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Questions tagged [offchain-worker]

Oracle-like capabilities for Substrate chains.

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Is there e2e testing framework/example for Substrate solo chain?

I am working on a live solo chain. I have to test a scenario where I want to hit HTTP API through off chain-worker. Unfortunately it's not possible to test in mock environment. We can take an example ...
Boleng's user avatar
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Encrypting data offchain / decrypting data with offchain worker

I want to create a StorageMap which looks like so: pub type EncryptedData<T: Config> = StorageMap<_, Blake2_128Concat, SomeId, SomeEncryptedValue, OptionQuery>; I plan to encrypt the data ...
WhisperingZebra's user avatar
3 votes
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Is there a way to use a crate that depends on the `std` in substrate OCW?

from what I've learned so far, the OCW is designed specifically for executing heavy and time-consuming computations outside of the runtime. As the OCW is not a part of runtime/wasm, I guess the OCW ...
Yahor Tsaryk's user avatar
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How can we monetize heavy computation using substrate blockchain?

Suppose a reputation system is built, where bad nodes (open source docker instances running computations such as a search engine) are penalized, and good nodes are incentivized. What is the secure way ...
Amiya Behera's user avatar
1 vote
1 answer
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Would it be possible to make HTTP request on chain through pallet extrinsic?

We can make HTTP Get and Post request through Offchain worker. Can we also do the same on chain through pallet extrinsic? Is there any restriction?
Boleng's user avatar
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execute_block, initialize_block, apply_extrinsic, finalize_block, offchain_worker exists for struct `Executive` but its trait bound were not satisfied

I developed substrate parachain with custom pallets. Actually I wanna add OCW functionality to one of my pallets. After I updated runtime code and added CreateSignedTransaction implementation I tried ...
Artem Levchuk's user avatar
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How to send HTTP POST request using Substrate Offchain worker

I am using Substrate official example to send HTTP POST request, which is mentioned here https://docs.substrate.io/reference/how-to-guides/offchain-workers/offchain-http-requests/#read-and-submit-the-...
Boleng's user avatar
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Substrate Offchain Worker - failed to fetch sample price

I am trying to use Substrate Offchain Worker. I implemented as mentioned here https://github.com/paritytech/polkadot-sdk/tree/master/substrate/frame/examples/offchain-worker. I am using same sample ...
Boleng's user avatar
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2 votes
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How can I create OCW that won't activates every block, but will activates only when I call function that it represents?

I wanna create OCW that will send a http request to the API and get the response and use this response in runtime code to call extrinsic with this data. This OCW should triggers only when I want to ...
Artem Levchuk's user avatar
1 vote
1 answer
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How to feed private data(confidential information) in Substrate chain through oracle?

Is there any Oracle solution available to feed private data to Substrate chain? Feeding data to chain has already been answered here How can I build a price feed oracle for my Substrate chain?. And ...
Boleng's user avatar
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How to make a fn only callable by an offchain worker?

I don't think this is possible but is it? I have data that comes from an API that ultimately needs to be stored onchain which I don't want to risk having done through a Pays::No fn in case the call ...
bobby dy's user avatar
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Troubleshooting Sequential Unsigned Transaction Processing with 200 Validators

we're attempting to send unsigned transactions from an offchain worker using the validation code snippet provided: ValidTransaction::with_tag_prefix("thea") .and_provides(...
ZKT's user avatar
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1 answer
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Set Off-chain worker with AccountId20

The examples in substrate use the sr25519 AccountId and Multisignature for creating offchain workers with signed transactions. Is there a way to use AccountId20 and EthereumSignature for a node using ...
Discardo's user avatar
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Access protected API from off-chain worker

Is it possible to access a protected API from an off-chain worker, e.g. using an API Key? Hard coding the API Key would be possible, but that's obviously a security risk. Is there a safe mechanism to ...
Ronin's user avatar
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How should I add offchain worker(OCW) in frontier when using AccountId20?

In order to add an offchain worker with using AccountId20 as the runtime account type I did following things. add associated type type AuthorityId: AppCrypto<Self::Public, Self::Signature>; in ...
xiao liang's user avatar
3 votes
1 answer
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Offchain indexing storage overwrites during forks

We are using offchain indexing to store some value that will be read in offchain worker . The keys that we are using to store data via offchain indexing is as following: key = some_prefix + ...
Aramik M's user avatar
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How to execute smart contract from offchain-worker?

