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lbcd/docs/json_rpc_api.md
Dave Collins 03433dad6a Update btcwire path import paths to new location.
2015-02-05 15:16:39 -06:00

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Table of Contents

  1. Overview
  2. HTTP POST Versus Websockets
  3. Authentication
    3.1. Overview
    3.2. HTTP Basic Access Authentication
    3.3. JSON-RPC Authenticate Command (Websocket-specific)
  4. Command-line Utility
  5. Standard Methods
    5.1. Method Overview
    5.2. Method Details
  6. Extension Methods
    6.1. Method Overview
    6.2. Method Details
  7. Websocket Extension Methods (Websocket-specific)
    7.1. Method Overview
    7.2. Method Details
  8. Notifications (Websocket-specific)
    8.1. Notification Overview
    8.2. Notification Details
  9. Example Code
    9.1. Go
    9.2. node.js
### 1. Overview

btcd provides a JSON-RPC API that is fully compatible with the original bitcoind/bitcoin-qt. There are a few key differences between btcd and bitcoind as far as how RPCs are serviced:

  • Unlike bitcoind that has the wallet and chain intermingled in the same process which leads to several issues, btcd intentionally splits the wallet and chain services into independent processes. See the blog post here for further details on why they were separated. This means that if you are talking directly to btcd, only chain-related RPCs are available. However both chain-related and wallet-related RPCs are available via btcwallet.
  • btcd is secure by default which means that the RPC connection is TLS-enabled by default
  • btcd provides access to the API through both HTTP POST requests and Websockets

Websockets are the preferred transport for btcd RPC and are used by applications such as btcwallet for inter-process communication with btcd. The websocket connection endpoint for btcd is wss://your_ip_or_domain:8334/ws.

In addition to the standard API, an extension API has been developed that is exclusive to clients using Websockets. In its current state, this API attempts to cover features found missing in the standard API during the development of btcwallet.

While the standard API is stable, the Websocket extension API should be considered a work in progress, incomplete, and susceptible to changes (both additions and removals).

The original bitcoind/bitcoin-qt JSON-RPC API documentation is available at https://en.bitcoin.it/wiki/Original_Bitcoin_client/API_Calls_list

### 2. HTTP POST Versus Websockets

The btcd RPC server supports both HTTP POST requests and the preferred Websockets. All of the standard and extension methods described in this documentation can be accessed through both. As the name indicates, the Websocket-specific extension methods can only be accessed when connected via Websockets.

As mentioned in the overview, the websocket connection endpoint for btcd is wss://your_ip_or_domain:8334/ws.

The most important differences between the two transports as it pertains to the JSON-RPC API are:

HTTP POST Requests Websockets
Allows multiple requests across a single connection No Yes
Supports asynchronous notifications No Yes
Scales well with large numbers of requests No Yes
### 3. Authentication **3.1 Authentication Overview**

The following authentication details are needed before establishing a connection to a btcd RPC server:

  • rpcuser is the username that the btcd RPC server is configured with
  • rpcpass is the password that the btcd RPC server is configured with
  • rpccert is the PEM-encoded X.509 certificate (public key) that the btcd server is configured with. It is automatically generated by btcd and placed in the btcd home directory (which is typically %LOCALAPPDATA%\Btcd on Windows and ~/.btcd on POSIX-like OSes)

NOTE: As mentioned above, btcd is secure by default which means the RPC server is not running unless configured with a rpcuser and rpcpass and uses TLS authentication for all connections.

Depending on which connection transaction you are using, you can choose one of two, mutually exclusive, methods.

 **3.2 HTTP Basic Access Authentication**

The btcd RPC server uses HTTP basic access authentication with the rpcuser and rpcpass detailed above. If the supplied credentials are invalid, you will be disconnected immediately upon making the connection.

**3.3 JSON-RPC Authenticate Command (Websocket-specific)**

While the HTTP basic access authentication method is the preferred method, the ability to set HTTP headers from websockets is not always available. In that case, you will need to use the authenticate JSON-RPC method.

The authenticate command must be the first command sent after connecting to the websocket. Sending any other commands before authenticating, supplying invalid credentials, or attempting to authenticate again when already authenticated will cause the websocket to be closed immediately.

### 4. Command-line Utility

btcd comes with a separate utility named btcctl which can be used to issue these RPC commands via HTTP POST requests to btcd after configuring it with the information in the Authentication section above. It can also be used to communicate with any server/daemon/service which provides a JSON-RPC API compatible with the original bitcoind/bitcoin-qt client.

### 5. Standard Methods **5.1 Method Overview**

The following is an overview of the RPC methods and their current status. Click the method name for further details such as parameter and return information.

