casper-client

A client library and binary for interacting with the Casper network.

Running the client

The client runs in one of several modes, each mode performing a single action. To see all available commands:

cargo run --release -- help

example output

Casper client 1.5.0
A client for interacting with the Casper network

USAGE:
    casper-client [SUBCOMMAND]

FLAGS:
    -h, --help       Prints help information
    -V, --version    Prints version information

SUBCOMMANDS:
    put-deploy                      Creates a deploy and sends it to the network for execution
    make-deploy                     Creates a deploy and outputs it to a file or stdout. As a file, the deploy can
                                    subsequently be signed by other parties using the 'sign-deploy' subcommand and
                                    then sent to the network for execution using the 'send-deploy' subcommand
    sign-deploy                     Reads a previously-saved deploy from a file, cryptographically signs it, and
                                    outputs it to a file or stdout
    send-deploy                     Reads a previously-saved deploy from a file and sends it to the network for
                                    execution
    transfer                        Transfers funds between purses
    make-transfer                   Creates a transfer deploy and outputs it to a file or stdout. As a file, the
                                    deploy can subsequently be signed by other parties using the 'sign-deploy'
                                    subcommand and then sent to the network for execution using the 'send-deploy'
                                    subcommand
    get-deploy                      Retrieves a deploy from the network
    get-block                       Retrieves a block from the network
    get-block-transfers             Retrieves all transfers for a block from the network
    list-deploys                    Retrieves the list of all deploy hashes in a given block
    get-state-root-hash             Retrieves a state root hash at a given block
    query-global-state              Retrieves a stored value from the network using either the state root hash or
                                    block hash
    get-dictionary-item             Query for values managed in a dictionary
    get-balance                     Retrieves a purse's balance from the network
    get-account-info                Retrieve account information from the network
    get-era-info-by-switch-block    Retrieves era information from the network
    get-auction-info                Returns the bids and validators as of either a specific block (by height or
                                    hash), or the most recently added block
    get-validator-changes           Retrieves status changes of active validators
    keygen                          Generates account key files in the given directory
    generate-completion             Generates a shell completion script
    list-rpcs                       List all currently supported RPCs
    account-address                 Generates an account hash from a given public key
    help                            Prints this message or the help of the given subcommand(s)

To get further info on any command, run help followed by the subcommand, e.g.

cargo run --release -- help keygen

example output

casper-client-keygen 
Generates account key files in the given directory. Creates ["secret_key.pem", "public_key.pem", "public_key_hex"].
"public_key_hex" contains the hex-encoded key's bytes with the hex-encoded algorithm tag prefixed

USAGE:
    casper-client keygen [FLAGS] [OPTIONS] [PATH]

FLAGS:
    -f, --force      If this flag is passed, any existing output files will be overwritten. Without this flag, if any
                     output file exists, no output files will be generated and the command will fail
    -h, --help       Prints help information
    -V, --version    Prints version information

OPTIONS:
    -a, --algorithm <STRING>    The type of keys to generate [default: Ed25519]  [possible values: Ed25519, secp256k1]

ARGS:
    <PATH>    Path to output directory where key files will be created. If the path doesn't exist, it will be
              created. If not set, the current working directory will be used

Generate asymmetric signing keys

Some commands require the use of a secret key for signing data. To generate a secret and public key pair:

cargo run --release -- keygen $HOME/.client_keys

Interacting with a local node

Many client commands require sending HTTP requests and receiving responses. To do this with a local node running on the same machine, follow the instructions in the nctl README to set up a local test network.

Ensure the network has fully started before running client commands. This can be determined by running nctl-view-node-peers and checking each node has connections to all others.

For client commands requiring a node address (specified via the --node-address or -n arg), the default value is http://localhost:7777, which is the address for a real network node. The --node-address=http://localhost:11101 argument must be included for the address of the first node of a testnet started via nctl.

Transfer funds between purses

The testnet will be set up so that the nodes each have an initial balance of tokens in their main purses. Let's say we want to create a new purse under the public key we just created (in the "Generate asymmetric signing keys" section). We can do this by creating a new deploy which will transfer funds between two purses once executed. The simplest way to achieve this is via the transfer subcommand.

