#
pezkuwi_sdk_docs/reference_docs/
frame_origin.rs

    1//! # FRAME Origin
    2//!
    3//! Let's start by clarifying a common wrong assumption about Origin:
    4//!
    5//! **ORIGIN IS NOT AN ACCOUNT ID**.
    6//!
    7//! FRAME's origin abstractions allow you to convey meanings far beyond just an account-id being the
    8//! caller of an extrinsic. Nonetheless, an account-id having signed an extrinsic is one of the
    9//! meanings that an origin can convey. This is the commonly used [`frame_system::ensure_signed`],
    10//! where the return value happens to be an account-id.
    11//!
    12//! Instead, let's establish the following as the correct definition of an origin:
    13//!
    14//! > The origin type represents the privilege level of the caller of an extrinsic.
    15//!
    16//! That is, an extrinsic, through checking the origin, can *express what privilege level it wishes
    17//! to impose on the caller of the extrinsic*. One of those checks can be as simple as "*any account
    18//! that has signed a statement can pass*".
    19//!
    20//! But the origin system can also express more abstract and complicated privilege levels. For
    21//! example:
    22//!
    23//! * If the majority of token holders agreed upon this. This is more or less what the
    24//!   [`pallet_democracy`] does under the hood ([reference](https://github.com/pezkuwichain/pezkuwi-sdk/blob/edd95b3749754d2ed0c5738588e872c87be91624/substrate/frame/democracy/src/lib.rs#L1603-L1633)).
    25//! * If a specific ratio of an instance of [`pallet_collective`]/DAO agrees upon this.
    26//! * If another consensus system, for example a bridged network or a teyrchain, agrees upon this.
    27//! * If the majority of validator/authority set agrees upon this[^1].
    28//! * If caller holds a particular NFT.
    29//!
    30//! and many more.
    31//!
    32//! ## Context
    33//!
    34//! First, let's look at where the `origin` type is encountered in a typical pallet. The `origin:
    35//! OriginFor<T>` has to be the first argument of any given callable extrinsic in FRAME:
    36#![doc = docify::embed!("./src/reference_docs/frame_origin.rs", call_simple)]
    37//!
    38//! Typically, the code of an extrinsic starts with an origin check, such as
    39//! [`frame_system::ensure_signed`].
    40//!
    41//! Note that [`OriginFor`](frame_system::pallet_prelude::OriginFor) is merely a shorthand for
    42//! [`frame_system::Config::RuntimeOrigin`]. Given the name prefix `Runtime`, we can learn that
    43//! `RuntimeOrigin` is similar to `RuntimeCall` and others, a runtime composite enum that is
    44//! amalgamated at the runtime level. Read [`crate::reference_docs::frame_runtime_types`] to
    45//! familiarize yourself with these types.
    46//!
    47//! To understand this better, we will next create a pallet with a custom origin, which will add a
    48//! new variant to `RuntimeOrigin`.
    49//!
    50//! ## Adding Custom Pallet Origin to the Runtime
    51//!
    52//! For example, given a pallet that defines the following custom origin:
    53#![doc = docify::embed!("./src/reference_docs/frame_origin.rs", custom_origin)]
    54//!
    55//! And a runtime with the following pallets:
    56#![doc = docify::embed!("./src/reference_docs/frame_origin.rs", runtime_exp)]
    57//!
    58//! The type [`crate::reference_docs::frame_origin::runtime_for_origin::RuntimeOrigin`] is expanded.
    59//! This `RuntimeOrigin` contains a variant for the [`frame_system::RawOrigin`] and the custom
    60//! origin of the pallet.
    61//!
    62//! > Notice how the [`frame_system::ensure_signed`] is nothing more than a `match` statement. If
    63//! > you want to know where the actual origin of an extrinsic is set (and the signature
    64//! > verification happens, if any), see
    65//! > [`sp_runtime::generic::CheckedExtrinsic#trait-implementations`], specifically
    66//! > [`sp_runtime::traits::Applyable`]'s implementation.
    67//!
    68//! ## Asserting on a Custom Internal Origin
    69//!
    70//! In order to assert on a custom origin that is defined within your pallet, we need a way to first
    71//! convert the `<T as frame_system::Config>::RuntimeOrigin` into the local `enum Origin` of the
    72//! current pallet. This is a common process that is explained in
    73//! [`crate::reference_docs::frame_runtime_types#
    74//! adding-further-constraints-to-runtime-composite-enums`].
