published Nov 03, 2021

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Stefan Antonelli and Peter Holzer: Modernize Plone’s Classic UI

published Dec 10, 2020

Talk at Plone Conference 2020

What was new in Plone 5? We had beautiful new theme: Barceloneta. Diazo theming by default. We switched to CSS compilation with less.

During the Tokyo conference Stefan thought up Tokyo Theme. Clean responsive theme for Plone 5. Tons of overrides to tackle problems in Plone 5. Issue with navigation and editing on mobile we solved with collective.sidebar.

We had community discussions, especially during several Plone events. Everyone tried to use Bootstrap (components). First idea: map variables from Barceloneta to Bootstrap, because they have similar ideas using different terms.

We have PLIP to modernize markup in templates, and another PLIP to modernize the default theme: Barceloneta LTS. Forms using z3c.form are already using the new classes.

Make things easier: UI, development. Creating a modern UI for the web is complex. You need to support different devices, responsiveness. In Bootstrap there are patterns for most useful things.

Developer perspective: expect one way to do things. Developers should not have to worry about design. When busy in the backend, you should focus on Python, not on it looking nice and shiny. Don't think about markup, just use components. The good news: there is documentation. The Bootstrap documentation is our documentation.

What is new in Plone 6?

  • Volto is the default UI.
  • There still is the Classic UI with Barceloneta look and feel, but updated.
  • No TTW (through the web) theming.
  • But there is a textarea to add some simple CSS (already in 5.2.3).
  • Some CSS variables may be changeable TTW.
  • Finally jQuery 3

Bootstrap is still the most popular front-end framework. Well documented, tested and maintained. It is so easy to create stuff, I enjoy it a lot.

What is new in Bootstrap 5?

  • Improved overall look and feel.
  • Updated and extended the color system
  • Custom properties: css variables
  • SVG Icon library
  • Pure javascript
  • Dropped IE10 and IE11 support
  • Bootstrap 5 is currently alpha 3.
  • See

Features: what do we get from these changes?

  • Core templates use Bootstrap 5 markup. Instead of overrides in, we have lots of branches for the actual packages.
  • All major templates have been touched already.
  • For the current state, see the unofficial demo at
  • The Bootstrap documentation has lots of snippets than you can copy.
  • You don't need much more CSS on top of it if you paste most examples. We added a little for own components, like navigation.

Barceloneta appearance is fully customizable. It is basically on opinionated set of bootstrap variables. Every aspect can be changed with variables: colors, fonts, sizes, spacings, grid gutters, etc. There are overall properties, like shadowed, rounded, gradients. Just turn on or off.

Theming workflow. plonetheme.barceloneta will also be published as npm package. bobtemplates.plone will have a template for the new theming workflow. You can do quick and dirty customizations through the CSS overrides field in the theme controlpanel.

Diazo will still be there, will work as before. Some optimizations in the rules.xml to make content are customizations easier.

How to deal with icons? What if you want to change the content type icons? Used to be hard. Now we come up with the idea of an icon resolver. We decided to use the bootstrap icons. Icons are registered via GenericSetup, for example with a record name plone.icon.alarm pointing to an SVG. You can then override this in your own GS profile.

Example icon use:

You get get back an inline SVG or an image tag.

Note: all z3c form widgets in Plone are now in, and not scattered over lots of packages.

We will restart our weekly Plone 6 Classic UI sprints, starting Januari 13 2021, 10:00 (UTC+1).

Keynote: The User Experience - Editing Composite Pages in Plone 6 and Beyond

published Dec 10, 2020

Panel discussion at Plone Conference 2020

It may be a surprise to non-technical people to learn that pages created in Volto are not currently interoperable with traditional Plone's page editing. If you think about it, the reason becomes obvious. Volto, like Mosaic, creates tiled layouts, and like Mosaic it stores page data in special fields for the individual blocks and their layout. Neither Volto nor Mosaic pages are editable in TinyMCE, which expects just one rich text field.

Is this divergence between sites created in Volto and sites created in traditional Plone a problem? It does make it harder to describe what Plone is, and it might mean that there is no way to mix both approaches - for instance when part of a larger site is available as a Volto-based sub-site. Would it be possible to have one tool and one representation for tiled layouts so that we can avoid this divergence? Is there some other solution? Is it even a problem? Will Plone 6 be backwards compatible with Plone 5 and include a smooth upgrade path?

We will tackle these questions in this strategic panel discussion, moderated by Sally Kleinfeldt. Panelists will include Paul Roeland, Philip Bauer, Timo Stollenwerk, Victor Fernandez de Alba, and Eric Steele.

First, Philip has a message from Max Jacob who is very ill with pancreatic cancer and may not survive this weekend. He wants to thank the Plone community for what they allowed him to do: like organize the German Plone Konferenz. Thanks for all the friendships. Such a pity that this is happening now, he wanted to jump into only doing Plone for the next few years, due to changes at his job, and looked forward to that.

