Page History

...

• $prefix - This function enhances the $frontend function just like $import but gives the ability to choose a prefix (unlike a constant @import in case of $import) e.g.

  Code Block
  <rewrite template="{$prefix[&#39;,url]}/zeppelin/components/{**}?{**}"/>

  • $prefix[PREFIX, url] - Adds a supplied PREFIX to the frontend url, e.g. in above case the rewritten url would be 'https://localhost:8443/

    zeppelin/components/navbar/navbar.html?v=1498928142479' (mind the single tick ' )

Rules Filter

Sometimes you want the ability to rewrite the *.js, *.css and other non-html pages. FIlters are a way to rewrite these non-html files. FIlters are based on the content-type of the page.

These are the different types of filters that are supported by Apache Knox.

There are three declarations needed for filters, 

1. Filter declaration, the Content-Type and the pattern to apply the filter to - rewrite.xml
2. Rewrite rule to apply to matched patter - rewrite.xml
3. Path to apply the filter to and to be applied on response or request body - service.xml

The is an example of Filters used in Proxying Zeppelin UI, the relevant code snippets in rewrite.xml and service.xml files are:

  <!-- Filters -->
  <rule dir="OUT" name="ZEPPELINUI/zeppelin/outbound/javascript/filter/app/home" >
    <rewrite template="{$frontend[path]}/zeppelin/app/home/home.html"/>
  </rule>
  
  <rule dir="OUT" name="ZEPPELINUI/zeppelin/outbound/javascript/filter/app/notebook" >
    <rewrite template="{$frontend[path]}/zeppelin/app/notebook/notebook.html"/>
  </rule>
  
  <rule dir="OUT" name="ZEPPELINUI/zeppelin/outbound/javascript/filter/app/jobmanager" >
    <rewrite template="{$frontend[path]}/zeppelin/app/jobmanager/jobmanager.html"/>
  </rule>
 
  <filter name="ZEPPELINUI/zeppelin/outbound/javascript/filter">
          <content type="application/javascript">
              <apply path="app/home/home.html" rule="ZEPPELINUI/zeppelin/outbound/javascript/filter/app/home"/>
              <apply path="app/notebook/notebook.html" rule="ZEPPELINUI/zeppelin/outbound/javascript/filter/app/notebook"/>
              <apply path="app/jobmanager/jobmanager.html" rule="ZEPPELINUI/zeppelin/outbound/javascript/filter/app/jobmanager"/>
          </content>
  </filter>

    <!-- Filter -->
    <route path="/zeppelin/scripts/**">
      <rewrite apply="ZEPPELINUI/zeppelin/outbound/javascript/filter" to="response.body"/>
    </route>

A good example of how to use the filters is Proxying a UI using Knox.

Following are the different types of Content-Types supported by Apache Knox.

Form URL Rewrite Filter

Uses Content-Type "application/x-www-form-urlencoded", "*/x-www-form-urlencoded"

HTML URL Rewrite Filter

Uses Content-Type "application/html", "text/html", "*/html"

JavaScript URL Rewrite Filter

Uses Content-Type "application/javascript", "text/javascript", "*/javascript", "application/x-javascript", "text/x-javascript", "*/x-javascript"

JSON URL Rewrite FIlter

Uses Content-Type "application/json", "text/json", "*/json"

XML URL Rewrite FIlter

Uses Content-Type "application/xml", "text/xml", "*/xml"

Pattern Matching

Pattern matching for Knox unfortunately does not match the standard Regex format. Following is how pattern matching works in some of the cases

...