    75//!
    76//! We use the same process here to express that `RuntimeOrigin` has a number of additional bounds,
    77//! as follows.
    78//!
    79//! 1. Defining a custom `RuntimeOrigin` with further bounds in the pallet.
    80#![doc = docify::embed!("./src/reference_docs/frame_origin.rs", custom_origin_bound)]
    81//!
    82//! 2. Using it in the pallet.
    83#![doc = docify::embed!("./src/reference_docs/frame_origin.rs", custom_origin_usage)]
    84//!
    85//! ## Asserting on a Custom External Origin
    86//!
    87//! Very often, a pallet wants to have a parameterized origin that is **NOT** defined within the
    88//! pallet. In other words, a pallet wants to delegate an origin check to something that is
    89//! specified later at the runtime level. Like many other parameterizations in FRAME, this implies
    90//! adding a new associated type to `trait Config`.
    91#![doc = docify::embed!("./src/reference_docs/frame_origin.rs", external_origin_def)]
    92//!
    93//! Then, within the pallet, we can simply use this "unknown" origin check type:
    94#![doc = docify::embed!("./src/reference_docs/frame_origin.rs", external_origin_usage)]
    95//!
    96//! Finally, at the runtime, any implementation of [`frame::traits::EnsureOrigin`] can be passed.
    97#![doc = docify::embed!("./src/reference_docs/frame_origin.rs", external_origin_provide)]
    98//!
    99//! Indeed, some of these implementations of [`frame::traits::EnsureOrigin`] are similar to the ones
    100//! that we know about: [`frame::runtime::prelude::EnsureSigned`],
    101//! [`frame::runtime::prelude::EnsureSignedBy`], [`frame::runtime::prelude::EnsureRoot`],
    102//! [`frame::runtime::prelude::EnsureNone`], etc. But, there are also many more that are not known
    103//! to us, and are defined in other pallets.
    104//!
    105//! For example, [`pallet_collective`] defines [`pallet_collective::EnsureMember`] and
    106//! [`pallet_collective::EnsureProportionMoreThan`] and many more, which is exactly what we alluded
    107//! to earlier in this document.
    108//!
    109//! Make sure to check the full list of [implementors of
    110//! `EnsureOrigin`](frame::traits::EnsureOrigin#implementors) for more inspiration.
    111//!
    112//! ## Obtaining Abstract Origins
    113//!
    114//! So far we have learned that FRAME pallets can assert on custom and abstract origin types,
    115//! whether they are defined within the pallet or not. But how can we obtain these abstract origins?
    116//!
    117//! > All extrinsics that come from the outer world can generally only be obtained as either
    118//! > `signed` or `none` origin.
    119//!
    120//! Generally, these abstract origins are only obtained within the runtime, when a call is
    121//! dispatched within the runtime.
    122//!
    123//! ## Further References
    124//!
    125//! - [Gavin Wood's speech about FRAME features at Protocol Berg 2023.](https://youtu.be/j7b8Upipmeg?si=83_XUgYuJxMwWX4g&t=195)
    126//! - [A related StackExchange question.](https://exchange.pezkuwichain.app/questions/10992/how-do-you-find-the-public-key-for-the-medium-spender-track-origin)
    127//!
    128//! [^1]: Inherents are essentially unsigned extrinsics that need an [`frame_system::ensure_none`]
    129//! origin check, and through the virtue of being an inherent, are agreed upon by all validators.
    130
    131use frame::prelude::*;
    132
    133#[frame::pallet(dev_mode)]
    134pub mod pallet_for_origin {
    135	use super::*;
    136
    137	#[pallet::config]
    138	pub trait Config: frame_system::Config {}
    139
    140	#[pallet::pallet]
    141	pub struct Pallet<T>(_);
    142
    143	#[docify::export(call_simple)]
    144	#[pallet::call]
    145	impl<T: Config> Pallet<T> {
    146		pub fn do_something(_origin: OriginFor<T>) -> DispatchResult {
    147			//              ^^^^^^^^^^^^^^^^^^^^^
    148			todo!();
    149		}
    150	}
    151}
    152
    153#[frame::pallet(dev_mode)]
    154pub mod pallet_with_custom_origin {
    155	use super::*;
    156
    157	#[docify::export(custom_origin_bound)]
    158	#[pallet::config]
    159	pub trait Config: frame_system::Config {
    160		type RuntimeOrigin: From<<Self as frame_system::Config>::RuntimeOrigin>
    161			+ Into<Result<Origin, <Self as Config>::RuntimeOrigin>>;
    162	}
    163
    164	#[pallet::pallet]
    165	pub struct Pallet<T>(_);
    166
    167	#[docify::export(custom_origin)]
    168	/// A dummy custom origin.
