how to use chain extensions to read/write runtime storage

[galaio]

can give a example in ink/examples, and compile with cargo-contract

rel #592

[Robbepop]

An example is given in the docs here: https://paritytech.github.io/ink/ink_lang/attr.chain_extension.html#example-definition
Note that for chain extensions to work you also need to provide a definition on the runtime side.
The #[ink::chain_extension] marked traits acts as a bridge between runtime and smart contract.

[galaio]

An example is given in the docs here: https://paritytech.github.io/ink/ink_lang/attr.chain_extension.html#example-definition
Note that for chain extensions to work you also need to provide a definition on the runtime side.
The #[ink::chain_extension] marked traits acts as a bridge between runtime and smart contract.

when I compile, get error use-ink/cargo-contract#158

[ascjones]

As metntioned in that issue the TypeInfo derive is only for std #[cfg_attr(feature = "std", derive(scale_info::TypeInfo))]

[galaio]

As metntioned in that issue the TypeInfo derive is only for std #[cfg_attr(feature = "std", derive(scale_info::TypeInfo))]

but it will be compiled to wasm.... have another solution?

[kuleleyokn42]

I have met the same problem, waiting for a solution. Thanks.

[ascjones]

As metntioned in that issue the TypeInfo derive is only for std #[cfg_attr(feature = "std", derive(scale_info::TypeInfo))]

but it will be compiled to wasm.... have another solution?

The TypeInfo is only required for metadata generation which is done in std. So this should work if you apply it to all your types.

If you did require the TypeInfo for whatever reason in the wasm environment then you could just remove optional = true from the scale-info dependency in your Cargo.toml. I don't think this is necessary in your case.

[galaio]

optional = true

when compile, got

cargo +nightly contract build                     
ERROR: Error invoking `cargo metadata`

Caused by:
    failed to run `cargo metadata`: error: failed to parse manifest at `/Users/galaio/RustProjects/kylin-node/contracts/get_prices/Cargo.toml`
    
    Caused by:
      feature `std` includes `scale-info`, but `scale-info` is not an optional dependency
      A non-optional dependency of the same name is defined; consider adding `optional = true` to its definition.

It seems scale-info is neccessary;

[galaio]

An example is given in the docs here: https://paritytech.github.io/ink/ink_lang/attr.chain_extension.html#example-definition
Note that for chain extensions to work you also need to provide a definition on the runtime side.
The #[ink::chain_extension] marked traits acts as a bridge between runtime and smart contract.

can ink give some compilable and runable example, like the example in ink/examples, https://github.com/paritytech/ink/tree/master/examples

[Robbepop]

It seems scale-info is neccessary;

No the error tells you to remove scale-info from the Cargo.toml list of your std feature implications, that's all. ;)

can ink give some compilable and runable example, like the example in ink/examples, https://github.com/paritytech/ink/tree/master/examples

We will be providing an example in the future! :)

[galaio]

It seems scale-info is neccessary;

No the error tells you to remove scale-info from the Cargo.toml list of your std feature implications, that's all. ;)

can ink give some compilable and runable example, like the example in ink/examples, https://github.com/paritytech/ink/tree/master/examples

We will be providing an example in the future! :)

when?

[Robbepop]

Since the chain extension feature needs to be orchestrated between ink! and the contracts-pallet from Substrate we plan on delivering such an example and documentation with cross-concerns (not only for ink!) as soon as we ship the orchestrated release between contracts-pallet 3.0 and ink! 3.0 which is expected to happen in roughly 2 weeks without guarantee.

[galaio]

Since the chain extension feature needs to be orchestrated between ink! and the contracts-pallet from Substrate we plan on delivering such an example and documentation with cross-concerns (not only for ink!) as soon as we ship the orchestrated release between contracts-pallet 3.0 and ink! 3.0 which is expected to happen in roughly 2 weeks without guarantee.

hi, How's it going?

[Robbepop]

https://github.com/paritytech/ink/tree/master/examples/rand-extension

[galaio]

https://github.com/paritytech/ink/tree/master/examples/rand-extension

what version of pallet contract？not found in substrate v2.0.1

[Robbepop]

it uses ink! master and Substrate master.

[HCastano]

This seems pretty stale. @galaio feel free to re-open if you think this is unresolved