module gets auto-installed if called from front-end?

[applab]

Hi All,

I'm making my first serious foray into module development and I've discovered some behaviour which I found surprising...

If I uninstall my module from the backend but do not delete the file, then I refresh a front-end page that is using that module, I would expect to see some kind of error but what happens is the module gets automatically re-installed.

I can mitigate this behaviour by wrapping my front-end code in:

if(modules()->isInstalled('MyModule')) { ... }

but that doesn't seem like the best approach if the module is used in multiple places.

Is there something I can add to my modules install() method to prevent it getting auto-installed in this situation?

Thanks.

[Zeka]

Hi @applab Probably somewhre in your code you are calling $modules->get("MyModule"). 

So just check before getting this module. 

if ($modules->isInstalled("MyModule")) {
    echo $modules->get("MyModule")->renderBlock();
}

Also if this module is required by another module it will be installed (Not sure, but looks like it behaves in this way).

[applab]

Hi @Zeka, 

Yes, I am using $modules->get("MyModule") in my front-end template.  I was just surprised to see MyModule get installed as a result of that code rather than throwing an error, which is what I was expecting. 

I've achieved my original goal of preventing the install in that situation but I've realised that I still need to use isInstalled() in my front-end templates to avoid runtime errors so, thanks.

[kongondo]

5 hours ago, applab said:

I was just surprised to see MyModule get installed as a result of that code rather than throwing an error, which is what I was expecting. 

That is the default behaviour.

Quote

• If the module is not installed, but is installable, it will be installed, instantiated, and initialized. If you don't want that behavior, call $modules->isInstalled('ModuleName') as a conditional first.

Alternatively, you can use the method $modules->getModule() with noInstall option.

<?php namespace ProcessWire;

$modules->getModule('MyModule', ['noInstall' => true]);

Quote

• noInstall (bool): Specify true to prevent a non-installed module from installing from this request. (default=false)

 

[applab]

Thanks @kongondo, that is precisely the info I needed.  Next time I'll RTFM a bit more before I post!