Would it be possible to execute smart contract call from an offchain-worker, either using ink! or pallet-contracts? Can someone please help me to provide the solution? is there any example?
Boleng's user avatar
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How to create web socket server through off chain worker?

I need to establish a web socket connection through off chain worker. I asked here How to establish web socket connection in offchain_worker but didn't get any response. Is there any way/example to ...
Boleng's user avatar
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1 vote
1 answer
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How to establish web socket connection in offchain_worker

Is there any way/example to establish web socket connection through off chain worker? There are many Rust examples but I can't use standard library. Can someone please help me?
Boleng's user avatar
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4 votes
1 answer
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Facing issue in adding offchain worker

I'm using pow substrate chain. I'm running 3 validators by using these commands: For bob ./target/release/node-template \ --base-path /tmp/bob \ --chain local \ --bob \ --port 30335 \ --rpc-port 9944 \...
Deepak Chaudhary's user avatar
1 vote
1 answer
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Iterating on a storage from Offchain Worker Concerns

I have a StorageMap named PublicKeyToMsaId which has around 300K inserted items and I want to iterate on all of those keys-values in offchain-worker to create a reverse map in offchain storage. To ...
Aramik M's user avatar
  • 139
2 votes
1 answer
67 views

How to fetch data through api?

I want to fetch the data through an api in our chain. More specifically, I have an api which gives me the latest news. How can i implement this in our substrate chain? can we have any doc or resources ...
Deepak Chaudhary's user avatar
2 votes
1 answer
41 views

How to register a custom extension for offchain workers?

I have the following code. #[cfg(feature = "std")] use sp_externalities::ExternalitiesExt; #[cfg(feature = "std")] sp_externalities::decl_extension! { pub struct CustomExt(u32)...
Sachin's user avatar
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offchain worker choose key to sign and send

I have multiple keys in my node storage with offchain worker running, there are currently 2 ways to sign and send transactions, it is done either for all of the keys stored locally, or 1 unspecified ...
cocokick's user avatar
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Is runtime upgrade needed when changing offchain worker?

Suppose I have a blockchain that has been running for some time, and at a certain point, I need to update the offchain worker code. What is the recommended approach for updating the blockchain: ...
subuser's user avatar
2 votes
0 answers
31 views

Are onchain storage reads cheaper from offchain worker versus from extrinsic?

Are reads from offchain workers less expensive than reads from extrinsics? I am determining how to do some large, asynchronous processing of data and determining whether the reads in this process see ...
Justin Frevert's user avatar
1 vote
0 answers
103 views

Is 'Ran out of free Wasm instances' a bad symptom?

I develop a custom chain based on Substrate. The chain business logic involves stateful sessions where the state is managed through Http and unsigned transactions submitted via Offchain workers. Until ...
Yury Yukhananov's user avatar
1 vote
1 answer
75 views

How to use Offchain Workers to create HTTP POST requests with JSON-RPC body?

Too my knowledge there are no guides on how to write HTTP POST requests to a JSON-RPC API with http utilities that are available to Substrate offchain workers. What I understand currently is that the ...
zimbabwe_slim's user avatar
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22 views

Unit testing an extrinsic submitted by an Offchain Worker?

As far as I could understand so far there is no a "normal" way to test extrinsics submitted by an Offchain Worker, rather a substitute transaction pool is involved. However it is possible to ...
Yury Yukhananov's user avatar
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URI creation best practice

What is the best practice to create a URI in an off-chain worker hook? The String and format! usage is discouraged. But what is the most convenient way to create a URI from given parts like hostname, ...
khassanov's user avatar
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Using http calls outside of offchain worker context

Is it possible make http requests outside of an offchain worker context. It seems like the only thing that is preventing http calls is simply that OffchainWorkerExt is not registered in the runtime. I'...
fastfist's user avatar
2 votes
1 answer
51 views

Calling external RPC method from OCW

I want to call an external RPC method from the offchain_worker. I checked multiple jsonrpc clients but none of them were no_std compatible. I want to know if there are any clients out there which can ...
StackedQ's user avatar
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1 vote
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37 views

Fetching offchain storage value returns different value than the value fetched using localStorageGet function

I need to get the rpc_url value set initially from the explorer. The localStorageGet rpc function returns the correct value of the rpc_url. This returns https://eth-mainnet.g.alchemy.com/v2/MY_API_KEY ...
strider's user avatar
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4 votes
1 answer
52 views

offchain-workers vs asynchronous task

There is not much info about using an asynchronous task in substrate docs i.e. task_manager in service.rs I want to know when one should be using offchain-worker and when one should use background ...
Rusty Pythonic Script's user avatar
4 votes
1 answer
50 views

Change state from a task

I have a asynchronous task running in service.spawn_essential_task(task). Which does some stuff and wants to write data in storage. How can i achieve this? Changing state by making runtime_apis to ...
Guest's user avatar
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2 votes
1 answer
92 views

AccountId in offchain worker

I'm working on Substrate based project. In the project, each blockchain validator has an offchain worker. author_insertKey() is used to set up a key so the offchain worker can sign transactions. Each ...
Maksim Ramanenkau's user avatar
2 votes
1 answer
85 views

Is it possible to write-access Local Storage from the Node?

