fcbuffer
v2.2.2
Published
Serialization library geared towards immutable data storage such as blockchains.
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FC Buffer
Serialization library geared towards immutable data storage such as blockchains.
For EOS compatible implementation use this library from eosjs instead.
FC Buffer is a recent refactor from serialization code used in Bitshares and Steem. Some of the serialization code was reduced and the definitions language added. The definition format may change.
Features
- Validation and error reporting
- Concise and intuitive binary format
- Compatible with the FC library used in Graphene blockchains
- Extendable JSON structure definitions
- Binary and JSON string serialization
- Unit testing and code coverage
Non Features
- Consider Cap'n Proto or Protocol Buffers if your data structures need to be extended at the serialization layer.
- No streams, smaller blockchain sized objects are used
Example
Fcbuffer = require('fcbuffer') // or: Fcbuffer = require('./src')
assert = require('assert')
definitions = {
message_type: 'fixed_string16', // CustomType: built-in type
account_name: 'fixed_string32', // CustomType: built-in type
message: { // struct
fields: {
from: 'account_name',
to: 'account_name',
cc: 'account_name[]',
type: 'message_type',
data: 'bytes' // built-in type
}
}
}
// Warning: Do not use {defaults: true} in production
fcbuffer = Fcbuffer(definitions, {defaults: true})
// Check for errors anywhere in the definitions structure
assert(fcbuffer.errors.length === 0, fcbuffer.errors)
// If there are no errors, you'll get your structs
var {message} = fcbuffer.structs
// Create JSON serializable object
// returns { from: '', to: '', cc: [ '' ], type: '', data: '' }
message.toObject()
// Convert JSON into a more compact fcbuffer serializable object
msg = { from: 'jc', to: 'dan', cc: [ 'abc' ], type: '', data: '0f0f0f' }
// Serialize fcbuffer object into a single binary buffer
buf = Fcbuffer.toBuffer(message, msg)
// returns <Buffer 02 6a 63 07 63 68 61 72 6c 65 73 01 03 61 62 63 00 03 0f 0f 0f>
// Convert binary back into a new (cloned) object
obj = Fcbuffer.fromBuffer(message, buf)
// Check that the new object matches the original
assert.deepEqual(msg, obj)
// A definition may extend and define other definitions. This works in the initial
// definition or later via the extend function.
fcbuffer2 = fcbuffer.extend({
permission_name: 'fixed_string16',
permission_level: {
fields: {
actor: 'account_name',
permission: 'permission_name'
}
}
})
assert(fcbuffer2.errors.length === 0, fcbuffer2.errors)
var {permission_level} = fcbuffer2.structs
permission_level.toObject()
// toObject returns: { actor: '', permission: '' }
References
Environment
Node 6+ and browser (browserify, webpack, etc)