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<LI><A href="node7.html#SECTION007100000000000000000">6.1 Introduction</a>
<LI><A href="node7.html#SECTION007200000000000000000">6.2 How does it work ?</a>
<LI><A href="node7.html#SECTION007300000000000000000">6.3 How to use it ?</a>
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<H1><A NAME="SECTION007000000000000000000">
6. How to use the hotReload feature of CherryPy</A>
</H1>
<H1><A NAME="SECTION007100000000000000000">
6.1 Introduction</A>
</H1>
The development cycle of a CherryPy web site is the same as the development cycle of a regular software:
<UL>
<LI>Write source files
</LI>
<LI>Compile them
</LI>
<LI>If compiler generated some errors, fix source files and try to compile again
</LI>
<LI>Once compilation was OK, stop running executable and restart the newly generated executable
</LI>
<LI>If we find some bugs or we want some new features, modify the source files and go back to the compilation stage
</LI>
</UL>
<P>
The compilation process is usually pretty fast (if you have a "decent" computer).
<P>
But what if the CherryPy server has a long initialization process (maybe it needs to connect to several ressources,
like databases, or it needs to precompute some data). All this work is usually done in the <var>initServer</var> special
function. If this initialization takes a lot of time, having to stop and restart the server everytime you make
a change is really a loss of time while developing your web site.
<P>
This is where the <var>hotReload</var> feature comes in. It allows you to refresh your code without having to stop
the server.
<P>
<H1><A NAME="SECTION007200000000000000000">
6.2 How does it work ?</A>
</H1>
When it receives a <var>hotReload</var> request, the server will just read its source code again, updating all the CherryClasses
code and recreating new CherryClasses instances with the new code. It will not execute <var>initServer</var> again. Instead,
it will execute <var>hotReloadInitServer</var> if any.
<P>
<H1><A NAME="SECTION007300000000000000000">
6.3 How to use it ?</A>
</H1>
<P>
The <var>hotReload</var> feature is enabled in the executable when the file is compiled with the <var>-D</var> flag (debug mode).
<P>
To send a <var>hotReload</var> request to a running CherryPy server, just use the little script called <span class="file">cherryhotreload.py</span>
provided with the distribution.
<P>
Let's take a practical example that shows how to use the <var>hotReload</var> feature:
<UL>
<LI>You write a first version of your source file called <span class="file">Root.cpy</span>
</LI>
<LI>You compile your source file in debug mode:
<div class="verbatim"><pre>
python ../cherrypy.py -D Root.cpy
</pre></div>
</LI>
<LI>In a window, you start the CherryPy server:
<div class="verbatim"><pre>
python RootServer.py
</pre></div>
</LI>
<LI>Now you have a running CherryPy server
</LI>
<LI>You realize that you want to change something in your code
</LI>
<LI>Just update your source file and recompile it (in another window, since the server is still running in the first window)
</LI>
<LI>Send the <var>hotReload</var> request to the running server to tell it to refresh its code:
<div class="verbatim"><pre>
python cherryhotreload.py localhost:8080
</pre></div>
(This assumes that the server is running on localhost:8080. Of course, you have to adapt it for your own configuration)
</LI>
<LI>In the window where the server is running, you see a message saying that it has performed the <var>hotReload</var>
</LI>
</UL>
Warning: After a <var>hotReload</var>, the line numbers that the python interpreter might give you in case of an error
may not match your source file. This happens if you add or remove lines of code before the <var>hotReload</var>
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<span class="release-info">Release 0.10, documentation updated on 19 March 2004.</span>
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