First, set the contents of the public_key_hex file to a variable. We'll use this as the target account:

PUBLIC_KEY=$(cat $HOME/.client_keys/public_key_hex)

Then execute the transfer subcommand. We'll specify that we want to transfer 1,234,567 tokens from the main purse of node 3, and that we'll pay a maximum of 10,000 tokens to execute this deploy:

cargo run --release -- transfer \
    --node-address=http://localhost:11101 \
    --secret-key=../casper-node/utils/nctl/assets/net-1/nodes/node-3/keys/secret_key.pem \
    --amount=1234567 \
    --target-account=$PUBLIC_KEY \
    --chain-name=casper-net-1 \
    --payment-amount=3000000000

example output

{
  "jsonrpc": "2.0",
  "result": {
    "api_version": "1.0.0",
    "deploy_hash": "c42210759368a07a1b1ff4f019f7e77e7c9eaf2961b8c9dfc4237ea2218246c9"
  },
  "id": 2564730065
}

The deploy_hash in the response is worth noting, as it can be used to identify this deploy.

Get details of a deploy

To see information about a deploy sent to the network via transfer, put-deploy, or send-deploy, you can use get-deploy, along with the deploy hash printed after executing one of these subcommands.

For example, to see if our previous transfer command generated a deploy which was executed by the network:

cargo run --release -- get-deploy --node-address=http://localhost:11101 c42210759368a07a1b1ff4f019f7e77e7c9eaf2961b8c9dfc4237ea2218246c9

example output

{
  "jsonrpc": "2.0",
  "result": {
    "api_version": "1.0.0",
    "deploy": {
      "approvals": [
        {
          "signature": "0140850c4f74aaad24894ce2d0e3efb64f599633fad4e280f39529dbd062ab49ca6a1f0bd6f20a8cddeab68e95ae5ea416a5b2ae3a02a0bc7a714c2915106e1c09",
          "signer": "015b7723f1d9499fa02bd17dfe4e1315cfe1660a071e27ab1f29d6ceb6e2abcd73"
        }
      ],
      "hash": "c42210759368a07a1b1ff4f019f7e77e7c9eaf2961b8c9dfc4237ea2218246c9",
      "header": {
        "account": "015b7723f1d9499fa02bd17dfe4e1315cfe1660a071e27ab1f29d6ceb6e2abcd73",
        "body_hash": "c66f1040f8f2aeafee73b7c0811e00fd6eb63a6a5992d7cc0f967e14704dd35b",
        "chain_name": "casper-net-1",
        "dependencies": [],
        "gas_price": 10,
        "timestamp": "2020-10-15T13:23:45.355Z",
        "ttl": "1h"
      },
      "payment": {
        "ModuleBytes": {
          "args": "0100000006000000616d6f756e740300000002102708",
          "module_bytes": ""
        }
      },
      "session": {
        "Transfer": {
          "args": "0200000006000000616d6f756e74040000000387d612080600000074617267657420000000018189fd2d42c36d951f9803e595795a3a0fc07aa999c88a28d286c7cbf338940f0320000000"
        }
      }
    },
    "execution_results": [
      {
        "block_hash": "80a09df67f45bfb290c8f36021daf2fb898587a48fa0e4f7c506202ae8f791b8",
        "result": {
          "cost": "0",
          "effect": {
            "operations": {
              "account-hash-018189fd2d42c36d951f9803e595795a3a0fc07aa999c88a28d286c7cbf33894": "Write",
              "hash-09480c3248ef76b603d386f3f4f8a5f87f597d4eaffd475433f861af187ab5db": "Write",
              "hash-d46e35465520ef9f868be3f26eaded1585dd66ac410706bab4b7adf92bdf528a": "Read",
              "hash-ea274222cc975e4daec2cced17a0270df7c282e865115d98f544a35877af5271": "Add",
              "uref-09480c3248ef76b603d386f3f4f8a5f87f597d4eaffd475433f861af187ab5db-000": "Write",
              "uref-8e7893be4b33bc5eacde4dd684b030593200364a211b8566ed9458ccbafbcde9-000": "Write",
              "uref-b645152645faa6c3f7708fd362a118296f7f4d39dc065c120877d13b6981cd67-000": "Write"
            },
            "transforms": {
              "account-hash-018189fd2d42c36d951f9803e595795a3a0fc07aa999c88a28d286c7cbf33894": "WriteAccount",
              "hash-09480c3248ef76b603d386f3f4f8a5f87f597d4eaffd475433f861af187ab5db": {
                "WriteCLValue": {
                  "bytes": "02b645152645faa6c3f7708fd362a118296f7f4d39dc065c120877d13b6981cd6707",
                  "cl_type": "Key"
                }
              },
              "hash-d46e35465520ef9f868be3f26eaded1585dd66ac410706bab4b7adf92bdf528a": "Identity",
              "hash-ea274222cc975e4daec2cced17a0270df7c282e865115d98f544a35877af5271": {
                "AddKeys": {
                  "uref-09480c3248ef76b603d386f3f4f8a5f87f597d4eaffd475433f861af187ab5db-000": "uref-b645152645faa6c3f7708fd362a118296f7f4d39dc065c120877d13b6981cd67-007"
                }
              },
              "uref-09480c3248ef76b603d386f3f4f8a5f87f597d4eaffd475433f861af187ab5db-000": {
                "WriteCLValue": {
                  "bytes": "",
                  "cl_type": "Unit"
                }
              },
              "uref-8e7893be4b33bc5eacde4dd684b030593200364a211b8566ed9458ccbafbcde9-000": {
                "WriteCLValue": {
                  "bytes": "087929775d78456301",
                  "cl_type": "U512"
                }
              },
              "uref-b645152645faa6c3f7708fd362a118296f7f4d39dc065c120877d13b6981cd67-000": {
                "WriteCLValue": {
                  "bytes": "0387d612",
                  "cl_type": "U512"
                }
              }
            }
          },
          "error_message": null
        }
      }
    ]
  },
  "id": 592430140
}

