btcd/wire/README.md
Dave Collins 3942a116e4 docs: Make various README.md files consistent.
First, it removes the documentation section from all the README.md files
and instead puts a web-based godoc badge and link at the top with the
other badges.  This is being done since the local godoc tool no longer
ships with Go by default, so the instructions no longer work without
first installing godoc. Due to this, pretty much everyone uses the
web-based godoc these days anyways.  Anyone who has manually installed
godoc won't need instructions.

Second, it makes sure the ISC license badge is at the top with the other
badges and removes the textual reference in the overview section.

Finally, it's modifies the Installation section to Installation and
Updating and adds a '-u' to the 'go get' command since it works for both
and thus is simpler.
2015-10-23 14:51:36 -05:00

3.9 KiB

wire

[Build Status] (https://travis-ci.org/btcsuite/btcd) ![ISC License] (http://img.shields.io/badge/license-ISC-blue.svg) [GoDoc] (http://godoc.org/github.com/btcsuite/btcd/wire)

Package wire implements the bitcoin wire protocol. A comprehensive suite of tests with 100% test coverage is provided to ensure proper functionality.

There is an associated blog post about the release of this package here.

This package has intentionally been designed so it can be used as a standalone package for any projects needing to interface with bitcoin peers at the wire protocol level.

Installation and Updating

$ go get -u github.com/btcsuite/btcd/wire

Bitcoin Message Overview

The bitcoin protocol consists of exchanging messages between peers. Each message is preceded by a header which identifies information about it such as which bitcoin network it is a part of, its type, how big it is, and a checksum to verify validity. All encoding and decoding of message headers is handled by this package.

To accomplish this, there is a generic interface for bitcoin messages named Message which allows messages of any type to be read, written, or passed around through channels, functions, etc. In addition, concrete implementations of most of the currently supported bitcoin messages are provided. For these supported messages, all of the details of marshalling and unmarshalling to and from the wire using bitcoin encoding are handled so the caller doesn't have to concern themselves with the specifics.

Reading Messages Example

In order to unmarshal bitcoin messages from the wire, use the ReadMessage function. It accepts any io.Reader, but typically this will be a net.Conn to a remote node running a bitcoin peer. Example syntax is:

	// Use the most recent protocol version supported by the package and the
	// main bitcoin network.
	pver := wire.ProtocolVersion
	btcnet := wire.MainNet

	// Reads and validates the next bitcoin message from conn using the
	// protocol version pver and the bitcoin network btcnet.  The returns
	// are a wire.Message, a []byte which contains the unmarshalled
	// raw payload, and a possible error.
	msg, rawPayload, err := wire.ReadMessage(conn, pver, btcnet)
	if err != nil {
		// Log and handle the error
	}

See the package documentation for details on determining the message type.

Writing Messages Example

In order to marshal bitcoin messages to the wire, use the WriteMessage function. It accepts any io.Writer, but typically this will be a net.Conn to a remote node running a bitcoin peer. Example syntax to request addresses from a remote peer is:

	// Use the most recent protocol version supported by the package and the
	// main bitcoin network.
	pver := wire.ProtocolVersion
	btcnet := wire.MainNet

	// Create a new getaddr bitcoin message.
	msg := wire.NewMsgGetAddr()

	// Writes a bitcoin message msg to conn using the protocol version
	// pver, and the bitcoin network btcnet.  The return is a possible
	// error.
	err := wire.WriteMessage(conn, msg, pver, btcnet)
	if err != nil {
		// Log and handle the error
	}

GPG Verification Key

All official release tags are signed by Conformal so users can ensure the code has not been tampered with and is coming from the btcsuite developers. To verify the signature perform the following:

  • Download the public key from the Conformal website at https://opensource.conformal.com/GIT-GPG-KEY-conformal.txt

  • Import the public key into your GPG keyring:

    gpg --import GIT-GPG-KEY-conformal.txt
    
  • Verify the release tag with the following command where TAG_NAME is a placeholder for the specific tag:

    git tag -v TAG_NAME
    

License

Package wire is licensed under the copyfree ISC License.