APAC submission (Part two) Example of creating a pallet which is using IPFS-core to talk to an IPFS ocw.

Cargo.toml

@@ -138,6 +138,7 @@ members = [
 	"frame/bags-list/fuzzer",
 	"pallets/template",
 	"pallets/ipfs-exmaple",
+	"pallets/ipfs-template",
 	"pallets/ipfs-core",
 	"pallets/pocket-mints",
 	"primitives/api",

bin/node/cli/src/service.rs

@@ -357,6 +357,13 @@ pub fn new_full_base(
 			Some("//Alice"),
 		).expect("Creating key with account Alice should succeed");
 
+		//ipfs-template
+		sp_keystore::SyncCryptoStore::sr25519_generate_new(
+			&*keystore,
+			sp_core::crypto::key_types::IPFS_EXAMPLE,
+			Some("//Alice"),
+		).expect("Creating key with account Alice should succeed");
+
 		//pocket-mints
 		sp_keystore::SyncCryptoStore::sr25519_generate_new(
 			&*keystore,

pallets/ipfs-template/Cargo.toml

@@ -0,0 +1,42 @@
+[package]
+name = 'pallet-ipfs-template'
+version = "4.0.0-dev"
+description = "A template pallet for interacting with ipfs-core."
+authors = ['Dan Henton <https://github.com/DanHenton>']
+homepage = "https://substrate.io/"
+edition = '2018'
+license = "Unlicense"
+publish = false
+repository = "https://github.com/substrate-developer-hub/substrate-node-template/"
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[dependencies]
+codec = { package = "parity-scale-codec", version = "2.0.0", default-features = false, features = ["derive"] }
+scale-info = { version = "1.0", default-features = false, features = ["derive"] }
+frame-support = { default-features = false, version = "4.0.0-dev", path = "../../frame/support" }
+frame-system = { default-features = false, version = "4.0.0-dev", path = "../../frame/system" }
+frame-benchmarking = { default-features = false, version = "4.0.0-dev", path = "../../frame/benchmarking", optional = true }
+log = { version = "0.4" }
+sp-std = { default-features = false, version = "4.0.0-dev", path = "../../primitives/std" }
+sp-core = { default-features = false, version = "4.0.0-dev", path = "../../primitives/core" }
+sp-io = { default-features = false, version = "4.0.0-dev", path = "../../primitives/io" }
+sp-runtime = { default-features = false, version = "4.0.0-dev", path = "../../primitives/runtime" }
+
+pallet-ipfs-core = { default-features = false, version = "4.0.0-dev", path = "../ipfs-core" }
+
+[features]
+default = ['std']
+std = [
+	'codec/std',
+	'scale-info/std',
+	'frame-support/std',
+	'frame-system/std',
+	'frame-benchmarking/std',
+	'sp-std/std',
+	'pallet-ipfs-core/std',
+]
+
+runtime-benchmarks = ["frame-benchmarking"]
+try-runtime = ["frame-support/try-runtime"]

pallets/ipfs-template/README.md

@@ -0,0 +1 @@
+License: Unlicense

pallets/ipfs-template/src/benchmarking.rs

@@ -0,0 +1,11 @@
+//! Benchmarking setup for pallet-template
+
+use super::*;
+
+#[allow(unused)]
+use crate::Pallet as Template;
+use frame_benchmarking::{benchmarks, whitelisted_caller};
+use frame_system::RawOrigin;
+
+benchmarks! {
+}

