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35 lines
1.2 KiB
Python
35 lines
1.2 KiB
Python
# Copyright 2002 by Jeffrey Chang. All rights reserved.
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# This code is part of the Biopython distribution and governed by its
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# license. Please see the LICENSE file that should have been included
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# as part of this package.
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# This module attempts to detect whether the internet is available.
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# To use it, import requires_internet into your Python code, and call
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# requires_internet.check(). If the internet is available, then the
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# import statement succeeds. If it is not, then the statement will
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# result in a MissingExternalDependencyError exception.
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"""Common code to check if the internet is available."""
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from Bio import MissingExternalDependencyError
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def check():
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try:
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check.available
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except AttributeError:
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# I'm going to check for internet availability
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RELIABLE_DOMAIN = "biopython.org"
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import socket
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try:
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socket.getaddrinfo(
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RELIABLE_DOMAIN, 80, socket.AF_UNSPEC, socket.SOCK_STREAM
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)
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except socket.gaierror as x:
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check.available = False
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else:
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check.available = True
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if not check.available:
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raise MissingExternalDependencyError("internet not available")
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