Application Data (appData) / Retrieve by appData hash • CoW Protocol Tutorial

As with most things in the Order Book API, we can also view the app data that we have uploaded. This is done via the getAppData method on the OrderBookApi class.

Instantiate the SDK

Since we're only using the OrderBookApi for this tutorial, we don't need to set up the adapter. The OrderBookApi works independently without requiring adapter configuration.

run.ts

import type { Web3Provider } from '@ethersproject/providers';
import { OrderBookApi, SupportedChainId } from '@cowprotocol/cow-sdk';

export async function run(provider: Web3Provider): Promise<unknown> {
	const orderBookApi = new OrderBookApi({ chainId: SupportedChainId.GNOSIS_CHAIN });
	// ...
}

Retrieving the app data

To retrieve the app data, we use the getAppData method on the OrderBookApi instance. This method takes the appDataHash and returns the app data document.

run.ts

import type { Web3Provider } from '@ethersproject/providers';
import { OrderBookApi, SupportedChainId } from '@cowprotocol/cow-sdk';

export async function run(provider: Web3Provider): Promise<unknown> {
	const orderBookApi = new OrderBookApi({ chainId: SupportedChainId.GNOSIS_CHAIN });

	// Example app data hash from a previous upload or order
	const appDataHash = '0x462ed5aa08a031342e30dcd1bc374da7ca9be2800ca7a87e43590880aa034554';

	const appDataDoc = await orderBookApi.getAppData(appDataHash);

	// ...
}

Processing the response

The response from getAppData contains a fullAppData field which is a stringified JSON object. We can parse this to get the original app data document structure.

run.ts

import type { Web3Provider } from '@ethersproject/providers';
import { OrderBookApi, SupportedChainId } from '@cowprotocol/cow-sdk';

export async function run(provider: Web3Provider): Promise<unknown> {
	const orderBookApi = new OrderBookApi({ chainId: SupportedChainId.GNOSIS_CHAIN });

	const appDataHash = '0x462ed5aa08a031342e30dcd1bc374da7ca9be2800ca7a87e43590880aa034554';
	const appDataDoc = await orderBookApi.getAppData(appDataHash);

	// Parse the stringified JSON to get the original app data structure
	const fullAppData = JSON.parse(appDataDoc.fullAppData);

	return fullAppData;
}

We can now interpret this using JSON.parse and JSON.stringify to prettify the output.

Run the code

To run the code, we can press the "Run" button in the bottom right panel (the web container).

Press the "Run" button
Observe the respective data returned to the output panel

An example output should look like:

output.json

{
	"appCode": "CoW Swap-SafeApp",
	"environment": "production",
	"metadata": {
		"orderClass": {
			"orderClass": "twap"
		},
		"quote": {
			"slippageBips": "7500"
		}
	},
	"version": "0.11.0"
}

Next: Advanced orders

import type { Web3Provider } from '@ethersproject/providers';

import { OrderBookApi, SupportedChainId } from '@cowprotocol/cow-sdk';

export async function run(provider: Web3Provider): Promise<unknown> {

	const orderBookApi = new OrderBookApi({ chainId: SupportedChainId.GNOSIS_CHAIN });

	// TODO: Retrieve app data using getAppData method

	return {};

initialising