Translate

JSON RPC

Methods Name Changed ！ For the user of V0.16 and older versions: Please pay attention that we deprecated the pre-fix in the name of JSON-RPC interfaces, which makes it looks more tidy and easier to use.

JSON RPC

• peerCount
• blockNumber
• sendRawTransaction
• getBlockByHash
• getBlockByNumber
• getTransactionReceipt
• getLogs
• call
• getTransaction
• getTransactionCount
• getCode
• getAbi
• getBalance
• newFilter
• newBlockFilter
• uninstallFilter
• getFilterChanges
• getFilterLogs
• getTransactionProof
• getMetaData
• getBlockHeader
• getStateProof
• getStorageAt

---

peerCount

当前节点连接数。

• Parameters

  None

• Returns

  Quantity - integer of the number of connected peers.

• Example

    // Request
    curl -X POST --data '{"jsonrpc":"2.0","method":"peerCount","params":[],"id":74}'
    ```

    ```json
    // Result
    {
        "id": 74,
        "jsonrpc": "2.0",
        "result": "0x3"
    }
    ```

***

### blockNumber
返回当前块高度。

* Parameters

    None

* Returns

    `Quantity` - integer of current block height of CITA.

* Example

    ```shell
    // Request
    curl -X POST --data '{"jsonrpc":"2.0","method":"blockNumber","params":[],"id":83}'
    ```

    ```json
    // Result
    {
        "id": 83,
        "jsonrpc": "2.0",
        "result": "0x1d10"
    }
    ```

***

### sendRawTransaction

通过序列化交易调用区块链接口。

* Parameters

    1. `Data`, The signed transaction data.

    ```js
    const signed_data = "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"
    params: [signed_data]
    ```

