[jira] [Work logged] (KNOX-2931) Some special characters in the rewrite rule cannot be escaped

[ASF GitHub Bot (Jira)]

     [ 
https://issues.apache.org/jira/browse/KNOX-2931?focusedWorklogId=869110&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-869110
 ]

ASF GitHub Bot logged work on KNOX-2931:
----------------------------------------

                Author: ASF GitHub Bot
            Created on: 04/Jul/23 13:12
            Start Date: 04/Jul/23 13:12
    Worklog Time Spent: 10m 
      Work Description: zeroflag opened a new pull request, #769:
URL: https://github.com/apache/knox/pull/769

   ## What changes were proposed in this pull request?
   
   Ozone SCM UI uses placeholders such as `{{typestat.portval.toLowerCase()}}` 
in the HTML which are supposed to be replaced by JavaScript code. However this 
is the same syntax what knox uses for template variables. If no escaping is 
used knox will populate the the template variable with an empty string since it 
has no value.
   
   But escaping `{` didn't work originally in rewrite templates (so `\{x\}` 
resulted literally `\{x\}`).
   
   ## How was this patch tested?
   
   sandbox topology:
   
   ```xml
   <service>
       <role>OZONE-SCM</role>
       <url>http://localhost:1701</url>
   </service>
   ```
   
   service.xml
   
   ```xml
   <service role="OZONE-SCM" name="ozone-scm" version="1.2.0">
       <metadata>
           <type>UI</type>
           <context>/ozone-scm/index.html?host={{BACKEND_HOST}}</context>
           <shortDesc>OZONE SCM UI</shortDesc>
       </metadata>
       <routes>
           <route path="/ozone-scm/index.html">
               <rewrite apply="OZONE-SCM/ozone-scm/inbound/request" 
to="request.url"/>
               <rewrite apply="OZONE-SCM/ozone-scm/outbound/response" 
to="response.body"/>
           </route>
       </routes>
       <dispatch 
classname="org.apache.knox.gateway.dispatch.URLDecodingDispatch" 
ha-classname="org.apache.knox.gateway.dispatch.URLDecodingDispatch"/>
   </service>
   ````
   
   rewrite.xml
   
   ```xml
   <rules>
       <rule dir="IN" name="OZONE-SCM/ozone-scm/inbound/request" 
pattern="*://*:*/**/ozone-scm/{path=**}?host={host}?{**}">
           <rewrite template="{host}/{path=**}?{**}"/>
       </rule>
   
       <rule dir="OUT" name="OZONE-SCM/ozone-scm/outbound/datanode/address">
           <rewrite 
template="{gateway.url}/ozone-scm/datanode/index.html?host=\{\{typestat.portval.toLowerCase()\}\}://\{\{typestat.hostname\}\}:\{\{typestat.portno\}\}"/>
       </rule>
   
       <filter name="OZONE-SCM/ozone-scm/outbound/response">
           <content type="*/html">
               <apply 
path="\{\{typestat\.portval\.toLowerCase\(\)\}\}\:\/\/\{\{typestat\.hostname\}\}\:\{\{typestat\.portno\}\}"
 rule="OZONE-SCM/ozone-scm/outbound/datanode/address"/>
   
           </content>
       </filter>
   </rules>
   ```
   
   Http server to emulate the service
   
   ```smalltalk
   Teapot on
       GET: 'index.html' -> 
           '<a 
href="{{typestat.portval.toLowerCase()}}://{{typestat.hostname}}:{{typestat.portno}}">{{typestat.hostname}}</a>';
        start. 
   ```
   
   URL to check: 
   
   
https://localhost:8443/gateway/sandbox/ozone-scm/index.html?host=http://localhost:1701
   
   Result:
   
   ```html
   <a 
href="https://localhost:8443/gateway/sandbox/ozone-scm/datanode/index.html?host={{typestat.portval.toLowerCase()}}://{{typestat.hostname}}:{{typestat.portno}}">{{typestat.hostname}}</a>
   ```




Issue Time Tracking
-------------------

            Worklog Id:     (was: 869110)
    Remaining Estimate: 0h
            Time Spent: 10m

> Some special characters in the rewrite rule cannot be escaped
> -------------------------------------------------------------
>
>                 Key: KNOX-2931
>                 URL: https://issues.apache.org/jira/browse/KNOX-2931
>             Project: Apache Knox
>          Issue Type: Task
>            Reporter: Attila Magyar
>            Assignee: Attila Magyar
>            Priority: Major
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> HTML content:
> {code}
> <td><a 
> href="{{typestat.portval.toLowerCase()}}://{{typestat.hostname}}:{{typestat.portno}}"
>  target="_blank">{{typestat.hostname}}</a></td>
> {code}
> Rule:
> {code}
>   <rule dir="OUT" name="OZONE-SCM/ozone-scm/outbound/datanode/address">
>         <match 
> pattern="{{typestat.portval.toLowerCase()}}://{{typestat.hostname}}:{{typestat.portno}}"/>
>         <rewrite 
> template="{gateway.url}/ozone-scm/datanode/index.html?host={{typestat.portval.toLowerCase()}}://{{typestat.hostname}}:{{typestat.portno}}
>  "/>
>     </rule>
> {code}
> The goal is to prepend knox URL in front of the href and have:
> {code}
> https://KNOX/gateway/topology/service?host={{typestat.portval.toLowerCase()}}://{{typestat.hostname}}:{{typestat.portno}}
> {code}
> It seems that the {{ ... }} part is interpreted as a place holder and the 
> host part is completely omitted. 
> Interestingly adding a dummy space at the end solves it.
> cc: [~zitadombi]



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