6.3 Scope of Global Data

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6.3 Scope of Global Data

Multiple instances of 'eval' or 'exec' code blocks may be used within the one page. Any changes to or creation of global data which is performed within one code block will be reflected in any following code blocks. Global data constitutes variables as well as module imports, function and class definitions.

    <!--#python exec="
    import cgi, time, os
    def _escape(object):
        return cgi.escape(str(object))
    now = time.time()
    " -->
    <html>
    <body>
    <pre>
    <!--#python eval="_escape(time.asctime(time.localtime(now)))"-->

    <!--#python exec="
    keys = os.environ.keys()
    keys.sort()
    for key in keys:
        print >> filter, _escape(key),
        print >> filter, '=',
        print >> filter, _escape(repr(os.environ.get(key)))
    " -->
    </pre>
    </body>
    </html>

The lifetime of any global data is for the current request only. If data must persist between requests, it must reside in external modules and as necessary be protected against multithreaded access in the event that a multithreaded Apache MPM is used.