How do I create a PDF file from a binary code using Python?

Question

I am trying to send myself PDF files per E-mail with Python. I am able to send myself the binary code of a PDF file, but I am not able to reconstruct the PDF file from this binary code.

Here is how I obtain the binary code of a PDF file:

file = open('code.txt', 'w')
for line in open('somefile.pdf', 'rb').readlines():
    file.write(str(line))
file.close()

Here is how I try to create a PDF file from the binary code:

file = open('new.pdf', 'wb')
for line in open('code.txt', 'r').readlines():
    file.write(bytes(line))
file.close()

I then recieve this error:

Traceback (most recent call last): File "something.py", line 3, in file.write(bytes(line)) TypeError: string argument without an encoding

What did I do wrong?

This ... isn't a thing. Why are you doing this? Why call `str` on the lines in the first place, and why call `bytes` on them later? Why not just email the PDF as it is? — Daniel Roseman, Mar 25 '17 at 17:10
You could do something like `base64.b64encode(cPickle.dumps(open('somefile.pdf', 'rb').read()))` then just undo that after — Peter, Mar 25 '17 at 17:12
It just turns it to text so you could send the text then decode it on the other end :P — Peter, Mar 25 '17 at 17:18
I think I read about this. Is the decodestring function the decoding function? @Peter — Ron Lauterbach, Mar 25 '17 at 17:20
Nah it's literally just changing a few letters for the most part :P Something like `decoded = cPickle.loads(base64.b64decode(encoded))`. Also it's better to do `with open(file) as f` instead of `f = open(file)`, gotta go now though so have a google of it — Peter, Mar 25 '17 at 17:25
It mostly keeps stuff in its original format, so for example, you shouldn't need to convert it to a string to transfer it. — Peter, Mar 25 '17 at 17:31
@Peter, I agree with @PM2Ring... why not b64encoding the bytes of `somefile.pdf` as returned by `open('somefile.pdf', 'rb').read()` directly? — Luca Citi, Mar 25 '17 at 19:28
If that works then it's cool, I just wasn't sure if base64 worked with the raw data from the file — Peter, Mar 25 '17 at 19:32

score 4 · Accepted Answer · answered Mar 25 '17 at 19:26

4

In your first block, open file in binary write mode (wb), since you are writing binary to it. Also, you don't need to convert it explicitly to str. It should look like this:

file = open('code.txt', 'wb')
for line in open('somefile.pdf', 'rb').readlines():
    file.write(line)
file.close()

For second block, open file in read binary mode (rb). Here also, no need to explicitly convert to bytes. It should look like this:

file = open('new.pdf', 'wb')
for line in open('code.txt', 'rb').readlines():
    file.write(line)
file.close()

This should do the trick. But why do you need to convert it in the first place? Keeping file intact will save your hardwork and computational power.

answered Mar 25 '17 at 19:26

Jay Bhavsar

159
1
14

1

How is this different from `shutil.copy`ing the file? The file is _not_ "converted". – Luca Citi Mar 25 '17 at 19:31
I am trying to send myself a PDF file per e-mail. I don't know how to directly send the file or if that is even possible. This is why I am trying to convert the code of the PDF file into a string and also back again later. – Ron Lauterbach Mar 26 '17 at 00:08
@RonLauterbach You can attach and send pdf with python's email module. No need to convert it. – Jay Bhavsar Mar 26 '17 at 02:56
@Jay Bhavsar How do I do that? – Ron Lauterbach Mar 26 '17 at 10:40
@RonLauterbach [this](http://stackoverflow.com/questions/11921188/how-to-send-email-with-pdf-attachment-in-python) should help – Jay Bhavsar Mar 28 '17 at 16:57

score 3 · Answer 2 · answered Jun 13 '22 at 02:16

Just to add. In my case, I was downloading the pdf file from an API and the 'response.content' came in base64 format. I also didn't need to write line by line I needed to convert the byte array first using:

import requests
import base64

response = requests.get(self.download_url,
                        allow_redirects=True,
                        headers=headers,
                        params=query_params)

bytes = base64.b64decode(response.content)

with open('file.pdf', 'wb') as f:
  f.write(bytes)

How do I create a PDF file from a binary code using Python?

2 Answers2

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