Deploying Express 4.x app to Windows Azure - node.js

Question

The new version of Express separates the modules from the "server" file. It now lives in /bin/www and I'd prefer to keep this convention if possible.
In the package.json file, the "start" script clearly points to the right place, but this is seemingly ignored by Azure.
How do I deploy an Express 4.x app without having a server.js file in the root directory? All I need to do is make it automatically call node ./bin/www instead of node server.js. Is there another root configuration file I can add specific to the cloud host (Azure?) This is how I got this working in Heroku, etc.

Answer 1

updated answer
The Azure team has since fixed this internally. A newly deployed express 4 app should work just fine on Azure Websites without any additional changes.
original answer
I'll start with the tl;dr. Create a web.config file in the root of your application and use this xml.
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<system.webServer>
<!--
By default IIS will block requests going to the bin directory for security reasons.
We need to disable this since that's where Express has put the application entry point.
-->
<security>
<requestFiltering>
<hiddenSegments>
<remove segment="bin" />
</hiddenSegments>
</requestFiltering>
</security>
<handlers>
<!-- Indicates that the www file is a node.js entry point -->
<add name="iisnode" path="/bin/www" verb="*" modules="iisnode"/>
</handlers>
<rewrite>
<rules>
<rule name="NodeInspector" patternSyntax="ECMAScript" stopProcessing="true">
<match url="^bin\/www\/debug[\/]?" />
</rule>
<!--
First we consider whether the incoming URL matches a physical file in the /public folder.
This means IIS will handle your static resources, and you don't have to use express.static
-->
<rule name="StaticContent">
<action type="Rewrite" url="public{REQUEST_URI}"/>
</rule>
<!-- All other URLs are mapped to the node.js entry point -->
<rule name="DynamicContent">
<conditions>
<add input="{REQUEST_FILENAME}" matchType="IsFile" negate="True"/>
</conditions>
<action type="Rewrite" url="/bin/www"/>
</rule>
</rules>
</rewrite>
</system.webServer>
</configuration>
This is a bit of a mess and took a while to track down. I really wish it was smart enough to look at package.json, but this is what we have to deal with for now. Normally Azure determine if it is a Node application by checking for an app.js or server.js file. If it finds that file, it will automatically create a web.config file very similar to what is above. In this case, it will detect app.js, but unlike 99% of other node applications, that's not actually the entry point. What we have to do is change the entry point to /bin/www like shown above.
The other issue we run into is that by default IIS blocks requests to the bin folder for security reasons. We can either rename the express bin folder, or tell IIS to get over it. That's what the hiddenSegments part of the xml file is for.