The following article will show the difference between vQmod and OCMOD Opencart modification systems.
What is vQmod and how/where is it used?
vQmod (or Virtual Quick Mod) is the one of the Opencart override systems. The developers widely used it to create additional extensions for Opencart 1.5. engine.
It’s specific code modifications specified as separate xml files. vQmod parses the xml files during page load and applies the modifications to the target files. The result is saved as a temporary modified file, which is then loaded by OpenCart instead of the original one.
This system doesn’t make any direct changes to the actual OpenCart core files. Because of this, the original files are left intact – you can always undo the changes by simply removing the xml file.
The drawback is that vQmod isn’t part of OpenCart – it needs to be installed separately.
Opencart 2.x engine release brought the new in-built modification system – OCMOD. That is much simpler and available by default.
Daniel Kerr, the main person behind OpenCart, claimed the following: “The problem also is vQmod, I just don’t like how there are a lot of unnecessary features”.
In fact, OCMOD is basically a stripped down version of vQmod system. It works in a similar way – modifications are stored in xml files and uploaded to the store via admin panel, then parsed and applied to OpenCart core code. Unlike vQmod, OpenCart has a built-in OCMOD modification uploader and manager.
OCMOD is missing advanced search/replacement modifiers such as top, bottom, iafter and ibefore, as well as partial line matching and a few other things. In addition to this, OpenCart’s modification cache needs to be refreshed every time there are changes to OCMOD files.
You can find vQmod to OCMOD conversion guide at the following link.
We also recommend checking the detailed official OCMOD description.
IMPORTANT for Opencart 2.x! Do not install vQmod, if you have already uploaded OCMOD extensions. You must use only 1 override system, otherwise you will likely get overriding conflicts. Opencart 2.x uses OCMOD system by default and we recommend installing OCMOD modifications. Our Opencart 2.x templates also include only OCMOD modifications, because they are native for this framework and there is no official confirmation, that Opencart 2.x supports vQmod.