Protobuf VS concise-encoding

For at least 4 years protobuf has had decent support for self-describing messages (very similar to avro) as well as reflection

https://github.com/protocolbuffers/protobuf/blob/main/src/go...

Xgooglers trying to make do on the cheap will just create a Union of all their messages and include the message def in a self-describing message pattern. Super-sensitive network I/O can elide the message def (empty buffer) and any for RecordIO clone well file compression takes care of the definition.

Definitely useful to be able to dig out old defs but protobuf maintainers have surprisingly added useful features so you don’t have to.

Bonus points tho for extracting the protobuf defs that e.g. Apple bakes into their binaries.

gRPC Gateway is a protoc plugin that reads gRPC service definitions and generates a reverse proxy server that translates a RESTful JSON API into gRPC.

To use more recent versions of protoc in future applications, you can download them from the Protobuf repository.

Use the Protobuf CLI protoc and the plugin protoc-gen-tonic.

> didn’t find any standard for separating protobuf messages

The fact that protobufs are not self-delimiting is an endless source of frustration, but I know of 2 standards:

- SerializeDelimited* is part of the protobuf library: https://github.com/protocolbuffers/protobuf/blob/main/src/go...

- Riegeli is "a file format for storing a sequence of string records, typically serialized protocol buffers. It supports dense compression, fast decoding, seeking, detection and optional skipping of data corruption, filtering of proto message fields for even faster decoding, and parallel encoding": https://github.com/google/riegeli

It looks like it is in fact universal. Just glancing at the code here, it looks like the tool searches any arbitrary file for bytes that look like encoded protobuf descriptors, specifically looking for bytes that are plausibly the beginning of a FileDescriptorProto message defined here:

https://github.com/protocolbuffers/protobuf/blob/main/src/go...

This takes advantage of the fact that such descriptors are commonly compiled into programs that use protobuf. The descriptors are usually embedded as constant byte arrays. That said, not all protobuf implementations embed the descriptors and those that do often have an option to inhibit such embedding (at the expense of losing some dynamic introspection features).

Not much. You can check the source code in https://github.com/protocolbuffers/protobuf. For example, for serializing a boolean in C#: https://github.com/protocolbuffers/protobuf/blob/main/csharp/src/Google.Protobuf/WritingPrimitives.cs#L165. Strings and objects are a bit more complicated, but it is all about turning the data into its byte representation.

One of the key feature of gRPC is protobuf .proto file(nothing but just a contract for me between two communicator code components) This file and protobuff compiler is so mature, then it generates a direct client implementation using protoccompiler. ref

"Local time" is time zone metadata. I've written a fair bit about timekeeping, because the context of what you're capturing becomes very important: https://github.com/kstenerud/concise-encoding/blob/master/ce...

This is basically why I ended up rolling my own text date format for Concise Encoding: https://github.com/kstenerud/concise-encoding/blob/master/ct...

ISO 8601 and RFC 3339 are fine for dates in the past, but they're not great as a general time format.

This looks similar to https://concise-encoding.org/

Dogma was developed as a consequence of trying to describe Concise Binary Encoding. The CBE spec used to look like the preserves binary spec, full of hex values, tables and various ad-hoc illustrations: https://preserves.dev/preserves-binary.html

Now the CBE formal description looks like this: https://github.com/kstenerud/concise-encoding/blob/master/cb...

And the regular documentation looks like this: https://github.com/kstenerud/concise-encoding/blob/master/cb...

Dogma also does text formats (Concise Encoding has a text and binary format, so I needed a metalanguage that could do both in order to make it less jarring for a reader):

https://github.com/kstenerud/concise-encoding/blob/master/ct...

https://github.com/kstenerud/concise-encoding/blob/master/ct...

Hey thanks for taking the time to critique!

I actually do have an ANTLR file that is about 90% of the way there ( https://github.com/kstenerud/concise-encoding/tree/master/an... ), so I could use those as a basis...

One thing I'm not sure about is how to define a BNF rule that says for example: "An identifier is a series of characters from unicode categories Cf, L, M, N, and these specific symbol characters". BNF feels very ASCII-centric...

It's still in the prerelease stage, but v1 will be released later this year. I'm mostly getting hits from China since they tend to be a lot more worried about security. I expect the rest of the world to catch on to the gaping security holes of JSON and friends in the next few years as the more sophisticated actors start taking advantage of them. For example https://github.com/kstenerud/concise-encoding/blob/master/ce...

There are still a few things to do:

- Update enctool (https://github.com/kstenerud/enctool) to integrate https://cuelang.org so that there's at least a command line schema validator for CE.

- Update the grammar file (https://github.com/kstenerud/concise-encoding/tree/master/an...) because it's a bit out of date.

- Revamp the compliance tests to be themselves written in Concise Encoding (for example https://github.com/kstenerud/go-concise-encoding/blob/master... but I'll be simplifying the format some more). That way, we can run the same tests on all CE implementations instead of everyone coming up with their own. I'll move the test definitions to their own repo when they're done and then you can just submodule it.

I'm thinking that they should look more like:

    c1

Ugh Unicode has been the bane of my existence trying to write a text format spec. I started by trying to forbid certain characters to keep files editable and avoid Unicode rendering exploits (like hiding text, or making structured text behave differently than it looks), but in the end it became so much like herding cats that I had to just settle on https://github.com/kstenerud/concise-encoding/blob/master/ct...

Basically allow everything except some separators, most control chars, and some lookalike characters (which have to be updated as more characters are added to Unicode). It's not as clean as I'd like, but it's at least manageable this way.

You might get a kick out of Concise Encoding then (shameless plug). It focuses on security and consistency of behavior.

https://concise-encoding.org/

In particular:

* How to deal with unrepresentable values: https://github.com/kstenerud/concise-encoding/blob/master/ce...

* Mandatory limits and security considerations: https://github.com/kstenerud/concise-encoding/blob/master/ce...

* Consistent error classification and processing: https://github.com/kstenerud/concise-encoding/blob/master/ce...

In the above example, `&a:` means mark the next object and give it symbolic identifier "a". `$a` means look up the reference to symbolic identifier "a". So this is a map whose "recusive link" key is a pointer to the map itself. How this data is represented internally by the receiver of such a document (a table, a struct, etc) is up to the implementation.

> - Time zones: ASN.1 supports ISO 8601 time types, including specification of local or UTC time.

Yes, this is the major failing of ISO 8601: They don't have true time zones. It only uses UTC offsets, which are a bad idea for so many reasons. https://github.com/kstenerud/concise-encoding/blob/master/ce...

> - Bin + txt: Again, I'm unclear on what you mean here, but ASN.1 has both binary and text-based encodings

Ah cool, didn't know about those.

> - Versioned: Also a little unclear to me

The intent is to specify the exact document formatting that the decoder can expect. For example we could in theory decide make CBE version 2 a bit-oriented format instead of byte-oriented in order to save space at the cost of processing time. It would be completely unreadable to a CBE 1 decoder, but since the document starts with 0x83 0x02 instead of 0x83 0x01, a CBE 1 decoder would say "I can't decode this" and a CBE 2 decoder would say "I can decode this".

With documents versioned to the spec, we can change even the fundamental structure of the format to deal with ANYTHING that might come up in future. Maybe a new security flaw in CBE 1 is discovered. Maybe a new data type becomes so popular that it would be crazy not to include it, etc. This avoids polluting the simpler encodings with deprecated types and bloating the format.