# Method Description
1 addnode Attempts to add or remove a persistent peer.
2 createrawtransaction Returns a new transaction spending the provided inputs and sending to the provided addresses.
3 decoderawtransaction Returns a JSON object representing the provided serialized, hex-encoded transaction.
4 decodescript Returns a JSON object with information about the provided hex-encoded script.
5 getaddednodeinfo Returns information about manually added (persistent) peers.
6 getbestblockhash Returns the hash of the of the best (most recent) block in the longest block chain.
7 getblock Returns information about a block given its hash.
8 getblockcount Returns the number of blocks in the longest block chain.
9 getblockhash Returns hash of the block in best block chain at the given height.
10 getconnectioncount Returns the number of active connections to other peers.
11 getdifficulty Returns the proof-of-work difficulty as a multiple of the minimum difficulty.
12 getgenerate Return if the server is set to generate coins (mine) or not.
13 gethashespersec Returns a recent hashes per second performance measurement while generating coins (mining).
14 getinfo Returns a JSON object containing various state info.
15 getmininginfo Returns a JSON object containing mining-related information.
16 getnettotals Returns a JSON object containing network traffic statistics.
17 getnetworkhashps Returns the estimated network hashes per second for the block heights provided by the parameters.
18 getpeerinfo Returns information about each connected network peer as an array of json objects.
19 getrawmempool Returns an array of hashes for all of the transactions currently in the memory pool.
20 getrawtransaction Returns information about a transaction given its hash.
21 getwork Returns formatted hash data to work on or checks and submits solved data.
NOTE: Since btcd does not have the wallet integrated to provide payment addresses, btcd must be configured via the --miningaddr option to provide which payment addresses to pay created blocks to for this RPC to function.
22 help Returns a list of all commands or help for a specified command.
23 ping Queues a ping to be sent to each connected peer.
24 sendrawtransaction Submits the serialized, hex-encoded transaction to the local peer and relays it to the network.
btcd does not yet implement the allowhighfees parameter, so it has no effect
25 setgenerate Set the server to generate coins (mine) or not.
NOTE: Since btcd does not have the wallet integrated to provide payment addresses, btcd must be configured via the --miningaddr option to provide which payment addresses to pay created blocks to for this RPC to function.
26 stop Shutdown btcd.
27 submitblock Attempts to submit a new serialized, hex-encoded block to the network.
28 validateaddress Verifies the given address is valid. NOTE: Since btcd does not have a wallet integrated, btcd will only return whether the address is valid or not.
29 verifychain Verifies the block chain database.
**5.2 Method Details**
Method addnode
Parameters 1. peer (string, required) - ip address and port of the peer tooperate on
2. command (string, required) - add to add a persistent peer, remove to remove a persistent peer, or onetry to try a single connection to a peer
Description Attempts to add or remove a persistent peer.
Returns Nothing
Return to Overview
Method createrawtransaction
Parameters 1. transaction inputs (JSON array, required) - json array of json objects
[
  {
    "txid": "hash", (string, required) the hash of the input transaction
    "vout": n (numeric, required) the specific output of the input transaction to redeem
  }, ...
]
2. addresses and amounts (JSON object, required) - json object with addresses as keys and amounts as values
{
  "address": n.nnn (numeric, required) the address to send to as the key and the amount in BTC as the value
  , ...
}
Description Returns a new transaction spending the provided inputs and sending to the provided addresses.
The transaction inputs are not signed in the created transaction.
The signrawtransaction RPC command provided by wallet must be used to sign the resulting transaction.
Returns "transaction" (string) hex-encoded bytes of the serialized transaction
Example Parameters 1. transaction inputs [{"txid":"e6da89de7a6b8508ce8f371a3d0535b04b5e108cb1a6e9284602d3bfd357c018","vout":1}]
2. addresses and amounts {"13cgrTP7wgbZYWrY9BZ22BV6p82QXQT3nY": 0.49213337}
Example Return 010000000118c057d3bfd3024628e9a6b18c105e4bb035053d1a378fce08856b7ade89dae6010000
0000ffffffff0199efee02000000001976a9141cb013db35ecccc156fdfd81d03a11c51998f99388
ac00000000
Newlines added for display purposes. The actual return does not contain newlines.
Return to Overview
Method decoderawtransaction
Parameters 1. data (string, required) - serialized, hex-encoded transaction
Description Returns a JSON object representing the provided serialized, hex-encoded transaction.
Returns { (json object)
  "txid": "hash", (string) the hash of the transaction
  "version": n, (numeric) the transaction version
  "locktime": n, (numeric) the transaction lock time
  "vin": [ (array of json objects) the transaction inputs as json objects
  For coinbase transactions:
    { (json object)
      "coinbase": "data", (string) the hex-dencoded bytes of the signature script
      "sequence": n, (numeric) the script sequence number
    }
  For non-coinbase transactions:
    { (json object)
      "txid": "hash", (string) the hash of the origin transaction
      "vout": n, (numeric) the index of the output being redeemed from the origin transaction
      "scriptSig": { (json object) the signature script used to redeem the origin transaction
        "asm": "asm", (string) disassembly of the script
        "hex": "data", (string) hex-encoded bytes of the script
      }
      "sequence": n, (numeric) the script sequence number
    }, ...
  ]
  "vout": [ (array of json objects) the transaction outputs as json objects
    { (json object)
      "value": n, (numeric) the value in BTC
      "n": n, (numeric) the index of this transaction output
      "scriptPubKey": { (json object) the public key script used to pay coins
        "asm": "asm", (string) disassembly of the script
        "hex": "data", (string) hex-encoded bytes of the script
        "reqSigs": n, (numeric) the number of required signatures
        "type": "scripttype" (string) the type of the script (e.g. 'pubkeyhash')
        "addresses": [ (json array of string) the bitcoin addresses associated with this output
          "bitcoinaddress", (string) the bitcoin address
          ...
        ]
      }
    }, ...
  ]
}
Example Return {
  "txid": "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b",
  "version": 1,
  "locktime": 0,
  "vin": [
  For coinbase transactions:
    { (json object)
      "coinbase": "04ffff001d0104455468652054696d65732030332f4a616e2f32303039204368616e63656c6c6...",
      "sequence": 4294967295,
    }
  For non-coinbase transactions:
    {
      "txid": "60ac4b057247b3d0b9a8173de56b5e1be8c1d1da970511c626ef53706c66be04",
      "vout": 0,
      "scriptSig": {
        "asm": "3046022100cb42f8df44eca83dd0a727988dcde9384953e830b1f8004d57485e2ede1b9c8f0...",
        "hex": "493046022100cb42f8df44eca83dd0a727988dcde9384953e830b1f8004d57485e2ede1b9c8...",
      }
      "sequence": 4294967295,
    }
  ]
  "vout": [
    {
      "value": 50,
      "n": 0,
      "scriptPubKey": {
        "asm": "04678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4ce...",
        "hex": "4104678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4...",
        "reqSigs": 1,
        "type": "pubkey"
        "addresses": [
          "1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa",
        ]
      }
    }
  ]
}
Return to Overview
Method decodescript
Parameters 1. script (string, required) - hex-encoded script
Description Returns a JSON object with information about the provided hex-encoded script.
Returns { (json object)
  "asm": "asm", (string) disassembly of the script
  "reqSigs": n, (numeric) the number of required signatures
  "type": "scripttype", (string) the type of the script (e.g. 'pubkeyhash')
  "addresses": [ (json array of string) the bitcoin addresses associated with this script
    "bitcoinaddress", (string) the bitcoin address
    ...
  ]
  "p2sh": "scripthash", (string) the script hash for use in pay-to-script-hash transactions
}
Example Return {
  "asm": "OP_DUP OP_HASH160 b0a4d8a91981106e4ed85165a66748b19f7b7ad4 OP_EQUALVERIFY OP_CHECKSIG",
  "reqSigs": 1,
  "type": "pubkeyhash",
  "addresses": [
    "1H71QVBpzuLTNUh5pewaH3UTLTo2vWgcRJ"
  ]
  "p2sh": "359b84ff799f48231990ff0298206f54117b08b6"
}
Return to Overview
Method getaddednodeinfo
Parameters 1. dns (boolean, required) - specifies whether the returned data is a JSON object including DNS and connection information, or just a list of added peers
2. node (string, optional) - only return information about this specific peer instead of all added peers.
Description Returns information about manually added (persistent) peers.
Returns (dns=false) ["ip:port", ...]
Returns (dns=true) [ (json array of objects)
  { (json object)
    "addednode": "ip_or_domain", (string) the ip address or domain of the added peer
    "connected": true or false, (boolean) whether or not the peer is currently connected
    "addresses": [ (json array or objects) DNS lookup and connection information about the peer
      { (json object)
        "address": "ip", (string) the ip address for this DNS entry
        "connected": "inbound/outbound/false" (string) the connection 'direction' (if connected)
      }, ...
    ]
  }, ...
]
Example Return (dns=false) ["192.168.0.10:8333", "mydomain.org:8333"]
Example Return (dns=true) [
  {
    "addednode": "mydomain.org:8333",
    "connected": true,
    "addresses": [
      {
        "address": "1.2.3.4",
        "connected": "outbound"
      },
      {
        "address": "5.6.7.8",
        "connected": "false"
      }
    ]
  }
]
Return to Overview
Method getbestblockhash
Parameters None
Description Returns the hash of the of the best (most recent) block in the longest block chain.
