> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cow.bleu.builders/llms.txt
> Use this file to discover all available pages before exploring further.

# App Data API

> API reference for app data management in the CoW Protocol Python SDK

The `app_data` module provides tools for creating, encoding, and managing app data for CoW Protocol orders.

## AppDataDoc

Creates and manages app data documents that can be hashed or converted to IPFS CIDs.

### Constructor

| Parameter             | Type             | Default | Description                                       |
| --------------------- | ---------------- | ------- | ------------------------------------------------- |
| `app_data_doc`        | `Dict[str, Any]` | `{}`    | Dictionary containing app data fields             |
| `app_data_doc_string` | `str`            | `""`    | Pre-serialized app data string (takes precedence) |

### Methods

| Method        | Returns | Description                                                |
| ------------- | ------- | ---------------------------------------------------------- |
| `to_string()` | `str`   | Serialize app data to deterministic JSON string            |
| `to_hex()`    | `str`   | Generate keccak256 hash of the app data (with `0x` prefix) |
| `to_cid()`    | `str`   | Convert app data to IPFS CID                               |

## AppDataHex

Converts app data hashes to IPFS CIDs and retrieves documents from IPFS.

### Constructor

| Parameter      | Type  | Description                    |
| -------------- | ----- | ------------------------------ |
| `app_data_hex` | `str` | Hex string without `0x` prefix |

### Methods

| Method                   | Returns | Description                                                |
| ------------------------ | ------- | ---------------------------------------------------------- |
| `to_cid()`               | `str`   | Returns IPFS CID (v1, base16 encoded with keccak-256 hash) |
| `async to_doc(ipfs_uri)` | `dict`  | Fetch the app data document from IPFS                      |

## AppDataCid

Converts IPFS CIDs to app data hashes and retrieves documents.

### Constructor

| Parameter      | Type  | Description     |
| -------------- | ----- | --------------- |
| `app_data_cid` | `str` | IPFS CID string |

### Methods

| Method                   | Returns | Description                                               |
| ------------------------ | ------- | --------------------------------------------------------- |
| `to_hex()`               | `str`   | Extract the app data hash from the CID (with `0x` prefix) |
| `async to_doc(ipfs_uri)` | `dict`  | Fetch app data document from IPFS                         |

## Utility Functions

### generate\_app\_data

Generate app data with common parameters like referrer address and partner fees.

```python theme={null}
from cowdao_cowpy.app_data.utils import generate_app_data, PartnerFee

result = generate_app_data(
    app_code="MyApp",
    partner_fee=PartnerFee(bps=50, recipient="0x..."),
    referrer_address="0x...",
    graffiti="Hello CoW Protocol!"
)
```

Returns a `CreateAppData` object containing `app_data_object` and `app_data_hash`.

### build\_and\_post\_app\_data

Build app data and upload it to the CoW Protocol orderbook API. Requires an `OrderBookApi` instance.

### build\_all\_app\_codes

Build and post app data across all supported chains.

### stringify\_deterministic

Serialize a dictionary to deterministic JSON (sorted keys).

### extract\_digest

Extract the hash digest from an IPFS CID.

### fetch\_doc\_from\_cid

Fetch a document from IPFS using a CID.

## Data Classes

### PartnerFee

| Field       | Type  | Description             |
| ----------- | ----- | ----------------------- |
| `bps`       | `int` | Basis points (100 = 1%) |
| `recipient` | `str` | Recipient address       |

### QuoteFee

| Field          | Type  | Default   | Description              |
| -------------- | ----- | --------- | ------------------------ |
| `slippageBips` | `int` | `1`       | Slippage in basis points |
| `version`      | `str` | `"0.2.0"` | Version string           |

### CreateAppData

| Field             | Type            | Description              |
| ----------------- | --------------- | ------------------------ |
| `app_data_object` | `AppDataObject` | The full app data object |
| `app_data_hash`   | `AppDataHash`   | The keccak256 hash       |

## Constants

```python theme={null}
from cowdao_cowpy.app_data.consts import (
    DEFAULT_APP_DATA_DOC,
    DEFAULT_IPFS_READ_URI,     # "https://cloudflare-ipfs.com/ipfs"
    DEFAULT_APP_CODE,          # "cowdao_cowpy"
    DEFAULT_GRAFFITI,
    LATEST_APP_DATA_VERSION,   # "1.3.0"
)
```

## Errors

**MetaDataError** -- Raised when there are issues with app data encoding, decoding, or CID conversion.