#### 生成签名交易的过程

#### 构造protobuf数据结构

```protobuf
// Transaction
syntax = "proto3";
enum Crypto {
    SECP = 0;
    SM2 = 1;
}

message Transaction {
    string to = 1;
    string nonce = 2;
    uint64 quota = 3; // gas
    uint64 valid_until_block = 4;
    bytes data = 5;
    bytes value = 6;
    uint32 chain_id = 7;
    uint32 version = 8;
}

message UnverifiedTransaction {
    Transaction transaction = 1;
    bytes signature = 2;
    Crypto crypto = 3;
}

一些交易字段的说明

• to -> 交易要发送到的地址。

  调用合约时即为被调用合约的地址，部署合约时不填写该字段。注意地址形式为 40 个十六进制字符(160 位)，前导 0 不能省略，必须补全。

• nonce -> 交易的填充字段。

  区块链为了防止重放攻击，会拒绝接受重复的交易。如果交易中仅包含有效的交易数据，会存在两个正常的交易完全一样的情况。比如两次转账，如果转账人，收款人和金额都一样，那么两个交易就完全一样。因此需要用户在交易中填充一些内容，使得两个交易不一样。

  填充内容的形式为字符串，最大长度 128，具体内容用户自己定义。

• quota -> 交易的配额。

  合约的能力是图灵完备的，具备强大功能的同时，也意味着交易执行过程中可能出现死循环等无法终止的情况。因此，每个交易都要填写一个配额，指定交易最大执行时间，使得交易执行一定可以终止。如果是 solidity 编写的合约，有配套工具可以估算调用合约中的函数需要的配额数量。

• valid_until_block -> 交易上链的最大区块高度。

  区块链的发送交易接口是异步的，交易进入交易池接口即返回。后面需要用户轮询交易什么时候真正上链得到确认。视系统的拥堵情况，等待时间并没有一个确定的值。甚至有可能在后续环节发生错误，最终没有上链。因此用户轮询一段时间之后，发现交易还没有上链，这时无法确定交易的状态(失败 or 拥堵)。发送交易操作没有幂等性，因此无法通过重复发送交易来解决。所以需要一个类似超时的机制，保证等待一段时间之后，交易的状态就确定是失败的。

  该字段就是起这个作用，表示用户愿意等待交易上链的最大区块高度。在区块链达到该高度之后，交易就确定不会再上链了，用户可以放心地重新发送交易，或者进行其他的后续处理。

  实际使用中，可选的值在当前区块高度到当前区块高度 +100 之间。

获得合约对应的bytecode

以下代码片段为示例代码，具体获取 contract bytecode 的方法参考文档

solidity相关文档

pragma solidity ^0.4.24;

contract SimpleStorage {
    uint storedData;

    function set(uint x) public {
        storedData = x;
    }

    function get() view public returns (uint) {
        return storedData;
    }
}

构造签名

1. 构造Transaction对象tx，填充to, nonce, valid_until_block, quota, data, value, chain_id, version 8个字段。
2. tx对象protobuf序列化后 sha3 -> hash
3. 对 hash 进行签名 -> signature
4. 构造UnverifiedTransaction, 使用hash, signature, SECP填充UnverifiedTransaction -> unverify_tx
5. unverify_tx对象protobuf序列化

伪代码描述:

let tx = Transaction::new();
// contract bytecode
let data = "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".from_hex();
tx.setdata(data);
if not depoly_contract {
    tx.setTo(address);
}

// current_block_height 可以通过CITA JSON-RPC接口 blockNumber 获取
let valid_util_block = current_block_height + 88;
tx.set_valid_until_block(valid_util_block);

tx.set_nonce(nonce);

// 如果是solidity合约，可以通过solc --gas获取估算gas值，在此基础上加50%，或者在remix中运行获取的实际消耗gas上加一点
tx.set_quota(quota);

// 当前version 默认为0
tx.set_version(verison);

// language_depend_method和sign 分别是相应的语言或库中处理私钥和签名的方法
let privkey = language_depend_method("966fc50326cf6e2b30b06d8214737fcc2cda5bdce84eb23e14b6dbf3540d3f84");
let signature = sign(privkey, tx.protobuf_serialize().hash());

let unverify_tx = UnverifiedTransaction::new();
unverify_tx.transaction = tx;
unverify_tx.signature = signature;
unverify_tx.crypto = SECP;

params = unverify_tx.protobuf_serialize().to_hex_string();

签名后的交易

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

• Returns

  Data32 - 交易hash

• Example

    // Request
    curl -X POST --data '{"jsonrpc":"2.0","method":"sendRawTransaction","params":["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"],"id":1}'
    ```

    ```json
    // Result
    {
        "jsonrpc": "2.0",
        "id": 1,
        "result": {
            "hash": "0x4b5d67c1debdd5899fc7b5cd77e71987b8a2d174b361ca2dd4d713434b4ff037",
            "status": "OK"
        }
    }
    ```

    ```json
    // 如果是近期发送的重复交易，则会提示重复交易
    {
        "jsonrpc": "2.0",
        "id": 1,
        "error": {
            "code": -32006,
            "message": "Dup"//重复交易
        }
    }
    ```

***

### getBlockByHash

根据块hash查询块的信息。

* Parameters

    1. `Data32` - Hash of a block.
    2. `Boolean` - 是否返回交易信息(True: 返回详细交易列表| False: 只返回交易hash).

```js
params: [
    '0x296474ecb4c2c8c92b0ba7800a01530b70a6f2b6e76e5c2ed2f89356429ef329',
    true
]

• Returns

  1. Object - A block object, or null when no block was found:

• Example

    // Request
    curl -X POST --data '{"jsonrpc":"2.0","method":"getBlockByHash","params":["0x296474ecb4c2c8c92b0ba7800a01530b70a6f2b6e76e5c2ed2f89356429ef329", true],"id":1}'
    ```

