ASP.NET Development Server or Localhost IIS?

问题:

Currently our dev team set up all the websites they're working on in IIS on their local machine. We're thinking of switching to using the built in ASP.NET development server instead.

Is this a good idea? What are the pros / cons of using the ASP.NET dev Server? Are there any gotchas we should be aware of?

Thanks.

NB: Running on Win XP / IIS 5 / VS2005

Edit:

Didn't realise it was called Cassini.. More answers for Cassini v IIS here.

回答1:

There is nothing that the ASP.NET Dev WebService can do that IIS can't (You can set breakpoints etc, just attach the VS debugger to the ASP.NET runtime).

However, the ASP.NET Dev WebService does not represent a true production environment, and as such you can get caught by gotchas that you wouldn't expect when you deploy to production.

Because of that, I mandate that all development is done using IIS on a local machine. It doesn't take much work to configure a site in IIS.

回答2:

It's a very good idea. Here are some reasons for:

• You no longer need admin access to your machine for web development (it can still be helpful).
• It's much easier to test a quick change and continue work, and faster iteration cycles are good.
• It can simplify setup and deployment of your development environments.
• The XP version of IIS has limitation that are not present in the Server version that Cassini side-steps.

The only argument I know against is that there are a couple very rare edge cases where the Cassini built-in server doesn't exactly mimic IIS because you're using odd port numbers. I doubt you'll ever run into them, and using Cassini as the primary dev environment does not preclude developers from also having access to IIS on the machine. In fact, my preferred setup is Cassini first for most small work, then deploy to my local IIS for more in-depth testing before moving code back to the shared source repository.

[Edit]
Forgot about url re-writing. You do need IIS for that. And an example of a limitation of the built-in XP IIS is that you are limited to one site in XP (can have multiple applications, but that's a different thing).

回答3:

I had to switch (back) to IIS for one project, because I needed to set some virtual directories which is not possible on the ASP.NET Development Web Server.

回答4:

As I stated here: https://stackoverflow.com/questions/103785/what-are-the-disadvantages-of-using-cassini-instead-of-iis your developers need to be aware that Cassini runs as the local user, which is typically an admin account for developers. The development will be able to access any file or resource that their account can, which is quite different from what they will see on an IIS 6 server.

The other thing that's a pretty big gotcha is debugging web services is much easier using IIS and vdirs rather than separate Cassini instances.

回答5:

I know at one point I had an issue with Authentication not working as expected on Cassini (built in development server)

Also, if you need to test things like ISAPI plugins (a re-writer for example) I'm not sure how that's done on Cassini.

The constantly changing port is also rather disconcerting to me. Also, for each web project in your solution it fires up another instance of a Casini server, and each one takes anywhere from 20 to 50 MB of memory.

I use IIS all the time, it's pretty easy to setup, and you guys are already doing that...

回答6:

I've used both methods and I prefer having IIS locally vs. using the built-in server. At very least you're more consistent with the final deployment setup.

回答7:

Also, when using IIS 5.1, be sure to get JetStat IIS Admin, it adds functionality that is disabled out of the box on IIS 5, such as being able to setup multiple sites.

回答8:

I have run into the following limitations with the asp.net dev server:

1. does not support virtual dirs. If you need them in your app, IIS seems to be your only choice

2. Classic asp pages dont run in dev server. So if you have a mixed web app (like I have at my client right now), IIS seems to be the solution

3. If you need an admin UI to configure settings, IIS works better

Of course IIS requires that you be a local admin.

回答9:

Another distinction I noticed is that Cassini runs as a 32-bit process and you have no control over it, whereas you can control the application pool of your IIS app to disallow 32-bit (assuming your IIS is running on a 64-bit server). This becomes especially important if your web application is going to call APIs in 64-bit processes such as SharePoint Foundation/Server 2010. When you debug your web app with Cassini as your debug server, you'll get "The Web application at url could not be found. Verify that you have typed the URL correctly" type errors when instantiating objects. If you debug using IIS with the app running in an app pool that runs as 64-bit with an identity that allows access to sharepoint database then you'll be able to debug properly.

回答10:

In VS12 the development server is way slow, takes a few seconds to download a 2kbyte file. This did not happen in vs10. When you have a bunch of jquery files and css this is a real problem. Also every page requeries all the css/js files. Very very slow regression testing.

回答11:

The main issue I've run into with the dev server is SerializationExceptions with custom security principals stored on the thread context. Details here.