1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>DBus Support — PyQt 4.11.2 Reference Guide</title>
<link rel="stylesheet" href="_static/default.css" type="text/css" />
<link rel="stylesheet" href="_static/pygments.css" type="text/css" />
<script type="text/javascript">
var DOCUMENTATION_OPTIONS = {
URL_ROOT: './',
VERSION: '4.11.2',
COLLAPSE_INDEX: false,
FILE_SUFFIX: '.html',
HAS_SOURCE: true
};
</script>
<script type="text/javascript" src="_static/jquery.js"></script>
<script type="text/javascript" src="_static/underscore.js"></script>
<script type="text/javascript" src="_static/doctools.js"></script>
<link rel="shortcut icon" href="_static/logo_tn.ico"/>
<link rel="top" title="PyQt 4.11.2 Reference Guide" href="index.html" />
<link rel="next" title="Selecting Incompatible APIs" href="incompatible_apis.html" />
<link rel="prev" title="Internationalisation of PyQt4 Applications" href="i18n.html" />
</head>
<body>
<div class="related">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="genindex.html" title="General Index"
accesskey="I">index</a></li>
<li class="right" >
<a href="py-modindex.html" title="Python Module Index"
>modules</a> |</li>
<li class="right" >
<a href="incompatible_apis.html" title="Selecting Incompatible APIs"
accesskey="N">next</a> |</li>
<li class="right" >
<a href="i18n.html" title="Internationalisation of PyQt4 Applications"
accesskey="P">previous</a> |</li>
<li><a href="index.html">PyQt 4.11.2 Reference Guide</a> »</li>
</ul>
</div>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body">
<div class="section" id="dbus-support">
<span id="ref-dbus"></span><h1>DBus Support<a class="headerlink" href="#dbus-support" title="Permalink to this headline">¶</a></h1>
<p>PyQt4 provides two different modules that implement support for DBus. The
<tt class="xref py py-mod docutils literal"><span class="pre">QtDBus</span></tt> module provides wrappers for the standard Qt DBus classes.
The <tt class="xref py py-mod docutils literal"><span class="pre">dbus.mainloop.qt</span></tt> module add support for the Qt event loop to the
standard <tt class="docutils literal"><span class="pre">dbus-python</span></tt> Python module.</p>
<div class="section" id="qtdbus">
<h2><tt class="xref py py-mod docutils literal"><span class="pre">QtDBus</span></tt><a class="headerlink" href="#qtdbus" title="Permalink to this headline">¶</a></h2>
<p>The <tt class="xref py py-mod docutils literal"><span class="pre">QtDBus</span></tt> module is used in a similar way to the C++ library it
wraps. The main difference is in the way it supports the demarshalling of
DBus structures. C++ relies on the template-based registration of types using
<tt class="docutils literal"><span class="pre">qDBusRegisterMetaType()</span></tt> which isn’t possible from Python. Instead a slot
that accepts a DBus structure in an argument should specify a slot with a
single <tt class="xref py py-class docutils literal"><span class="pre">QDBusMessage</span></tt> argument. The implementation of the
slot should then extract the arguments from the message using its
<tt class="xref py py-meth docutils literal"><span class="pre">arguments()</span></tt> method.</p>
<p>For example, say we have a DBus method called <tt class="docutils literal"><span class="pre">setColors()</span></tt> that has a single
argument that is an array of structures of three integers (red, green and
blue). The DBus signature of the argument would then be <tt class="docutils literal"><span class="pre">a(iii)</span></tt>. In C++
you would typically define a class to hold the red, green and blue values and
so your code would include the following (incomplete) fragments:</p>
<div class="highlight-python"><div class="highlight"><pre>struct Color
{
int red;
int green;
int blue;
};
Q_DECLARE_METATYPE(Color)
qDBusRegisterMetaType<Color>();
class ServerAdaptor : public QDBusAbstractAdaptor
{
Q_OBJECT
public slots:
void setColors(QList<const Color &> colors);
};
</pre></div>
</div>
<p>The Python version is, of course, much simpler:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="k">class</span> <span class="nc">ServerAdaptor</span><span class="p">(</span><span class="n">QDBusAbstractAdaptor</span><span class="p">):</span>
<span class="nd">@pyqtSlot</span><span class="p">(</span><span class="n">QDBusMessage</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">setColors</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">message</span><span class="p">):</span>
<span class="c"># Get the single argument.</span>
<span class="n">colors</span> <span class="o">=</span> <span class="n">message</span><span class="o">.</span><span class="n">arguments</span><span class="p">()[</span><span class="mi">0</span><span class="p">]</span>
