🚀 HeaderProtocol: Event Indexer Service

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📚 Table of Contents

• 📖 Overview
• ✨ Key Features
• 📂 Directory Structure
• 🗂 Data Structure
• ⚡️ Usage in a Client Interface
• ⚙️ Running the Indexer
• 📊 Diagrams

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Overview

The HeaderProtocol Event Indexer listens to blockchain events for requested block headers, responses, commits, and refunds. It efficiently organizes this data, enabling 🔎 fast lookups and 🛠 incremental updates, even when new events arrive long after the initial request.

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Key Features

1. 🗃 Granular Storage
   Each argsBlockNumber is stored in its own file, making lookups and updates lightning-fast 🚀.

2. 📍 Instant Lookup via map.json
map.json provides an O(1) lookup from argsBlockNumber to its corresponding date directory, simplifying file access.

3. 📦 Commit Event Standardization

   • If commit is the only event for a block, it remains standalone.
   • If other events are added, the commit data is replicated in all event entries for the block, ensuring consistent structure.

4. 📜 Update History
   history.json maintains a chronological log of updates, so you can process only the latest changes.

5. 📊 Aggregated Snapshots
   Aggregates are rebuilt at 📅 daily, 🗓 monthly, and 📆 yearly levels for streamlined access to analytics.

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Directory Structure

📂 data/<network>/
├── 🗂 map.json           # 🗺 Maps argsBlockNumber → "YYYY/MM/DD"
├── 🗂 history.json       # 📜 Chronological record of updates
├── 📂 YYYY/              # 📆 Yearly directory
│   ├── 📂 MM/            # 🗓 Monthly directory
│   │   ├── 📂 DD/        # 📅 Daily directory
│   │   │   ├── 🗂 [blockNumber].json  # 🗃 Events for blockNumber
│   │   │   └── 🗂 index.json         # 📊 Daily aggregated data
│   │   └── 🗂 index.json             # 📊 Monthly aggregated data
│   └── 🗂 index.json                 # 📊 Yearly aggregated data

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Data Structure

Example [blockNumber].json:

[
  {
    "chainId": "31337",
    "blockNumber": "20",
    "headerIndex": "9",
    "createdAt": "2024-12-20T19:28:42.156Z",
    "updatedAt": "2024-12-20T19:28:42.157Z",
    "request": { "rewardAmount": "0", ... },
    "responses": [ { "responder": "0xf39Fd6...", ... } ],
    "commit": { "blockNumber": "27", ... }
  }
]

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Usage in a Client Interface

Quick Lookup 🚀

1. Use map.json to find the directory path for argsBlockNumber:

   { "1000000": "2024/12/20" }

2. Retrieve the file at data/<network>/2024/12/20/1000000.json.

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⚙️ Running the Indexer

1. Install Dependencies:

   npm install

2. Run Anvil:

   anvil

3. Deploy and Indexer HeaderProtocol:

   sudo bash ./src/anvil.sh

4. Verify Outputs:

   • ✅ map.json: Lookup table.
   • ✅ history.json: Update logs.
   • ✅ [blockNumber].json: Event data.
   • ✅ Aggregated index.json files for analytics.

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Diagrams

Sequence Diagram: How the Indexer Works

sequenceDiagram
    participant Client
    participant Indexer
    participant Blockchain
    participant Storage

    Client->>Indexer: Request indexing for block headers
    Indexer->>Blockchain: Listen for events (request, response, commit)
    Blockchain-->>Indexer: Emit events
    Indexer->>Storage: Write `argsBlockNumber.json`
    Indexer->>Storage: Update `map.json` and `history.json`
    Storage-->>Client: Return updated JSON files

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