    ```json
    // Result
    {
        "jsonrpc": "2.0",
        "id": 1,
        "result": {
            "version": 0,
            "hash": "0x5038c222d460c32fd06df36d58bb7cf5c368a55e207a46ecb18695451bfe4069",
            "header": {
                "timestamp": 1499756200950,
                "prevHash": "0xb28ec1911d375350664b9673a61d952e9a748f3e63606f1440f313c4911fde58",
                "proof": {
                    "proposal": "0x0f25d396361c7d54bb16389f6a14bf95207915f91d180d382093e19adfc4133b",
                    "height": 902,
                    "round": 0,
                    "commits": {
                        "0x2b027dacd33a41ddb09e21805778f19951776ed5": "0x1532c58faedf9e103dd84aa6aacbd2121aa3a8102faa506e7e152fb10e45bafd31b1c3d372cf5d42f8b27a8bfea112ae194de76d99206f73837ad8c30267e6a501",
                        "0x2d74a106464fbdf94e47bb28605a1aa244ab7788": "0x2ec53371cee732d59d23a58cf6cf53d818fb906fdeb5b0521a3a4cdbb75cf29658a1ff5fa95e4dc71563cbed10070c68e2eec0f812fa3be8e019b6df6e9ea66201",
                        "0x3efd4959af72e1214ab83caa0f04a0cc3e54d383": "0xb051f0cc41bc3caed472d3c7a35e06d805e8f6d15ccb3efc257d71ee96932c5877a8e52fc29cb3bef73e0edbad62c617c4dd16763709b2604ab8b1db2d87736301",
                        "0x5223818f7096520bfad68ce3d5ac959267dbc45f": "0x1cf6f8dc9654d461a317db199de0ed0d2d008762833b3358e269ceb3c412b60b3f1a2bd08f969e0dc1c9ebe1a0710002f853438a6ef3ea048de9b4e67387827400"
                    }
                },
                "stateRoot": "0xe29266e5574bc0c848b513d36403d4da71f99f328d3324e8d3134809c33d4fb4",
                "transactionsRoot": "0xf31e32611322f410f430ef8141c2237c19dd1034eddef8dedba692ec9851799b",
                "receiptsRoot": "0x9646cf2572734b4b13fe1616446ab2658e208cfdbaf25e47ebea9b6327e10c5b",
                "gasUsed": "0x0",
                "number": "0x387",
                "proposer":"0xe6d430a2d830236d3774d148cbee72bbf26cd481",
            },
            "body": {
                "transactions": [
                    {
                        "hash": "0xf31e32611322f410f430ef8141c2237c19dd1034eddef8dedba692ec9851799b",
                        "content":"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"
                    }
                ]
            }
        }
    }

    ```

***

### getBlockByNumber

根据块高度查询块信息。

* Parameters

    1. `Quantity` - integer of a block height.
    2. `Boolean` - 是否返回交易信息(True: 返回详细交易列表| False: 只返回交易hash).

```shell
params: [
    0x1da3,
    true
]

• Returns

  See getBlockByHash

• Example

    // Request
    curl -X POST --data '{"jsonrpc":"2.0","method":"getBlockByNumber","params":["0xF9", true],"id":1}'
    ```

* Invalid Params

    ```shell
    curl -X POST --data '{"jsonrpc":"2.0","method":"getBlockByNumber","params":["0XF9", true],"id":1}'
    # 或者
    curl -X POST --data '{"jsonrpc":"2.0","method":"getBlockByNumber","params":[249, true],"id":1}'
    ```

高度参数可以用0x开头的十六进制。0X开头或者十进制整数都是错误的参数格式。

同 [getBlockByHash](#getblockbyhash)

***

### getTransactionReceipt

根据交易hash获取交易回执。

* Parameters

    1. `Data32` - hash of a transaction

```json
params: [
    "0xb38e5b6572b2613cab8088f93e6835576209f2b796104779b4a43fa5adc737af"
]

• Returns

  Object - A receipt object:

  • transactionHash: Data32 - hash of the transaction.
  • transactionIndex: Quantity - transaction index.
  • blockHash: Data32 - hash of the block where this transaction was in. null when its not in block.
  • blockNumber: Quantity - block number where this transaction was in. null when its not in block.
  • cumulativeGasUsed: Quantity - The total amount of gas used when this transaction was executed in the block.
  • gasUsed: Quantity - The amount of gas used by this specific transaction alone.
  • contractAddress: Data20 - The contract address created, if the transaction was a contract creation, otherwise null.
  • logs: Array - Array of log objects, which this transaction generated.
  • root: Data32 of post-transaction stateroot.
  • errorMessage: String execution error message.

  Receipt error messages:

  • No transaction permission.
  • No contract permission.
  • Not enough base quota.
  • Block quota limit reached.
  • Account quota limit reached.
  • Out of quota.
  • Jump position wasn't marked with JUMPDEST instruction.
  • Instruction is not supported.
  • Not enough stack elements to execute instruction.
  • Execution would exceed defined Stack Limit.
  • EVM internal error.
  • Mutable call in static context.
  • Out of bounds.
  • Reverted.