The block_hash in the response's execution_results is worth noting, as it can be used to identify the block in which the deploy is included. If the deploy was successfully received and parsed by the node, but failed to execute, the error_message in execution_results may provide useful information.

Get details of a Block

To see information about a Block created by the network, you can use get-block. For example:

cargo run --release -- get-block \
    --node-address=http://localhost:11101 \
    --block-hash=80a09df67f45bfb290c8f36021daf2fb898587a48fa0e4f7c506202ae8f791b8

example output

{
  "jsonrpc": "2.0",
  "result": {
    "api_version": "1.0.0",
    "block": {
      "body": null,
      "hash": "80a09df67f45bfb290c8f36021daf2fb898587a48fa0e4f7c506202ae8f791b8",
      "header": {
        "accumulated_seed": "e8c65524331dc950d9065c289deb05458d3f9d8beba15e663a5418f5a6c7bed5",
        "body_hash": "0e5751c026e543b2e8ab2eb06099daa1d1e5df47778f7787faab45cdf12fe3a8",
        "deploy_hashes": [
          "c42210759368a07a1b1ff4f019f7e77e7c9eaf2961b8c9dfc4237ea2218246c9"
        ],
        "era_end": null,
        "era_id": 89,
        "state_root_hash": "c79f4c9a017532fe265593d86d3917581479fd1601093e16d17ec90aeaa63b83",
        "height": 987,
        "parent_hash": "ffb95eac42eae1112d37797a1ecc67860e88a9364c44845cb7a96eb426dca502",
        "proposer": "015b7723f1d9499fa02bd17dfe4e1315cfe1660a071e27ab1f29d6ceb6e2abcd73",
        "random_bit": true,
        "timestamp": "2020-10-15T13:23:48.352Z"
      },
      "proofs": [
        "0104df3fe39567d22a48b68c4b046dadf5af6552c45b1a93613c89a65caa98b12a4564ba1a794e77787eb3d37c19617ca344f2a304387a0364fee0e8f89da2da0d"
      ]
    }
  },
  "id": 3484548969
}

The state_root_hash in the response's header is worth noting, as it can be used to identify the state root hash for the purposes of querying the global state.

