C Nostr Relay - Event-Based Configuration System

A high-performance Nostr relay implemented in C with SQLite backend, featuring a revolutionary zero-configuration approach using event-based configuration management.

📜 Supported NIPs

• NIP-01: Basic protocol flow implementation
• NIP-09: Event deletion
• NIP-11: Relay information document
• NIP-13: Proof of Work
• NIP-15: End of Stored Events Notice
• NIP-20: Command Results
• NIP-33: Parameterized Replaceable Events
• NIP-40: Expiration Timestamp
• NIP-42: Authentication of clients to relays
• NIP-45: Counting results
• NIP-50: Keywords filter
• NIP-70: Protected Events

🔧 Administrator API

C-Relay uses an innovative event-based administration system where all configuration and management commands are sent as signed Nostr events using the admin private key generated during first startup. All admin commands use NIP-44 encrypted command arrays for security and compatibility.

Authentication

All admin commands require signing with the admin private key displayed during first-time startup. Save this key securely - it cannot be recovered and is needed for all administrative operations.

Event Structure

All admin commands use the same unified event structure with NIP-44 encrypted content:

Admin Command Event:

{
  "id": "event_id",
  "pubkey": "admin_public_key",
  "created_at": 1234567890,
  "kind": 23456,
  "content": "AqHBUgcM7dXFYLQuDVzGwMST1G8jtWYyVvYxXhVGEu4nAb4LVw...",
  "tags": [
    ["p", "relay_public_key"]
  ],
  "sig": "event_signature"
}

The content field contains a NIP-44 encrypted JSON array representing the command.

Admin Response Event:

["EVENT", "temp_sub_id", {
  "id": "response_event_id",
  "pubkey": "relay_public_key",
  "created_at": 1234567890,
  "kind": 23457,
  "content": "BpKCVhfN8eYtRmPqSvWxZnMkL2gHjUiOp3rTyEwQaS5dFg...",
  "tags": [
    ["p", "admin_public_key"]
  ],
  "sig": "response_event_signature"
}]

The content field contains a NIP-44 encrypted JSON response object.

Admin Commands

All commands are sent as NIP-44 encrypted JSON arrays in the event content. The following table lists all available commands:

Command Type	Command Format	Description
Configuration Management
config_update	["config_update", [{"key": "auth_enabled", "value": "true", "data_type": "boolean", "category": "auth"}, {"key": "relay_description", "value": "My Relay", "data_type": "string", "category": "relay"}, ...]]	Update relay configuration parameters (supports multiple updates)
config_query	["config_query", "all"]	Query all configuration parameters
Auth Rules Management
auth_add_blacklist	["blacklist", "pubkey", "abc123..."]	Add pubkey to blacklist
auth_add_whitelist	["whitelist", "pubkey", "def456..."]	Add pubkey to whitelist
auth_delete_rule	["delete_auth_rule", "blacklist", "pubkey", "abc123..."]	Delete specific auth rule
auth_query_all	["auth_query", "all"]	Query all auth rules
auth_query_type	["auth_query", "whitelist"]	Query specific rule type
auth_query_pattern	["auth_query", "pattern", "abc123..."]	Query specific pattern
System Commands
system_clear_auth	["system_command", "clear_all_auth_rules"]	Clear all auth rules
system_status	["system_command", "system_status"]	Get system status

Available Configuration Keys

Basic Relay Settings:

• relay_name: Relay name (displayed in NIP-11)
• relay_description: Relay description text
• relay_contact: Contact information
• relay_software: Software URL
• relay_version: Software version
• supported_nips: Comma-separated list of supported NIP numbers (e.g., "1,2,4,9,11,12,13,15,16,20,22,33,40,42")
• language_tags: Comma-separated list of supported language tags (e.g., "en,es,fr" or "*" for all)
• relay_countries: Comma-separated list of supported country codes (e.g., "US,CA,MX" or "*" for all)
• posting_policy: Posting policy URL or text
• payments_url: Payment URL for premium features
• max_connections: Maximum concurrent connections
• max_subscriptions_per_client: Max subscriptions per client
• max_event_tags: Maximum tags per event
• max_content_length: Maximum event content length

Authentication & Access Control:

• auth_enabled: Enable whitelist/blacklist auth rules (true/false)
• nip42_auth_required: Enable NIP-42 cryptographic authentication (true/false)
• nip42_auth_required_kinds: Event kinds requiring NIP-42 auth (comma-separated)
• nip42_challenge_timeout: NIP-42 challenge expiration seconds

Proof of Work & Validation:

• pow_min_difficulty: Minimum proof-of-work difficulty
• nip40_expiration_enabled: Enable event expiration (true/false)

Response Format

All admin commands return signed EVENT responses via WebSocket following standard Nostr protocol. Responses use JSON content with structured data.

