Module Version Control

[teppo]

This module is improved and extended successor to Version Control For Text Fields. It handles everything it's predecessor did -- providing basic version control features for page content -- and quite a bit more. Download or clone from GitHub: https://github.com/teppokoivula/VersionControl.

This module requires ProcessWire 2.4.1 or later, mostly because of the file features, which require certain Pagefile and Pageimage methods to be hookable. There's no sensible way around this limitation; for those stuck with < 2.4.1, Version Control For Text Fields will remain a viable option.

What does it do?

While editing pages, fields with old revisions available show up with a new icon in their header bars. By hovering that icon you get a list of available revisions and by clicking any one of those the value of that particular field is reverted to that revision. No changes are made to page until you choose a revision and save the page, which means that you can keep switching between revisions to get an idea what's really changed without inadvertently causing any content to change.

The module also adds a History tab to page edit. This tab opens a view to the history of current page in the form of "revisions" -- each of which is a group of changes to page fields processed during one page save (similar to revisions in various source control applications). There are three actions you can perform on these revisions: adding comments, live previewing what the page might've looked in that revision and restoring the page to specific revision.

One specific feature that has been a big thing for me personally is support for file (and image) fields, as the original version control module felt rather incomplete without it. I'm hoping to take this a lot further performance, stability and feature wise, but as it stands right now, it's already included here and should be fully functional.

Watch the video preview here

I prepared a little screencast outlining most of this: http://youtu.be/AkEt3W7meic. Considering that it was my first screencast ever, I'd like to think that it wasn't that bad.. but I might give it another shot at some point, this time planning a bit before hitting "record" 

Upgrading from Version Control For Text Fields

For those already using Version Control For Text Fields, I've added something extra. If you upgrade that module to it's latest version, you should see a new checkbox in it's settings screen saying "Don't drop tables during uninstall". If you check this, uninstall the module and then remove it's files (this is required in order to install Version Control), your old data should be automagically imported to Version Control.

Import has only been tested with limited amounts of demo data. Proper tests are yet to come, so please be careful with this feature!

Update, 21.6.2015: as of today, this module is no longer in beta. While all the regular warnings still apply (making changes, including installing any new modules, on a production site should always be considered risky) Version Control has gone through pretty extensive testing, and should be as stable as any other module out there.

Edited June 21, 2015 by teppo
Added a note about not being a beta release anymore

[cstevensjr]

Very nice and I believe it will be a very useful tool.

[marcus]

Amazing module with impressive ease of use! And really slick and jaw dropping inline-page-version preview!

[apeisa]

Huge release! Congratulations Teppo! I love the preview UI, very neat.

[Pete]

This is awesome Teppo!

Of course near the end it looks like many versions are created as adding images saves the page behind the scenes via Ajax so that's one way you'll end up with a lot of revisions (did I remember that correctly or make it up?). I'm wondering if it's worth making it so it only stores revisions when updating image and file fields AFTER the Save button is pressed? Or did you already take that into account?

Loving this module and it will be fascinating to see how you handled the image and file fields when I dig into the code

[teppo]

Thanks guys, really appreciate all the kind words!

@Pete: you're right, each AJAX upload creates new revision at the moment. This is difficult to circumvent without sacrificing reliability, but I'll give it some thought.

Since each asynchronous file upload creates separate POST request updating value of given field, it's actually logical that each of those would also create new revision. From technical point of view this is no different than doing something like "$page->title = 'foo'; $page->save('title');" via API, since the end result is exactly same; whether or not user actually realises it, page content changes instantly each time a file has been uploaded.

Anyway, I'll have to see if this could be somehow improved

[apeisa]

I don't see any other way for files really. Maybe bundling multiple (meaning no other changes in between and max few minutes time) additions or removes into same revision. That could be done in UI only.

[Pete]

My thinking was simply checking if the input button has been clicked and only creating a revision if $this->input->post->submit_save is present.

Along similar lines, it would be great to have the option of not creating a version of any field until the page is published (no versions for an unpublished page).

