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<li><a class="reference internal" href="#">zipimport – Load Python code from inside ZIP archives</a><ul>
<li><a class="reference internal" href="#example">Example</a></li>
<li><a class="reference internal" href="#finding-a-module">Finding a Module</a></li>
<li><a class="reference internal" href="#accessing-code">Accessing Code</a></li>
<li><a class="reference internal" href="#source">Source</a></li>
<li><a class="reference internal" href="#packages">Packages</a></li>
<li><a class="reference internal" href="#data">Data</a></li>
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<div class="section" id="module-zipimport">
<span id="zipimport-load-python-code-from-inside-zip-archives"></span><span id="zipimport-ref"></span><h1>zipimport – Load Python code from inside ZIP archives<a class="headerlink" href="#module-zipimport" title="Permalink to this headline">¶</a></h1>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Purpose:</th><td class="field-body">Load Python code from inside ZIP archives.</td>
</tr>
<tr class="field"><th class="field-name">Python Version:</th><td class="field-body">2.3 and later</td>
</tr>
</tbody>
</table>
<p>The <a class="reference internal" href="#module-zipimport" title="zipimport: Load Python code from inside ZIP archives."><tt class="xref py py-mod docutils literal"><span class="pre">zipimport</span></tt></a> module implements the <tt class="xref py py-class docutils literal"><span class="pre">zipimporter</span></tt> class,
which can be used to find and load Python modules inside ZIP
archives. The <tt class="xref py py-class docutils literal"><span class="pre">zipimporter</span></tt> supports the “import hooks” API
specified in <span class="target" id="index-0"></span><a class="pep reference external" href="http://www.python.org/dev/peps/pep-0302"><strong>PEP 302</strong></a>; this is how Python Eggs work.</p>
<p>You probably won’t need to use the <a class="reference internal" href="#module-zipimport" title="zipimport: Load Python code from inside ZIP archives."><tt class="xref py py-mod docutils literal"><span class="pre">zipimport</span></tt></a> module directly,
since it is possible to import directly from a ZIP archive as long as
that archive appears in your <a class="reference internal" href="../sys/imports.html#sys-path"><em>sys.path</em></a>. However, it
is interesting to see the features available.</p>
<div class="section" id="example">
<h2>Example<a class="headerlink" href="#example" title="Permalink to this headline">¶</a></h2>
<p>For the examples this week, I’ll reuse some of the code from last
week’s discussion of zipfile to create an example ZIP archive
containing some Python modules. If you are experimenting with the
sample code on your system, run <tt class="docutils literal"><span class="pre">zipimport_make_example.py</span></tt> before
any of the rest of the examples. It will create a ZIP archive
containing all of the modules in the example directory, along with
some test data needed for the code below.</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">import</span> <span class="nn">sys</span>
<span class="kn">import</span> <span class="nn">zipfile</span>
<span class="k">if</span> <span class="n">__name__</span> <span class="o">==</span> <span class="s">'__main__'</span><span class="p">:</span>
<span class="n">zf</span> <span class="o">=</span> <span class="n">zipfile</span><span class="o">.</span><span class="n">PyZipFile</span><span class="p">(</span><span class="s">'zipimport_example.zip'</span><span class="p">,</span> <span class="n">mode</span><span class="o">=</span><span class="s">'w'</span><span class="p">)</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">zf</span><span class="o">.</span><span class="n">writepy</span><span class="p">(</span><span class="s">'.'</span><span class="p">)</span>
<span class="n">zf</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="s">'zipimport_get_source.py'</span><span class="p">)</span>
<span class="n">zf</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="s">'example_package/README.txt'</span><span class="p">)</span>
<span class="k">finally</span><span class="p">:</span>
<span class="n">zf</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
<span class="k">for</span> <span class="n">name</span> <span class="ow">in</span> <span class="n">zf</span><span class="o">.</span><span class="n">namelist</span><span class="p">():</span>
<span class="k">print</span> <span class="n">name</span>
</pre></div>
</div>
<div class="highlight-python"><pre>$ python zipimport_make_example.py
__init__.pyc
example_package/__init__.pyc
zipimport_find_module.pyc
zipimport_get_code.pyc
zipimport_get_data.pyc
zipimport_get_data_nozip.pyc
zipimport_get_data_zip.pyc
zipimport_get_source.pyc
zipimport_is_package.pyc
zipimport_load_module.pyc
zipimport_make_example.pyc
zipimport_get_source.py
example_package/README.txt</pre>
</div>
</div>
<div class="section" id="finding-a-module">
<h2>Finding a Module<a class="headerlink" href="#finding-a-module" title="Permalink to this headline">¶</a></h2>
<p>Given the full name of a module, <tt class="xref py py-func docutils literal"><span class="pre">find_module()</span></tt> will try to