Returns string
Example Return 0000000000000001f356adc6b29ab42b59f913a396e170f80190dba615bd1e60
Return to Overview
Method getblock
Parameters 1. block hash (string, required) - the hash of the block
2. verbose (boolean, optional, default=true) - specifies the block is returned as a JSON object instead of hex-encoded string
3. verbosetx (boolean, optional, default=false) - specifies that each transaction is returned as a JSON object and only applies if the verbose flag is true.This parameter is a btcd extension
Description Returns information about a block given its hash.
Returns (verbose=false) "data" (string) hex-encoded bytes of the serialized block
Returns (verbose=true, verbosetx=false) { (json object)
  "hash": "blockhash", (string) the hash of the block (same as provided)
  "confirmations": n, (numeric) the number of confirmations
  "size": n, (numeric) the size of the block
  "height": n, (numeric) the height of the block in the block chain
  "version": n, (numeric) the block version
  "merkleroot": "hash", (string) root hash of the merkle tree
  "tx": [ (json array of string) the transaction hashes
    "transactionhash", (string) hash of the parent transaction
    ...
  ]
  "time": n, (numeric) the block time in seconds since 1 Jan 1970 GMT
  "nonce": n, (numeric) the block nonce
  "bits", n, (numeric) the bits which represent the block difficulty
  difficulty: n.nn, (numeric) the proof-of-work difficulty as a multiple of the minimum difficulty
  "previousblockhash": "hash", (string) the hash of the previous block
  "nextblockhash": "hash", (string) the hash of the next block
}
Returns (verbose=true, verbosetx=true) { (json object)
  "hash": "blockhash", (string) the hash of the block (same as provided)
  "confirmations": n, (numeric) the number of confirmations
  "size": n, (numeric) the size of the block
  "height": n, (numeric) the height of the block in the block chain
  "version": n, (numeric) the block version
  "merkleroot": "hash", (string) root hash of the merkle tree
  "rawtx": [ (array of json objects) the transactions as json objects
    (see getrawtransaction json object details)
  ]
  "time": n, (numeric) the block time in seconds since 1 Jan 1970 GMT
  "nonce": n, (numeric) the block nonce
  "bits", n, (numeric) the bits which represent the block difficulty
  difficulty: n.nn, (numeric) the proof-of-work difficulty as a multiple of the minimum difficulty
  "previousblockhash": "hash", (string) the hash of the previous block
  "nextblockhash": "hash", (string) the hash of the next block
}
Example Return (verbose=false) "010000000000000000000000000000000000000000000000000000000000000000000000
3ba3edfd7a7b12b27ac72c3e67768f617fc81bc3888a51323a9fb8aa4b1e5e4a29ab5f49
ffff001d1dac2b7c01010000000100000000000000000000000000000000000000000000
00000000000000000000ffffffff4d04ffff001d0104455468652054696d65732030332f
4a616e2f32303039204368616e63656c6c6f72206f6e206272696e6b206f66207365636f
6e64206261696c6f757420666f722062616e6b73ffffffff0100f2052a01000000434104
678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f
4cef38c4f35504e51ec112de5c384df7ba0b8d578a4c702b6bf11d5fac00000000"
Newlines added for display purposes. The actual return does not contain newlines.
Example Return (verbose=true, verbosetx=false) {
  "hash": "000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f",
  "confirmations": 277113,
  "size": 285,
  "height": 0,
  "version": 1,
  "merkleroot": "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b",
  "tx": [
    "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b"
  ],
  "time": 1231006505,
  "nonce": 2083236893,
  "bits": "1d00ffff",
  "difficulty": 1,
  "previousblockhash": "0000000000000000000000000000000000000000000000000000000000000000",
  "nextblockhash": "00000000839a8e6886ab5951d76f411475428afc90947ee320161bbf18eb6048"
}
Return to Overview
Method getblockcount
Parameters None
Description Returns the number of blocks in the longest block chain.
Returns numeric
Example Return 276820
Return to Overview
Method getblockhash
Parameters 1. block height (numeric, required)
Description Returns hash of the block in best block chain at the given height.
Returns string
Example Return 000000000000000096579458d1c0f1531fcfc58d57b4fce51eb177d8d10e784d
Return to Overview
Method getconnectioncount
Parameters None
Description Returns the number of active connections to other peers
Returns numeric
Example Return 8
Return to Overview
Method getdifficulty
Parameters None
Description Returns the proof-of-work difficulty as a multiple of the minimum difficulty.
Returns numeric
Example Return 1180923195.260000
Return to Overview
Method getgenerate
Parameters None
Description Return if the server is set to generate coins (mine) or not.
Returns false (boolean)
Return to Overview
Method gethashespersec
Parameters None
Description Returns a recent hashes per second performance measurement while generating coins (mining).
Returns 0 (numeric)
Return to Overview
Method getinfo
Parameters None
Description Returns a JSON object containing various state info.
Notes NOTE: Since btcd does NOT contain wallet functionality, wallet-related fields are not returned. See getinfo in btcwallet for a version which includes that information.
Returns { (json object)
  "version": n, (numeric) the version of the server
  "protocolversion": n, (numeric) the latest supported protocol version
  "blocks": n, (numeric) the number of blocks processed
  "timeoffset": n, (numeric) the time offset
  "connections": n, (numeric) the number of connected peers
  "proxy": "host:port", (string) the proxy used by the server
  "difficulty": n.nn, (numeric) the current target difficulty
  "testnet": true or false, (boolean) whether or not server is using testnet
  "relayfee": n.nn, (numeric) the minimum relay fee for non-free transactions in BTC/KB
}
Example Return {
  "version": 70000
  "protocolversion": 70001,
  "blocks": 298963,
  "timeoffset": 0,
  "connections": 17,
  "proxy": "",
  "difficulty": 8000872135.97,
  "testnet": false,
  "relayfee": 0.00001,
}
Return to Overview
Method getmininginfo
Parameters None
Description Returns a JSON object containing mining-related information.
Returns { (json object)
  "blocks": n, (numeric) latest best block
  "currentblocksize": n, (numeric) size of the latest best block
  "currentblocktx": n, (numeric) number of transactions in the latest best block
  "difficulty": n.nn, (numeric) current target difficulty
  "errors": "errors", (string) any current errors
  "generate": true or false, (boolean) whether or not server is set to generate coins
  "genproclimit": n, (numeric) number of processors to use for coin generation (-1 when disabled)
  "hashespersec": n, (numeric) recent hashes per second performance measurement while generating coins
  "networkhashps": n, (numeric) estimated network hashes per second for the most recent blocks
  "pooledtx": n, (numeric) number of transactions in the memory pool
  "testnet": true or false, (boolean) whether or not server is using testnet
}
Example Return {
  "blocks": 236526,
  "currentblocksize": 185,
  "currentblocktx": 1,
  "difficulty": 256,
  "errors": "",
  "generate": false,
  "genproclimit": -1,
  "hashespersec": 0,
  "networkhashps": 33081554756,
  "pooledtx": 8,
  "testnet": true,
}
Return to Overview
Method getnettotals
Parameters None
Description Returns a JSON object containing network traffic statistics.
Returns {
  "totalbytesrecv": n, (numeric) total bytes received
  "totalbytessent": n, (numeric) total bytes sent
  "timemillis": n (numeric) number of milliseconds since 1 Jan 1970 GMT
}
Example Return {
  "totalbytesrecv": 1150990,
  "totalbytessent": 206739,
  "timemillis": 1391626433845
}
Return to Overview
Method getnetworkhashps
Parameters 1. blocks (numeric, optional, default=120) - The number of blocks, or -1 for blocks since last difficulty change
2. height (numeric, optional, default=-1) - Perform estimate ending with this height or -1 for current best chain block height
Description Returns the estimated network hashes per second for the block heights provided by the parameters.
Returns numeric
Example Return 6573971939
Return to Overview
Method getpeerinfo
Parameters None
Description Returns data about each connected network peer as an array of json objects.
Returns [
  {
    "addr": "host:port", (string) the ip address and port of the peer
    "services": "00000001", (string) the services supported by the peer
    "lastrecv": n, (numeric) time the last message was received in seconds since 1 Jan 1970 GMT
    "lastsend": n, (numeric) time the last message was sent in seconds since 1 Jan 1970 GMT
    "bytessent": n, (numeric) total bytes sent
    "bytesrecv": n, (numeric) total bytes received
    "conntime": n, (numeric) time the connection was made in seconds since 1 Jan 1970 GMT
    "pingtime": n, (numeric) number of microseconds the last ping took
    "pingwait": n, (numeric) number of microseconds a queued ping has been waiting for a response
    "version": n, (numeric) the protocol version of the peer
    "subver": "useragent", (string) the user agent of the peer
    "inbound": true_or_false, (boolean) whether or not the peer is an inbound connection
    "startingheight": n, (numeric) the latest block height the peer knew about when the connection was established
    "syncnode": true_or_false, (boolean) whether or not the peer is the sync peer
  }, ...
]
Example Return [
  {
    "addr": "178.172.xxx.xxx:8333",
    "services": "00000001",
    "lastrecv": 1388183523,
    "lastsend": 1388185470,
    "bytessent": 287592965,
    "bytesrecv": 780340,
    "conntime": 1388182973,
    "pingtime": 405551,
    "pingwait": 183023,
    "version": 70001,
    "subver": "/btcd:0.4.0/",
    "inbound": false,
    "startingheight": 276921,
    "syncnode": true,
  }
]
Return to Overview
Method getrawtransaction
Parameters 1. transaction hash (string, required) - the hash of the transaction
2. verbose (int, optional, default=0) - specifies the transaction is returned as a JSON object instead of hex-encoded string
Description Returns information about a transaction given its hash.