My use case is this: an Offchain Worker sends Http requests to certain endpoints. These endpoints are hardcoded on chain under current implementation. I would like to be able to configure those ...
Yury Yukhananov's user avatar
2 votes
0 answers
85 views

Offchain cache/view of on-chain storage data

I am implementing a pallet, that stores in on-chain storage (aka StorageNMap's) some user provided data. Pallet is performing offchain computations by iterating on-chain storage from offchain-worker ...
Klapeyron's user avatar
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4 votes
2 answers
210 views

Read a value from offchain storage of a node

I want to read a single value from OffchainStorage of a live substrate node. Is it possible? Assume I can not use localStorageGet rpc request because it is an unsafe rpc.
Matt Duncan's user avatar
2 votes
1 answer
36 views

Configure offchain worker with command line argument

Is configuring an off-chain worker with a command line argument possible? e.g. ./target/release/cere --dev --alice --my-custom-url "http://my-..." If not what are the other options?
Maksim Ramanenkau's user avatar
1 vote
0 answers
24 views

How to connect with phala contract for creation of anonymous accounts using phala network?

I want to create anonymous account using phala network. Here is my logic. You need to sign with your kyc account using the password as message and verify that the account is yours inside phala ...
Amiya Behera's user avatar
1 vote
1 answer
55 views

Configure OCW to run every x blocks or on demand

I understand that off-chain workers are spawned during block import, quote: Offchain workers are spawned during each block import. However, they aren't executed during initial blockchain ...
Ronin's user avatar
  • 189
1 vote
1 answer
67 views

Off-chain worker. Error submitting a transaction to the pool: InvalidTransaction::ExhaustsResources [duplicate]

Error submitting a transaction to the pool: Transaction pool error: Invalid transaction validity: InvalidTransaction::ExhaustsResources It works fine in standalone but in parachain it fails. Off chain ...
rust.dev's user avatar
  • 519
0 votes
1 answer
58 views

How to enable off-chain workers for parachain via command line?

There is no any logs and off-chain workers does not work by default. How to specify to enable workers for parachain via command?
rust.dev's user avatar
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1 vote
1 answer
57 views

Iterate storage maps inside an offchain worker

I need to iterate over the following double map inside an offchain worker: How can I access this map outside the pallet assets? Can I use an RPC method to get all the values for that double map ...
Mateo Baldassarre's user avatar
0 votes
0 answers
73 views

offchain indexing for large files

I'm new to the project and currently working on a pallet, which is supposed to deal with large files offchain. Pallet, offchain indexing and the offchain worker are all working fine, still I get "...
langi667's user avatar
0 votes
1 answer
148 views

Is there any way to interact between ink smart contract and off-chain worker?

I know that we can interact between smart contract and runtime (and vice versa) but I can not find a way that I can fetch data from API (in off-chain worker pallet) and pass those data to the smart ...
Hoang Viet Nguyen's user avatar
4 votes
1 answer
157 views

How to verify that a signed payload of an unsigned extrinsic is signed by a local account?

I've been following the how-to guide to implementing unsigned extrinsic call with a signed payload. My pallet defines the following KeyTypeId: pub const KEY_TYPE: KeyTypeId = KeyTypeId(*b"ver!&...
digital illusion's user avatar
0 votes
1 answer
94 views

Implementing an Identity Management pallet, would be more efficient in a Relay or Parachain?

I'm implementing an Identity Management pallet for an administrative ecosystem. Suppose that using the same architecture as Polkadot. Questions It would be more secure, efficient and scalable to have ...
Alexandre Ribeiro's user avatar
2 votes
1 answer
130 views

Offchain Worker Not Initializing - Cumulus Parachain Template

I am observing unexpected behavior with the Cumulus Parachain Template. Our pallet uses off-chain workers (OCW), and the functionality successfully runs when we attach it to the Substrate Node ...
Brendan's user avatar
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