locate that module inside the ZIP archive.</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">import</span> <span class="nn">zipimport</span>
<span class="n">importer</span> <span class="o">=</span> <span class="n">zipimport</span><span class="o">.</span><span class="n">zipimporter</span><span class="p">(</span><span class="s">'zipimport_example.zip'</span><span class="p">)</span>
<span class="k">for</span> <span class="n">module_name</span> <span class="ow">in</span> <span class="p">[</span> <span class="s">'zipimport_find_module'</span><span class="p">,</span> <span class="s">'not_there'</span> <span class="p">]:</span>
<span class="k">print</span> <span class="n">module_name</span><span class="p">,</span> <span class="s">':'</span><span class="p">,</span> <span class="n">importer</span><span class="o">.</span><span class="n">find_module</span><span class="p">(</span><span class="n">module_name</span><span class="p">)</span>
</pre></div>
</div>
<p>If the module is found, the <tt class="xref py py-class docutils literal"><span class="pre">zipimporter</span></tt> instance is
returned. Otherwise, <tt class="xref docutils literal"><span class="pre">None</span></tt> is returned.</p>
<div class="highlight-python"><pre>$ python zipimport_find_module.py
zipimport_find_module : <zipimporter object "zipimport_example.zip">
not_there : None</pre>
</div>
</div>
<div class="section" id="accessing-code">
<h2>Accessing Code<a class="headerlink" href="#accessing-code" title="Permalink to this headline">¶</a></h2>
<p>The <tt class="xref py py-func docutils literal"><span class="pre">get_code()</span></tt> method loads the code object for a module from
the archive.</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">import</span> <span class="nn">zipimport</span>
<span class="n">importer</span> <span class="o">=</span> <span class="n">zipimport</span><span class="o">.</span><span class="n">zipimporter</span><span class="p">(</span><span class="s">'zipimport_example.zip'</span><span class="p">)</span>
<span class="n">code</span> <span class="o">=</span> <span class="n">importer</span><span class="o">.</span><span class="n">get_code</span><span class="p">(</span><span class="s">'zipimport_get_code'</span><span class="p">)</span>
<span class="k">print</span> <span class="n">code</span>
</pre></div>
</div>
<p>The code object is not the same as a module object.</p>
<div class="highlight-python"><pre>$ python zipimport_get_code.py
<code object <module> at 0x1002b73b0, file "./zipimport_get_code.py", line 7></pre>
</div>
<p>To load the code as a usable module, use <tt class="xref py py-func docutils literal"><span class="pre">load_module()</span></tt>
instead.</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">import</span> <span class="nn">zipimport</span>
<span class="n">importer</span> <span class="o">=</span> <span class="n">zipimport</span><span class="o">.</span><span class="n">zipimporter</span><span class="p">(</span><span class="s">'zipimport_example.zip'</span><span class="p">)</span>
<span class="n">module</span> <span class="o">=</span> <span class="n">importer</span><span class="o">.</span><span class="n">load_module</span><span class="p">(</span><span class="s">'zipimport_get_code'</span><span class="p">)</span>
<span class="k">print</span> <span class="s">'Name :'</span><span class="p">,</span> <span class="n">module</span><span class="o">.</span><span class="n">__name__</span>
<span class="k">print</span> <span class="s">'Loader :'</span><span class="p">,</span> <span class="n">module</span><span class="o">.</span><span class="n">__loader__</span>
<span class="k">print</span> <span class="s">'Code :'</span><span class="p">,</span> <span class="n">module</span><span class="o">.</span><span class="n">code</span>
</pre></div>
</div>
<p>The result is a module object as though the code had been loaded from a
regular import:</p>
<div class="highlight-python"><pre>$ python zipimport_load_module.py
<code object <module> at 0x100431d30, file "./zipimport_get_code.py", line 7>
Name : zipimport_get_code
Loader : <zipimporter object "zipimport_example.zip">
Code : <code object <module> at 0x100431d30, file "./zipimport_get_code.py", line 7></pre>
</div>
</div>
<div class="section" id="source">
<h2>Source<a class="headerlink" href="#source" title="Permalink to this headline">¶</a></h2>
<p>As with the <a class="reference internal" href="../inspect/index.html#module-inspect" title="inspect: Inspect live objects"><tt class="xref py py-mod docutils literal"><span class="pre">inspect</span></tt></a> module, it is possible to retrieve the
source code for a module from the ZIP archive, if the archive includes
the source. In the case of the example, only
<tt class="docutils literal"><span class="pre">zipimport_get_source.py</span></tt> is added to <tt class="docutils literal"><span class="pre">zipimport_example.zip</span></tt> (the
rest of the modules are just added as the .pyc files).</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">import</span> <span class="nn">zipimport</span>
<span class="n">importer</span> <span class="o">=</span> <span class="n">zipimport</span><span class="o">.</span><span class="n">zipimporter</span><span class="p">(</span><span class="s">'zipimport_example.zip'</span><span class="p">)</span>
