Python Forum

I have a larger piece of python code, called from Apache2 on a Raspberry Pi. Python release is 3.11.4 on my Raspberry. The code snippet which creates strange behavior is:
(input data is a tuple of a dict and the result of a MariaDB query)

def jsonify(input_data):
  l_request=input_data[0]
  result=input_data[1]
  first_record=True
  for record in result.fetchall():
    if (l_request['TYP']=="LUFTE"): 
      if record[2]=="ON": oper=40
      else: oper=0
    t=record[1].strftime('%Y-%m-%d %H:%M:%S')
    if first_record:
      match l_request['TYP']:
        case "LUFTE":
          answer='[{{"ti":"{:s}","OP":{:d},"t":{:.1f},"h":{:.1f},"l":{:d}}}'.format(t,oper,record[3],record[4],record[5])
        case "TEMP":
          print (t)
          print (type(t))
          print (record[2])
          print (type(record[2]))
          answer='[{{“ti":"{:s}","t":{:.1f}}}'.format(t,record[2])      <======  generates strange extra characters !!
          print (answer)
          print (type(answer))
        case _:
          print ("jsonify no valid TYP:")
          print (l_request)
          return(1000)      
      first_record=False
    else:
      match l_request['TYP']:
        case "LUFTE":
          answer=answer+',{{"ti":"{:s}","OP":{:d},"t":{:.1f},"h":{:.1f},"l":{:d}}}'.format(t,oper,record[3],record[4],record[5]) 
        case "TEMP":
          answer=answer+',{{"ti":"{:s}","t":{:.1f}}}'.format(t,record[2])
        case _: 
          print ("jsonify 2 no valid TYP:")
          print (l_request)
          return(1000)    
  answer=answer+']'
  return(answer)

Please look at the arrow: "<===== generates strange extra characters"

The output of the print statements of this program are (as found in the apache2 error log:
(as you can see, "t" is a timestamp and record[2] a floating point (temperature) value.
But watch the "(hex) e2,80,x9" bytes in front of the answer string - where do these come from ??
About 6 lines above the marked line, there is a similar construct, with more characters and variables which works perfect over and over again)

Output:[Tue Sep 05 13:03:40.059054 2023] [wsgi:error] [pid 17430] [client 192.168.1.5:59518] 2023-09-05 12:59:23, referer: http://192.168.1.199/temp.html
[Tue Sep 05 13:03:40.059131 2023] [wsgi:error] [pid 17430] [client 192.168.1.5:59518] <class 'str'>, referer: http://192.168.1.199/temp.html
[Tue Sep 05 13:03:40.059164 2023] [wsgi:error] [pid 17430] [client 192.168.1.5:59518] 22.0, referer: http://192.168.1.199/temp.html
[Tue Sep 05 13:03:40.059192 2023] [wsgi:error] [pid 17430] [client 192.168.1.5:59518] <class 'float'>, referer: http://192.168.1.199/temp.html
[Tue Sep 05 13:03:40.059238 2023] [wsgi:error] [pid 17430] [client 192.168.1.5:59518] [{\xe2\x80\x9cti":"2023-09-05 12:59:23","t":22.0}, referer: http://192.168.1.199/temp.html
[Tue Sep 05 13:03:40.059266 2023] [wsgi:error] [pid 17430] [client 192.168.1.5:59518] <class 'str'>, referer: http://192.168.1.199/temp.html

I also tried the code in a stand-alone program:

t="2023-09-03 16:18:31"
print (type(t))
record=21.3
print (type(record))
answer='[{{“ti":"{:s}","t":{:.1f}}}'.format(t,record)
print(answer)
print (type(answer))

which produces correct results:

Output:<class 'str'>
<class 'float'>
[{“ti":"2023-09-03 16:18:31","t":21.3}
<class 'str'>

I am aware that possibly some errors in the code elsewhere in the program can cause this, though in my experience this turns into another error once I change the program slightly (like e.g. adding the print statements) - this is not the case.

Is there anyone who can either shed some light on this strange behavior, or tell me how I can debug this more.

As a full reference I added the full code file as a file.

The leading double quote character is wrong. Cannot see this in the post, because the post converts the character to a ascii double quote, but you can see it in the file.

(Sep-05-2023, 12:19 PM)deanhystad Wrote: [ -> ]The leading double quote character is wrong. Cannot see this in the post, because the post converts the character to a ascii double quote, but you can see it in the file.

Many THANKS !!!! good eyes !!!

It is obvious when you stop trying to overanalyze. Think simple. The output showed the bytes where you expect to see ". Where is the "? I knew what I was going to see before I opened the file.

(Sep-05-2023, 12:34 PM)deanhystad Wrote: [ -> ]It is obvious when you stop trying to overanalyze. Think simple. The output showed the bytes where you expect to see ". Where is the "? I knew what I was going to see before I opened the file.

You must have had a bit of previous knowledge: that \xe2\x80\x9c is the Figure Dash in UTF-8 - I noticed that the quotation mark was gone, but never figured why it became now three bytes... And being 68 makes one sometimes sees a bit less sharp...

Anyway thanks a lot Heart

... this has cost me some hours. Debugging an apache script is time consuming always through the error.log.

ToniE

deanhystad

ToniE

deanhystad

ToniE