Questions tagged [rust]
Questions about the Rust programming language, the primary language used in the Substrate ecosystem.
32
questions
11
votes
3
answers
557
views
How to have a mapping in a custom structure inside an ink! contract?
I'm a newbie with rust and substrate. I'm currently trying to build a PSP34 compatible smart contract (NFT) for documents. In this contract, I'd like to have the following structure:
#[derive(Default, ...
- 489
10
votes
4
answers
1k
views
ERROR: Loading of original wasm failed
I having some trouble running the Flipper example from the Ink! webpage.
The cargo contract build outputs the following error log:
ERROR: Loading of original wasm failed
Caused by:
0: Loading of ...
14
votes
2
answers
1k
views
Why do we need #![cfg_attr(not(feature = "std"), no_std)]
This attribute is applied to the item it is defined in and conditionally applies the no_std attribute if we are not using the "std" feature. Why do we need this and in which cases would the ...
4
votes
1
answer
182
views
Balance division in Substrate runtime
I am a bit confused with how to do operations with the Balances in the Substrate runtime. More concrete the division.
The example I want to implement is similar to the Lottery pallet but with shared ...
- 5,364
4
votes
1
answer
287
views
How to return the whole Mapping from a contract method?
I'm a newbie in Rust, Substrate, and blockchain development. I'm developing an ink! smart contract that store a list of items. Since the storage version of Vec is not available yet, I use a Mapping to ...
1
vote
3
answers
408
views
How can manually generate same address from mnemonic as subkey without it?
Can someone tell me how can I generate a secret/privateKey/miniSecretKey, publicKey without subkey the tool from a mnemonic?
I am working on a c# implementation of the wallet generation and I'd ...
- 21
1
vote
1
answer
335
views
Substrate Rust generate key pair using sp_core::crypto::Pair
I'm pretty new with Substrate and Rust, but I was trying to generate a key pair using the from_string function of sp_core::crypto::Pair . I haven't had any luck and kept getting either ...
- 145
10
votes
3
answers
365
views
Why is it a bad idea to use String in an ink! smart contract?
I've heard that it is a bad idea to use Rust's String type in an ink! smart contract.
Why is this so? And what is your recommendation to use instead for typical use cases of String ‒ so parsing input ...
- 313
9
votes
2
answers
273
views
Trait bounds not satisfied for `Balance` type
I was following this guide Configuring Genesis for Balances.
In my parachain, I replaced T::Balance with BalanceOf<T>
type BalanceOf<T> =
<<T as Config>::Currency as ...
- 1,193
8
votes
1
answer
132
views
How to setup and RPC call that accepts a u128 input?
I cannot seem to setup a RPC call that accepts a u128 param.
I can input the following
let u128Input = new BN("10")
let output = await api.rpc.template.testRpc(u128Input);
but get an error ...
- 83
6
votes
1
answer
254
views
With subxt how can I subscribe to watch extrinsics?
There's some great examples of how to use subxt to listen to all events.
Polkadot-js events screen seem to show events grouped by the extrinsic that created them. Can I do the same in rust?
(if not ...
- 3,759
5
votes
1
answer
221
views
How to set base_fee and len_fee to zero?
I was trying to modify the transaction fee and for that I only want the congestion of the network. In FeeDetails, that is present in the transaction-payment pallet, we have three fields, i.e., ...
- 975
4
votes
1
answer
76
views
How to parse an ss58 address in no_std rust
In another question
How do I work with SS58 encoded addresses? the same question was addressed, this is however about how to do it without the std lib.
How to convert an ss58 stored in a String to an ...
- 1,080
4
votes
1
answer
133
views
Rust ink. Division wont return a number with float point
I'm trying to calculate a value of token by using division operator,
it will return a number higher then 1, but never returns
here is the code of the price calculation:
#[ink(message)]
...
4
votes
2
answers
158
views
std in conditional compilation [closed]
#![cfg_attr(not(feature = "std"), no_std)]
Does the "std" above reflect the rust standard library or the std feature defined in the cargo.toml for a given crate?
Also, for many of ...
4
votes
1
answer
120
views
Is there any way to access the accountid inside the offchain worker?
I am coding a pallet in which I need to know who I am inside a offchain worker to check if I should send a transaction or not. Right now I have access to the account in the send_signed_transaction ...