Returns (verbose=0) "data" (string) hex-encoded bytes of the serialized transaction
Returns (verbose=1) { (json object)
  "hex": "data", (string) hex-encoded transaction
  "txid": "hash", (string) the hash of the transaction
  "version": n, (numeric) the transaction version
  "locktime": n, (numeric) the transaction lock time
  "vin": [ (array of json objects) the transaction inputs as json objects
  For coinbase transactions:
    { (json object)
      "coinbase": "data", (string) the hex-dencoded bytes of the signature script
      "sequence": n, (numeric) the script sequence number
    }
  For non-coinbase transactions:
    { (json object)
      "txid": "hash", (string) the hash of the origin transaction
      "vout": n, (numeric) the index of the output being redeemed from the origin transaction
      "scriptSig": { (json object) the signature script used to redeem the origin transaction
        "asm": "asm", (string) disassembly of the script
        "hex": "data", (string) hex-encoded bytes of the script
      }
      "sequence": n, (numeric) the script sequence number
    }, ...
  ]
  "vout": [ (array of json objects) the transaction outputs as json objects
    { (json object)
      "value": n, (numeric) the value in BTC
      "n": n, (numeric) the index of this transaction output
      "scriptPubKey": { (json object) the public key script used to pay coins
        "asm": "asm", (string) disassembly of the script
        "hex": "data", (string) hex-encoded bytes of the script
        "reqSigs": n, (numeric) the number of required signatures
        "type": "scripttype" (string) the type of the script (e.g. 'pubkeyhash')
        "addresses": [ (json array of string) the bitcoin addresses associated with this output
          "bitcoinaddress", (string) the bitcoin address
          ...
        ]
      }
    }, ...
  ]
}
Example Return (verbose=0) "010000000104be666c7053ef26c6110597dad1c1e81b5e6be53d17a8b9d0b34772054bac60000000
008c493046022100cb42f8df44eca83dd0a727988dcde9384953e830b1f8004d57485e2ede1b9c8f
022100fbce8d84fcf2839127605818ac6c3e7a1531ebc69277c504599289fb1e9058df0141045a33
76eeb85e494330b03c1791619d53327441002832f4bd618fd9efa9e644d242d5e1145cb9c2f71965
656e276633d4ff1a6db5e7153a0a9042745178ebe0f5ffffffff0280841e00000000001976a91406
f1b6703d3f56427bfcfd372f952d50d04b64bd88ac4dd52700000000001976a9146b63f291c295ee
abd9aee6be193ab2d019e7ea7088ac00000000
Newlines added for display purposes. The actual return does not contain newlines.
Example Return (verbose=1) {
  "hex": "01000000010000000000000000000000000000000000000000000000000000000000000000f...",
  "txid": "90743aad855880e517270550d2a881627d84db5265142fd1e7fb7add38b08be9",
  "version": 1,
  "locktime": 0,
  "vin": [
  For coinbase transactions:
    { (json object)
      "coinbase": "03708203062f503253482f04066d605108f800080100000ea2122f6f7a636f696e4065757374726174756d2f",
      "sequence": 0,
    }
  For non-coinbase transactions:
    {
      "txid": "60ac4b057247b3d0b9a8173de56b5e1be8c1d1da970511c626ef53706c66be04",
      "vout": 0,
      "scriptSig": {
        "asm": "3046022100cb42f8df44eca83dd0a727988dcde9384953e830b1f8004d57485e2ede1b9c8f0...",
        "hex": "493046022100cb42f8df44eca83dd0a727988dcde9384953e830b1f8004d57485e2ede1b9c8...",
      }
      "sequence": 4294967295,
    }
  ]
  "vout": [
    {
      "value": 25.1394,
      "n": 0,
      "scriptPubKey": {
        "asm": "OP_DUP OP_HASH160 ea132286328cfc819457b9dec386c4b5c84faa5c OP_EQUALVERIFY OP_CHECKSIG",
        "hex": "76a914ea132286328cfc819457b9dec386c4b5c84faa5c88ac",
        "reqSigs": 1,
        "type": "pubkeyhash"
        "addresses": [
          "1NLg3QJMsMQGM5KEUaEu5ADDmKQSLHwmyh",
        ]
      }
    }
  ]
}
Return to Overview
Method getwork
Parameters 1. data (string, optional) - The hex
Description Returns information about a transaction given its hash.
Notes NOTE: Since btcd does not have the wallet integrated to provide payment addresses, btcd must be configured via the --miningaddr option to provide which payment addresses to pay created blocks to for this RPC to function.
Returns (data not specified) { (json object)
  "data": "hex", (string) hex-encoded block data
  "hash1": "hex", (string) (DEPRECATED) hex-encoded formatted hash buffer
  "midstate": "hex", (string) (DEPRECATED) hex-encoded precomputed hash state after hashing first half of the data
  "target": "hex", (string) the hex-encoded little-endian hash target
}
Returns (data specified) true or false (boolean)
Example Return (data not specified) {
  "data": "00000002c39b5d2b7a1e8f7356a1efce26b24bd15d7d906e85341ef9cec99b6a000000006474f...",
  "hash1": "00000000000000000000000000000000000000000000000000000000000000000000008000000...",
  "midstate": "ae4a80fc51476e452de855b4e20d5f33418c50fc7cae3b1ecd5badb819b8a584",
  "target": "0000000000000000000000000000000000000000000000008c96010000000000",
}
Example Return (data specified) true
Return to Overview
Method help
Parameters 1. command (string, optional) - the command to get help for
Description Returns a list of all commands or help for a specified command.
When no command parameter is specified, a list of avaialable commands is returned
When command is a valid method, the help text for that method is returned.
Returns string
Example Return getblockcount
Returns a numeric for the number of blocks in the longest block chain.
Return to Overview
Method ping
Parameters None
Description Queues a ping to be sent to each connected peer.
Ping times are provided by getpeerinfo via the pingtime and pingwait fields.
Returns Nothing
Return to Overview
Method getrawmempool
Parameters 1. verbose (boolean, optional, default=false)
Description Returns an array of hashes for all of the transactions currently in the memory pool.
The verbose flag specifies that each transaction is returned as a JSON object.
Notes Since btcd does not perform any mining, the priority related fields startingpriority and currentpriority that are available when the verbose flag is set are always 0.
Returns (verbose=false) [ (json array of string)
  "transactionhash", (string) hash of the transaction
  ...
]
Returns (verbose=true) { (json object)
  "transactionhash": { (json object)
    "size": n, (numeric) transaction size in bytes
    "fee" : n, (numeric) transaction fee in bitcoins
    "time": n, (numeric) local time transaction entered pool in seconds since 1 Jan 1970 GMT
    "height": n, (numeric) block height when transaction entered the pool
    "startingpriority": n, (numeric) priority when transaction entered the pool
    "currentpriority": n, (numeric) current priority
    "depends": [ (json array) unconfirmed transactions used as inputs for this transaction
      "transactionhash", (string) hash of the parent transaction
      ...
    ]
  }, ...
}
Example Return (verbose=false) [
  "3480058a397b6ffcc60f7e3345a61370fded1ca6bef4b58156ed17987f20d4e7",
  "cbfe7c056a358c3a1dbced5a22b06d74b8650055d5195c1c2469e6b63a41514a"
]
Example Return (verbose=true) {
  "1697a19cede08694278f19584e8dcc87945f40c6b59a942dd8906f133ad3f9cc": {
    "size": 226,
    "fee" : 0.0001,
    "time": 1387992789,
    "height": 276836,
    "startingpriority": 0,
    "currentpriority": 0,
    "depends": [
      "aa96f672fcc5a1ec6a08a94aa46d6b789799c87bd6542967da25a96b2dee0afb",
    ]
}
Return to Overview
Method setgenerate
Parameters 1. generate (boolean, required) - true to enable generation, false to disable it
2. genproclimit (numeric, optional) - the number of processors (cores) to limit generation to or -1 for default
Description Set the server to generate coins (mine) or not.
Notes NOTE: Since btcd does not have the wallet integrated to provide payment addresses, btcd must be configured via the --miningaddr option to provide which payment addresses to pay created blocks to for this RPC to function.
Returns Nothing
Return to Overview
Method sendrawtransaction
Parameters 1. signedhex (string, required) serialized, hex-encoded signed transaction
2. allowhighfees (boolean, optional, default=false) whether or not to allow insanely high fees
Description Submits the serialized, hex-encoded transaction to the local peer and relays it to the network.
Notes btcd does not yet implement the allowhighfees parameter, so it has no effect
Returns "hash" (string) the hash of the transaction
Example Return "1697a19cede08694278f19584e8dcc87945f40c6b59a942dd8906f133ad3f9cc"
Return to Overview
Method submitblock
Parameters 1. data (string, required) serialized, hex-encoded block
2. params (json object, optional, default=nil) this parameter is currently ignored
Description Attempts to submit a new serialized, hex-encoded block to the network.
Returns (success) Success: Nothing
Failure: "rejected: reason" (string)
Return to Overview
Method stop
Parameters None
Description Shutdown btcd.
Returns "btcd stopping." (string)
Return to Overview
Method validateaddress
Parameters 1. address (string, required) - bitcoin address
Description Verify an address is valid.
Returns { (json object)
  "isvalid": true or false, (bool) whether or not the address is valid.
  "address": "bitcoinaddress", (string) the bitcoin address validated.
}
Return to Overview
Method verifychain
Parameters 1. checklevel (numeric, optional, default=3) - how in-depth the verification is (0=least amount of checks, higher levels are clamped to the highest supported level)
2. numblocks (numeric, optional, default=288) - the number of blocks starting from the end of the chain to verify
Description Verifies the block chain database.
The actual checks performed by the checklevel parameter is implementation specific. For btcd this is:
checklevel=0 - Look up each block and ensure it can be loaded from the database.
checklevel=1 - Perform basic context-free sanity checks on each block.
Notes Btcd currently only supports checklevel 0 and 1, but the default is still 3 for compatibility. Per the information in the Parameters section above, higher levels are automatically clamped to the highest supported level, so this means the default is effectively 1 for btcd.
Returns true or false (boolean)
Example Return true
Return to Overview
### 6. Extension Methods **6.1 Method Overview**

