Table of Contents

Class ActionBase

Namespace
Nekoyume.Action
Assembly
Lib9c.dll
[Serializable]
public abstract class ActionBase : IAction
Inheritance
ActionBase
Implements
IAction
Derived
Inherited Members

Properties

PlainValue

Serializes values bound to an action, which is held by properties (or fields) of an action, so that they can be transmitted over network or saved to persistent storage.

Serialized values are deserialized by Libplanet.Action.IAction.LoadPlainValue(Bencodex.Types.IValue) method later.

public abstract IValue PlainValue { get; }

Property Value

IValue

A Bencodex value which encodes this action's bound values (held by properties or fields).

See Also
LoadPlainValue(IValue)

Methods

CheckObsolete(long, IActionContext) 

protected void CheckObsolete(long obsoleteIndex, IActionContext ctx)

Parameters

obsoleteIndex long
ctx IActionContext

CheckPermission(IActionContext) 

protected void CheckPermission(IActionContext ctx)

Parameters

ctx IActionContext

Execute(IActionContext)

Executes the main game logic of an action. This should be deterministic.

Through the context object, it receives information such as a transaction signer, its states immediately before the execution, and a deterministic random seed.

Other “bound” information resides in the action object in itself, as its properties (or fields).

A returned Libplanet.Action.State.IWorld object functions as a delta which shifts from previous states to next states.

public abstract IWorld Execute(IActionContext context)

Parameters

context IActionContext

A context object containing addresses that signed the transaction, states immediately before the execution, and a PRNG object which produces deterministic random numbers. See Libplanet.Action.IActionContext for details.

Returns

IWorld

A map of changed states (so-called "dirty").

Remarks

This method should be deterministic: for structurally (member-wise) equal actions and Libplanet.Action.IActionContexts, the same result should be returned. Side effects should be avoided, because an action's Libplanet.Action.IAction.Execute(Libplanet.Action.IActionContext) method can be called more than once, the time it's called is difficult to predict.

For changing in-memory game states or drawing graphics, implement the Blockchain.Renderers.IRenderer interface separately and attach it to a Blockchain.BlockChain instance.

For randomness, never use Random nor any other PRNGs provided by other than Libplanet. Use IActionContext.Random instead. IActionContext.Random guarantees the same action has the consistent result for every node in the network.

Also do not perform I/O operations such as file system access or networking. These bring an action indeterministic. You maybe fine to log messages for debugging purpose, but equivalent messages could be logged multiple times.

Although it might be surprising, floating-point arithmetics are underspecified so that it can make different results on different machines, platforms, runtimes, compilers, and builds.

Lastly, you need to be aware and keep in mind that there is a global state named CurrentCulture on .NET; if you format numbers, dates and times, currencies, or other such things into strings and parse these strings back these can rely on CurrentCulture, so that the same action make different results on two differently configured systems like Thai language and French language. In order to make these types of conversions deterministic, you have to explicitly pass InvariantCulture.

For more on determinism in general, please read also Tendermint ABCI's docs on determinism.

Lastly, you can conduct static analysis on your code using Libplanet.Analyzers. The analyzer can be enabled by adding its NuGet package into your project as a dependency.

See Also
IActionContext

GetSignerAndOtherAddressesHex(IActionContext, params Address[])

returns "[Signer Address, AvatarState Address, ...]"

protected string GetSignerAndOtherAddressesHex(IActionContext ctx, params Address[] addresses)

Parameters

ctx IActionContext
addresses Address[]

Returns

string

LoadPlainValue(IValue)

Deserializes serialized data (i.e., data Libplanet.Action.IAction.PlainValue property made), and then fills this action's properties (or fields) with the deserialized values.

public abstract void LoadPlainValue(IValue plainValue)

Parameters

plainValue IValue

Data (made by Libplanet.Action.IAction.PlainValue property) to be deserialized and assigned to this action's properties (or fields).

See Also
PlainValue

TryGetAdminState(IActionContext, out AdminState) 

protected bool TryGetAdminState(IActionContext ctx, out AdminState state)

Parameters

ctx IActionContext
state AdminState

Returns

bool
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