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# Copyright 2002 by Jeffrey Chang. All rights reserved. This code is
# part of the Biopython distribution and governed by its license.
# Please see the LICENSE file that should have been included as part
# of this package.
# This module attempts to detect whether the internet is available.
# To use it, just insert "import requires_internet" into your Python
# code. If the internet is available, then the import statement
# succeeds. If it is not, then the statement will result in an
# MissingExternalDependencyError exception.
from Bio import MissingExternalDependencyError
AVAILABLE = None # Was the internet available the last time I checked?
TESTED = 0 # Have I checked before? If so, just re-use the result.
# I'm going to check for internet availability
RELIABLE_DOMAIN = "biopython.org"
if not TESTED:
# Not thread-safe...
TESTED = 1
import socket
try:
socket.getaddrinfo(RELIABLE_DOMAIN, 80, socket.AF_UNSPEC, socket.SOCK_STREAM)
except socket.gaierror, x:
AVAILABLE = 0
else:
AVAILABLE = 1
if not AVAILABLE:
raise MissingExternalDependencyError("internet not available")
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