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Ank4n committed Jan 16, 2024
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185 changes: 99 additions & 86 deletions syllabus/5-Substrate/9-Substrate-Interactions_Slides.md
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Expand Up @@ -9,18 +9,25 @@ duration: 60 minutes

## Before we start

- Clone substrate node template
Find all the commands that will be used in this workshop:
[hackmd.io/@ak0n/hk24-substrate-interaction](https://hackmd.io/@ak0n/hk24-substrate-interaction)

---

## Before we start

- Clone polkadot-sdk

```sh
git clone https://github.com/substrate-developer-hub/substrate-node-template`
git clone https://github.com/paritytech/polkadot-sdk.git
```

<br/>

- Compile your node

```sh
cargo build --release
cargo build --release -p minimal-node
```

---
Expand All @@ -29,6 +36,10 @@ cargo build --release

> How does a user or an application interact with a blockchain?
Notes:

- Wait for 1 answer from students or at least for 10 seconds.

---v

## Interacting With a Substrate Blockchain
Expand All @@ -37,7 +48,7 @@ cargo build --release

<br/>

- Run your own node.
- Run their own node.

<!-- .element: class="fragment" -->

Expand Down Expand Up @@ -123,13 +134,15 @@ recall:
https://paritytech.github.io/substrate/master/sc_rpc_api/index.html
https://paritytech.github.io/substrate/master/sc_rpc/index.html

The full list can also be seen here: https://polkadot.js.org/docs/substrate/rpc/
- The full list can also be seen here: https://polkadot.js.org/docs/substrate/rpc/
- Specs: https://paritytech.github.io/json-rpc-interface-spec/introduction.html
- Upcoming changes to JSON-RPC api: https://forum.polkadot.network/t/new-json-rpc-api-mega-q-a/3048

---

### Workshop: Intro

- Transfer some tokens from Alice to Charlie.
- Transfer tokens from one account to another.

<br/>

Expand All @@ -139,8 +152,8 @@ The full list can also be seen here: https://polkadot.js.org/docs/substrate/rpc/

Notes:

- When we start up a dev chain, some well known accounts are already minted some balance at genesis. Alice and Charlie
are well known accounts.
- When we start up a dev chain, some well known accounts are already minted some balance at genesis. We will use Alice
and Bob which are well known accounts.
- The parts we cheat is because we will need to know more about FRAME to be able to calculate some storage keys.

---v
Expand All @@ -150,35 +163,28 @@ Notes:
- Check out cli docs

```sh
./target/release/node-template --help
./target/release/minimal-node --help
```

<br/>

- Spin up your dev node.

```sh
./target/release/node-template --chain=dev --force-authoring --alice --tmp
./target/release/minimal-node --chain=dev --tmp
```

<!-- .element: class="fragment" -->

Notes:

- What does each flag do? What other flag can you use?
- What does --chain=dev and --tmp do? What other flag can you use?

---v

### Workshop: Check balance

- Query current balance of Charlie.
- Storage key where Charlie's balance is stored
```
0x26aa394eea5630e07c48ae0c9558cef7b99d880ec681799c0cf30e8886371da9b0edae20838083f2cde1c4080db8cf8090b5ab205c6974c9ea841be688864633dc9ca8a357843eeacf2314649965fe22
```
- We will use `state_getStorage` to query balance.
- Query current balance of Alice and Bob.

```sh
wscat \
Expand All @@ -188,96 +194,98 @@ wscat \
```

Notes:
You will learn how the storage key is calculated in FRAME based substrate chains in the FRAME module.

- You will learn how the storage key is calculated in FRAME based substrate chains in the FRAME module.
- What do you get?

---v

### Workshop: Transfer some tokens
### Workshop: Metadata

- Take PJS help to get the signed extrinsic.
- Use the following command to submit the extrinsic.
- Recall type information is lost in SCALE encoded data.
- Substrate exposes type information using metadata.

```sh
wscat \
-c ws://localhost:9944 \
-x '{"jsonrpc":"2.0", "id": 42, "method":"author_submitExtrinsic", "params": [""] }' \
-x '{"jsonrpc":"2.0", "id": 42, "method":"state_getMetadata" }' \
| jq
```

<br/>

- Check balance now.
- What happens if you execute the same payload again?
- This itself is Scale Encoded. See [frame-metadata](https://github.com/paritytech/frame-metadata).
- Derive type of Balance using this metadata.

