Before we jump into the hidden infrastructure of our digital world, we want to thank the supporter of this deep dive.

SafeServer takes care of the hosting of this software and supports you in your digital transformation.

More information at www.safeserver.de OK, so let's try to unpack this.

We are diving deep into what is really the engine room of digital life.

It's a place you probably never see, but you rely on it every single day.

We're talking about the the foundational internet protocols that let your calendar, your contacts, all your files sync seamlessly across everything, you know, your phone, your desktop, the cloud, all of it.

And these protocols are often called the DAV standards, and they're just they're so critical for digital collaboration.

So our deep dive today is focused on this super popular open source tool that developers use.

It's a powerful PHP framework called Sabredive.

The source material we have, I mean, it's pretty technical.

It's documentation, GitHub repositories.

But our mission here is really simple.

We want to make this accessible.

We're going to break down what web devy called devy and car devy actually are, and maybe more importantly, why this specific framework is such a trusted solution for it all.

That's the core of it, isn't it?

I mean, for a lot of people, you know, your phone's calendar works, but you don't know why.

There's this incredibly complex, structured conversation happening in the background to make sure that meeting invite shows up everywhere at once.

And Sabredive is like the architect for that whole conversation.

OK, so let's start right at the beginning.

Then if we want to understand what people are building with this framework, we need to define those three little acronyms first.

So what are the DAV standards?

Right.

So it all starts with the foundation, which is WebDAV.

WebDAV stands for Web Distributed Authoring and Versioning.

And you should just think of it as, well, it takes the normal web, which is for reading things like a website.

Exactly.

And it flips it so you can also write to it.

You can manage files, move them around, even lock them.

It essentially turns a web server into a shared network drive.

That makes perfect sense.

It's like a shared folder you can get to from anywhere using a web address.

It just standardizes how you manage files remotely.

Precisely.

And once you have that standard for files and folders, you can build more specialized things right on top of it.

And that's where call DAV and Cardiva come in.

These are for managing structured data, you know, data that needs rules to be understood.

OK, so let's start with CalDAV.

I think everyone knows the headache of trying to schedule meetings with people on different systems.

How does CalDAV help with that?

CalDAV is all about calendar management.

It provides the rules for sharing calendars, for updating events, for recurring appointments, and most importantly, for scheduling and invitations.

It uses a specific data format called iCalendar.

Oh, yeah, the .ic files.

That's the one.

It's the universal language for event data.

So by using CalDAV, platforms like Google Calendar, Outlook, your phone, they can all speak the same language.

No translation problems.

So CalDAV is basically the protocol that makes sure those calendar files get where they need to go reliably.

It's like the Internet's meeting coordinator.

That's a great way to put it.

And then you have CardAV.

If CalDAV manages time, CardAV manages people.

It's the protocol for your address book, your contacts, making sure that's consistent everywhere.

I'm guessing it uses a similar kind of data format.

It does.

It relies on vCard, which is basically the standardized electronic business card format.

It tells the server what a contact record needs, name, phone, email, all of that.

And the real magic of a framework like SaberDAV is that it just it implements all these very specific old rules for developers.

So they don't have to go read decade old documents just to build a sync server.

And the project docs make it really clear this is not a hobby project.

They actually say that SaberDAV is trusted and fully supported on all major platforms.

That tells you right away that this code is robust enough for huge companies managing tons of sensitive data.

That's a massive vote of confidence for an open source tool.

It really speaks to the power of open standards.

When a core piece of infrastructure is managed openly like this, big companies don't have to worry about being locked into one vendor for their users contacts or schedules.

They can just rely on the stable foundation built on PHP, which has one of the biggest ecosystems out there.

That stable foundation, that brings us to the how, right?

So moving past the protocols, let's look at the framework itself.

The material highlights features designed for serious performance.

When they say scalable, what does that actually mean for a company using this?

Scalability here means two things.

It's the sheer volume of data, but also the volume of users hitting that data at the same time.

I mean, building a sync server is really hard.

You're dealing with multiple devices trying to update the same calendar entry at the exact same moment.

The framework scalable design is engineered to handle that kind of load without falling over.

And those challenges must just explode when you think about how people use this in a team setting.

It's not just my calendar anymore.

It's about sharing and delegating.

Absolutely.

The documentation specifically lists robust sharing and delegation features.

For any company, this is mission critical.

I might need my assistant to manage my work calendar or share a read only vacation schedule for my whole team.

The framework just provides all the scaffolding to build those rules easily.

And going back to call that for a second, the framework offers powerful scheduling and free, busy capabilities.

That seems like a subtle feature, but it's vital, isn't it?

It's the difference between a calendar that works and a tool that's actually useful.