    169	#[pallet::origin]
    170	#[derive(
    171		PartialEq,
    172		Eq,
    173		Clone,
    174		RuntimeDebug,
    175		Encode,
    176		Decode,
    177		DecodeWithMemTracking,
    178		TypeInfo,
    179		MaxEncodedLen,
    180	)]
    181	pub enum Origin {
    182		/// If all holders of a particular NFT have agreed upon this.
    183		AllNftHolders,
    184		/// If all validators have agreed upon this.
    185		ValidatorSet,
    186	}
    187
    188	#[docify::export(custom_origin_usage)]
    189	#[pallet::call]
    190	impl<T: Config> Pallet<T> {
    191		pub fn only_validators(origin: OriginFor<T>) -> DispatchResult {
    192			// first, we convert from `<T as frame_system::Config>::RuntimeOrigin` to `<T as
    193			// Config>::RuntimeOrigin`
    194			let local_runtime_origin = <<T as Config>::RuntimeOrigin as From<
    195				<T as frame_system::Config>::RuntimeOrigin,
    196			>>::from(origin);
    197			// then we convert to `origin`, if possible
    198			let local_origin =
    199				local_runtime_origin.into().map_err(|_| "invalid origin type provided")?;
    200			ensure!(matches!(local_origin, Origin::ValidatorSet), "Not authorized");
    201			todo!();
    202		}
    203	}
    204}
    205
    206pub mod runtime_for_origin {
    207	use super::pallet_with_custom_origin;
    208	use frame::{runtime::prelude::*, testing_prelude::*};
    209
    210	#[docify::export(runtime_exp)]
    211	construct_runtime!(
    212		pub struct Runtime {
    213			System: frame_system,
    214			PalletWithCustomOrigin: pallet_with_custom_origin,
    215		}
    216	);
    217
    218	#[derive_impl(frame_system::config_preludes::TestDefaultConfig)]
    219	impl frame_system::Config for Runtime {
    220		type Block = MockBlock<Self>;
    221	}
    222
    223	impl pallet_with_custom_origin::Config for Runtime {
    224		type RuntimeOrigin = RuntimeOrigin;
    225	}
    226}
    227
    228#[frame::pallet(dev_mode)]
    229pub mod pallet_with_external_origin {
    230	use super::*;
    231	#[docify::export(external_origin_def)]
    232	#[pallet::config]
    233	pub trait Config: frame_system::Config {
    234		type ExternalOrigin: EnsureOrigin<Self::RuntimeOrigin>;
    235	}
    236
    237	#[pallet::pallet]
    238	pub struct Pallet<T>(_);
    239
    240	#[docify::export(external_origin_usage)]
    241	#[pallet::call]
    242	impl<T: Config> Pallet<T> {
    243		pub fn externally_checked_ext(origin: OriginFor<T>) -> DispatchResult {
    244			T::ExternalOrigin::ensure_origin(origin)?;
    245			todo!();
    246		}
    247	}
    248}
    249
    250pub mod runtime_for_external_origin {
    251	use super::*;
    252	use frame::{runtime::prelude::*, testing_prelude::*};
    253
    254	construct_runtime!(
    255		pub struct Runtime {
    256			System: frame_system,
    257			PalletWithExternalOrigin: pallet_with_external_origin,
    258		}
    259	);
    260
    261	#[derive_impl(frame_system::config_preludes::TestDefaultConfig)]
    262	impl frame_system::Config for Runtime {
    263		type Block = MockBlock<Self>;
    264	}
    265
    266	#[docify::export(external_origin_provide)]
    267	impl pallet_with_external_origin::Config for Runtime {
    268		type ExternalOrigin = EnsureSigned<<Self as frame_system::Config>::AccountId>;
    269	}
    270}