Treat a string as a file in python

Question

In the interest of not rewriting an open source library, I want to treat a string of text as a file in python 3.

Suppose I have the file contents as a string:

not_a_file = 'there is a lot of blah blah in this so-called file'

I want to treat this variable, i.e. the contents of a file, as a path-like object that way I can use it in python's open() function.

Here is a simple example which shows my dilemma:

not_a_file = 'there is a lot of blah blah in this so-called file'
file_ptr = open(not_a_file, 'r')

Clearly the example doesn't work because not_a_file is not a path-like object. I don't want to write a file nor create any temporary directories for portability purposes.

With that said, I need is to solve this mystery:

not_a_file = 'there is a lot of blah blah in this so-called file'
... Something goes here ... 
file_ptr = open(also_not_a_file, 'r') 

What I've Tried So Far

1. I've looked into StringIO and tried using that as a path-like object and no dice: import StringIO output = StringIO.StringIO() output.write('First line.\n') file_ptr = open(output,'r') Well this doesn't work because StringIO isn't a path-like object.

2. I've tried tempfile in a similar fashion with no success. import tempfile tp = tempfile.TemporaryFile() tp.write(b'there is a lot of blah blah in this so-called file') open(tp,'r')

3. Finally I tried mmap to see if I can write the string into memory and then open the memory pointer with open with no success.

Any help is appreciated! :-)

Edit 1: What I'm thinking of to possibly solve problem

So pathlib.PurePath can work with open() if PurePath is initialized to a file. Perhaps I can create an instance of a class that inherits PurePath and when read by open(), it reads my string. Let me give an example:

from pathlib import PurePath

not_a_file = 'there is a lot of blah blah in this so-called file'
class Magic(PurePath):
    def __init__(self, string_input):
        self.file_content = string_input
        PurePath.__init__(self, 'Something magical goes here')
    #some more magic happens in this class

also_not_a_file = Magic(not_a_file)
fp = open(also_not_a_file,'r')
print(fp.readlines()) # 'there is a lot of blah blah in this so-called file'

Answer 1

StringIO returns an StringIO object, it's almost equivalent to the file object returned by the open statement. So basically, you can use the StringIO in place of the open statement.

# from StringIO import StringIO  # for Python 2, old
from io import StringIO
with StringIO('there is a lot of blah blah in this so-called file') as f:
    print(f.read())

Output:

there is a lot of blah blah in this so-called file

Answer 2

You can create a temporary file and pass its name to open:

On Unix:

tp = tempfile.NamedTemporaryFile()
tp.write(b'there is a lot of blah blah blah in this so-called file')
tp.flush()
open(tp.name, 'r')

On Windows, you need to close the temporary file before it can be opened:

tp = tempfile.NamedTemporaryFile(delete=False)
tp.write(b'there is a lot of blah blah blah in this so-called file')
tp.close()
open(tp.name, 'r')

You then become responsible for deleting the file once you're done using it.