- 148
3
votes
1
answer
88
views
Division operation in `u128` results false value
In my node, Balance type is u128. I have following variable
let per_block = 100_000_000_000_000_000_u128;
let total = 50_000_000_000_000_000_000_000_u128;
let ratio = per_block.checked_div(total);
...
- 686
3
votes
1
answer
146
views
Contract call returns error "Found input with 28 bits, expected 8". Polkadot.js and ink contracts
as the title suggest, Im trying to call PSP22 token contract and read balanceOf() function, but i get error that im passing a too big of a input (27 instead of 8)
Im trying to invoke balanceOf() PSP22 ...
2
votes
2
answers
120
views
error: duplicate lang item in crate `std` (which `arrayvec` depends on): `panic_impl`
I am use the latest rust toolchain, compiler the pallet-ibc at the branch feature/dv-ics20 : https://github.com/octopus-network/substrate-ibc, this give the blow error.
suyinrong@suyinrongdeMacBook-...
- 21
2
votes
1
answer
250
views
How to decode events help on substrate using polkadot.js?
I have a base smart contract in rust with package manager cargo. In that smart contract I have some events which I'm emitting while function calling. For listing that events I have a service in java ...
2
votes
1
answer
123
views
How to upgrade Frontier to use a specific Substrate version
The Substrate team(https://github.com/paritytech/substrate/) produces releases like polkadot-v0.9.25 every a few weeks,
and my team needs to upgrade our parachain to follow those Substrate versions.
...
- 1,193
2
votes
1
answer
59
views
MultiAddress to Address String
I'm trying to retrieve the author's address as a string, and I've successfully obtained the MultiAddress using the following code:
let validator_address = if let Some(author_multi_address) = ...
- 219
1
vote
1
answer
48
views
Calculate Session/Epoch time remaining
I've seen some websites display the estimated time remaining for the current session/epoch. Is there a Rust call for this? Is there a sample of that code?
- 140
1
vote
1
answer
270
views
How to connect substrate node to metamask?
My node is compatible with EVM and I would like to connect it to metamask?
How can I do it?
What should I put in RPC URL and chain id? (Where can I find my chain id)
- 171
1
vote
1
answer
112
views
How do I work with SS58 encoded addresses?
I want to reason about SS58 addresses in any context with access to std, using Rust. What tools and techniques are needed to access the underlying keys?
[Related What is the SS58 Format?]
Nuke♦
- 1,822
1
vote
3
answers
235
views
How to store a string in substrate storage?
I would like to store a string/message in substrate storage because I am writing a pallet, later on, I would like to use the Polkadot.js portal to write the message on the front-end and store it, and ...
- 171
0
votes
3
answers
291
views
Mac m1 substrate node template can't be build
I get this issue when I try to build the substrate-node-template
error: failed to run custom build command for `prost-build v0.10.4`
Caused by:
process didn't exit successfully: `/Users/elioprifti/...
- 171
0
votes
2
answers
84
views
Smoldot Documentation
How to run smoldot repository code and connect with our substrate based chain or substrate node ?
On official documentation of smoldot on github is not in detail .Please answer here complete way to ...
- 138
0
votes
1
answer
44
views
Compiled code withe #[cfg(feature = "std")] and facing issues while setting up staging environment
I have compiled my code successfully and it is running fine in development mode, when I make the staging environment for the same with 3 nodes the code written inside #[cfg(feature = "std")] ...
- 975
0
votes
1
answer
96
views
#[ink(constructor)] cause a error, What is wrong with it?
error: encountered unexpected ink! attribute
--> lib.rs:80:15
|
80 | #[ink(constructor)]
| ^^^^^^^^^^^
when I execute $cargo +nightly contract test , the above error ...
- 83
0
votes
2
answers
2k
views
error: linking with `cc` failed: exit status: 1 (Mac m1)
Not able to build a project because of this issue:
error: linking with `cc` failed: exit status: 1
|
= note: "cc" "-arch" "arm64" "/var/folders/5w/...
- 171
0
votes
1
answer
46
views
Delegator-based contract causes UI interface to crash
I have a funny problem, hopefully, someone can help.
I have an environment similar to the delegator example contract: one delegator-like contract, one accumulator-like contract, and one adder-like ...
- 1