pallets/ipfs-template/src/lib.rs

@@ -0,0 +1,253 @@
+#![cfg_attr(not(feature = "std"), no_std)]
+
+/// Edit this file to define custom logic or remove it if it is not needed.
+/// Learn more about FRAME and the core library of Substrate FRAME pallets:
+/// <https://docs.substrate.io/v3/runtime/frame>
+
+use codec::{ Decode, Encode };
+use frame_system::{
+	offchain::{ AppCrypto, CreateSignedTransaction, SendSignedTransaction, Signer},
+};
+use sp_runtime::{
+	offchain::{
+		ipfs,
+		storage::{MutateStorageError, StorageRetrievalError, StorageValueRef},
+	},
+	RuntimeDebug
+};
+
+use frame_support::{
+	traits::Randomness,
+	dispatch::DispatchResult,
+};
+
+#[cfg(feature = "std")]
+use frame_support::serde::{ Deserialize, Serialize };
+
+use sp_core::{
+	offchain::{ Duration, IpfsRequest, IpfsResponse, OpaqueMultiaddr, Timestamp},
+};
+use log::{ error, info };
+use sp_std::str;
+use sp_std::vec::Vec;
+use core::{convert::TryInto};
+
+#[cfg(test)]
+mod mock;
+
+#[cfg(test)]
+mod tests;
+
+#[cfg(feature = "runtime-benchmarks")]
+mod benchmarking;
+
+pub mod crypto {
+	use sp_core::{
+		sr25519::Signature as Sr25519Signature,
+	};
+	use sp_runtime::{
+		app_crypto::{app_crypto, sr25519},
+		traits::Verify,
+		MultiSignature, MultiSigner
+	};
+
+	app_crypto!(sr25519, sp_core::crypto::key_types::IPFS_EXAMPLE);
+
+	pub struct TestAuthId;
+
+	impl frame_system::offchain::AppCrypto<MultiSigner, MultiSignature> for TestAuthId {
+		type RuntimeAppPublic = Public;
+		type GenericPublic = sp_core::sr25519::Public;
+		type GenericSignature = sp_core::sr25519::Signature;
+	}
+
+	// Implemented for mock runtime in tests
+	impl frame_system::offchain::AppCrypto<<Sr25519Signature as Verify>::Signer, Sr25519Signature> for TestAuthId {
+		type RuntimeAppPublic = Public;
+		type GenericPublic = sp_core::sr25519::Public;
+		type GenericSignature = sp_core::sr25519::Signature;
+	}
+}
+
+pub use pallet::*;
+
+#[frame_support::pallet]
+pub mod pallet {
+	use super::*;
+	use frame_support::pallet_prelude::*;
+	use frame_system::pallet_prelude::*;
+	use sp_core::crypto::KeyTypeId;
+	use pallet_ipfs_core as IpfsCore;
+	use pallet_ipfs_core::{
+		generate_id, ipfs_request, ocw_process_command,
+		ocw_parse_ipfs_response, addresses_to_utf8_safe_bytes,
+		IpfsCommand, CommandRequest,
+		Event as IpfsEvent,
+		Error as IpfsError,
+	};
+
+	pub const KEY_TYPE: KeyTypeId = sp_core::crypto::key_types::IPFS_EXAMPLE;
+	const PROCESSED_COMMANDS: &[u8; 24] = b"ipfs::ipfs-example-comds";
+
+	/// Configure the pallet by specifying the parameters and types on which it depends.
+	#[pallet::config]
+	pub trait Config: frame_system::Config + pallet_ipfs_core::Config + CreateSignedTransaction<Call<Self>> {
+		/// The identifier type for an offchain worker.
+		type AuthorityId: AppCrypto<Self::Public, Self::Signature>;
+
+		/// Because this pallet emits events, it depends on the runtime's definition of an event.
+		type Event: From<Event<Self>> + IsType<<Self as frame_system::Config>::Event>;
+
+		/// overarching dispatch call type.
+		type Call: From<Call<Self>>;
+
+		type IpfsRandomness: Randomness<Self::Hash, Self::BlockNumber>;
+	}
+
+	#[pallet::pallet]
+	#[pallet::generate_store(pub(super) trait Store)]
+	pub struct Pallet<T>(_);
+
+	// The pallet's runtime storage items.
+	// https://docs.substrate.io/v3/runtime/storage
+
+	/** Store a list of Commands for the ocw to process */
+	// EXAMPLE: store the CommandRequests in a StorageValue for fast iteration.
+	#[pallet::storage]
+	#[pallet::getter(fn commands)]
+	pub type Commands<T: Config> = StorageValue<_, Vec<CommandRequest<T>>>;
+
+	/** Pallets use events to inform users when important changes are made.
+	 */
+	#[pallet::event]
+	#[pallet::generate_deposit(pub(super) fn deposit_event)]
+	pub enum Event<T: Config> {
+		OcwCallback(T::AccountId),
+	}
+
+	/** Errors inform users that something went wrong.
+	- RequestFailed,
+	 */
+	#[pallet::error]
+	pub enum Error<T> {
+		StorageError,
+		FailedToFindCid,
+	}
+
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {
