I'd like to do something like this:
data = json.load(open(sys.argv[1]) if len(sys.argv) > 1 else sys.stdin)
which for this example can be reduced to
data = json.load(sys.stdin)
But json.load runs a single .read() which might not contain the whole JSON string I provided via
generate_json_output | myprogram.py
Is there a recommended way to read from stdin until generate_json_output terminates? I tried to catch BrokenPipeError but it doesn't get raised when I run
while True:
data += sys.stdin.read()
Instead of a while loop, you can use for loop like below to iterate over stdin.
import sys
data = ''
for line in sys.stdin:
data += line
which can be written as one expression:
data = "".join(sys.stdin)
Running this with input generated using a pipe reads the stdin until it terminates.
t.json:
{
'a': 2,
'b': 3
}
Running cat t.json | python a.py prints the complete file to stdout.
This is as straight forward as I was hoping it would be :) shorter version:
data = "".join(sys.stdin)