eth_getStorageAt - Arbitrum

GET https://arb-mainnet.unifra.io/v1/{your-api-key}

Arbitrum API - Returns the value from a storage position at a given address, or in other words, returns the state of the contract's storage, which may not be exposed via the contract's methods.

Parameters

• DATA, 20 Bytes - address of the storage.
• QUANTITY - integer of the position in the storage.
• QUANTITY|TAG - integer block number, or the string "latest", "earliest" or "pending", see the default block parameter.

---

Returns

• DATA - the value at this storage position.

---

Example

Result

JSON

{
	"jsonrpc": "2.0",
	"id": 1,
	"result": "0x00000000000000000000000000000000000000000000000000000000000004d2"
}

Retrieving an element of the map is harder. The position of an element in the map is calculated with:

keccack(LeftPad32(key, 0), LeftPad32(map position, 0))

This means to retrieve the storage on

pos1[“0x391694e7e0b0cce554cb130d723a9d27458f9298”] we need to calculate the position with:

keccak(
	decodeHex(
		"000000000000000000000000391694e7e0b0cce554cb130d723a9d27458f9298" +
			"0000000000000000000000000000000000000000000000000000000000000001"
	)
);

The geth console which comes with the web3 library can be used to make the calculation:

> var key = "000000000000000000000000391694e7e0b0cce554cb130d723a9d27458f9298" + "0000000000000000000000000000000000000000000000000000000000000001"
undefined
> web3.sha3(key, {"encoding": "hex"})
"0x6661e9d6d8b923d5bbaab1b96e1dd51ff6ea2a93520fdc9eb75d059238b8c5e9"

Now to fetch the storage:

Request

Curl

curl https://arb-mainnet.unifra.io/v1/your-api-key \
-X POST \
-H "Content-Type: application/json" \
-d '{"jsonrpc":"2.0", "method": "eth_getStorageAt", "params": ["0x295a70b2de5e3953354a6a8344e616ed314d7251", "0x6661e9d6d8b923d5bbaab1b96e1dd51ff6ea2a93520fdc9eb75d059238b8c5e9", "latest"], "id": 1}'

Postman

URL: https://arb-mainnet.unifra.io/v1/your-api-key
RequestType: POST
Body:
{
    "jsonrpc":"2.0",
    "method":"eth_getStorageAt",
    "params":["0x295a70b2de5e3953354a6a8344e616ed314d7251", "0x6661e9d6d8b923d5bbaab1b96e1dd51ff6ea2a93520fdc9eb75d059238b8c5e9", "latest"],
    "id":1
}

Result

JSON

{
	"jsonrpc": "2.0",
	"id": 1,
	"result": "0x000000000000000000000000000000000000000000000000000000000000162e"
}