<span class="k">for</span> <span class="n">module_name</span> <span class="ow">in</span> <span class="p">[</span><span class="s">'zipimport_get_code'</span><span class="p">,</span> <span class="s">'zipimport_get_source'</span><span class="p">]:</span>
<span class="n">source</span> <span class="o">=</span> <span class="n">importer</span><span class="o">.</span><span class="n">get_source</span><span class="p">(</span><span class="n">module_name</span><span class="p">)</span>
<span class="k">print</span> <span class="s">'='</span> <span class="o">*</span> <span class="mi">80</span>
<span class="k">print</span> <span class="n">module_name</span>
<span class="k">print</span> <span class="s">'='</span> <span class="o">*</span> <span class="mi">80</span>
<span class="k">print</span> <span class="n">source</span>
<span class="k">print</span>
</pre></div>
</div>
<p>If the source for a module is not available, <tt class="xref py py-func docutils literal"><span class="pre">get_source()</span></tt>
returns <tt class="xref docutils literal"><span class="pre">None</span></tt>.</p>
<div class="highlight-python"><pre>$ python zipimport_get_source.py
================================================================================
zipimport_get_code
================================================================================
None
================================================================================
zipimport_get_source
================================================================================
#!/usr/bin/env python
#
# Copyright 2007 Doug Hellmann.
#
"""Retrieving the source code for a module within a zip archive.
"""
#end_pymotw_header
import zipimport
importer = zipimport.zipimporter('zipimport_example.zip')
for module_name in ['zipimport_get_code', 'zipimport_get_source']:
source = importer.get_source(module_name)
print '=' * 80
print module_name
print '=' * 80
print source
print</pre>
</div>
</div>
<div class="section" id="packages">
<h2>Packages<a class="headerlink" href="#packages" title="Permalink to this headline">¶</a></h2>
<p>To determine if a name refers to a package instead of a regular module, use
<tt class="xref py py-func docutils literal"><span class="pre">is_package()</span></tt>.</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">import</span> <span class="nn">zipimport</span>
<span class="n">importer</span> <span class="o">=</span> <span class="n">zipimport</span><span class="o">.</span><span class="n">zipimporter</span><span class="p">(</span><span class="s">'zipimport_example.zip'</span><span class="p">)</span>
<span class="k">for</span> <span class="n">name</span> <span class="ow">in</span> <span class="p">[</span><span class="s">'zipimport_is_package'</span><span class="p">,</span> <span class="s">'example_package'</span><span class="p">]:</span>
<span class="k">print</span> <span class="n">name</span><span class="p">,</span> <span class="n">importer</span><span class="o">.</span><span class="n">is_package</span><span class="p">(</span><span class="n">name</span><span class="p">)</span>
</pre></div>
</div>
<p>In this case, <tt class="docutils literal"><span class="pre">zipimport_is_package</span></tt> came from a module and the
<tt class="docutils literal"><span class="pre">example_package</span></tt> is a package.</p>
<div class="highlight-python"><pre>$ python zipimport_is_package.py
zipimport_is_package False
example_package True</pre>
</div>
</div>
<div class="section" id="data">
<h2>Data<a class="headerlink" href="#data" title="Permalink to this headline">¶</a></h2>
<p>There are times when source modules or packages need to be distributed
with non-code data. Images, configuration files, default data, and
test fixtures are just a few examples of this. Frequently, the module
<tt class="docutils literal"><span class="pre">__path__</span></tt> attribute is used to find these data files relative to
where the code is installed.</p>
<p>For example, with a normal module you might do something like:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">import</span> <span class="nn">os</span>
<span class="kn">import</span> <span class="nn">example_package</span>
<span class="n">data_filename</span> <span class="o">=</span> <span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">dirname</span><span class="p">(</span><span class="n">example_package</span><span class="o">.</span><span class="n">__file__</span><span class="p">),</span>
<span class="s">'README.txt'</span><span class="p">)</span>
<span class="k">print</span> <span class="n">data_filename</span><span class="p">,</span> <span class="s">':'</span>
<span class="k">print</span> <span class="nb">open</span><span class="p">(</span><span class="n">data_filename</span><span class="p">,</span> <span class="s">'rt'</span><span class="p">)</span><span class="o">.</span><span class="n">read</span><span class="p">()</span>
</pre></div>
</div>
<p>The output will look something like this, with the path changed based on where
the PyMOTW sample code is on your filesystem.</p>
<div class="highlight-python"><pre>$ python zipimport_get_data_nozip.py
/Users/dhellmann/Documents/PyMOTW/src/PyMOTW/zipimport/example_package/README.txt :