• Example

    // Request
    curl -X POST --data '{"jsonrpc":"2.0","method":"getTransactionReceipt","params":["0x019abfa50cbb6df5b6dc41eabba47db4e7eb1787a96fd5836820d581287e0236"],"id":1}'
    ```

    ```json
    // Result
    {
        "jsonrpc":"2.0",
        "id":1,
        "result":{
            "transactionHash":"0xb38e5b6572b2613cab8088f93e6835576209f2b796104779b4a43fa5adc737af",
            "transactionIndex":"0x0",
            "blockHash":"0xe068cf7299450b78fe97ed370fd9ebe09ecbd6786968e474fae862ccbd5c5020",
            "blockNumber":"0xa",
            "cumulativeGasUsed":"0x17a0f",
            "gasUsed":"0x17a0f",
            "contractAddress":"0xea4f6bc98b456ef085da5c424db710489848cab5",
            "logs":[
                {
                    "address":"0xea4f6bc98b456ef085da5c424db710489848cab5",
                    "topics":[
                        "0x8fb1356be6b2a4e49ee94447eb9dcb8783f51c41dcddfe7919f945017d163bf3"
                    ],
                    "data":"0x0000000000000000000000005b073e9233944b5e729e46d618f0d8edf3d9c34a0000000000000000000000000000000000000000000000000000000000000064",
                    "blockHash":"0xe068cf7299450b78fe97ed370fd9ebe09ecbd6786968e474fae862ccbd5c5020",
                    "blockNumber":"0xa",
                    "transactionHash":"0xb38e5b6572b2613cab8088f93e6835576209f2b796104779b4a43fa5adc737af",
                    "transactionIndex":"0x0",
                    "logIndex":"0x0",
                    "transactionLogIndex":"0x0"
                }
            ],
            "root":"0xe702d654a292a8d074fd5ba3769b3dead8095d2a8f2207b3a69bd49c91a178af",
            "logsBloom":"0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000100040000000010000200000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000040000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"
        }
    }
    ```

    ```json
    // error
    {
        "contractAddress": "0xbb6f8266fae605da373c2526c386fe07542b4957",
        "cumulativeGasUsed": "0x0",
        "logs": [],
        "blockHash": "0x296474ecb4c2c8c92b0ba7800a01530b70a6f2b6e76e5c2ed2f89356429ef329",
        "transactionHash": "0x019abfa50cbb6df5b6dc41eabba47db4e7eb1787a96fd5836820d581287e0236",
        "root": null,
        "errorMessage": "No contract permission.",
        "blockNumber": "0x1da3",
        "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
        "transactionIndex": "0x0",
        "gasUsed": "0x0"
    }
    ```

如果出现**Timeout，errorcode 99**,请查看可能的解决方法[Can't assign requested Address](https://vincent.bernat.im/en/blog/2014-tcp-time-wait-state-linux)

***

### getLogs

根据Topic查询logs。

* Parameters

    1. `Filter` - The filter object，详见 `Filter` 的说明。

* Returns

    `Array` - Array of log objects, or an empty array if no logs

    * `address` - 合约地址
    * `topics`- 用来构造过滤器的topics
    * `data`- 经过 topics 筛选的 log 数据

* Example

    ```shell
    // Request
    curl -X POST --data '{"jsonrpc":"2.0","method":"getLogs","params":[{"topics":["0x8fb1356be6b2a4e49ee94447eb9dcb8783f51c41dcddfe7919f945017d163bf3"],"fromBlock": "0x0"}],"id":74}'
    ```

    ```json
    // Result
    {
        "jsonrpc":"2.0",
        "id":74,
        "result":[
            {
                "address":"0xea4f6bc98b456ef085da5c424db710489848cab5",
                "topics":[
                    "0x8fb1356be6b2a4e49ee94447eb9dcb8783f51c41dcddfe7919f945017d163bf3"
                ],
                "data":"0x0000000000000000000000005b073e9233944b5e729e46d618f0d8edf3d9c34a0000000000000000000000000000000000000000000000000000000000000064",
                "blockHash":"0x3e83b74560860344f4c48d7b8089a18173aecd96b6b2148653c61b5d3f559764",
                "blockNumber":"0x4",
                "transactionHash":"0xb38e5b6572b2613cab8088f93e6835576209f2b796104779b4a43fa5adc737af",
                "transactionIndex":"0x0",
                "logIndex":"0x0",
                "transactionLogIndex":"0x0"
            }
        ]
    }
    ```

