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STATUS-URL-DATA

Abstract​

This document specifies serialization, compression, and encoding techniques used to transmit data within URLs in the context of Status protocols.

Motivation​

When sharing URLs, link previews often expose metadata to the websites behind those links. To reduce reliance on external servers for providing appropriate link previews, this specification proposes a standard method for encoding data within URLs.

Terminology​

Wire Format​

syntax = "proto3";

message Community {
    // Display name of the community
    string display_name = 1;
    // Description of the community
    string description = 2;
    // Number of members in the community
    uint32 members_count = 3;
    // Color of the community title
    string color = 4;
    // List of tag indices
    repeated uint32 tag_indices = 5;
}

message Channel {
    // Display name of the channel
    string display_name = 1;
    // Description of the channel
    string description = 2;
    // Emoji of the channel
    string emoji = 3;
    // Color of the channel title
    string color = 4;
    // Community the channel belongs to
    Community community = 5;
    // UUID of the channel
    string uuid = 6;
}

message User {
    // Display name of the user
    string display_name = 1;
    // Description of the user
    string description = 2;
    // Color of the user title
    string color = 3;
}

message URLData {
    // Community, Channel, or User
    bytes content = 1;
    uint32 shard_cluster = 2;
    uint32 shard_index = 3;
}

Implementation​

The above wire format describes the data encoded in the URL. The data MUST be serialized, compressed, and encoded using the following standards:

Encoding

Compression​

Serialization​

Implementation Pseudocode​

Encoding

Encoding the URL MUST be done in the following order:

raw_data = {User | Channel | Community}
serialized_data = protobuf_serialize(raw_data)
compressed_data = brotli_compress(serialized_data)
encoded_url_data = base64url_encode(compressed_data)

The encoded_url_data is then used to generate a signature using the private key.

Decoding​

Decoding the URL MUST be done in the following order:

url_data = base64url_decode(encoded_url_data)
decompressed_data = brotli_decompress(url_data)
deserialized_data = protobuf_deserialize(decompressed_data)
raw_data = deserialized_data.content

The raw_data is then used to construct the appropriate data structure (User, Channel, or Community).

Example​

Discussions​

Proof of concept​

Copyright and related rights waived via CC0.

References​

  1. Proposal Google Sheet
  2. Base64url
  3. Brotli
  4. Protocol buffers version 3
  5. STATUS-URL-SCHEME