Check if two PDF documents are identical with Python
Last Updated :
17 May, 2022
Improve
Python is an interpreted and general purpose programming language. It is a Object-Oriented and Procedural paradigms programming language. There are various types of modules imported in python such as difflib, hashlib.
Modules used:
- difflib : It is a module that contains function that allows to compare set of data.
- SequenceMatcher : It is used to compare pair of input sequences.
Function Used:
- hash_file ( string $algo , string $filename , bool $binary = false ): It is a function which has the hash of a file.
- object.hexdigest(): It is a function which returns string.
- fileObject.read(size): It is a function that returns the specified number of bytes of a file.
Approach
- Import module
- Declare a function with 2 arguments which is for file.
- Declare two objects for hashlib.sha1()
- Open files
- Read the file by breaking the line into smaller chunks
- Now return both file such as h1.hexdigest() which is of 160 bits.
- Use hash_file() function to store the hash of a file.
- Compare and generate appropriate message
Files in Use
Program:
import hashlib
from difflib import SequenceMatcher
def hash_file(fileName1, fileName2):
# Use hashlib to store the hash of a file
h1 = hashlib.sha1()
h2 = hashlib.sha1()
with open(fileName1, "rb") as file:
# Use file.read() to read the size of file
# and read the file in small chunks
# because we cannot read the large files.
chunk = 0
while chunk != b'':
chunk = file.read(1024)
h1.update(chunk)
with open(fileName2, "rb") as file:
# Use file.read() to read the size of file a
# and read the file in small chunks
# because we cannot read the large files.
chunk = 0
while chunk != b'':
chunk = file.read(1024)
h2.update(chunk)
# hexdigest() is of 160 bits
return h1.hexdigest(), h2.hexdigest()
msg1, msg2 = hash_file("pd1.pdf ", "pd1.pdf")
if(msg1 != msg2):
print("These files are not identical")
else:
print("These files are identical")
Output
These files are not identical
