BCHSocket

Bitcoin BCH Websocket!

Takes raw blocks and transactions from your node. Accepts websocket connections and allows clients to subscribe to broadcasts for Blocks, OpReturns, and Output Addresses.

Getting Started

BCHSocket requires minimal configuration to get started with your own Websocket server. Presuming you already have a node, there isn't even any sync time required! Edit bitcoin.conf to include zmqpubrawtx and zmqpubrawblock, setup BCHSocket's app.config to match, then just start BCHSocket!

Development Environment and Tools

BCHSocket and SharpBCH can be built under any DotNET Core 2.2 environment.

Recommended Development Environment:

• Visual Studio 2017 Community Edition https://visualstudio.microsoft.com/downloads/
• JetBrains Resharper https://www.jetbrains.com/resharper/
• DotNET Core 2.2 https://dotnet.microsoft.com/download/dotnet-core/2.2

Dependencies

BCHSocket and it's main dependency SharpBCH (https://github.com/ProtocolCash/SharpBCH) aim to keep dependency trees minimal.

BCHSocket depends on:

• NETCore 2.2.0
• System.Configuration.ConfigurationManager
• SharpBCH

Building

Build Release from CLI:

• dotnet publish -c release -r {target_system}

Where {target_system} is e.g. win10-x64 or linux-x64 or osx.10.14-x64. (see RID catalog for all runtime IDs: https://docs.microsoft.com/en-us/dotnet/core/rid-catalog)

Configuration

See app.config (or, in release version, BCHSocket.exe.config). The following options are available:

Option Name	Description	Example
ZMQTxHostname	Hostname for ZMQ Raw Transaction Publisher	e.g. 127.0.0.1 or specific IP
ZMQTxPort	Port number for ZMQ Raw Transaction Publisher	e.g. 28333
ZMQBlockHostname	Hostname for ZMQ Raw Block Publisher	e.g. 127.0.0.1 or specific IP
ZMQBlockPort	Hostname for ZMQ Raw Block Publisher	e.g. 28331
WebsocketBindIP	Local IP to which to bind Websocket Server	e.g. 127.0.0.1 or 0.0.0.0 for all interfaces
WebsocketBindPort	Local Port to which to bind Websocket Server	e.g. 8181

ZMQ options must match local ZMQ publisher configuration.

Websocket Client Commands

The following commands are valid:

Command	Details
{"op": "block"}	Subscribe to block updates
{"op": "address", "address": "[CASH_ADDRESS]"}	Subscribe to transaction updates that include outputs to CASH_ADDRESS
{"op": "opreturn", "prefix": "[PREFIX(HEX)]"}	Subscribe to transaction updates that include an OP_RETURN output with matching prefix (represented as hex).

Any command above can also be sent with "rm_" prefixed to the op string to remove an existing subscription. e.g. {"op": "rm_block"} will remove an existing block subscription.

Websocket Responses and Broadcasts

Errors

Websocket will respond with JSON object where "op" param is "error", and "error" param is the error message. An error in response to a subscription request means the subscription request failed.

Examples:

• { "op": "error", "error": "Error while parsing JSON request. Expected 'op' parameter as string." }
• { "op": "error", "error": "Error while parsing JSON request. Expected 'prefix' parameter as string." }
• { "op": "error", "error": "Error while parsing JSON request. Expected 'prefix' parameter to be less than 32 hex characters long." }

Subscriptions Requests

Websocket will confirm all subscription requests with a JSON response indicating success or failure.

Generically, this will look like: { "op": "[SUBSCRIPTION_TYPE]", "result": "ok" }, { "op": "rm_[SUBSCRIPTION_TYPE]", "result": "ok" }, or { "op": "rm_[SUBSCRIPTION_TYPE]", "result": "failed" }

Examples:

• { "op": "address", "result": "ok" }
• { "op": "opreturn", "result": "ok" }
• { "op": "rm_address", "result": "ok" }
• { "op": "rm_address", "result": "failed" }

Broadcasts

Subscribed Websocket clients will receive broadcasts for all subscribed events.

A client subscribed to block updates would receive these broadcasts when the new blocks were seen:

• { "op": "new_block", "blockHash": "00000000000000000301C020CA2F01B9B8C5B665F649DDC417EE7BE59B8F99E8", "prevBlockHash": "000000000000000000E6D9A0A73B6C803A1A1200FEF7DB64445B7366FBEFB781", "transactions": 283 }
• { "op": "new_block", "blockHash": "000000000000000000A2A32BA22DA5732A5C97AFCBE5BC28F5CCB20121F2342F", "prevBlockHash": "00000000000000000301C020CA2F01B9B8C5B665F649DDC417EE7BE59B8F99E8", "transactions": 416 }

A client subscribed to transaction updates (based on matching output address or opreturn) will receive updates as follows:

• { "op": "new_tx", "txid": "[TXID(HEX)]", "inputs": [NUMBER_OF_INPUTS], "outputs": { [OUTPUTS] } }

Where [OUTPUTS] is an array of outputs, where each output is formatted:

• { "type": "[OUTPUT_TYPE]", "address": "[ADDRESS]", "value": "[VALUE_IN_SATOSHI]", "script": "[RAW_SCRIPT(HEX)]" }

Where:

• [OUTPUT_TYPE] is one of: P2PKH, P2SH, DATA, or OTHER
• [ADDRESS] is a Cash Address, or blank string if output type is not P2SH or P2PKH
• [VALUE_IN_SATOSHI] is the amount spent to that output
• [RAW_SCRIPT(HEX)] is the raw bitcoin script for this output, represented in HEX.