***

### call

合约接口调用。

* Parameters

    1. `CallRequest` - The transaction call object. 详见 `CallRequest` 的说明。
    2. `BlockNumber` - block parameter.

```shell
params: [
    {
        "from":"0xca35b7d915458ef540ade6068dfe2f44e8fa733c",
        "to":"0xea4f6bc98b456ef085da5c424db710489848cab5",
        "data":"0x6d4ce63c"
    },
    "0x1d23"
]

• Returns

  Data32 - the transaction hash.

• Example

  contract中get方法Hash和编码后的数据

    0x6d4ce63c
    ```

发送和获取数据

```shell
// Request
curl -X POST --data '{"jsonrpc":"2.0","method":"call","params":[{"from":"0xca35b7d915458ef540ade6068dfe2f44e8fa733c","to":"0xea4f6bc98b456ef085da5c424db710489848cab5","data":"0x6d4ce63c"}, "latest"],"id":2}'

// Result
{
  "jsonrpc": "2.0",
  "id": 2,
  "result": "0x0000000000000000000000000000000000000000000000000000000000000064"
}

---

getTransaction

根据交易hash查询交易。

• Parameters

  1. Data32 - hash of a transaction

params: [
    "0x019abfa50cbb6df5b6dc41eabba47db4e7eb1787a96fd5836820d581287e0236"
]

• Returns

  Object - A transaction object, or null when no transaction was found:

  • hash: Data32 - hash of the transaction.
  • content: Data 交易内容.
  • from: Data20 - address of the transaction sender.
  • blockHash: Data32 - hash of the block where this transaction was in. null when its not in block.
  • blockNumber: Quantity - block number where this transaction was in. null when its not in block.
  • index: Quantity - integer of the transactions index position in the block. null when its not in block.

• Example

    // Request
    curl -X POST --data '{"jsonrpc":"2.0","method":"getTransaction","params":["0x019abfa50cbb6df5b6dc41eabba47db4e7eb1787a96fd5836820d581287e0236"],"id":1}'
    ```

    ```json
    // Result
    {
        "jsonrpc": "2.0",
        "id": 1,
        "result": {
            "hash": "0x019abfa50cbb6df5b6dc41eabba47db4e7eb1787a96fd5836820d581287e0236",
            "content": "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",
            "from": "0x5b073e9233944b5e729e46d618f0d8edf3d9c34a",
            "blockNumber": "0x1da3",
            "blockHash": "0x296474ecb4c2c8c92b0ba7800a01530b70a6f2b6e76e5c2ed2f89356429ef329",
            "index": "0x0"
        }
    }
    ```

***

### getTransactionCount

获取账户发送交易的数量。

* Parameters

    1. `Data20` - address.
    2. `BlockNumber` - `BlockNumber`

* Returns

    `Quantity` - integer of the number of transactions send from this address.

* Example

    ```shell
    curl -X POST --data '{"jsonrpc":"2.0","method":"getTransactionCount","params":["0x5b073e9233944b5e729e46d618f0d8edf3d9c34a","latest"],"id":1}'
    ```

    ```json
    // Result:
    {
        "jsonrpc": "2.0",
        "id": 1,
        "result": "0x1"
    }

    ```

***

### getCode

获取合约代码。

* Parameters

    1. `Data20` - address.
    2. `BlockNumber` - `BlockNumber`

* Returns

    `Data` - the code from the given address.

* Example

    ```shell
    curl -X POST --data '{"jsonrpc":"2.0","method":"getCode","params":["0xea4f6bc98b456ef085da5c424db710489848cab5", "latest"],"id":1}'
    ```

    ```json
    // Result:
    {
        "jsonrpc": "2.0",
        "id": 1,
        "result": "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"
    }
    ```

***

### getAbi

获取合约ABI

* Parameters

    1. `Data20` - address.
    2. `BlockNumber` - `BlockNumber`

* Returns

    `Data` - the abi from the given address.

