Weekly update – 1 December 2023

[ryan]

Something I've wanted in ProcessWire for a long time is full version support for pages. It's one of those things I've been trying to build since ProcessWire 1.0, but never totally got there. Versioning text and number fields (and similar types) is straightforward. But field types in ProcessWire are plugin modules, making any type of data storage possible. That just doesn't mix well with being version friendly, particularly when getting into repeaters and other complex types. 

ProDrafts got close, but full version support was dropped from it before the first version was released. It had just become too much to manage, and I wanted it to focus just on doing drafts, and doing them as well as we could. ProDrafts supports repeaters too, though nested repeaters became too complex to officially support, so there are still some inherent limitations. 

I tried again to get full version support with a module called PageSnapshots developed a couple years ago, and spent weeks developing it. But by the time I got it fully working with all the core Fieldtypes (including repeaters), I wasn't happy with it. It was functional but had become too complex for comfort. So it was never released. This happens with about 1/2 of the code I write – it gets thrown out or rewritten. It's part of the process.

What I learned from all this is that it's not practical for any single module to effectively support versions across all Fieldtypes in ProcessWire. Instead, the Fieldtypes themselves have to manage versions of their own data, at least in the more complicated cases (repeaters, ProFields and such). The storage systems behind Fieldtypes are sometimes unique to the type, and version management needs to stay internal [to the Fieldtype] in those cases. Repeaters are a good example, as they literally use other pages as storage, in addition to the field_* tables. 

For the above reasons, I've been working on a core interface for Fieldtypes to provide their own version support. Alongside that, I've been working on something that vaguely resembles the Snapshots module's API. But rather than trying to manage versions for page field data itself, it delegates to the Fieldtypes when appropriate. If a Fieldtype implements the version interface, it calls upon that Fieldtype to save, get, restore and delete versions of its own data. It breaks the complexity down into smaller chunks, to the point where it's no longer "complexity", and thus reasonable and manageable. 

It's a work in progress and I've not committed any of it to the core yet, but some of this is functional already. So far it's going more smoothly than past attempts due to the different approach. My hope is to have core version support so that modules like ProDrafts and others can eventually use that API to handle their versioning needs rather than trying to do it all themselves. I also hope this will enable us to effectively version the repeater types (including nested). I'm not there yet, but it's in sight. 

If it all works out as intended, the plan is to have a page versions API, as part of the $pages API. I'll follow up more as work continues. Thanks for reading and have a great weekend!

[MrSnoozles]

I'm excited to see what you're coming up with and if this attempt will make it to a release. It's a really useful feature and I think letting Fieldtypes handle it themselves is a good decision.

[Pete]

Thanks Ryan, I've really wanted something like this for a long time so good to hear you're making progress.

ProDrafts is useful, but if this allows for a more complete version history like you might get in other CMS' and you can also then add in approval workflows down the line (separate module I reckon) that would be amazing too as I have a few sites where there are several people working on stuff at once and I know at least one of our mutual clients might find it useful too ?

[gebeer]

Thank you very much @ryanfor working on this. For larger corporate sites this is a must have. We are using ProDrafts atm and got it kind of working with nested repeaters with some dirty hacks. Approval workflow like mentioned by @Pete would be awesome ?