The following is an overview of the RPC methods which are implemented by btcd, but not the original bitcoind client. Click the method name for further details such as parameter and return information.

# Method Description
1 debuglevel Dynamically changes the debug logging level.
2 getbestblock Get block height and hash of best block in the main chain.
3 getcurrentnet Get bitcoin network btcd is running on.
**6.2 Method Details**
Method debuglevel
Parameters 1. levelspec (string)
Description Dynamically changes the debug logging level.
The levelspec can either a debug level or of the form <subsystem>=<level>,<subsystem2>=<level2>,...
The valid debug levels are trace, debug, info, warn, error, and critical.
The valid subsystems are AMGR, BCDB, BMGR, BTCD, CHAN, DISC, PEER, RPCS, SCRP, SRVR, and TXMP.
Additionally, the special keyword show can be used to get a list of the available subsystems.
Returns string
Example Return Done.
Example show Return Supported subsystems [AMGR BCDB BMGR BTCD CHAN DISC PEER RPCS SCRP SRVR TXMP]
Return to Overview
Method getbestblock
Parameters None
Description Get block height and hash of best block in the main chain.
Returns { (json object)
 "hash": "data", (string) the hex-encoded bytes of the best block hash
 "height": n (numeric) the block height of the best block
}
Return to Overview
Method getcurrentnet
Parameters None
Description Get bitcoin network btcd is running on.
Returns numeric
Example Return 3652501241 (mainnet)
118034699 (testnet3)
Return to Overview
### 7. Websocket Extension Methods (Websocket-specific) **7.1 Method Overview**