* Example

    ```shell
    curl -X POST --data '{"jsonrpc":"2.0","method":"getAbi","params":["0x73552bc4e960a1d53013b40074569ea05b950b4d", "latest"],"id":1}'
    ```

    ```json
    // Result:
    {
        "jsonrpc": "2.0",
        "id": 1,
        "result": "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"
    }

    ```

### 在Account中保存ABI和获取ABI

默认将接收方地址为`0xffffffffffffffffffffffffffffffffff010001` 的交易为保存合约ABI交易类型。

#### 保存ABI

保存合约 ABI 到 Account，主要步骤为：

1. 需要先成功创建合约，得到合约地址；
2. 使用 solc 编译合约代码得到 ABI，以 String 类型编码成相应参数，详情见[Ethereum Contract ABI](https://github.com/ethereum/wiki/wiki/Ethereum-Contract-ABI)；
3. 构造交易 data，前 20 字节为合约地址，后面字节为 abi 的编码成的 bytes；
4. 发送交易，使用`sendRawTransaction`接口；

Example

以`https://github.com/cryptape/test-contracts/blob/master/SimpleStorage.sol`这个合约为例子，正常在链上创建该合约；

用 [cita-cli](https://github.com/cryptape/cita-cli) 命令行模式（与交互式模式的命令是一致的）进行演示。

- 首先可以通过solc得到合约的ABI；

```shell
$ solc --abi SimpleStorage.sol

输出：

[{"constant":false,"inputs":[{"name":"x","type":"uint256"}],"name":"set","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"get","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"}]

• 将abi作为String类型，编码结果如下：

  0x4ed3885e000000000000000000000000000000000000000000000000000000000000002 000000000000000000000000000000000000000000000000000000000000001275b7b2263 6f6e7374616e74223a66616c73652c22696e70757473223a5b7b226e616d65223a2278222 c2274797065223a2275696e74323536227d5d2c226e616d65223a22736574222c226f7574 70757473223a5b5d2c2270617961626c65223a66616c73652c2273746174654d757461626 96c697479223a226e6f6e70617961626c65222c2274797065223a2266756e6374696f6e22 7d2c7b22636f6e7374616e74223a747275652c22696e70757473223a5b5d2c226e616d652 23a22676574222c226f757470757473223a5b7b226e616d65223a22222c2274797065223a 2275696e74323536227d5d2c2270617961626c65223a66616c73652c2273746174654d757 46162696c697479223a2276696577222c2274797065223a2266756e6374696f6e227d5d00 000000000000000000000000000000000000000000000000

• Store abi

$ cita-cli store abi \
    --code 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 \
    --private-key 0x5f0258a4778057a8a7d97809bd209055b2fbafa654ce7d31ec7191066b9225e6 \
    --address 0x5839153e0efe76efe0c974b728c4f49ca7ed75cc \
    --url http://127.0.0.1:1337

输出：

{
  "id": 3,
  "jsonrpc": "2.0",
  "result": {
    "hash": "0x3690665c3ce5548e74113ab88b1bc81b72f48564211f1341735b9fb17914ff91",
    "status": "OK"
  }
}

查询abi

<br />$ cita-cli rpc getAbi \
    --address 0x5839153e0efe76efe0c974b728c4f49ca7ed75cc \
    --url http://127.0.0.1:1337

输出：

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

---

getBalance

获取合约余额。

• Parameters

  1. Data20 - address.
  2. BlockNumber - BlockNumber

• Returns

  Quantity - the balance from the given address.

• Example

    curl -X POST --data '{"jsonrpc":"2.0","method":"getBalance","params":["0xea4f6bc98b456ef085da5c424db710489848cab5", "latest"],"id":1}'
    ```

    ```json
    // Result:
    {
        "jsonrpc": "2.0",
        "id": 1,
        "result": "0x0"
    }
    ```

***

### newFilter

Creates a filter object, based on filter options, to notify when the state changes (logs). To check if the state has changed, call getFilterChanges.

* Parameters

    1. `Filter` - The filter object, see [getLogs](#getlogs)

* Returns

    `Quantity` - A filter id.

* Example

    ```shell
    curl -X POST --data '{"jsonrpc":"2.0","method":"newFilter","params":[{"topics":["0x8fb1356be6b2a4e49ee94447eb9dcb8783f51c41dcddfe7919f945017d163bf3"]}],"id":1}'
    ```

    ```json
    // Result
    {
        "id":1,
        "jsonrpc": "2.0",
        "result": "0x1"
    }
    ```

***

### newBlockFilter

Creates a filter in the node, to notify when a new block arrives. To check if the state has changed, call getFilterChanges.

* Parameters

    None

* Returns

    `Quantity` - A filter id.

* Example

    ```shell
    curl -X POST --data '{"jsonrpc":"2.0","method":"newBlockFilter","params":[],"id":73}'
    ```

    ```json
    // Result
    {
        "id":1,
        "jsonrpc":  "2.0",
        "result": "0x1"
    }
    ```

***

### uninstallFilter

Uninstalls a filter with given id. Should always be called when watch is no longer needed.
Additonally Filters timeout when they aren't requested with getFilterChanges for a period of time.

* Parameters

    1. `Quantity` - The filter id.

* Returns

    `Boolean` - true if the filter was successfully uninstalled, otherwise false.

* Example

    ```shell
    curl -X POST --data '{"jsonrpc":"2.0","method":"uninstallFilter","params":["0xb"],"id":73}'
    ```

    ```json
    // Result
    {
        "id":1,
        "jsonrpc": "2.0",
        "result": true
    }
    ```

***

### getFilterChanges

Polling method for a filter, which returns an array of logs which occurred since last poll.

* Parameters

    1. `Quantity` - The filter id.

* Returns

    `Array` - Array of log objects, or an empty array if nothing has changed since last poll.
    同 [getLogs](#getlogs)

* Example

    ```shell
    curl -X POST --data '{"jsonrpc":"2.0","method":"getFilterChanges","params":["0x16"],"id":74}'
    ```

    ```json
    // Result
    {
        "jsonrpc":"2.0",
        "id":74,
        "result":[
            {
                "address":"0xea4f6bc98b456ef085da5c424db710489848cab5",
                "topics":[
                    "0x8fb1356be6b2a4e49ee94447eb9dcb8783f51c41dcddfe7919f945017d163bf3"
                ],
                "data":"0x0000000000000000000000005b073e9233944b5e729e46d618f0d8edf3d9c34a0000000000000000000000000000000000000000000000000000000000000064",
                "blockHash":"0x3e83b74560860344f4c48d7b8089a18173aecd96b6b2148653c61b5d3f559764",
                "blockNumber":"0x4",
                "transactionHash":"0xb38e5b6572b2613cab8088f93e6835576209f2b796104779b4a43fa5adc737af",
                "transactionIndex":"0x0",
                "logIndex":"0x0",
                "transactionLogIndex":"0x0"
            }
        ]
    }
    ```

***

### getFilterLogs

Returns an array of all logs matching filter with given id.

* Parameters

    1. `Quantity` - The filter id.

* Returns

    `Array` - Array of log objects, or an empty array if nothing has changed since last poll.

* Example

    同 [getFilterChanges](#getfilterchanges)

***

### getTransactionProof

根据交易hash获取交易执行的证明。

* Parameters

    1. `Data32` - hash of a transaction

