Updating a config file [solved]

[ebolisa]

Hi,

I've a config.py file with the following content:

from mqtt_as import config

config['ssid'] = 'my router'
config['ssid_pw'] = 'pwd'
config['mqtt_user'] = 'user'
config['mqtt_pw'] = 'pwd'
config['pub_topic'] = 'main/esp'  
config['sub_topic'] = 'main/esp/32/relays'

I know how to read from it but how do I modify say, the 'ssid_pw' password string?
TIA

[bowlofred]

I'm assuming you just edit it with a text editor and overwrite the placeholders on the right. Unless someone has written a GUI that prompts for it directly.

[ebolisa]

I'm assuming you just edit it with a text editor and overwrite the placeholders on the right. Unless someone has written a GUI that prompts for it directly.

I'm using wifimgr.py library to obtain the ssid/password of a router. So, I need to update the config.py via code which is running in a microcontroller. Don't have access to the config file once burned the code into the mcontroller.

[bowlofred]

I'm not sure I understand the environment, but I think you can modify them before you hand the config off to the client. Are you using it something like this?

from mqtt_as import MQTTClient, config
...
client = MQTTClient(config)

If so, you can modify them before handing to the client.

from mqtt_as import MQTTClient, config

ssid, password = get_from_wifimgr() 
config["ssid"] = ssid
config["ssid_pw"] = password
client = MQTTClient(config)

[ebolisa]

from mqtt_as import MQTTClient, config

ssid, password = get_from_wifimgr() 
config["ssid"] = ssid
config["ssid_pw"] = password
client = MQTTClient(config)

Thanks but in my case it won't work.
For an easy understanding, I worked up this code which gets me closer to a solution but:

filename = "test_file.py"
# open file for writing
my_file = open(filename, "w")
my_file.write("config['ssid'] = 'my_ssid'\n")
my_file.write("config['wifi_pw'] = 'my_pw'\n")
my_file.write("config['mqtt_user'] = 'user'\n")

# open file for reading
my_file = open(filename)
# read the file's entire content
content = my_file.read()
my_file.close()
print('Original file content:')
print(content)
print()

# edit file
new_ssid = 'new_ssid'
new_pw = 'new_pw'
# open file for writing
my_file = open(filename, "w")
text_list = ["config['ssid'] = " + new_ssid + '\n', "config['wifi_pw'] = " + new_pw + '\n']
my_file.writelines(text_list)
# open file for reading
my_file = open(filename)
# read the file's entire content
content = my_file.read()
my_file.close()
print('Edited file content:')
print(content)

Output:
Original file content:
config['ssid'] = 'my_ssid'
config['wifi_pw'] = 'my_pw'
config['mqtt_user'] = 'user'

Edited file content:
config['ssid'] = new_ssid
config['wifi_pw'] = new_pw

it has two errors.
1. It erases the file's content thus showing 2 lines instead of 3 (or more)
2. The new variables' strings are missing quotes.

[Gribouillis]

Parse each line with the re module

import io
import re

initial = io.StringIO("""\
# spam
config['ssid'] = 'my_ssid'
config['wifi_pw'] = 'my_pw'
config['mqtt_user'] = 'user'
# more spam
""")

pat = re.compile(r"^config\[\'([^']*)\'\]")

def trans(line, dic):
    match = pat.match(line)
    if match and match.group(1) in dic:
        param = match.group(1)
        return f"config['{param}'] = '{dic[param]}'\n"
    else:
        return line
        
dic = {
    'ssid': 'new_ssid',
    'wifi_pw': 'new_pw'
}

lines = initial.readlines()

with io.StringIO() as out:
    for line in lines:
        out.write(trans(line, dic))
    print(out.getvalue())

Output:
# spam
config['ssid'] = 'new_ssid'
config['wifi_pw'] = 'new_pw'
config['mqtt_user'] = 'user'
# more spam

[ebolisa]

Parse each line with the re module

Thanks, those are the results I'm looking for but the config data is in the config.py file along with some functions. So, I need to read the data, edit it and update the file without affecting the rest of the code within the config.py as shown in my last post.

[ebolisa]

Parse each line with the re module

Got it! Thank you!!

import io, re

filename = "config.py"
# open file for reading
my_file = open(filename)
# read the file's entire content
content = my_file.read()
my_file.close()
print('Original file content:')
print(content)

initial = io.StringIO(content)
pat = re.compile(r"^config\[\'([^']*)\'\]")


def trans(line, dic):
    match = pat.match(line)
    if match and match.group(1) in dic:
        param = match.group(1)
        return f"config['{param}'] = '{dic[param]}'\n"
    else:
        return line


dic = {
    'ssid': 'new_ssid',
    'wifi_pw': 'new_pw'
}

lines = initial.readlines()
with io.StringIO() as out:
    for line in lines:
        out.write(trans(line, dic))
    new_content = out.getvalue()

# update file
my_file = open(filename, 'w')
my_file.write(new_content)
my_file.close()
# read file
readable_file = open(filename)
read_file = readable_file.read()
print('Updated file content:')
print(read_file)

[Gribouillis]

You can simplify your code by removing the StringIOs. I used them only to simulate real files contents.