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<H3><A NAME="SECTION0014222000000000000000">
12.2.2.2 Parser class API</A>
</H3>

<P>
The <tt class="class">Parser</tt> provides an API that can be used to parse a message when
the complete contents of the message are available in a string or file.  The
<tt class="module">email.Parser</tt> module also provides a second class, called
<tt class="class">HeaderParser</tt> which can be used if you're only interested in
the headers of the message. <tt class="class">HeaderParser</tt> can be much faster in
these situations, since it does not attempt to parse the message body,
instead setting the payload to the raw body as a string.
<tt class="class">HeaderParser</tt> has the same API as the <tt class="class">Parser</tt> class.

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><span class="typelabel">class</span>&nbsp;<tt id='l2h-3879' xml:id='l2h-3879' class="class">Parser</tt></b>(</nobr></td>
  <td><var></var><big>[</big><var>_class</var><big>[</big><var>, strict</var><big>]</big><var></var><big>]</big><var></var>)</td></tr></table></dt>
<dd>
The constructor for the <tt class="class">Parser</tt> class takes an optional
argument <var>_class</var>.  This must be a callable factory (such as a
function or a class), and it is used whenever a sub-message object
needs to be created.  It defaults to <tt class="class">Message</tt> (see
<tt class="module"><a href="module-email.Message.html">email.Message</a></tt>).  The factory will be called without
arguments.

<P>
The optional <var>strict</var> flag is ignored.  <div class="versionnote"><b>Deprecated since release 2.4.</b>
Because the
<tt class="class">Parser</tt> class is a backward compatible API wrapper around the
new-in-Python 2.4 <tt class="class">FeedParser</tt>, <em>all</em> parsing is effectively
non-strict.  You should simply stop passing a <var>strict</var> flag to the
<tt class="class">Parser</tt> constructor.</div><p></p>

<P>

<span class="versionnote">Changed in version 2.2.2:
The <var>strict</var> flag was added.</span>

<span class="versionnote">Changed in version 2.4:
The <var>strict</var> flag was deprecated.</span>

</dl>

<P>
The other public <tt class="class">Parser</tt> methods are:

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-3880' xml:id='l2h-3880' class="method">parse</tt></b>(</nobr></td>
  <td><var>fp</var><big>[</big><var>, headersonly</var><big>]</big><var></var>)</td></tr></table></dt>
<dd>
Read all the data from the file-like object <var>fp</var>, parse the
resulting text, and return the root message object.  <var>fp</var> must
support both the <tt class="method">readline()</tt> and the <tt class="method">read()</tt> methods
on file-like objects.

<P>
The text contained in <var>fp</var> must be formatted as a block of <a class="rfc" id='rfcref-90842' xml:id='rfcref-90842'
href="http://www.faqs.org/rfcs/rfc2822.html">RFC 2822</a>
style headers and header continuation lines, optionally preceded by a
envelope header.  The header block is terminated either by the
end of the data or by a blank line.  Following the header block is the
body of the message (which may contain MIME-encoded subparts).

<P>
Optional <var>headersonly</var> is as with the <tt class="method">parse()</tt> method.

<P>

<span class="versionnote">Changed in version 2.2.2:
The <var>headersonly</var> flag was added.</span>

</dl>

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-3881' xml:id='l2h-3881' class="method">parsestr</tt></b>(</nobr></td>
  <td><var>text</var><big>[</big><var>, headersonly</var><big>]</big><var></var>)</td></tr></table></dt>
<dd>
Similar to the <tt class="method">parse()</tt> method, except it takes a string
object instead of a file-like object.  Calling this method on a string
is exactly equivalent to wrapping <var>text</var> in a <tt class="class">StringIO</tt>
instance first and calling <tt class="method">parse()</tt>.

<P>
Optional <var>headersonly</var> is a flag specifying whether to stop
parsing after reading the headers or not.  The default is <code>False</code>,
meaning it parses the entire contents of the file.

<P>

<span class="versionnote">Changed in version 2.2.2:
The <var>headersonly</var> flag was added.</span>

</dl>

<P>
Since creating a message object structure from a string or a file
object is such a common task, two functions are provided as a
convenience.  They are available in the top-level <tt class="module">email</tt>
package namespace.

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-3882' xml:id='l2h-3882' class="function">message_from_string</tt></b>(</nobr></td>
  <td><var>s</var><big>[</big><var>, _class</var><big>[</big><var>, strict</var><big>]</big><var></var><big>]</big><var></var>)</td></tr></table></dt>
<dd>
Return a message object structure from a string.  This is exactly
equivalent to <code>Parser().parsestr(s)</code>.  Optional <var>_class</var> and
<var>strict</var> are interpreted as with the <tt class="class">Parser</tt> class constructor.

<P>

<span class="versionnote">Changed in version 2.2.2:
The <var>strict</var> flag was added.</span>

</dl>

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-3883' xml:id='l2h-3883' class="function">message_from_file</tt></b>(</nobr></td>
  <td><var>fp</var><big>[</big><var>, _class</var><big>[</big><var>, strict</var><big>]</big><var></var><big>]</big><var></var>)</td></tr></table></dt>
<dd>
Return a message object structure tree from an open file object.  This
is exactly equivalent to <code>Parser().parse(fp)</code>.  Optional
<var>_class</var> and <var>strict</var> are interpreted as with the
<tt class="class">Parser</tt> class constructor.

<P>

<span class="versionnote">Changed in version 2.2.2:
The <var>strict</var> flag was added.</span>

</dl>

<P>
Here's an example of how you might use this at an interactive Python
prompt:

<P>
<div class="verbatim"><pre>
&gt;&gt;&gt; import email
&gt;&gt;&gt; msg = email.message_from_string(myString)
</pre></div>

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<span class="release-info">Release 2.4.2, documentation updated on 28 September 2005.</span>
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