When you invite someone to a meeting, the server needs to check their availability, their free, busy status without actually showing you all the private details of their schedule.

Sabredev implements the complex negotiation required to exchange just that little bit of data securely.

And security is of course the big one.

The framework talks about a flexible ACL and authentication system.

Now ACL is some developer jargon.

Can you break down what an access control list does here?

Think of the ACL.

Think of it like a digital key card system in an office building.

Every user has a key card, but that card only opens certain doors.

In this case, certain calendars or contact lists.

The flexibility means you can get really granular.

I might let you read my personal calendar, but only my boss can write new events to my work one.

The ACL system is what enforces all of those rules.

Okay.

That makes the security part crystal clear.

Now on the community side, the project is licensed under the BSD three clause license.

For a developer, what's the big deal about that kind of license?

It means freedom, a huge amount of freedom.

The BSD license basically says, do whatever you want with this code.

Even in your own commercial products, just don't remove our name from it.

This is why big companies feel so safe adopting it.

They know they can build massive systems on top without any legal strings attached.

And the GitHub stats, you know, over 1.7 thousand stars, hundreds of forks that shows developers really trust it.

And it's built almost entirely in PHP, like 99.0%, which is interesting because some people have this idea that PHP isn't great for high performance stuff.

It completely flips that old narrative on its head.

I mean, the success of Sabredev shows that modern PHP, when it's engineered professionally, is absolutely capable of handling this kind of demanding infrastructure and it's clearly active.

The latest release 4.7.0 was just in October 2024.

That's continuous professional maintenance.

And that longevity kind of leads us to the ecosystem.

This isn't just some random project.

The material says it's spearheaded by a company called Frouk.

Why is having a real company behind an open source project like this such a game changer?

Trust and commitment.

And enterprise needs guarantees.

They need a number to call when something breaks and they need to know security issues will be patched immediately.

Frouk provides that commercial safety net.

They take this amazing open source code and turn it into a solution that a big business can actually bet on.

And what do they offer that you don't get with just the free code?

They offer the services that large organizations really need.

Things like enterprise support with guaranteed response times, customization to fit it into their existing messy IT systems and deployment flexibility.

They'll help you run it on premise, you know, on your own servers or as a managed sauce solution, that dual offering is key.

The strength of SabreDove also seems to come from all its supporting libraries.

It's like a whole toolkit.

It is.

The most important one is probably SabreObject.

This is the workhorse for handling the data.

Since you're dealing with iCalendar and vCard files, you need a super reliable tool to parse and manipulate those formats.

Without SabreObject, every developer would have to write their own code just to read a meeting invite correctly, which that would be a nightmare.

So if SabreObject handles the data formats, the next step is sending that data over the web.

I see libraries for that too.

Yes, specifically SabreAxML.

Now these protocols often use XML and working with XML can be notoriously painful for developers.

The documentation has this great little bit of humor calling SabreAxML the only XML library that you may not hate.

Yeah, right.

That tells you it's built by people who get it.

They understand the common frustrations and they're trying to solve them.

And then you have these other utilities like SabreTP and Sibriory.

It really reinforces that this is a fully engineered system, not just a one trick pony.

Which brings us back to that crucial point about maintenance.

For anyone building a core business system on open source, you have to know what's being supported.

And the developers here are incredibly professional about it in their documentation.

They laid it all out.

The current four dot something branch is maintained needs modern PHP, but the older branches like 3.2, 3.1, they are explicitly labeled unmaintained.

And that's a loud and clear message.

It says you must track the active branch for security and reliability.

It's interesting they cite an old release from 2018, the 3.2.3 one, but it's really just a warning.

If a company is still on that code, they're using an abandoned product.

The real story is the active maintenance of the current branch.

That's what matters for today's projects.

So if we were to summarize the key takeaway from all this, separate to have isn't just some PHP code, it's the fundamental architecture that lets all our different apps and platforms communicate, sharing our calories and contacts securely and at a massive scale.

And it's all backed by a dedicated team at frus, which makes it safe for businesses to adopt.

It's the invisible glue.

I mean, the next time your phone syncs a critical meeting invite across three different devices instantly.

Just remember, you're seeing the principles and maybe even the actual code from a tool just like this doing its job perfectly in the background.

A really fascinating look at the plumbing of the Internet.

And it does lead to a final thought for you to consider.

Given how sensitive all this data is, our schedules, our contacts or work relationships, think about the impact of relying on well-maintained open source projects like this instead of, you know, closed proprietary systems.

Does the transparency of open standards actually guarantee a more reliable and interoperable future for how we all collaborate digitally?

Something to think about.

Thank you for joining us for this deep dive.

This episode was supported by Safe Server.

Safe Server takes care of the hosting of this software and supports you in your digital transformation.

More information at www.safeserver.de