eth_getStorageAt

Returns the value from a storage position at a given address.

Parameters

• ADDRESS [required] a string representing the address (20 bytes) of the storage

• STORAGE-POSITION [required] a hex code of the position in the storage

• BLOCK-NUMBER [required] a hexadecimal block number, or the string latest, earliest or pending, See the default block parameter.

Request

curl

curl https://eth-mainnet.solarpath.io/v1/YOUR-API-KEY \
    -X POST \
    -H "Content-Type: application/json" \
    -d '{"jsonrpc": "2.0", "id": 1, "method": "eth_getStorageAt", "params": ["0x295a70b2de5e3953354a6a8344e616ed314d7251", "0x0", "latest"]}'

Postman

URL: https://eth-mainnet.solarpath.io/v1/YOUR-API-KEY
Request_Type: POST
Body: 
{
    "jsonrpc":"2.0",
    "method":"eth_getStorageAt",
    "params":[
        "0x295a70b2de5e3953354a6a8344e616ed314d7251",
        "0x0",
        "latest"
    ],
    "id":1
}

Response

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x0000000000000000000000000000000000000000000000000000000000000000"
}

Example

Calculating the correct position depends on the storage to retrieve. Consider the following contract deployed at 0x295a70b2de5e3953354a6a8344e616ed314d7251 by address 0x391694e7e0b0cce554cb130d723a9d27458f9298,

contract Storage {
    uint pos0;
    mapping(address => uint) pos1;
    function Storage() {
        pos0 = 1234;
        pos1[msg.sender] = 5678;
    }
}

Retrieving the value of pos0 is straight forward:

curl https://eth-mainnet.solarpath.io/v1/YOUR-API-KEY \
    -X POST \
    -H "Content-Type: application/json" \
    -d '{"jsonrpc": "2.0", "id": 1, "method": "eth_getStorageAt", "params": ["0x295a70b2de5e3953354a6a8344e616ed314d7251", "0x0", "latest"]}'

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:

curl https://eth-mainnet.solarpath.io/v1/YOUR-API-KEY \
    -X POST \
    -H "Content-Type: application/json" \
    -d '{"jsonrpc": "2.0", "id": 1, "method": "eth_getStorageAt", "params": ["0x295a70b2de5e3953354a6a8344e616ed314d7251", "0x6661e9d6d8b923d5bbaab1b96e1dd51ff6ea2a93520fdc9eb75d059238b8c5e9", "latest"]}'

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