+		fn offchain_worker(block_number: T::BlockNumber) {
+			if let Err(_err) = Self::ocw_process_command_requests(block_number) { error!("IPFS: command request"); }
+		}
+	}
+
+
+	// Dispatchable functions allows users to interact with the pallet and invoke state changes.
+	// These functions materialize as "extrinsics", which are often compared to transactions.
+	// Dispatchable functions must be annotated with a weight and must return a DispatchResult.
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
+		// EXAMPLE: Add extrinsics here.
+
+		/** Process a signed callback from the ocw */
+		#[pallet::weight(0)]
+		pub fn ocw_callback(origin: OriginFor<T>, identifier: [u8; 32], data: Vec<u8>) -> DispatchResult {
+			let signer = ensure_signed(origin)?;
+
+			// Side effect:, swap_remove will change the ordering of the Vec!
+			// TODO: the lock still exists in the ocw storage
+			let mut callback_command :Option<CommandRequest<T>> = None;
+			Commands::<T>::mutate(|command_requests| {
+				let mut commands = command_requests.clone().unwrap();
+
+				if let Some(index) = commands.iter().position(|cmd| { cmd.identifier == identifier }) {
+					info!("Removing at index {}", index.clone());
+					callback_command = Some(commands.swap_remove(index).clone());
+				};
+
+				*command_requests = Some(commands);
+			});
+
+			Self::deposit_event(Event::OcwCallback(signer));
+
+			Self::command_callback(&callback_command.unwrap(), data);
+
+			Ok(())
+		}
+	}
+
+	impl<T: Config> Pallet<T> {
+		/**
+		Iterate over all of the Active CommandRequests calling them.
+
+		Im sure some more logic will go in here.
+		 */
+		fn ocw_process_command_requests(block_number: T::BlockNumber) -> Result<(), Error<T>> {
+			let commands: Vec<CommandRequest<T>> = Commands::<T>::get().unwrap_or(Vec::<CommandRequest<T>>::new());
+
+			for command_request in commands {
+
+				match ocw_process_command::<T>(block_number, command_request.clone(), PROCESSED_COMMANDS) {
+					Ok(responses) => {
+						let callback_response = ocw_parse_ipfs_response::<T>(responses);
+
+						// EXAMPLE: Some more logic can be put here.
+
+						Self::signed_callback(&command_request, callback_response);
+					}
+					Err(e) => {
+						match e {
+							IpfsError::<T>::RequestFailed => { error!("IPFS: failed to perform a request") },
+							_ => {}
+						}
+					}
+				}
+			}
+
+			Ok(())
+		}
+
+		/** callback to the on-chain validators to continue processing the CID  **/
+		fn signed_callback(command_request: &CommandRequest<T>, data: Vec<u8>) -> Result<(), IpfsError<T>> {
+			// TODO: Dynamic signers so that its not only the validator who can sign the request.
+			let signer = Signer::<T, T::AuthorityId>::all_accounts();
+			if !signer.can_sign() {
+				error!("*** IPFS *** ---- No local accounts available. Consider adding one via `author_insertKey` RPC.");
+				return Err(IpfsError::<T>::RequestFailed)?
+			}
+
+			let results  = signer.send_signed_transaction(|_account| {
+				Call::ocw_callback{
+					identifier: command_request.identifier,
+					data: data.clone()
+				}
+			});
+			for (account, result) in &results {
+				match result {
+					Ok(()) => { info!("callback sent") },
+					Err(e) => { error!("Failed to submit transaction {:?}", e)}
+				}
+			}
+			// TODO: return a better Result
+			Ok(())
+		}
+
+		// - Ideally the callback function can be override by another pallet that is coupled to this one allowing for custom functionality.
+		// - data can be used for callbacks IE add a cid to the signer / uploader.
+		// - Validate a connected peer has the CID, and which peer has it etc.
+		// TODO: Result
+		fn command_callback(command_request: &CommandRequest<T>, data: Vec<u8>) -> Result<(), Error<T>>{
+			let owner = &command_request.clone().requester;
+
+			for command in command_request.clone().ipfs_commands {
+				match command {
+					// EXAMPLE: Callback logic goes in here. Matching pallet_ipfs_core::pallet::IpfsCommand's
+					_ => {}
+				}
+			}
+
+			// TODO: return a better Result
+			Ok(())
+		}
+	}
+}