nodemcu v2 espruino wifi problem

Posted on Thu 20th, December 2018

• #1

Michal

Hi, I have a small app with rest api deployed on NodeMcu with Espruino. App works fine and is able to successfully reconnect NodeMcu to wifi router after turning router off and on. I tested it several times. I use console.log to log all important information. The problem is that after some time (for example one day) NodeMcu loses wifi connection and is not able to reconnect to wifi. I would like to find the root cause of this problem. When the problem occurs I'm not able to connect to NodeMcu using telnet. I need to disconnect usb power supply and connect my laptop to this board. Is it possible to read/display somehow logs written earlier using console.log? If not maybe I could use some physical file instead of console.log for logging information and display its content later? Is it possible to use "fs" module?
• #2

MaBe

hi @Michal,

wifi tries to reconnect if connection is lost.
maybe you are running into a out of socket error or something else
do you like to share your code?

fs is to large for ESP8266 boards, use Storage and same name or use a numeric like 00000001 to 99999999. for numeric name use esptool.py to dump save area to file and analyse with strings or hexdump.
• #3

Michal
Hi @MaBe

Thank you very much for your precise reply. I added log functionality to my application using recommended by you Storage module. Thanks to it when I'm connecting using telnet I'm able to:
- printLog() - display all logged information (even logged before nodemcu restart)
- clearLog() - clear all log entries
  I'm attaching my application code. Now I'm able to check what is going on when the problem occurs. Thanks a lot for your help.
1 Attachment
- code.js
• #4

MaBe
Nice, thanks for sharing, will run some test and let you know how it works on my side

There are some technical details you might like to add log too:
```
// free heap space
require('ESP8266').getState().freeHeap
// free jVars
process.memory().free
```
• #5

Michal

Thanks. I will add this memory info to my log and additionally timestamp at the beginning of each line.
Below sample curl calls (in my app I have D1 and D2 configured as relays and D5 as temperature sensor):
1) curl -X GET http://nodemcuip -H "Content-Type: application/json"
result:
{"error":"","result":{"D1":0,"D2":0,"D5":22.75}}
2) curl -X POST http://nodemcuip -H "Content-Type: application/json" -d '{"D1":"1", "D2": "0"}'
turns on D1 relay and turns off D2 relay.
• #6

MaBe
here is my suggestion: extend your header like this to be sure that the client is not blocking a socket
```
header = {}; 
//tell client  to close the connection
header['Connection'] =  'close' ;   
 .....
res.writeHead(200, header);
res.end();
```
You can also send a tiny page to let the browser know that there is no need to call for a favicon.
```
page = `<!DOCTYPE html>
  <head><link rel="icon" href="data:,"></head>
<body></body></html>`;
....
res.end(page);
```
Hope this is helpful to make your Espruino app more stable and think about how cool it would be to have a label (Donated/Patreon) below your tag ;-)

• #7

MaBe

Here is the reason why 'close' is helpful when connection via browser

printing details on Espruino site for calling by browser

req.headers {
  "Host": "192.168.194.139",
  "Connection": "keep-alive",       <--- reason for sending close
  "Cache-Control": "max-age=0",
  "Upgrade-Insecure-Requests": "1",
  "User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36",
  "Sec-Metadata": "cause=\"forced\", destination=\"document\", site=\"cross-site\"",
  "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8",
  "Accept-Encoding": "gzip, deflate",
  "Accept-Language": "de-DE,de;q=0.9,en-US;q=0.8,en;q=0.7"
 }
>

I realized this when trying to upload the code again and got a port in use error

this is how curl handles it:

curl -v  192.168.194.139?led1=1
* Rebuilt URL to: 192.168.194.139/?led1=1
*   Trying 192.168.194.139...
* TCP_NODELAY set
* Connected to 192.168.194.139 (192.168.194.139) port 80 (#0)
> GET /?led1=1 HTTP/1.1
> Host: 192.168.194.139
> User-Agent: curl/7.54.0
> Accept: */*
> 
< HTTP/1.1 200 OK
< Server: Espruino 2v00.101
* no chunk, no close, no size. Assume close to signal end   <----
< 
* Closing connection 0

• #8

MaBe

missed E.getErrorFlags() might be of interest too.
• #9

Gordon

As of cutting edge builds or Espruino 2v02 (when released) Connection:close is added automatically

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