to catch some of the errors from the http.request code.

I suspect the only way to fix this will be to go replace all the http.request calls with a different http client library (not request as that is deprecated). This will be a relatively large bit of work, especially testing it all.

[Achronite]

Does it need a res.on('error'... adding? (as opposed to the post_request.on('error'...

[hardillb]

You can give it a try, but res is the result object, there shouldn't be any results (or the underlying stream it extends) until a connection has been made

[hardillb]

OK, I'm testing this with the standard shipped 0.2.0 and I can't get this to fail.
I'm having to use a socket as the light switches are not available outside the US (and don't work with UK wiring)
But it prints the error to the log, but doesn't crash

[Achronite]

It is a wemo switch I am using, and I'm in the UK too. It still consistently fails when I unplug the socket.

I believe the error is in the 'subscribe' function code that is causing it to fail. It console.logs the 'Callback URL = ... ' line just before it has the uncaught exception. I've managed to catch the error now, by adding the following:

                sub_request.on('error', function() {
                    console.log("failed to subscribe to ", device.ip);
                    //need to find a way to resubsribe
                    //delete subscriptions[subs[s]];
                    //delete sub2dev[sub.sid];
                    //subscribe({dev: subs[s]});
                });

But what should I do about resubscribing?

[hardillb]

Errr, the wemo-lookup node doesn't use the subscribe code at all so that's not possible

[Achronite]

I'm using the wemo-in node at the moment, I maybe switched after the other node failed.