<span class="c"># The argument will be a list of 3-tuples of ints.</span>
<span class="k">for</span> <span class="n">red</span><span class="p">,</span> <span class="n">green</span><span class="p">,</span> <span class="n">blue</span> <span class="ow">in</span> <span class="n">colors</span><span class="p">:</span>
<span class="k">print</span><span class="p">(</span><span class="s">"RGB:"</span><span class="p">,</span> <span class="n">red</span><span class="p">,</span> <span class="n">green</span><span class="p">,</span> <span class="n">blue</span><span class="p">)</span>
</pre></div>
</div>
<p>Note that this technique can be used for arguments of any type, it is only
require if DBus structures are involved.</p>
</div>
<div class="section" id="dbus-mainloop-qt">
<h2><tt class="xref py py-mod docutils literal"><span class="pre">dbus.mainloop.qt</span></tt><a class="headerlink" href="#dbus-mainloop-qt" title="Permalink to this headline">¶</a></h2>
<p>The <tt class="xref py py-mod docutils literal"><span class="pre">dbus.mainloop.qt</span></tt> module provides support for the Qt event loop to
<tt class="docutils literal"><span class="pre">dbus-python</span></tt>. The module’s API is almost identical to that of the
<tt class="xref py py-mod docutils literal"><span class="pre">dbus.mainloop.glib</span></tt> modules that provides support for the GLib event
loop.</p>
<p>The <tt class="xref py py-mod docutils literal"><span class="pre">dbus.mainloop.qt</span></tt> module contains the following function.</p>
<dl class="function">
<dt id="DBusQtMainLoop">
<tt class="descname">DBusQtMainLoop</tt><big>(</big><em>set_as_default=False</em><big>)</big><a class="headerlink" href="#DBusQtMainLoop" title="Permalink to this definition">¶</a></dt>
<dd><p>Create a <tt class="docutils literal"><span class="pre">dbus.mainloop.NativeMainLoop</span></tt> object that uses the the Qt event
loop.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>set_as_default</strong> – is optionally set to make the main loop instance the default for all
new Connection and Bus instances. It may only be specified as a
keyword argument, and not as a positional argument.</td>
</tr>
</tbody>
</table>
</dd></dl>
<p>The following code fragment is all that is normally needed to set up the
standard <tt class="docutils literal"><span class="pre">dbus-python</span></tt> language bindings package to be used with PyQt4:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">dbus.mainloop.qt</span> <span class="kn">import</span> <span class="n">DBusQtMainLoop</span>
<span class="n">DBusQtMainLoop</span><span class="p">(</span><span class="n">set_as_default</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span>
</pre></div>
</div>
</div>
</div>
</div>
</div>
</div>
<div class="sphinxsidebar">
<div class="sphinxsidebarwrapper">
<p class="logo"><a href="index.html">
<img class="logo" src="_static/logo.png" alt="Logo"/>
</a></p>
<h3><a href="index.html">Table Of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">DBus Support</a><ul>
<li><a class="reference internal" href="#qtdbus"><tt class="docutils literal"><span class="pre">QtDBus</span></tt></a></li>
<li><a class="reference internal" href="#dbus-mainloop-qt"><tt class="docutils literal"><span class="pre">dbus.mainloop.qt</span></tt></a></li>
</ul>
</li>
</ul>
<h4>Previous topic</h4>
<p class="topless"><a href="i18n.html"
title="previous chapter">Internationalisation of PyQt4 Applications</a></p>
<h4>Next topic</h4>
<p class="topless"><a href="incompatible_apis.html"
title="next chapter">Selecting Incompatible APIs</a></p>
<div id="searchbox" style="display: none">
<h3>Quick search</h3>
<form class="search" action="search.html" method="get">
<input type="text" name="q" />
<input type="submit" value="Go" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
<p class="searchtip" style="font-size: 90%">
Enter search terms or a module, class or function name.
</p>
</div>
<script type="text/javascript">$('#searchbox').show(0);</script>
</div>
</div>
<div class="clearer"></div>
</div>
<div class="related">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="genindex.html" title="General Index"
>index</a></li>
<li class="right" >
<a href="py-modindex.html" title="Python Module Index"
>modules</a> |</li>
<li class="right" >
<a href="incompatible_apis.html" title="Selecting Incompatible APIs"
>next</a> |</li>
<li class="right" >
<a href="i18n.html" title="Internationalisation of PyQt4 Applications"
>previous</a> |</li>
<li><a href="index.html">PyQt 4.11.2 Reference Guide</a> »</li>
</ul>
</div>
<div class="footer">
© Copyright 2014 Riverbank Computing Limited.
Created using <a href="http://sphinx-doc.org/">Sphinx</a> 1.2.2.
</div>
</body>
</html>
|