Response Examples

Success Response:

["EVENT", "temp_sub_id", {
  "id": "response_event_id",
  "pubkey": "relay_public_key",
  "created_at": 1234567890,
  "kind": 23457,
  "content": "nip44 encrypted:{\"query_type\": \"config_update\", \"status\": \"success\", \"message\": \"Operation completed successfully\", \"timestamp\": 1234567890}",
  "tags": [
    ["p", "admin_public_key"]
  ],
  "sig": "response_event_signature"
}]

Error Response:

["EVENT", "temp_sub_id", {
  "id": "response_event_id",
  "pubkey": "relay_public_key",
  "created_at": 1234567890,
  "kind": 23457,
  "content": "nip44 encrypted:{\"query_type\": \"config_update\", \"status\": \"error\", \"error\": \"invalid configuration value\", \"timestamp\": 1234567890}",
  "tags": [
    ["p", "admin_public_key"]
  ],
  "sig": "response_event_signature"
}]

Auth Rules Query Response:

["EVENT", "temp_sub_id", {
  "id": "response_event_id",
  "pubkey": "relay_public_key",
  "created_at": 1234567890,
  "kind": 23457,
  "content": "nip44 encrypted:{\"query_type\": \"auth_rules_all\", \"total_results\": 2, \"timestamp\": 1234567890, \"data\": [{\"rule_type\": \"blacklist\", \"pattern_type\": \"pubkey\", \"pattern_value\": \"abc123...\", \"action\": \"allow\"}]}",
  "tags": [
    ["p", "admin_public_key"]
  ],
  "sig": "response_event_signature"
}]

Configuration Query Response:

["EVENT", "temp_sub_id", {
  "id": "response_event_id",
  "pubkey": "relay_public_key",
  "created_at": 1234567890,
  "kind": 23457,
  "content": "nip44 encrypted:{\"query_type\": \"config_all\", \"total_results\": 27, \"timestamp\": 1234567890, \"data\": [{\"key\": \"auth_enabled\", \"value\": \"false\", \"data_type\": \"boolean\", \"category\": \"auth\", \"description\": \"Enable NIP-42 authentication\"}, {\"key\": \"relay_description\", \"value\": \"My Relay\", \"data_type\": \"string\", \"category\": \"relay\", \"description\": \"Relay description text\"}]}",
  "tags": [
    ["p", "admin_public_key"]
  ],
  "sig": "response_event_signature"
}]

Configuration Update Success Response:

["EVENT", "temp_sub_id", {
  "id": "response_event_id",
  "pubkey": "relay_public_key",
  "created_at": 1234567890,
  "kind": 23457,
  "content": "nip44 encrypted:{\"query_type\": \"config_update\", \"total_results\": 2, \"timestamp\": 1234567890, \"status\": \"success\", \"data\": [{\"key\": \"auth_enabled\", \"value\": \"true\", \"status\": \"updated\"}, {\"key\": \"relay_description\", \"value\": \"My Updated Relay\", \"status\": \"updated\"}]}",
  "tags": [
    ["p", "admin_public_key"]
  ],
  "sig": "response_event_signature"
}]

Configuration Update Error Response:

["EVENT", "temp_sub_id", {
  "id": "response_event_id",
  "pubkey": "relay_public_key",
  "created_at": 1234567890,
  "kind": 23457,
  "content": "nip44 encrypted:{\"query_type\": \"config_update\", \"status\": \"error\", \"error\": \"field validation failed: invalid port number '99999' (must be 1-65535)\", \"timestamp\": 1234567890}",
  "tags": [
    ["p", "admin_public_key"]
  ],
  "sig": "response_event_signature"
}]