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45<H2><A NAME="SECTION000530000000000000000">&nbsp;</A>
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474.3 Acessing Socket Methods
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49<P>
50<EM><EM><EM>We quickly saw the benefit of wrapping socket methods in the
51<tt class="class">SSL.Connection</tt> class, for an easy transition into using SSL. The
52problem here is that the <tt class="module">socket</tt> module lacks a C API, and all the
53methods are declared static. One approach would be to have <tt class="module">OpenSSL</tt> as
54a submodule to the <tt class="module">socket</tt> module, placing all the code in
55<span class="file">socketmodule.c</span>, but this is obviously not a good solution, since you
56might not want to import tonnes of extra stuff you're not going to use when
57importing the <tt class="module">socket</tt> module. The other approach is to somehow get a
58pointer to the method to be called, either the C function, or a callable Python
59object. This is not really a good solution either, since there's a lot of
60lookups involved.
61</EM></EM></EM>
62<P>
63<EM><EM><EM>The way it works is that you have to supply a ``<tt class="class">socket</tt>-like'' transport
64object to the <tt class="class">SSL.Connection</tt>. The only requirement of this object is
65that it has a <tt class="method">fileno()</tt> method that returns a file descriptor that's
66valid at the C level (i.e. you can use the system calls read and write). If you
67want to use the <tt class="method">connect()</tt> or <tt class="method">accept()</tt> methods of the
68<tt class="class">SSL.Connection</tt> object, the transport object has to supply such
69methods too. Apart from them, any method lookups in the <tt class="class">SSL.Connection</tt>
70object that fail are passed on to the underlying transport object.
71</EM></EM></EM>
72<P>
73<EM><EM><EM>Future changes might be to allow Python-level transport objects, that instead
74of having <tt class="method">fileno()</tt> methods, have <tt class="method">read()</tt> and <tt class="method">write()</tt>
75methods, so more advanced features of Python can be used. This would probably
76entail some sort of OpenSSL ``BIOs'', but converting Python strings back and
77forth is expensive, so this shouldn't be used unless necessary. Other nice
78things would be to be able to pass in different transport objects for reading
79and writing, but then the <tt class="method">fileno()</tt> method of <tt class="class">SSL.Connection</tt>
80becomes virtually useless. Also, should the method resolution be used on the
81read-transport or the write-transport?
82</EM></EM></EM>
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