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https://github.com/pezkuwichain/pezkuwi-subxt.git
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Benjamin Kampmann
2416aa7999
* Bump version * update test-utils crates to be ready for publishing * adding changelog * Adding automaticly generated READMEs * fixing versions * another version mishap
74 lines
2.1 KiB
Markdown
74 lines
2.1 KiB
Markdown
# Timestamp Module
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The Timestamp module provides functionality to get and set the on-chain time.
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- [`timestamp::Trait`](./trait.Trait.html)
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- [`Call`](./enum.Call.html)
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- [`Module`](./struct.Module.html)
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## Overview
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The Timestamp module allows the validators to set and validate a timestamp with each block.
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It uses inherents for timestamp data, which is provided by the block author and validated/verified
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by other validators. The timestamp can be set only once per block and must be set each block.
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There could be a constraint on how much time must pass before setting the new timestamp.
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**NOTE:** The Timestamp module is the recommended way to query the on-chain time instead of using
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an approach based on block numbers. The block number based time measurement can cause issues
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because of cumulative calculation errors and hence should be avoided.
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## Interface
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### Dispatchable Functions
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* `set` - Sets the current time.
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### Public functions
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* `get` - Gets the current time for the current block. If this function is called prior to
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setting the timestamp, it will return the timestamp of the previous block.
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### Trait Getters
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* `MinimumPeriod` - Gets the minimum (and advised) period between blocks for the chain.
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## Usage
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The following example shows how to use the Timestamp module in your custom module to query the current timestamp.
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### Prerequisites
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Import the Timestamp module into your custom module and derive the module configuration
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trait from the timestamp trait.
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### Get current timestamp
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```rust
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use frame_support::{decl_module, dispatch};
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use frame_system::ensure_signed;
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pub trait Trait: timestamp::Trait {}
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decl_module! {
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pub struct Module<T: Trait> for enum Call where origin: T::Origin {
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#[weight = 0]
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pub fn get_time(origin) -> dispatch::DispatchResult {
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let _sender = ensure_signed(origin)?;
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let _now = <timestamp::Module<T>>::get();
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Ok(())
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}
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}
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}
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```
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### Example from the FRAME
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The [Session module](https://github.com/paritytech/substrate/blob/master/frame/session/src/lib.rs) uses
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the Timestamp module for session management.
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## Related Modules
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* [Session](../pallet_session/index.html)
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License: Apache-2.0 |