```json
params: [
    "0x37f1261203d7b81a5a5cfc4a5c4abf15297555a47fd8686580d5a211876516c4"
]

• Returns

  Data - A proof include transaction, receipt, receipt merkle tree proof, block header. There will be a tool to verify the proof and extract some info.

• Example

    // Request
    curl -X POST --data '{"jsonrpc":"2.0","method":"getTransactionProof","params":["0x37f1261203d7b81a5a5cfc4a5c4abf15297555a47fd8686580d5a211876516c4"],"id":1}'
    ```

    ```json
    // Result
    {
        "jsonrpc": "2.0",
        "id": 1,
        "result": "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"
    }
    ```

***

### getMetaData

根据高度查询链上元数据。

* Parameters

    1. `BlockNumber`, `BlockNumber`

```json
params: [
    "0x1da3"
]

• Returns
  • chainId, Integer - Deal with transaction replay attack
  • chainIdV1, Quantity - ChainId in version 1
  • chainName, String - Chain name
  • operator, String - Chain operator
  • genesisTimestamp, Integer - Genesis timestamp
  • validators, [Data20] - Validator array
  • blockInterval Integer - block interval by millisecond
  • tokenName, String - Token name
  • tokenSymbol, String - Token symbol
  • tokenAvatar, String - Token avatar url
  • version, Integer - chain's version
  • economicalModel, EconomicalModel - The economical model
• Example

    curl -X POST --data '{"jsonrpc":"2.0","method":"getMetaData","params":["latest"],"id":1}' 127.0.0.1:1337
    ```

    ```json
    {
        "id": 1,
        "jsonrpc": "2.0",
        "result": {
            "blockInterval": 3000,
            "chainId": 0,
            "chainIdV1": "0x1",
            "chainName": "test-chain",
            "economicalModel": 1,
            "genesisTimestamp": 1541058686340,
            "operator": "test-operator",
            "tokenAvatar": "https://cdn.cryptape.com/icon_appchain.png",
            "tokenName": "Nervos AppChain Test Token",
            "tokenSymbol": "NATT",
            "validators": [
                "0xc489d5cb6f497e4708cc8c3805473b9528f83c7a",
                "0x497c68f02bbe335cc879356af120371ebf6cbc29",
                "0x6fbb4c8bb76ace631d634545fe39cbee979dd08e",
                "0x3c0f681e13f18b51d5350823eae45cb502231cf4"
            ],
            "version": 1,
            "website": "https://www.example.com"
        }
    }
    ```
***

### getBlockHeader

Get block header by block number. For sidechain.

* Parameters

    1. `BlockNumber`, `BlockNumber`