Get all Transfers contained in a Block

To retrieve all Transfer transactions processed in a Block created by the network, you can use get-block-transfers. For example:

cargo run --release -- get-block-transfers \
    --node-address=http://localhost:11101 \
    --block-hash=80a09df67f45bfb290c8f36021daf2fb898587a48fa0e4f7c506202ae8f791b8

example output

{
  "jsonrpc": "2.0",
  "result": {
    "api_version": "1.0.0",
    "block_hash": "80a09df67f45bfb290c8f36021daf2fb898587a48fa0e4f7c506202ae8f791b8",
    "transfers": [
      {
        "amount": "100000000",
        "deploy_hash": "ab87c5f2c0f6f331bf488703676fb0c68f897282dfbb8e085752f220a3dfc25e",
        "from": "account-hash-1ace33e66142d5a0679ba5507ef75b9c09888d1567e86100d1db535fa819a962",
        "gas": "0",
        "id": null,
        "source": "uref-21f7316e72d1baa7b706a9083077d643665ad3a56673c594db9762ceac4f3788-007",
        "target": "uref-c5eb9788156b53c9a599dfb5e591c6399580b491c72086a6bc028dd18fdfcb2d-004"
      }
    ]
  },
  "id": 7229488934468542904
}

Query the global state

To view data stored to global state after executing a deploy, you can use query-global-state. For example, to see the value stored under our new account's public key:

cargo run --release -- query-global-state \
    --node-address=http://localhost:11101 \
    --state-root-hash=242666f5959e6a51b7a75c23264f3cb326eecd6bec6dbab147f5801ec23daed6 \
    --key=$PUBLIC_KEY

example output

{
  "jsonrpc": "2.0",
  "result": {
    "api_version": "1.0.0",
    "stored_value": {
      "Account": {
        "account_hash": "018189fd2d42c36d951f9803e595795a3a0fc07aa999c88a28d286c7cbf33894",
        "action_thresholds": {
          "deployment": 1,
          "key_management": 1
        },
        "associated_keys": [
          {
            "account_hash": "018189fd2d42c36d951f9803e595795a3a0fc07aa999c88a28d286c7cbf33894",
            "weight": 1
          }
        ],
        "main_purse": "uref-09480c3248ef76b603d386f3f4f8a5f87f597d4eaffd475433f861af187ab5db-007",
        "named_keys": {}
      }
    }
  },
  "id": 3649040235
}

This yields details of the newly-created account object, including the URef of the account's main purse.

Get the balance of a purse

This can be done via get-balance. For example, to get the balance of the main purse of our newly-created account:

cargo run --release -- get-balance \
    --node-address=http://localhost:11101 \
    --state-root-hash=242666f5959e6a51b7a75c23264f3cb326eecd6bec6dbab147f5801ec23daed6 \
    --purse-uref=uref-09480c3248ef76b603d386f3f4f8a5f87f597d4eaffd475433f861af187ab5db-007

example output

{
  "jsonrpc": "2.0",
  "result": {
    "api_version": "1.0.0",
    "balance_value": "1234567"
  },
  "id": 4193583276
}

Note that the system mint contract is required to retrieve the balance of any given purse. If you execute a query-global-state specifying a purse URef as the --key argument, you'll find that the actual value stored there is a unit value (). This makes the get-balance subcommand particularly useful.

---

Client library

The lib directory contains source for the client library, which may be called directly rather than through the CLI binary. The CLI app casper-client makes use of this library to implement its functionality.

---

Client library C wrapper

An optional feature of the client library is to use cbindgen to build a C wrapper for functions in the library. This can then be leveraged to build bindings for the library in any language that can access an extern "C" interface.

The feature is named ffi and is enabled by default.

See the examples README for more information.

---

License

Licensed under the Apache License Version 2.0.