Classic, Mosaic and Volto Pages

We have Classic, Mosaic and Volto Pages. They have different internal representations and are not compatible. Is this a problem? Is there a solution? Is one tool, one representation possible? If we really need three, how to position?

Paul: for me as user this presents a problem. When do you switch over your site? We would like to not write 700 pages from scratch, again, like we did for previous composite pages.

Timo: We migrated quite a few large projects from classic Plone to Volto. One of those had collective.cover (other composite page system). Problem in general with such systems, is that they are pretty specific. They solve specific use cases and come from different eras. After any migration, it will not look the same any more. Whatever you do: the page will initially look ugly. So you put a lot of effort into migration, but then have to put manual effort into every page anyway. It can help: you at least have a start. We created a system where we migrated overview pages, and editors could click to migrate other pages one at a time.

Philip: We have code to migrate from non-folderish to folderish content types. There will be code to migrate to dexterity site root on Plone 6. We can make sure to migrate any standard content types. Mosaic is another story. So for pages you would at least have the text available. Maybe only visible for editors to pick and choose from. You may lose portlets, unless they get implemented in Volto.

Timo: When you go to Plone 6 and do a redesign at the same time, then you can jump on Volto. Otherwise you could stay at Classic Plone for now. There will be an overlap period.

Victor: For Mosaic you could dump all tiles into html and insert it in a block.

How to have a big Classic site with a subsite made in Volto?

Victor: Definitely doable, though we have not done this ourselves.

Sally: But what happens when an editor in Classic goes to the Volto subsite? The Volto page would not be editable then, right?

Philip: You should not offer this. I see no upside, no use case. Split them into separate applications, with shared authentication maybe.

Paul: Use case: large site with several departments. The marketing department may want snazzy new Volto things.

Timo: Just create another site then.

Cost and benefit of upgrading big Classic Site to Plone 6

So you just had a big migration to Plone5, and now what would you get for going to Plone 6.

Philip: We have this discussion every major upgrade. Communicate every upgrade as a relaunch. The relaunch is the reason for the upgrade. "There is a new version so you need to upgrade" does not fly for my clients.

Timo: We became a very developer oriented community, and every develop understands the need and benefits. We should really get back to giving more value at major releases, so clients really want to upgrade themselves. Plone releases should sell themselves.

Eric: It looks like we think Plone 6 + Volto is a costly upgrade with lots of benefits. For Classic 5 to Classic 6 the upgrade is not costly.

Alex Limi's vision for Deco: are we there yet?

Was this fulfilled by Mosaic? Volto? Something still needed?

Paul: Not quite, but slowly getting there. For me it would be Volto, plus some power features that Eau de Web (EEA) adds.

Timo: I think we went beyond what Limi envisioned.

Eric and Victor: What we have seen from Volto, is pretty close to what Alex wanted.

Victor: We gave the users powerful tools, so beware of them.

Philip: Partly yes. Volto is close, and it is for normal users.

Now some questions from users.


Philip: Plone 4 to 5.2 was three migrations in one. Plone 6 is less of a problem.

Eric: 5.2 had a lot of backend migrations. A split between backend and frontend with plone.restapi in between makes things easier.

[The question on multiple variations of Volto, especially editors, went a bit too fast for me to write intelligible notes down.]

What's the future of using CT's/behaviors in Plone to design information architecture?

With Volto the trend seems mixing/adding 40 different blocks for every page.

Timo: Blocks are definitely the way to work. But the underlying power of content types and behaviors still exists.

Philip: We need blocks that represent a field or a behavior. That is unavoidable.

Next steps

Timo: We plan to have an open space on page compositions and Volto, and want to sprint on it.

Paul: Good if there is a longer term vision. I would rather have more power that a Site Admin can lock down, than having to choose between three different versions. I don't want choice stress.

Lightning Talks Wednesday

published Dec 09, 2020

Lightning Talks on Wednesday at the Plone Conference 2020

Lukas Guziel: Continuous Deployment

CD means deploying code automatically. It saves time, reduces human error. It Gitlab you can add gitlib-ci.yml and configure it. Include a base template that you use in multiple projects. End result can be a site that the customer can test.

Erico Andrei: World Plone Day 2021

We are a global community. Almost 300 people from 36 countries are at this online conference. World Plone Day is an annual Plone event. Next year of course online. April 28th 2021.

We want to stream 24 hours live on our YouTube channel. Showcase Plone. Technical talk, use cases, interviews, demo.

It should not all be in English, please use your own language. Talk to your local community.

Please help and join. See

Andreas Jung: collective.contentsync2

Syncing content between Plone sites through plone.restapi. It is a behavior. You have a source Plone site and one or more target Plone sites. You need Plone 5.2 under Python 3.

