( words)
This blog post primarily serves as a record for me but hopefully it may be useful to others too. Often, we need to develop rewrite rules that work with more than one web server – after all, Apache is by no means the be-all-and-end-all. In this case I’m going to focus on converting Apache .htaccess rules to IIS’s equivalent: web.config.
Before anything else, I recommend trying an automatic converter #lazy! Here’s some I found with a quick search:
If you’re able to setup IIS then you can also try Microsofts built-in converter: https://blogs.msdn.microsoft.com/azureossds/2015/04/23/converting-apache-htaccess-rules-to-iis-web-config-using-iis-manager-for-azure-websites/
Sadly in my case, I burst out in tears as none of the above worked. Conveniently that’s lead to this blog post.
Automation sucks, what now?
So the first step to producing a web.config file is you need to start with the below template:
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.webServer>
<rewrite>
<rules>
<-- Rules to come later... -->
</rules>
</rewrite>
</system.webServer>
</configuration>
Now we can start with the painful process of converting the rewrite rules to IIS’s xml-based format.
Rule Element
The <rule> element is the parent element that defines the match clause, conditions and action clause.
Attributes
The <rule> element can contain the following attributes:
| Name | Value Type | Description | Apache Equivalent |
|---|---|---|---|
| name | string | Human-readable name for the rule. | |
| stopProcessing | boolean | Whether this should be the last rule. | [L] |
Match Element
The <match> element is a child element of the <rule> and defines what the URL that should trigger the rule.
Attributes
The <match> element can contain the following attributes:
| Name | Value Type | Description | Apache Equivalent |
|---|---|---|---|
| url | string | Regular expression. | RewriteRule <url> <action> |
| ignoreCase | boolean | Whether this should be the last rule. | [NC] |
Conditions Element
The <conditions> element is a child element of the <rule> and defines the conditions under which the rule should be matched. I’m not sure if there are other values for logicalGrouping but I found I have to create separate rules if my conditions were particularly complex e.g. (x AND y) OR (a AND b)
Attributes
The <conditions> element can contain the following attributes:
| Name | Value Type | Description | Apache Equivalent |
|---|---|---|---|
| logicalGrouping | “MatchAll” or “MatchAny” | Whether to match all or any of the conditions. | [OR] |
Add Element
The <add> element is a child element of the <conditions> and defines each individual condition. This is equivalent to the RewriteCond directive in Apache.
Attributes
The <add> element can contain the following attributes:
| Name | Value Type | Description | Apache Equivalent |
|---|---|---|---|
| input | string | A server variable, a full list of supported variables can be found here. | RewriteCond <input> <pattern> |
| pattern | string | Regular expression. | RewriteCond <input> <pattern> |
Action Element
The <action> element is a child element of the <rule> and defines what should happen when a rule is matched. This is the equivalent of the RewriteRule directive in Apache.
Attributes
The <action> element can contain the following attributes:
| Name | Value Type | Description | Apache Equivalent |
|---|---|---|---|
| type | “Redirect” or “Rewrite” or “CustomResponse” or “AbortResponse” or “None” | Type of action. | Redirect = [R=301] AbortReponse = [F] |
| url | string | Whether this should be the last rule. | RewriteRule <pattern> <action> |
| appendQueryString | boolean | Whether the query string from the current URL should be preserved during substitution. Defaults to true. Only applicable to types: “Redirect” / “Rewrite” |
[QSA] |
| redirectType | “Permanent” or “Found” or “Temporary” | Only applicable to type: “Redirect” | [R=301] |
For more reference on IIS rewrite module please read: https://www.iis.net/learn/extensions/url-rewrite-module/url-rewrite-module-configuration-reference