Simulating ESI's when working on localhost

Question

I've started using ESI's in Akamai. They work perfectly fine when I've got a site running on int/test/stage/production environments which actually run through Akamai.

However, when we work locally on a PC, we tend to just use a simple jetty server and the site is not served using Akamai. This makes it a bit challenging to see if the work is correct without deploying our solution to Akamai.

Is there a way to simulate an ESI locally for development without using Akamai?

Answer 1

I could not find any official way of doing this, so I emulated a ESI on the server side as if it were an SSI, using an IF statement in our freemarker.

I use spring, freemarker + java to do this solution:

1) Create a macro that will decide to use the ESI or emulate it via SSI if running local (noescape may not be required, depends how you have set things up)

<#macro esi url>
  <#if esiUrl?contains("localhost")>
    <#noescape>${ssiInclude(url)}</#noescape>
  <#else>
    <esi:include src="${esiUrl}/${url}" />
  </#if>
</#macro>

2) use the macro with the url <@html.esi url="my/url" />

3) Exposed the SSI Include method in java/spring (you'll need to have setup some environment specific values for esiUrl and the sites base url)

<bean id="freemarkerViewResolver" class="org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver">
    ......
    <property name="attributesMap" ref="staticAttributesMap"/>
</bean>

<util:map id="staticAttributesMap">
    <entry key="esiUrl" value="${esi.url}" />

    <!-- formatters -->
    <entry key="ssiInclude" >
        <bean class="com.channel4.bips.web.freemarker.SsiIncludeMethodModel">
            <property name="urlBase" value="${base.url}/"/>
        </bean>
    </entry>

</util:map>

4) The java to emulate a SSI in freemarker

import freemarker.template.TemplateMethodModel;
import freemarker.template.TemplateModelException;
import org.apache.commons.lang.Validate;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;
import java.util.List;

public class SsiIncludeMethodModel implements TemplateMethodModel {
    private String urlBase;

    @Override
    public Object exec(List list) throws TemplateModelException {
        String uri = (String) list.get(0);
        Validate.notNull(uri);
        return readContents(urlBase + uri.trim());
    }

    public String readContents(String address) {
        StringBuilder contents = new StringBuilder(2048);
        BufferedReader br = null;

        try {
            URL url = new URL(address);
            br = new BufferedReader(new InputStreamReader(url.openStream()));
            String line;
            while ((line = br.readLine()) != null) {
                contents.append(line);
            }
        } catch (IOException x) {
            x.printStackTrace();
            return "Error getting SSI data";
        } finally {
            close(br);
        }

        return contents.toString();
    }

    private static void close(Reader br) {
        try {
            if (br != null) {
                br.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void setUrlBase(String urlBase) {
        this.urlBase = urlBase;
    }
}

Answer 2

You could set up Akamai's ETS (ESI Test Server) in a virtual machine and reverse proxy it back to your localhost server. I've done something similar before with Vagrant.

It seems to support most of the ESI language features including variables, if/else, etc.

Answer 3

Bruce - I am thinking aloud here, but have you tried modifying hostfile ? I am pretty sure ESI needs processing on the Akamai Edge Server but if you are able to modify it to say a Staging server of Akamai, that should let you test it locally ?

Again, i am just thinking aloud here.

Answer 4

Just in case someone still need it. You can use FireFox and add-on I wrote:
https://addons.mozilla.org/en-US/developers/addons
This is source:
https://github.com/DKurilo/esi_testing_extension
So if someone want to add something, esi:variable, for example, you're welcome!