The Echo-Pipe Trap [Updated]

What's Better?

The stdin parameter to Popen() can be used to provide the required stream of bytes.

from pathlib import Path
import subprocess

temp = Path.cwd() / "temp.tmp"
temp.write_text("Firefox\0icon\0x1fweechat")  # I think.

with temp.open() as echo_file:
    subprocess.Popen(['fuzzel', '-d', '-w', '100', '-l', '10'], stdin=echo_file)

Something like the above will avoid the echo-pipe construct.

But. It leaves a temporary file lying around. What to do?

Slightly Better

This will cleanup the file. And. You don't have to pick a name.

import tempfile
import subprocess

temp = tempfile.TemporaryFile(mode='w+')
with temp:
    temp.write("Firefox\0icon\0x1fweechat")  # I think.
    temp.seek(0)
    subprocess.Popen(['fuzzel', '-d', '-w', '100', '-l', '10'], stdin=temp)

Seems kind of long. And it involves an additional problem. A file.

But. There's a FILE!

Yes. We can create a pipe. I think it's kind of hideous, though.

import os
import subprocess

r, w = os.pipe()
readable = os.fdopen(r, 'r')
writeable = os.fdopen(w, 'w')
writeable.write("Firefox\0icon\0x1fweechat")  # I think.
writeable.close()
subprocess.Popen(['fuzzel', '-d', '-w', '100', '-l', '10'], stdin=readable)
readable.close()

However. It's not too long.

We can create a pleasant wrapper in the form of a context manager.

How's This?

This seems pleasant, if you do a lot of this sort of thing.

import os
import subprocess

class EchoPipe:
    def __init__(self, content):
        self.content = content

    def __enter__(self):
        r, w = os.pipe()
        self.readable = os.fdopen(r, 'r')
        writeable = os.fdopen(w, 'w')
        writeable.write(self.content)
        writeable.close()
        return self.readable

    def __exit__(self, exc_type, exc_value, traceback):
        self.readable.close()

Once you have the EchoPipe context, you can now write this.

with EchoPipe("Firefox\0icon\0x1fweechat") as echo_pipe:
    subprocess.Popen(['fuzzel', '-d', '-w', '100', '-l', '10'], stdin=echo_pipe)

Which is pretty close to the original terse shell stuff.

And this [Update]

Consider this...

subprocess.run(
    ['fuzzel', '-d', '-w', '100', '-l', '10'],
    input="Firefox\0icon\0x1fweechat",
    text=True
)

It a very useful variant. This is -- perhaps -- the best of them all.

I found the documentation is a bit hard to follow around this topic, so I was completely taken by surprise when I was shown this.