Both of these are useful/desirable in some scenarios and not in others so I'm happy for them to be configurable options - as it is the module is already awesome

[teppo]

@Pete: thanks for both suggestions. I'll have to see if I can find a way to add these without affecting current behaviour negatively and creating unwanted inconsistencies between API and GUI behaviour

This is getting slightly off-topic, but as I've been diving into various version and/or source control systems lately, I've started seeing them, first and foremost, as a way to keep track of what really happened, so that you can later review the full chain of events that led to current state and retrace your steps.

That's apparently not how everyone else feels, though. Even Pro Git, which I've been browsing every now and then for ideas as well as Git tips, has an entire chapter titled "Git Tools - Rewriting History", explaining how to alter (prettify, falsify, whatever you call it) local commit history.

I guess it's, in the end, all about finding the right balance between flexibility and consistency

[cstevensjr]

as a way to keep track of what really happened, so that you can later review the full chain of events that led to current state and retrace your steps.

I hope that you will be able to stay faithful to some type of reliable transactional based version control.  I believe it will play a big part in where and how applications built on this can be deployed.

Anyway, I have always been impressed with your version control module.  Good Luck.

[renobird]

Wow! This looks really amazing. Appears that I'll be having lunch at my desk today and testing this out.

I really like @pete's suggestions, and @antti's idea of a time interval for bundling. 

[sid]

After a vanilla Processwire 2.4 install, I can't get Version Control module working fully...

Module compatibility is stated as Processwire 2.4 (current stable version).

After Version Control install, Page Snapshot dependancy is not installed and states it requires 2.4.1 minimum.

‘Preview revision’ on the ‘History’ tab gives:

'TemplateFile: Method Page::snapshot does not exist or is not callable in this context'

Upgrading to Processwire 2.4.4 (current dev) allows module and dependancies to install.

‘Preview revision’ on the ‘History’ tab gives:

'TemplateFile: SQLSTATE[HY093]: Invalid parameter number: number of bound variables does not match number of tokens'

and php error:

'Undefined variable: page_ids in site/modules/VersionControl/PageSnapshot.module on line 253'

Version Control 0.9.15 installed. 

Version Control history is enabled for basic-page template.

Any ideas? Have I missed something?

[teppo]

@sid: sounds kind of like you could have an earlier version of Page Snapshot module installed. Could please you check that you're running version 1.1.18 of it?

I'm sorry for the confusion about supported ProcessWire version. Dev branch is really needed to run this module. My original post mentioned that the module requires "2.4.1 or later, i.e. current dev branch", but since modules directory doesn't allow submissions unless you define a version ranging from 2.0 to 2.4 as compatible.. well, I can see how that could happen.

[sid]

Thanks for the reply - I have:

Page Snapshot 1.1.18

Process Version Control 0.9.5

Version Control 0.9.15

All 3 PHP errors are:

Undefined variable: page_ids in site/modules/VersionControl/PageSnapshot.module on line 253

Undefined variable: page_ids in site/modules/VersionControl/PageSnapshot.module on line 261

array_merge(): Argument #2 is not an array in site/modules/VersionControl/PageSnapshot.module on line 261

all of which feed into the SQL query missing parameter error when the statement is executed on PageSnapshot.module line 263 I guess?

[teppo]

Thanks! There was an issue in PageSnapshot.module preventing it from working properly unless FieldtypeRepeater was installed too.

I've just pushed fix for that to GitHub, so if you could fetch latest version and see if it works any better?

[sid]

Page Snapshot 1.1.19 fixes the problem for me - thank you very much

[teppo]

That's good to hear

[Pierre-Luc]

Hi teppo, is there a way to get the changes from the api?

$page->currentVersion->typicalFunctions;

$page->previousVersion->typicalFunctions;

I’m looking at implementing a status notification system for a project and this would be handy. For this I would need to grab different fields or a specific one and check for differences using a hook.

[teppo]

Sorry for the delayed answer, Pierre-Luc! Been busy with other stuff and this totally slipped my mind.
 