  • Create a dedicated user account with global role Editor.
  • Configure on the content sync control panel.
  • Automatically creates two content rules to sync content when added or modified.
  • You can enable it on all content types, also Folders.


Philip Bauer: Why relations are weird

These packages have a part in relations:

  • zc.relation: abstract relation catalog
  • z3c.relationfield: fields and values on objects
  • converters from field to widget and vv
  • widgets
  • mockup: actual widget UI

In a schema use a RelationChoice field with vocabulary, and set pattern directives.

It is not straightforward. So I wrote collective.relationhelpers.


Maybe use uuid instead of all this code.

[About ten people in the chat want to merge this package into plone.api. Actually, see this issue.]

Christopher Lozinski: Simple JSON Schema GUIs

Create a JSON schema, automatically generate the UI. Search for basic JSON editor library. He shows JSON in ZODB, so you can browse it, if I understood correctly.🙂

Eric Brehault: Second Guessing the Single-Page-App Pattern

published Dec 09, 2020

Talk at Plone Conference 2020

SPA (Single Page App) is about providing an entire app by exposing a single physical web page containing an enormous javascript bundle. It breaks the original web paradigm in many ways. Surprisingly enough, we invest a lot of efforts to mimic the regular web behaviour.

Isn’t it time for modern frontend to reconsider the SPA approach?

[Note: Eric presented by using a projector to show his slides on a black Plone conference T-shirt. :-)]

Why are we doing this? Originally we always requested a whole page and this was considered slow. But we have good bandwidth now. And if you don't have good bandwidth, the super big bundle is not good either.

With SPA we try very hard to bring back the original working of the page, especially the browser history, being able to browse and then share the link to the current page.

To mitigate problems, we created an enormous stack. And we deny the complexity. New tools create new problems, even when their individual creators does not see the complexity.

"SPA isn't stable or efficient." But there is no way back. For example, you cannot create Google Docs with server side rendered pages. Web 2.0 is 15 years old. It is still about content.

SPA is separation of concern, which is a good principle. But we mix the browser layer (how you get and view the page) and the content layer (the page content).

It seems a take it or leave it situation: either use SPA or don't. What do we want? We want proportionate complexity. Do we need 100 percent SPA?

You can use micro components, see for example the demo of Maik Derstappen in the lightning talks on Monday, using Svelte. Micro frontend is bigger than that. It is a part of the application, that you develop separately. For example, you could do the Plone Sharing page like this.

Can we compile each page separately? Then each page is an app.

ES6 native support would be interesting. Combine with HTTP/2 and you need no bundles. Bundling is the most brutal thing ever. Horrible. Get rid of it.

Respect the layers. SPAs are monolithic. Break them down.

We should have a generic browser layer, common to many different use cases, for example for logging in. I don't want to code that, but plug it. Second step: push this layer to the browsers themselves.

Asko Soukka: Deploying Plone and Volto, the Hard Way

published Dec 09, 2020

Talk at Plone Conference 2020

Here are the slides.

How about building Plone without buildout? Running Plone on Python 3 without WSGI? Deploying Plone and Volto with containers without Docker? Building all this in re-usable and safe manner in sandbox with restricted network access with Nix? Welcome to hear about our hipster setup where we lock, build and configure Plone deployments with Nix, insist to keep ZServer running on Python 3 for the love's sake, build software deployments into standalone tarball archives, and run them with Nomad – the simple on-premises-friendly alternative for K8S.

  • The easy, documented way: buildout, WSGI, Docker (if you need containers), Registry.
  • Our way: pip, TxZServer, Nomad, Nix

When you use a container infrastructure, you have multiple containers for running a Plone site, for example zeo clients, zeo servers, load balancer. Nomad helps there, and is much simpler than Kubernetes. We have one job file to rule them all: task groups, instance count, update policy, server resources, volumen mounts, tasks, consul services, vault secrets, environment variables, exec artifacts.

Nomad has "isolated fork / exec driver". No docker image needed. We have a Nix-built artifact, a tarball that we extract in the root of the container.

With Nix, you get 100 percent reproducible artifacts. Production equals development. You have a full dependency graph. The result is a standalone tarball, perhaps 100 MB. Disadvantage is that there are no conventions, no metadata, no shared layers, no documentation. It needs learning and practice. Well, some documentation now: and, partially made by people that were using Plone previously.

Some ugly parts from Nix:

  • Every language has their own Nix-conventions
  • dependency generator ecosystem is comples
  • cyclic dependencies are not supported
  • no storage device is big enough for /nix/store

Our (legacy) approach for Plone 5.2.1 without Buildout and with pip:

  • generated requirements.txt with buildout
  • create Python env with pip and nix
  • use pip-branch of z3c.autoinclude
  • disabled />
  • generate instance skeleton with nix
  • forked plone.recipe.zope2instance

Plone 6 without Buildout should be pip-installable out of the box, but that is hear-say.

We use TxZServer in production, so ZServer using Twisted.