Capture output from psspy commands

psspy_redirect.py

import pssepath
pssepath.add_pssepath()

import psspy
import redirect
redirect.psse2py()

import sys

# This command prints results to console
psspy.psseinit(50000)

import contextlib
@contextlib.contextmanager
def redirect_stdout(new_target=None):
    # sometimes you don't care about messages.
    if new_target is None:
        new_target = open(os.devnull, 'w')
    old_target, sys.stdout = sys.stdout, new_target # replace sys.stdout
    try:
        yield new_target # run some code with the replaced stdout
    finally:
        sys.stdout = old_target # restore to the previous value


import StringIO
f = StringIO.StringIO()
print "before redirect"
with redirect_stdout(f):
    psspy.report('123xxx(report)')
    psspy.alert('abcyyy(alert)')
    psspy.progress('foobar(progress)')
    f.seek(0)
    var = f.read()

print "after redirect"
print "var: %s" % var