How to get production build using the same _dc invalidate cache for that build?

[SebTardif]

Sencha has the functionality to append _dc=xyz to almost everything with the goal to invalidate always the cache. The value change all the time, each time the application is loaded even if it's the same build, and nothing changed.

Well, I would like production build to still append _dc but the value should be fixed/stable for that build. So mainly invalidating stale version of the application in my customer browsers.

Is this a scenario already supported?

If yes, what are the settings?

If no, could we get an enhancement request open right away?

[israelroldan]

A quick way to do this would be to add the following targets to your build.xml file:

    <target name="-before-init">
        <buildnumber file="build.num"/> <!-- this task generates a build.num file to track the builds -->
    </target>


    <target name="-after-page">
        <if>
            <resourcecontains resource="${build.dir}/index.html" substring="=+new Date:" />
            <then>
                <!-- here we replace the appearance of +new Date (which is used as value for the cache buster with the build id -->
                <replaceregexp file="${build.dir}/index.html" match="\+new\sDate" replace="${build.number}" />
            </then>
        </if>
    </target>

After building, the value of _dc will be your build id instead of the current timestamp.

This is just a quick suggestion and it may need to be adjusted to suit your needs, for example, to use a different approach to getting the value used as cache buster or to account for a non-embedded manifest (if that's your configuration).

[SebTardif]

Thanks for the pointer. I will try.

[Greendrake]

A quick way to do this would be to add the following targets to your build.xml file

I can confirm it works. What happens there is the replacement of the following red-highlighted piece of code found in bootstrap.js and eventually making its way to index.html in compressed format:

if(cache === false) {
    buster = +new Date();
} else if(cache !== true) {
    buster = cache;
}

So basically the workaround is to replace that bit with your own build number — does not matter where you actually take the number from and how you inject it in there.

Still it would be nice to be able to do that in some framework-provided way rather than applying dirty hacks.

[EPV]

I have asked the same question here:
https://www.sencha.com/forum/showthr...-in-production

Mitchell suggested to change app.json like this:

"loader": {
    "cache": "${build.timestamp}"
}

Though, this makes the files cache in dev-mode as well. I guess that the hack from israelroldan will work both in dev & prod. Strange that there's no out of the box solution for this.

/ E

[MDSIII]

There are build environment specific settings so you can specify the cache busting for just production like:

    "production": {
        "loader": {
            "cache": "${build.timestamp}"
        }
    },

That way in development env the _dc parameter is not added to modules loaded by the loader (still added to Ajax.requests etc. from the application), you can turn off caching in your dev browser (see numerous posts on how to do this) and breakpoints will still work.