```json
params: [
    "0x1da3"
]

• Returns Data - Block header serialized into bytes.
• Example

    curl -X POST --data '{"jsonrpc":"2.0","method":"getBlockHeader","params":["latest"],"id":1}' 127.0.0.1:1337
    ```

    ```json
    // Result
    {
        "jsonrpc": "2.0",
        "id": 1,
        "result": "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"
    }
    ```

***

### getStateProof

Get proof of a special variable at special block number. For sidechain.

* Parameters

    1. `Data20` - address.
    2. `Data32` - key, position of the variable
    3. `BlockNumber` - `BlockNumber`

* Returns
    `Data` - State proof of special value. Include address, account proof, key, value proof.
* Example

    ```shell
    curl -X POST --data '{"jsonrpc":"2.0","method":"getStateProof","params":["0xad54ae137c6c39fa413fa1da7db6463e3ae45664", "0xa40893b0c723e74515c3164afb5b2a310dd5854fac8823bfbffa1d912e98423e", "latest"],"id":1}' 127.0.0.1:1337
    ```

    ```json
    // Result
    {
        "jsonrpc": "2.0",
        "id": 1,
        "result": "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"
    }
    ```

***

### getStorageAt

获取合约中在指定高度的 Key 对应的值。

* Parameters

    1. `Data20` - address.
    2. `Data32` - key, position of the variable
    3. `BlockNumber` - integer block number(Hex string), or the string "latest", "earliest"

* Returns
    `Data` - H256 value of the key in address.
* Example

    ```shell
    curl -X POST --data '{"jsonrpc":"2.0","method":"getStorageAt","params":["0xffffffffffffffffffffffffffffffffff020000", "0x0000000000000000000000000000000000000000000000000000000000000007", "latest"],"id":1}' 127.0.0.1:1337
    ```

    ```json
    // Result
    {
        "jsonrpc": "2.0",
        "id": 1,
        "result": "0x000000000000000000000000ffffffffffffffffffffffffffffffffff02000d"
    }
    ```

***

## RPC Errors

### Invalid Request

```shell
// 正确方式：POST 方法
curl -X GET -d '{"jsonrpc":"2.0","method":"blockNumber","params":[]}' 127.0.0.1:1337

{"jsonrpc":"2.0","error":{"code":-32600,"message":"Invalid Request"},"id":null}

Method not found

// 正确方式： method应该是getBlockByNumber
curl -X POST -d '{"jsonrpc":"2.0","method":"getblockByHeight","params":[true],"id":3}' 127.0.0.1:1337

{"jsonrpc":"2.0", "error":{"code":-32601,"message":"Method not found"},"id":3 }

Invalid params

// 正确方式：params 应该是 ["0x019abfa50cbb6df5b6dc41eabba47db4e7eb1787a96fd5836820d581287e0236"]
curl -X POST -d '{"jsonrpc":"2.0","method":"getTransaction","params":[0x019abfa50cbb6df5b6dc41eabba47db4e7eb1787a96fd5836820d581287e0236],"id":2}' 127.0.0.1:1337

{"jsonrpc":"2.0", "error":{"code":-32602,"message":"Invalid params"},"id":2}

Null

// 原因：块高度未达到99999
curl -X POST -d '{"jsonrpc":"2.0","method":"getBlockByNumber","params":["0x1869F",true],"id":2}' 127.0.0.1:1337

{"jsonrpc":"2.0","id":2,"result":null}