The following is an overview of the RPC method requests available exclusively to Websocket clients. Click the method name for further details such as parameter and return information.

# Method Description Notifications
1 authenticate Authenticate the connection against the username and passphrase configured for the RPC server.
NOTE: This is only required if an HTTP Authorization header is not being used.		 None
2 notifyblocks Send notifications when a block is connected or disconnected from the best chain. blockconnected and blockdisconnected
3 notifyreceived Send notifications when a txout spends to an address. recvtx and redeemingtx
4 notifyspent Send notification when a txout is spent. redeemingtx
5 rescan Rescan block chain for transactions to addresses and spent transaction outpoints. recvtx, redeemingtx, rescanprogress, and rescanfinished
6 notifynewtransactions Send notifications for all new transactions as they are accepted into the mempool. txaccepted or txacceptedverbose
**7.2 Method Details**
Method authenticate
Parameters 1. username (string, required)
2. passphrase (string, required)
Description Authenticate the connection against the username and password configured for the RPC server.
Invoking any other method before authenticating with this command will close the connection.
NOTE: This is only required if an HTTP Authorization header is not being used.
Returns Success: Nothing
Failure: Nothing (websocket disconnected)
Return to Overview
Method notifyblocks
Notifications blockconnected and blockdisconnected
Parameters None
Description Request notifications for whenever a block is connected or disconnected from the main (best) chain.
Returns Nothing
Return to Overview
Method notifyreceived
Notifications recvtx and redeemingtx
Parameters 1. Addresses (JSON array, required)
 [ (json array of strings)
  "bitcoinaddress", (string) the bitcoin address
  ...
 ]
Description Send a recvtx notification when a transaction added to mempool or appears in a newly-attached block contains a txout pkScript sending to any of the passed addresses. Matching outpoints are automatically registered for redeemingtx notifications.
Returns Nothing
Return to Overview
Method notifyspent
Notifications redeemingtx
Parameters 1. Outpoints (JSON array, required)
 [ (JSON array)
  { (JSON object)
   "hash":"data", (string) the hex-encoded bytes of the outpoint hash
   "index":n (numeric) the txout index of the outpoint
  },
  ...
 ]
Description Send a redeemingtx notification when a transaction spending an outpoint appears in mempool (if relayed to this btcd instance) and when such a transaction first appears in a newly-attached block.
Returns Nothing
Return to Overview
Method rescan
Notifications recvtx, redeemingtx, rescanprogress, and rescanfinished
Parameters 1. BeginBlock (string, required) block hash to begin rescanning from
2. Addresses (JSON array, required)
 [ (json array of strings)
  "bitcoinaddress", (string) the bitcoin address
  ...
 ]
3. Outpoints (JSON array, required)
 [ (JSON array)
  { (JSON object)
   "hash":"data", (string) the hex-encoded bytes of the outpoint hash
   "index":n (numeric) the txout index of the outpoint
  },
  ...
 ]
4. EndBlock (string, optional) hash of final block to rescan
Description Rescan block chain for transactions to addresses, starting at block BeginBlock and ending at EndBlock. If EndBlock is omitted, the rescan continues through the best block in the main chain. The current known UTXO set for all passed addresses at height BeginBlock should included in the Outpoints argument. Rescan results are sent as recvtx and redeemingtx notifications. This call returns once the rescan completes.
Returns Nothing
Return to Overview
Method notifynewtransactions
Notifications txaccepted or txacceptedverbose
Parameters 1. verbose (boolean, optional, default=false) - specifies which type of notification to receive. If verbose is true, then the caller receives txacceptedverbose, otherwise the caller receives txaccepted
Description Send either a txaccepted or a txacceptedverbose notification when a new transaction is accepted into the mempool.
Returns Nothing
Return to Overview
### 8. Notifications (Websocket-specific)

btcd uses standard JSON-RPC notifications to notify clients of changes, rather than requiring clients to poll btcd for updates. JSON-RPC notifications are a subset of requests, but do not contain an ID. The notification type is categorized by the method field and additional details are sent as a JSON array in the params field.

 **8.1 Notification Overview**

The following is an overview of the JSON-RPC notifications used for Websocket connections. Click the method name for further details of the context(s) in which they are sent and their parameters.

