Override Livesite Rendered Output

Hi All,
We are using TS 6.7.2 SP1 and LiveSite 3.1. At production environment we want to replace the src attributes of image files with another domain. (we want to replace img src="a.gif" as img src="http://test.domain/a.gif") Can we use post-controllers for this purpose? Or should we use another solution? Has anyone did something like this before?
Thanks

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vpatel

Post controllers execute after the response has been sent to the browser -- a little too late to manipulate it at this time.

I've done something similar with a great deal of success using a servlet filter. Look up "servlet filter" on google. This is a Java web application thing -- nothing LS specific.

cagatayk

Hi VPatel,
I have thought about using filter but since I need to override response everytime this can cause performance problems, isn't that right? Isn't there any OOTB solution that I can use?
Thanks

vpatel

Hi VPatel,
I have thought about using filter but since I need to override response everytime this can cause performance problems, isn't that right? Isn't there any OOTB solution that I can use?
Thanks

If you need to do this everytime then why would it matter? You are going to take a hit for however long your "post-rendered manipulation" takes anyway.

karel


if server == production
    domain = "servername.com"

<img src="$domain/$filename" />

AlexC

Which version of Teamsite/Livesite? You can create a custom page token that will do this for you.

Like

img src="$MYDOMAIN[img.png]"

The token code gets called to replace its content during rendering and you can add anything you want in there and contents between brakets get passed to your token so you can do whatever you need, even pass a parameter list if needed (the contents are passes as they are found so you can even do $MYDOMAIN[a,b,c,d] and you get "a,b,c,d" into the page token method and you simply write to the provided PrintWriter. See the page token customization part in the docs and let me know if you have questions.

cagatayk

We are using TS 6.7.2 SP1 and LiveSite 3.1. Where will I define this custom page token? It seems a good solution but I couldn't find a way to implement it.
Thanks

AlexC

How to add custom page tokens?

Requires: LiveSite 3.1 or newer

NOTE: This is an advanced topic and unless you understand how LiveSite pages are generated you should avoid implementing custom page tokens. Page tokens give you access to the actual stream sent to the browser and can cause unexpected behavior if not careful. Caveat Emptor!

Quick overview of how page tokens work

See class below and note that there are 3 main methods: init, preRender, render
1. Content is parsed for tokens
2. init() is called when the page token is first detected
3. Content is cached
4. preRender() is called for ALL tokens once the content is retrieved from the cache
5. render() is called to generate output for the Content

init is where you should do lookup that is true for all instances of that token on a given page or component, this is data that is a constant to the context and can be stored as a class variable. You should only set class members in this method to avoid race conditions. Some things that do not change in the context: url prefix, path of the page, component id, et. al.
preRender is where you should do token related work that may affect other tokens and needs to be processed before render is called (this is rare and this method is not often overridden).
render is where you should output the token content, you have access to the PrintWriter so be careful not to confuse browser rendering with scripts/tags that may affect the display. This is the most commonly overridden method if implementing a custom token.

Creating a page token class

NOTE: Please make sure you can't do what you need with existing tokens, you understand how tokens work, and how they will impact your site before creating new ones

See: com.interwoven.livesite.external.runtime.example.PageTokenVariableSample


public class PageTokenVariableSample extends PageTokenVariable
{
  /**
   * {@inheritDoc}
   */
  public void init(BaseRequestContext context)
  {
    super.init(context);

    // Do additional initialization here or remove this method if there if none
  }

  /**
   * {@inheritDoc}
   */
  public void preRender(BaseRequestContext context)
  {
    super.preRender(context);

    // Do additional pre-rendering here or remove this method if there if none
  }

  /**
   * {@inheritDoc}
   */
  public void render(PrintWriter writer, BaseRequestContext context) throws Exception
  {
    // Do some work here
    writer.print("$"+mTokenName+" has been replaced with this text");
  }
}

Registering the page token

See: rendering-resource-config.xml (you must add your custom token to ALL the existing configs for it to work, there is one for every context) NOTE: Do not add $ to the token name in spring config, it is assumed that all tokens start with $.

Add entry for your new token:

[html]

com.interwoven.livesite.external.runtime.example.PageTokenVariableSample

[/html]
to all rendering-resource-config.xml files:

[html]

com.interwoven.livesite.runtime.page.PageTokenVariableLivesiteAnalytics

com.interwoven.livesite.external.runtime.example.PageTokenVariableSample

[/html]

Using your new token

Add your token $SAMPLE_TOKEN[] to the component and preview/view.

cagatayk

Hi Alex,
Thanks for your great concern. One last question, where can I find rendering-resource-config.xml file? I searched within iw-home dir but couldn't find it.
Thanks

AlexC

Should be in httpd/content_center/livesite somewhere, it is in a 'conf' directory.

RonaldV

See the page token customization part in the docs and let me know if you have questions.

Alex,

can you point out which docs you refer to (name of the docs, chapter, page?). I can't find any reference in the ts_71_spdev.

josephbreese

Hi Alex, where can I find:
com.interwoven.livesite.external.runtime.example.PageTokenVariableSample

Can parameters be sent to a Custom Page Token in the same manner that one can sent parameters to a Page Token? If so, how does one gain access to the bean path sent to a Custom Page Token? There is no mention of this in any of the documentation I have (ts_72_spdev_en.pdf) so anything information you have is helpful.

I also want to echo RonaldV's request for documentation. If you mention a "doc" please specify what "doc" it is (internal only doesn't help the community) and what page number you found this information.

Thanks

Migrateduser

Only place I have found the code is explained in the comment


// Decompiled by Jad v1.5.8g. Copyright 2001 Pavel Kouznetsov.
// Jad home page: http://www.kpdus.com/jad.html
// Decompiler options: packimports(3) radix(10) lradix(10) 
// Source File Name:   PageTokenVariableSample.java

package com.interwoven.livesite.external.runtime.example;

import com.interwoven.livesite.runtime.impl.BaseRequestContext;
import com.interwoven.livesite.runtime.page.PageTokenVariable;
import java.io.PrintWriter;

public class PageTokenVariableSample extends PageTokenVariable
{

 public PageTokenVariableSample()
 {
 }

 public void init(BaseRequestContext context)
 {
  super.init(context);
 }

 public void preRender(BaseRequestContext context)
 {
  super.preRender(context);
 }

 public void render(PrintWriter writer, BaseRequestContext context)
  throws Exception
 {
  writer.print((new StringBuilder()).append("$").append(mTokenName).append(" has been replaced with this text").toString());
 }

 private static final long serialVersionUID = 1L;
}

Manual of trial/error/and this post is where I am getting info from. Oh, and JAD

josephbreese

CyberPop, thanks for the suggestion to decompile. I never thought of that approach. I was even skeptical that the decompiler would even work; I thought Interwoven would run their code through an obfuscater before compiling. The raw Java Code is the best documentation out there.

Thanks again.

AlexC

That file was supposed to be in impl.zip but the installed for 7.0 dropped that file, it was re-added in 7.2.1 release after the bug was fixed. Until then you can use JAD as see above.