WebDAV was really complex, and required (ugh) locking for concurrent edits, which really sucks.

Let's compare WebDAV with Braid for something simple like looking up the current version of the resource.

In WebDAV, you have to:

- Send a PROPFIND request to the URL of the resource you want to check. In the request body, specify the DAV:version-controlled-binding property you want to retrieve, using a custom XML syntax. Here's an example:

    PROPFIND /path/to/resource HTTP/1.1
    Host: example.com
    Depth: 0
    Content-Type: application/xml
    
    <?xml version="1.0" encoding="utf-8"?>
    <propfind xmlns="DAV:">
      <prop>
        <version-controlled-binding />
      </prop>
    </propfind>

- The server responds with a 207 Multi-Status response, with XML to parse:

    HTTP/1.1 207 Multi-Status
    Content-Type: application/xml
    
    <?xml version="1.0" encoding="utf-8"?>
    <multistatus xmlns="DAV:">
      <response>
        <href>/path/to/resource</href>
        <propstat>
          <prop>
            <version-controlled-binding>
              <href>/path/to/version/history</href>
            </version-controlled-binding>
          </prop>
          <status>HTTP/1.1 200 OK</status>
        </propstat>
      </response>
    </multistatus>

This does not yet give you the version -- it tells you a separate URL that contains the version history. So now you have to query that for the version:

- Send a REPORT request to that url, and in the request body, specify the DAV:version-tree report you want to retrieve:

    REPORT /path/to/version/history HTTP/1.1
    Host: example.com
    Content-Type: application/xml
    
    <?xml version="1.0" encoding="utf-8"?>
    <version-tree xmlns="DAV:">
      <prop>
        <version-name />
        <creator-displayname />
        <creation-date />
        <comment />
      </prop>
    </version-tree>

- The server responds with a 207 Multi-Status, with more custom XML for you to parse:

    HTTP/1.1 207 Multi-Status
    Content-Type: application/xml
    
    <?xml version="1.0" encoding="utf-8"?>
    <multistatus xmlns="DAV:">
      <response>
        <href>/path/to/version/1</href>
        <propstat>
          <prop>
            <version-name>1.0</version-name>
            <creator-displayname>John Doe</creator-displayname>
            <creation-date>2023-05-26T10:00:00Z</creation-date>
            <comment>Initial version</comment>
          </prop>
          <status>HTTP/1.1 200 OK</status>
        </propstat>
      </response>
      <response>
        <href>/path/to/version/2</href>
        <propstat>
          <prop>
            <version-name>2.0</version-name>
            <creator-displayname>Jane Smith</creator-displayname>
            <creation-date>2023-05-27T14:30:00Z</creation-date>
            <comment>Updated version</comment>
          </prop>
          <status>HTTP/1.1 200 OK</status>
        </propstat>
      </response>
    </multistatus>

You can find the versions in there, and if you then parse and filter to the most recent version, you can see that the current version is 2.0.

That was a LOT of work!

Now let's see it in Braid.

To get the current version, just do a normal GET or a HEAD, and look at the Version: header in the response:

Request:

    GET /path/to/resource HTTP/1.1

Response:

    HTTP 200 Ok    
    Version: "2.0"

    <body of resource>

That's it! It's that simple!

Braid is this simple because it is baked into HTTP. It turns out that HTTP itself is already very close to a State Synchronization protocol -- it just needs a few headers, and the ability to stream updated responses when a resource changes. I encourage you to check out the spec, and see how easy it is to do things that were complicated or impossible in WebDAV:

https://datatracker.ietf.org/doc/html/draft-toomim-httpbis-b...