Introduction
The Internet Information Services 7 (IIS 7) URL Rewrite Module provides rule importing functionality that greatly simplifies the process of converting Apache mod_rewrite rules to IIS URL rewrite rules. This walkthrough guides you through the process of importing several mod_rewrite rules into an IIS configuration file by using the Import Rules feature provided in the URL Rewrite Module.
Set Up a Walkthrough Scenario
To test that the rules that are converted from mod_rewrite work correctly, you can implement a common scenario of enforcing canonical host names for the Web site. You can force the use of www.mysite.com instead of mysite.com, so when a request is made using a host name other than www.mysite.com, you redirect the request to a canonical hostname.
1. Start IIS Manager, and then click Default Web Site.
2. In the Actions pane, click on Bindings, and add a new http binding for port 8088.
Figure 1: Add a new binding
3. Using Notepad, open %SystemDrive%\windows\system32\drivers\etc\hosts and add the two following lines at the end:
127.0.0.1 www_mysite_com
127.0.0.1 mysite_com
Note you are using “_” instead of “.” for domain separators. This is to prevent a Web browser from trying to resolve the domain name by using a Domain Name System (DNS) server.
4. Verify that the host names were setup correctly by opening a Web browser and going to the sites http://www_mysite_com/iisstart.htm and to http://mysite_com/iisstart.htm.
Convert mod_rewrite Rules
The Apache mod_rewrite rules to use for enforcing canonical host names are:
#For sites running on a port other than 80:
RewriteCond %{HTTP_HOST} !^www_mysite_com [NC]
RewriteCond %{HTTP_HOST} !^$
RewriteCond %{SERVER_PORT} !^80$
RewriteRule ^/(.*) http://www_mysite_com:%{SERVER_PORT}/$1 [L,R]
#And for a site running on port 80
RewriteCond %{HTTP_HOST} !^www_mysite_com [NC]
RewriteCond %{HTTP_HOST} !^$
RewriteRule ^/(.*) http://www_mysite_com/$1 [L,R]
To convert these rules to IIS URL rewrite–specific format, start IIS Manager, and then click URL Rewrite.
Figure 2: Click URL Rewrite
Paste the mod_rewrite rules into the Rewrite rules text box.
Figure 3: Rules to import
The Tree View in the Converted rules group box shows the result of the conversion. You can also switch to the XML View to see how the rules are stored in the Web.config file.
Figure 4: Converted rules
If you switch back to Tree View and select a node in the Tree View, the corresponding mod_rewrite rule directive in the Rewrite rules text box is highlighted.
Figure 5: Tree view
Note that during the rules conversion the rules were assigned default names. You can change the names to convey some meaningful information about what the rule does. To rename a rule, select the rule in the Tree View, and then right-click to view a context menu.
Figure 6: Rename
Change the name of the first rule from ImportedRule1 to Redirect to www_mysite_com:non-80. Change the name of the second rule from ImportedRule2 to Redirect to www_mysite_com:80.
Click Apply to save the converted rules to the Web.config file, and then click Back to rules.
Figure 7: Back to Rules
Test the Converted Rules
To test that the rules imported from mod_rewrite format work correctly, open a Web browser, and go to either one of the following URLs:
http://localhost/iisstart.htm
http://mysite_com/iisstart.htm
In both cases, the Web browser is redirected to http://www_mysite_com/iisstart.htm.
Also, if you try either of these URLs:
http://localhost:8088/iisstart.htm
http://mysite_com:8088/iisstart.htm
The Web browser gets redirected to http://www_mysite_com:8088/iisstart.htm.
Note that the rules that were imported from mod_rewrite enabled the enforcement of canonical host names for a Web site. You can see other examples of Apache mod_rewrite rules.
Disclaimer
IMPORTANT - The URL Rewrite Module tries to convert Apache mod_rewrite rules to functionally equivalent IIS URL rewrite rules. However, not all mod_rewrite rules can be converted because of architectural differences between Apache and IIS. It is highly recommended that you study a mod_rewrite rule set until you understand its functionality before you begin the conversion process. Then, after converting to IIS URL rewrite rules, review and test the result of the conversion to make sure that the corresponding IIS rewrite rule set provides the same URL rewriting logic.
Note that only rules that follow Apache mod_rewrite syntax can be converted. Any other formats of rewrite rules (for example, ISAPI_Rewrite, Ionic ISAPI Rewrite, IISRewrite, and others) are not recognized or are converted incorrectly.
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