What you've described there wasn't really possible without direct SQL queries until just a few moments ago. I've just pushed to GitHub an update to VersionControl.module (0.10.0) that adds new $page->versionControlRevisions() method. This isn't properly tested yet, but something like this should work:

// current value of field 'headline'
echo "Headline for current revision: {$page->headline}<br />";

// value of field 'headline' in previous revision
$revisions = array_keys($page->versionControlRevisions(2));
$page->snapshot(null, $revisions[1]);
echo "Headline for previous revision: {$page->headline}<br />";

// return Page to it's original (current) state
$page->snapshot();
echo "Back to current revision: {$page->headline}<br />";

Since snapshot() returns Page object to given revision or point in time ($page->snapshot($time, $revision)) you'll want to make sure it's back to it's original state in case you're going to make changes and save the page -- otherwise the revision you fetched with snapshot will be returned from history once you save the page.
 
$page->versionControlRevisions() returns an array of revisions for current page and can optionally take one param, $limit, to fetch only that many revisions if more exist. It's return value is in the form of array([revision] => [timestamp]), i.e. array(4 => '2014-01-01 02:00:00', 3 => '2014-01-01 01:00:00') etc. so in order to get just the revision IDs out of that I'm using array_keys() in the example above.
 
You could probably also do something like this, if you want to make sure that Page doesn't get accidentally returned from history (this'll consume more memory, though):

$revisions = array_keys($page->versionControlRevisions(2));
$page->previousVersion = clone $page;
$page->previousVersion->snapshot(null, $revisions[1]);
echo "Headline for previous revision: {$page->previousVersion->headline}<br />";

Not sure if you're still working on this, but this kind of feature felt useful so I'm glad you brought it up..

[Pierre-Luc]

That’s pretty neat teppo! The feature will be implemented a bit further down the road on this project so it’s far from too late! I’ll let you know when I’ll start playing with it. Awesome, thanks again!

[Macrura]

ran into a snafu today, here's the setup and behavior:

- Page table field (called reviews)

when adding a review, the review would save but then the field itself wouldn't save so the related page wouldn't be added into the page table and there would be a 500 error;  tried uninstalling various modules, but in the end it came down to this one, when i removed the template from the selected list of templates, the field started saving again; i will try and provide more info, but the errors were not specific to anything other than setting output formatting as false for the the page table field before saving...

[owzim]

I just unliked the first post just to like it again. silly.

Sorry Macrura, if that doesn't help with you problem

[teppo]

@Macrura: if I'm getting this right, you're just adding a page to a PageTable field, and when Version Control is installed, this fails with a 500 error (internal server error). The page (review) itself gets added and saved properly, apparently.

To be clear, which template did you remove from Version Control enabled templates -- the one used for reviews or the one containing the PageTable field? Also, is there anything added to the error logs of Apache or PW?

I was kind of assuming that this module would attempt to store values for the PageTable field itself, which could've easily resulted in an error (don't think that I ever tested that), but since it's not in the supported fields by default, that's unlikely. Unless you've manually added PageTable to the list of supported fields?

Any additional info would be helpful. I'll continue testing, but at the moment I'm kind of lost here, and haven't been able to reproduce this issue.

Edit: added PageTable to supported fieldtypes locally. Doesn't work (as expected), but doesn't seem to break anything either. Will continue debugging.

Edited December 19, 2014 by teppo

[Macrura]

@teppo - many thanks for replying and sorry for the vagueness of my bug report;

to clarify, yes, there is a page table field where the ajax saving of the field fails when the Version Control is enabled for this template; i only have 3 fields enabled for VC, which are all simple text and body fields.

I removed the template of the containing page from the VC preferences and that allowed the pt field to be saved.

there were errors in the error log (cleared it though), but I'm not sure if they would help, but if so i can re-enable the VC on this template to generate the error if that would help... this site is still in testing, not live, so it's no problem to do that; i can probably get to that later today...

[teppo]

there were errors in the error log (cleared it though), but I'm not sure if they would help, but if so i can re-enable the VC on this template to generate the error if that would help... this site is still in testing, not live, so it's no problem to do that; i can probably get to that later today...

Thanks. That would be very helpful (probably), since right now I'm kind of out of ideas here. It's probably something simple, I'm just failing to see what it could be.