This file represents sample data which could be embedded in the ZIP
archive. You could include a configuration file, images, or any other
sort of non-code data.</pre>
</div>
<p>If the <tt class="docutils literal"><span class="pre">example_package</span></tt> is imported from the ZIP archive instead of
the filesystem, that method does not work:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">import</span> <span class="nn">sys</span>
<span class="n">sys</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">insert</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="s">'zipimport_example.zip'</span><span class="p">)</span>
<span class="kn">import</span> <span class="nn">os</span>
<span class="kn">import</span> <span class="nn">example_package</span>
<span class="k">print</span> <span class="n">example_package</span><span class="o">.</span><span class="n">__file__</span>
<span class="n">data_filename</span> <span class="o">=</span> <span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">dirname</span><span class="p">(</span><span class="n">example_package</span><span class="o">.</span><span class="n">__file__</span><span class="p">),</span>
<span class="s">'README.txt'</span><span class="p">)</span>
<span class="k">print</span> <span class="n">data_filename</span><span class="p">,</span> <span class="s">':'</span>
<span class="k">print</span> <span class="nb">open</span><span class="p">(</span><span class="n">data_filename</span><span class="p">,</span> <span class="s">'rt'</span><span class="p">)</span><span class="o">.</span><span class="n">read</span><span class="p">()</span>
</pre></div>
</div>
<p>The <tt class="docutils literal"><span class="pre">__file__</span></tt> of the package refers to the ZIP archive, and not a directory. So
we cannot just build up the path to the <tt class="docutils literal"><span class="pre">README.txt</span></tt> file.</p>
<div class="highlight-python"><pre>$ python zipimport_get_data_zip.py
zipimport_example.zip/example_package/__init__.pyc
zipimport_example.zip/example_package/README.txt :
Traceback (most recent call last):
File "zipimport_get_data_zip.py", line 40, in <module>
print open(data_filename, 'rt').read()
IOError: [Errno 20] Not a directory: 'zipimport_example.zip/example_package/README.txt'</pre>
</div>
<p>Instead, we need to use the <tt class="xref py py-func docutils literal"><span class="pre">get_data()</span></tt> method. We can access
<tt class="xref py py-class docutils literal"><span class="pre">zipimporter</span></tt> instance which loaded the module through the
<tt class="docutils literal"><span class="pre">__loader__</span></tt> attribute of the imported module:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">import</span> <span class="nn">sys</span>
<span class="n">sys</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">insert</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="s">'zipimport_example.zip'</span><span class="p">)</span>
<span class="kn">import</span> <span class="nn">os</span>
<span class="kn">import</span> <span class="nn">example_package</span>
<span class="k">print</span> <span class="n">example_package</span><span class="o">.</span><span class="n">__file__</span>
<span class="k">print</span> <span class="n">example_package</span><span class="o">.</span><span class="n">__loader__</span><span class="o">.</span><span class="n">get_data</span><span class="p">(</span><span class="s">'example_package/README.txt'</span><span class="p">)</span>
</pre></div>
</div>
<div class="highlight-python"><pre>$ python zipimport_get_data.py
zipimport_example.zip/example_package/__init__.pyc
This file represents sample data which could be embedded in the ZIP
archive. You could include a configuration file, images, or any other
sort of non-code data.</pre>
</div>
<p>The <tt class="docutils literal"><span class="pre">__loader__</span></tt> is not set for modules not imported via
<a class="reference internal" href="#module-zipimport" title="zipimport: Load Python code from inside ZIP archives."><tt class="xref py py-mod docutils literal"><span class="pre">zipimport</span></tt></a>.</p>
<div class="admonition-see-also admonition seealso">
<p class="first admonition-title">See also</p>
<dl class="last docutils">
<dt><a class="reference external" href="http://docs.python.org/lib/module-zipimport.html">zipimport</a></dt>
<dd>Standard library documentation for this module.</dd>
<dt><a class="reference internal" href="../imp/index.html#module-imp" title="imp: Interface to module import mechanism."><tt class="xref py py-mod docutils literal"><span class="pre">imp</span></tt></a></dt>
<dd>Other import-related functions.</dd>
<dt><span class="target" id="index-1"></span><a class="pep reference external" href="http://www.python.org/dev/peps/pep-0302"><strong>PEP 302</strong></a></dt>
<dd>New Import Hooks</dd>
<dt><a class="reference internal" href="../pkgutil/index.html#module-pkgutil" title="pkgutil: Package utilities"><tt class="xref py py-mod docutils literal"><span class="pre">pkgutil</span></tt></a></dt>
<dd>Provides a more generic interface to <tt class="xref py py-func docutils literal"><span class="pre">get_data()</span></tt>.</dd>
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