IIS and Url-Rewrite: rewriting the outbound response contents

Your final web.config is missing some of the things that the body of the text defines. For example, for the custom Form Action.

I took your advice re differentiating the ResponseIs* preConditions.

My web.config is below, redacted slightly

So what happens to the usual things like normal A and IMG and SCRIPT? Do they get rewritten with these rules or do I need to explicitly handle them?

<rewrite>
            <rules>
                <rule name="ReverseProxyInboundRule1" stopProcessing="true">
                    <match url="(.*)" />
                    <action type="Rewrite" url="http://mysite/{R:1}" logRewrittenUrl="true" />
                    <serverVariables>
                        <set name="HTTP_X_ORIGINAL_ACCEPT_ENCODING" value="{HTTP_ACCEPT_ENCODING}" />
                        <set name="HTTP_ACCEPT_ENCODING" value="" />
                    </serverVariables>
                </rule>
            </rules>
            <outboundRules>
                <rule name="ReverseProxyOutboundRule1" preCondition="ResponseIsTextHtml" stopProcessing="false">
                    <match filterByTags="None" pattern="^http(s)?://mysite/(.*)" />
                    <action type="Rewrite" value="http{R:1}://theirsite/{R:2}" />
                </rule>
                <rule name="RestoreAcceptEncoding" preCondition="NeedsRestoringAcceptEncoding">
                    <match serverVariable="HTTP_ACCEPT_ENCODING" pattern="^(.*)" />
                    <action type="Rewrite" value="{HTTP_X_ORIGINAL_ACCEPT_ENCODING}" />
                </rule>
                <rule name="CustomAnchorHref" preCondition="ResponseIsTextAnything">
                    <match pattern="href=(.*?)https://mysite/(.*?)\s" />
                    <action type="Rewrite" value="href={R:1}https://theirsite/{R:2} " />
                </rule>
                <rule name="CustomFormAction" preCondition="ResponseIsTextAnything">
                    <match pattern="action=(.*?)https://mysite/(.*?)\\" />
                    <action type="Rewrite" value="action={R:1}https://theirsite/{R:2}\" />
                </rule>
                <preConditions>
                    <preCondition name="ResponseIsTextHtml">
                        <add input="{RESPONSE_CONTENT_TYPE}" pattern="^text/html" />
                    </preCondition>
                    <preCondition name="ResponseIsTextAnything">
                        <add input="{RESPONSE_CONTENT_TYPE}" pattern="^text/(.+)" />
                    </preCondition>
                    <preCondition name="NeedsRestoringAcceptEncoding">
                        <add input="{HTTP_X_ORIGINAL_ACCEPT_ENCODING}" pattern=".*" />
                    </preCondition>
                </preConditions>
            </outboundRules>
        </rewrite>