# Method Description Request
1 blockconnected Block connected to the main chain. notifyblocks
2 blockdisconnected Block disconnected from the main chain. notifyblocks
3 recvtx Processed a transaction output spending to a wallet address. notifyreceived and rescan
4 redeemingtx Processed a transaction that spends a registered outpoint. notifyspent and rescan
5 txaccepted Received a new transaction after requesting simple notifications of all new transactions accepted into the mempool. notifynewtransactions
6 txacceptedverbose Received a new transaction after requesting verbose notifications of all new transactions accepted into the mempool. notifynewtransactions
7 rescanprogress A rescan operation that is underway has made progress. rescan
8 rescanfinished A rescan operation has completed. rescan
**8.2 Notification Details**
Method blockconnected
Request notifyblocks
Parameters 1. BlockHash (string) hex-encoded bytes of the attached block hash
2. BlockHeight (numeric) height of the attached block
Description Notifies when a block has been added to the main chain. Notification is sent to all connected clients.
Example Example blockconnected notification for mainnet block 280330 (newlines added for readability):
{
 "jsonrpc": "1.0",
 "method": "blockconnected",
 "params":
  [
   "000000000000000004cbdfe387f4df44b914e464ca79838a8ab777b3214dbffd",
   280330
  ],
 "id": null
}
Return to Overview
Method blockdisconnected
Request notifyblocks
Parameters 1. BlockHash (string) hex-encoded bytes of the disconnected block hash
2. BlockHeight (numeric) height of the disconnected block
Description Notifies when a block has been removed from the main chain. Notification is sent to all connected clients.
Example Example blockdisconnected notification for mainnet block 280330 (newlines added for readability):
{
 "jsonrpc": "1.0",
 "method": "blockdisconnected",
 "params":
  [
   "000000000000000004cbdfe387f4df44b914e464ca79838a8ab777b3214dbffd",
   280330
  ],
 "id": null
}
Return to Overview
Method recvtx
Request rescan or notifyreceived
Parameters 1. Transaction (string) full transaction encoded as a hex string
2. Block details (object, optional) details about a block and the index of the transaction within a block, if the transaction is mined
Description Notifies a client when a transaction is processed that contains at least a single output with a pkScript sending to a requested address. If multiple outputs send to requested addresses, a single notification is sent. If a mempool (unmined) transaction is processed, the block details object (second parameter) is excluded.
Example Example recvtx notification for mainnet transaction 61d3696de4c888730cbe06b0ad8ecb6d72d6108e893895aa9bc067bd7eba3fad when processed by mempool (newlines added for readability):
{
 "jsonrpc": "1.0",
 "method": "recvtx",
 "params":
  [
   "010000000114d9ff358894c486b4ae11c2a8cf7851b1df64c53d2e511278eff17c22fb737300000000..."
  ],
 "id": null
}
The recvtx notification for the same txout, after the transaction was mined into block 276425:
{
 "jsonrpc": "1.0",
 "method": "recvtx",
 "params":
  [
   "010000000114d9ff358894c486b4ae11c2a8cf7851b1df64c53d2e511278eff17c22fb737300000000...",
   {
    "height": 276425,
    "hash": "000000000000000325474bb799b9e591f965ca4461b72cb7012b808db92bb2fc",
    "index": 684,
    "time": 1387737310
   }
  ],
 "id": null
}
Return to Overview
Method redeemingtx
Requests notifyspent and rescan
Parameters 1. Transaction (string) full transaction encoded as a hex string
2. Block details (object, optional) details about a block and the index of the transaction within a block, if the transaction is mined
Description Notifies a client when an registered outpoint is spent by a transaction accepted to mempool and/or mined into a block.
Example Example redeemingtx notification for mainnet outpoint 61d3696de4c888730cbe06b0ad8ecb6d72d6108e893895aa9bc067bd7eba3fad:0 after being spent by transaction 4ad0c16ac973ff675dec1f3e5f1273f1c45be2a63554343f21b70240a1e43ece (newlines added for readability):
{
 "jsonrpc": "1.0",
 "method": "redeemingtx",
 "params":
  [
   "0100000003ad3fba7ebd67c09baa9538898e10d6726dcb8eadb006be0c7388c8e46d69d3610000000..."
  ],
 "id": null
}
The redeemingtx notification for the same txout, after the spending transaction was mined into block 279143:
{
 "jsonrpc": "1.0",
 "method": "recvtx",
 "params":
  [
   "0100000003ad3fba7ebd67c09baa9538898e10d6726dcb8eadb006be0c7388c8e46d69d3610000000...",
   {
    "height": 279143,
    "hash": "00000000000000017188b968a371bab95aa43522665353b646e41865abae02a4",
    "index": 6,
    "time": 1389115004
   }
  ],
 "id": null
}
Return to Overview
Method txaccepted
Request notifynewtransactions
Parameters 1. TxSha (string) hex-encoded bytes of the transaction hash
2. Amount (numeric) sum of the value of all the transaction outpoints
Description Notifies when a new transaction has been accepted and the client has requested standard transaction details.
Example Example txaccepted notification for mainnet transaction id "16c54c9d02fe570b9d41b518c0daefae81cc05c69bbe842058e84c6ed5826261" (newlines added for readability):
{
 "jsonrpc": "1.0",
 "method": "txaccepted",
 "params":
  [
   "16c54c9d02fe570b9d41b518c0daefae81cc05c69bbe842058e84c6ed5826261",
   55838384
  ],
 "id": null
}
Return to Overview
Method txacceptedverbose
Request notifynewtransactions
Parameters 1. RawTx (json object) the transaction as a json object (see getrawtransaction json object details)
Description Notifies when a new transaction has been accepted and the client has requested verbose transaction details.
Example Example txacceptedverbose notification (newlines added for readability):
{
 "jsonrpc": "1.0",
 "method": "txacceptedverbose",
 "params":
  [
   {
    "hex": "01000000010000000000000000000000000000000000000000000000000000000000000000f...",
    "txid": "90743aad855880e517270550d2a881627d84db5265142fd1e7fb7add38b08be9",
    "version": 1,
    "locktime": 0,
    "vin": [
    For coinbase transactions:
      { (json object)
        "coinbase": "03708203062f503253482f04066d605108f800080100000ea2122f6f7a636f696e4065757374726174756d2f",
        "sequence": 0,
      }
    For non-coinbase transactions:
      {
        "txid": "60ac4b057247b3d0b9a8173de56b5e1be8c1d1da970511c626ef53706c66be04",
        "vout": 0,
        "scriptSig": {
          "asm": "3046022100cb42f8df44eca83dd0a727988dcde9384953e830b1f8004d57485e2ede1b9c8f0...",
          "hex": "493046022100cb42f8df44eca83dd0a727988dcde9384953e830b1f8004d57485e2ede1b9c8...",
        }
        "sequence": 4294967295,
      }
    ],
    "vout": [
     {
      "value": 25.1394,
      "n": 0,
      "scriptPubKey": {
       "asm": "OP_DUP OP_HASH160 ea132286328cfc819457b9dec386c4b5c84faa5c OP_EQUALVERIFY OP_CHECKSIG",
       "hex": "76a914ea132286328cfc819457b9dec386c4b5c84faa5c88ac",
       "reqSigs": 1,
       "type": "pubkeyhash"
       "addresses": [
        "1NLg3QJMsMQGM5KEUaEu5ADDmKQSLHwmyh",
       ]
     }
    ]
   }
  ],
 "id": null
}
Return to Overview
Method rescanprogress
Request rescan
Parameters 1. Hash (string) hash of the last processed block
2. Height (numeric) height of the last processed block
3. Time (numeric) UNIX time of the last processed block
Description Notifies a client with the current progress at periodic intervals when a long-running rescan is underway.
Example {
 "jsonrpc": "1.0",
 "method": "rescanprogress",
 "params":
  [
   "0000000000000ea86b49e11843b2ad937ac89ae74a963c7edd36e0147079b89d",
   127213,
   1306533807
  ],
 "id": null
}
Return to Overview
Method rescanfinished
Request rescan
Parameters 1. Hash (string) hash of the last rescanned block
2. Height (numeric) height of the last rescanned block
3. Time (numeric) UNIX time of the last rescanned block
Description Notifies a client that the rescan has completed and no further notifications will be sent.
Example {
 "jsonrpc": "1.0",
 "method": "rescanfinished",
 "params":
  [
   "0000000000000ea86b49e11843b2ad937ac89ae74a963c7edd36e0147079b89d",
   127213,
   1306533807
  ],
 "id": null
}
Return to Overview
### 9. Example Code

This section provides example code for interacting with the JSON-RPC API in various languages.

 **9.1 Go**

This section provides examples of using the RPC interface using Go and the btcrpcclient package.

**9.1.1 Using getblockcount to Retrieve the Current Block Height**

The following is an example Go application which uses the btcrpcclient package to connect with a btcd instance via Websockets, issues getblockcount to retrieve the current block height, and displays it.

package main

import (
	"github.com/btcsuite/btcrpcclient"
	"github.com/btcsuite/btcutil"
	"io/ioutil"
	"log"
	"path/filepath"
)

func main() {
	// Load the certificate for the TLS connection which is automatically
	// generated by btcd when it starts the RPC server and doesn't already
	// have one.
	btcdHomeDir := btcutil.AppDataDir("btcd", false)
	certs, err := ioutil.ReadFile(filepath.Join(btcdHomeDir, "rpc.cert"))
	if err != nil {
		log.Fatal(err)
	}

	// Create a new RPC client using websockets.  Since this example is
	// not long-lived, the connection will be closed as soon as the program
	// exits.
	connCfg := &btcrpcclient.ConnConfig{
		Host:         "localhost:8334",
		Endpoint:     "ws",
		User:         "yourrpcuser",
		Pass:         "yourrpcpass",
		Certificates: certs,
	}
	client, err := btcrpcclient.New(connCfg, nil)
	if err != nil {
		log.Fatal(err)
	}
	defer client.Shutdown()

	// Query the RPC server for the current block count and display it.
	blockCount, err := client.GetBlockCount()
	if err != nil {
		log.Fatal(err)
	}
	log.Printf("Block count: %d", blockCount)
}

