chadtmiller.com / honk
An ATProto Lexicon validator for Gleam.
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honk / example /
at v1.2.0 2 folders 3 files
src
test
README.md
gleam.toml
manifest.toml
README.md

Jetstream Validation Example#

This example demonstrates using honk to validate AT Protocol records from Bluesky's Jetstream firehose in real-time.

What it does#

  1. Connects to Jetstream using goose (WebSocket consumer)
  2. Filters for xyz.statusphere.status records
  3. Validates each record using honk
  4. Displays validation results with emoji status

Running the example#

cd example
gleam run

The example will connect to the live Jetstream firehose and display validation results as records are created:

🦢 Honk + Goose: Jetstream Validation Example
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Connecting to Jetstream...
Filtering for: xyz.statusphere.status
Validating records with honk...

✓ VALID   | q6gjnaw2blty... | 👍 | 3l4abc123
✓ VALID   | wa7b35aakoll... | 🎉 | 3l4def456
✗ INVALID | rfov6bpyztcn... | Data: status exceeds maxGraphemes | 3l4ghi789
✓ UPDATED | eygmaihciaxp... | 😀 | 3l4jkl012
🗑️  DELETED | ufbl4k27gp6k... | 3l4mno345

How it works#

Lexicon Definition#

The example defines the xyz.statusphere.status lexicon:

{
  "lexicon": 1,
  "id": "xyz.statusphere.status",
  "defs": {
    "main": {
      "type": "record",
      "record": {
        "type": "object",
        "required": ["status", "createdAt"],
        "properties": {
          "status": {
            "type": "string",
            "minLength": 1,
            "maxGraphemes": 1,
            "maxLength": 32
          },
          "createdAt": {
            "type": "string",
            "format": "datetime"
          }
        }
      }
    }
  }
}

Validation Flow#

  1. goose receives Jetstream events via WebSocket
  2. Events are parsed into typed Gleam structures
  3. For create and update operations:
    • Extract the record field (contains the status data)
    • Pass to honk.validate_record() with the lexicon
    • Display ✓ for valid or ✗ for invalid records
  4. For delete operations:
    • Just log the deletion (no record to validate)

Dependencies#

  • honk: AT Protocol lexicon validator (local path)
  • goose: Jetstream WebSocket consumer library
  • gleam_json: JSON encoding/decoding
  • gleam_stdlib: Standard library

Code Structure#

example/
├── gleam.toml          # Dependencies configuration
├── README.md           # This file
└── src/
    └── example.gleam   # Main application
        ├── main()                      # Entry point
        ├── handle_event()              # Process Jetstream events
        ├── handle_create/update()      # Validate records
        ├── create_statusphere_lexicon()# Define lexicon
        └── format_error/extract_status # Display helpers

Learn More#