Help me with python read file and save file

[wereak]

import json

file = open("input.txt", "r")
print ("Name of the file is : ",file.name)
print(file.read())

with open('input.txt') as f:
    read_data = f.read()
file.closed

#a for loop will be created to look for emails, password and email associate with
#re.findall(r'([a-z0-9]+(\.[a-z0-9]+)*@[a-z]+(\.[a-z]+)+)

#trying to read the file from input.txt and safe the output to output.txt with the help of json.dumps
file2 = open("output.txt", "rb+")
json.dumps(file)


file2.closed

Traceback (most recent call last):
  File "p.py", line 16, in <module>
    json.dumps(file)
  File "/usr/lib/python3.6/json/__init__.py", line 231, in dumps
    return _default_encoder.encode(obj)
  File "/usr/lib/python3.6/json/encoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/lib/python3.6/json/encoder.py", line 257, in iterencode
    return _iterencode(o, 0)
  File "/usr/lib/python3.6/json/encoder.py", line 180, in default
    o.__class__.__name__)
TypeError: Object of type 'TextIOWrapper' is not JSON serializable

---

This is the file called input.txt

"1":"[email protected]","p":"password1","r":"PYTHON DEMO OUTPUT","d":"yahoo.com"
"2":"[email protected]","p":"password2","r":"PYTHON DEMO OUTPUT","d":"mail.bg"
"3":"[email protected]","p":"password3","r":"PYTHON DEMO OUTPUT,"d":"ya.ru"
"4":"[email protected]","p":"password4","r":"PYTHON DEMO OUTPUT","d":"yandex.ua"
"5":"[email protected]","p":"password5","r":"PYTHON DEMO OUTPUT","d":"yandex.by"
"6":"[email protected]","p":"password6","r":"PYTHON DEMO OUTPUT","d":"yahoo.com"
"7":"Demo_V;7829837","r":"PYTHON DEMO OUTPUT","d":null
"8":"[email protected]","p":"password8","r":"PYTHON DEMO OUTPUT","d":"gmail.com"
"9":"demo9_email@Tut.by","p":"password9","r":"PYTHON DEMO OUTPUT","d":"tut.by"
"10":"[email protected]","p":"password10","r":"PYTHON DEMO OUTPUT,"d":"t-online.de"

by default output.txt is empty file. I want to grab the email using the function

findall(r'([a-z0-9]+(\.[a-z0-9]+)*@[a-z]+(\.[a-z]+)+)

and also grab password and the last line. So after the scraping the out should look like this

[email protected]:password1:yahoo.com
[email protected]:password2:ymail.bg
[email protected]:password3:ya.ru
[email protected]:password4:yandex.ua
[email protected]:password5:yandex.by
[email protected]:password6:yahoo.com
[email protected]:password8:gmail.com
demo9_email@Tut.by:password9:tut.by
[email protected]:password10:t-online.de

Line 7 has a value "null" so if the null value is found skip the line and continue outputting other lines.
the line 7 has bee removed because it encounter the null value

"7":"Demo_V;7829837","r":"PYTHON DEMO OUTPUT","d":null