Which results in:

Block count: 276978
**9.1.2 Using getblock to Retrieve the Genesis Block**

The following is an example Go application which uses the btcrpcclient package to connect with a btcd instance via Websockets, issues getblock to retrieve information about the Genesis block, and display a few details about it.

package main

import (
	"github.com/btcsuite/btcrpcclient"
	"github.com/btcsuite/btcutil"
	"github.com/btcsuite/btcd/wire"
	"io/ioutil"
	"log"
	"path/filepath"
	"time"
)

func main() {
	// Load the certificate for the TLS connection which is automatically
	// generated by btcd when it starts the RPC server and doesn't already
	// have one.
	btcdHomeDir := btcutil.AppDataDir("btcd", false)
	certs, err := ioutil.ReadFile(filepath.Join(btcdHomeDir, "rpc.cert"))
	if err != nil {
		log.Fatal(err)
	}

	// Create a new RPC client using websockets.  Since this example is
	// not long-lived, the connection will be closed as soon as the program
	// exits.
	connCfg := &btcrpcclient.ConnConfig{
		Host:         "localhost:18334",
		Endpoint:     "ws",
		User:         "yourrpcuser",
		Pass:         "yourrpcpass",
		Certificates: certs,
	}
	client, err := btcrpcclient.New(connCfg, nil)
	if err != nil {
		log.Fatal(err)
	}
	defer client.Shutdown()

	// Query the RPC server for the genesis block using the "getblock"
	// command with the verbose flag set to true and the verboseTx flag
	// set to false.
	genesisHashStr := "000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f"
	blockHash, err := wire.NewShaHashFromStr(genesisHashStr)
	if err != nil {
		log.Fatal(err)
	}
	block, err := client.GetBlockVerbose(blockHash, false)
	if err != nil {
		log.Fatal(err)
	}

	// Display some details about the returned block.
	log.Printf("Hash: %v\n", block.Hash)
	log.Printf("Previous Block: %v\n", block.PreviousHash)
	log.Printf("Next Block: %v\n", block.NextHash)
	log.Printf("Merkle root: %v\n", block.MerkleRoot)
	log.Printf("Timestamp: %v\n", time.Unix(block.Time, 0).UTC())
	log.Printf("Confirmations: %v\n", block.Confirmations)
	log.Printf("Difficulty: %f\n", block.Difficulty)
	log.Printf("Size (in bytes): %v\n", block.Size)
	log.Printf("Num transactions: %v\n", len(block.Tx))
}

Which results in:

Hash: 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f
Previous Block: 0000000000000000000000000000000000000000000000000000000000000000
Next Block: 00000000839a8e6886ab5951d76f411475428afc90947ee320161bbf18eb6048
Merkle root: 4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b
Timestamp: 2009-01-03 18:15:05 +0000 UTC
Confirmations: 277290
Difficulty: 1.000000
Size (in bytes): 285
Num transactions: 1
**9.1.3 Using notifyblocks to Receive blockconnected and blockdisconnected Notifications (Websocket-specific)**

The following is an example Go application which uses the btcrpcclient package to connect with a btcd instance via Websockets and registers for blockconnected and blockdisconnected notifications with notifyblocks. It also sets up handlers for the notifications.

package main

import (
	"github.com/btcsuite/btcrpcclient"
	"github.com/btcsuite/btcutil"
	"github.com/btcsuite/btcd/wire"
	"io/ioutil"
	"log"
	"path/filepath"
	"time"
)

func main() {
	// Setup handlers for blockconnected and blockdisconnected
	// notifications.
	ntfnHandlers := btcrpcclient.NotificationHandlers{
		OnBlockConnected: func(hash *wire.ShaHash, height int32) {
			log.Printf("Block connected: %v (%d)", hash, height)
		},
		OnBlockDisconnected: func(hash *wire.ShaHash, height int32) {
			log.Printf("Block disconnected: %v", hash, height)
		},
	}

	// Load the certificate for the TLS connection which is automatically
	// generated by btcd when it starts the RPC server and doesn't already
	// have one.
	btcdHomeDir := btcutil.AppDataDir("btcd", false)
	certs, err := ioutil.ReadFile(filepath.Join(btcdHomeDir, "rpc.cert"))
	if err != nil {
		log.Fatal(err)
	}

	// Create a new RPC client using websockets.
	connCfg := &btcrpcclient.ConnConfig{
		Host:         "localhost:8334",
		Endpoint:     "ws",
		User:         "yourrpcuser",
		Pass:         "yourrpcpass",
		Certificates: certs,
	}
	client, err := btcrpcclient.New(connCfg, &ntfnHandlers)
	if err != nil {
		log.Fatal(err)
	}

	// Register for blockconnected and blockdisconneted notifications.
	if err := client.NotifyBlocks(); err != nil {
		client.Shutdown()
		log.Fatal(err)
	}

	// For this example, gracefully shutdown the client after 10 seconds.
	// Ordinarily when to shutdown the client is highly application
	// specific.
	log.Println("Client shutdown in 10 seconds...")
	time.AfterFunc(time.Second*10, func() {
		log.Println("Client shutting down...")
		client.Shutdown()
		log.Println("Client shutdown complete.")
	})

	// Wait until the client either shuts down gracefully (or the user
	// terminates the process with Ctrl+C).
	client.WaitForShutdown()
}

Example output:

2014/05/12 20:33:17 Client shutdown in 10 seconds...
2014/05/12 20:33:19 Block connected: 000000000000000007dff1f95f7b3f5eac2892a4123069517caf34e2c417650d (300461)
2014/05/12 20:33:27 Client shutting down...
2014/05/12 20:31:27 Client shutdown complete.
### 9.2. Example node.js Code **9.2.1 Using notifyblocks to be Notified of Block Connects and Disconnects**

The following is example node.js code which uses ws (can be installed with npm install ws) to connect with a btcd instance, issues notifyblocks to register for blockconnected and blockdisconnected notifications, and displays all incoming messages.

var fs = require('fs');
var WebSocket = require('ws');

// Load the certificate for the TLS connection which is automatically
// generated by btcd when it starts the RPC server and doesn't already
// have one.
var cert = fs.readFileSync('/path/to/btcd/appdata/rpc.cert');
var user = "yourusername";
var password = "yourpassword";


// Initiate the websocket connection.  The btcd generated certificate acts as
// its own certificate authority, so it needs to be specified in the 'ca' array
// for the certificate to properly validate.
var ws = new WebSocket('wss://127.0.0.1:8334/ws', {
  headers: {
    'Authorization': 'Basic '+new Buffer(user+':'+password).toString('base64')
  },
  cert: cert,
  ca: [cert]
});
ws.on('open', function() {
    console.log('CONNECTED');
    // Send a JSON-RPC command to be notified when blocks are connected and
    // disconnected from the chain.
    ws.send('{"jsonrpc":"1.0","id":"0","method":"notifyblocks","params":[]}');
});
ws.on('message', function(data, flags) {
    console.log(data);
});
ws.on('error', function(derp) {
  console.log('ERROR:' + derp);
})
ws.on('close', function(data) {
  console.log('DISCONNECTED');
})