<!-- .element: class="fragment" -->

Notes:
Let students do the second part themselves.

- Use PJS app to get frame-metadata: Developer > RPC Calls > state > getMetadata.
- [Metadata](https://hackmd.io/@ak0n/rJUhmXmK6) with most details not relevant stripped off.
- Read more about
metadata: https://docs.substrate.io/build/application-development/#exposing-runtime-information-as-metadata.

---v

### Workshop: Metadata
### Workshop: Transfer some tokens

- Substrate exposes type information using metadata.
- Take PJS help to get the signed extrinsic.
- Use the following command to submit the extrinsic.

```sh
wscat \
-c ws://localhost:9944 \
-x '{"jsonrpc":"2.0", "id": 42, "method":"state_getMetadata" }' \
-x '{"jsonrpc":"2.0", "id": 42, "method":"author_submitExtrinsic", "params": [""] }' \
| jq
```

<br/>

- This itself is Scale Encoded. See [frame-metadata](https://github.com/paritytech/frame-metadata).
- Derive type of Balance using this metadata.
- Check balance again for both accounts.
- What happens to nonce of Alice?

<!-- .element: class="fragment" -->

Notes:

- Metadata help users and apps understand the type information. Remember with SCALE, type information is lost.
- [Metadata](https://hackmd.io/@ak0n/rJUhmXmK6) with most details stripped off.
- Read more about
metadata: https://docs.substrate.io/build/application-development/#exposing-runtime-information-as-metadata.
- Can also use https://www.shawntabrizi.com/substrate-js-utilities/codec/ to decode balance with the following custom
type
- Students will learn how to build the signed extrinsic themselves in their assignment.
- Let students do the second part themselves.

---v

### Workshop: Decoding balance

- Use https://www.shawntabrizi.com/substrate-js-utilities/codec/ to decode balance.
- Use the following balance struct

```json
{
"Balance": {
"info": {
"nonce": "u32",
"consumers": "u32",
"providers": "u32",
"sufficients": "u32",
"data": {
"free": "u128",
"reserved": "u128",
"frozen": "u128",
"flags": "u128"
"ignore": "(u32, u32, u32)",
"balance": {
"free": "u64",
"ignore": "(u64, u64, u128)"
}
}
}
```

---v
### Workshop: Decoding balance
- Use https://www.shawntabrizi.com/substrate-js-utilities/codec/ to decode balance.
- Use the following balance struct
Notes:
The actual type is:

```json
{
"Balance": {
"info": {
"nonce": "u32",
"consumers": "u32",
"ignore": "u32",
"providers": "u32",
"sufficients": "u32",
"data": {
"free": "u128",
"reserved": "u128",
"frozen": "u128",
"balance": {
"free": "u64",
"reserved": "u64",
"frozen": "u64",
"flags": "u128"
}
}
Expand All @@ -292,12 +300,17 @@ Notes:
- Find node version of the polkadot and westend chain `system_version`.
- Change RPC provider and see if any of the above value changes?

<br/>

- For runtime version, you read `specVersion` : `1,005,000` as `1.5.0`.

<!-- .element: class="fragment" -->

Notes:

- `wscat -c wss://polkadot-rpc.dwellir.com -x '{"jsonrpc":"2.0", "id":1, "method":"state_getRuntimeVersion"}' | jq`.
- `wscat -c wss://polkadot-rpc.dwellir.com -x '{"jsonrpc":"2.0", "id":1, "method":"system_version"}' | jq`.
- For runtime version, you read `specVersion` : `1,005,000` as `1.5.0`.
- Polkadot Telemetry: https://telemetry.polkadot.io/.
- Show polkadot telemetry: https://telemetry.polkadot.io/.

---

Expand All @@ -317,14 +330,37 @@ more here: https://project-awesome.org/substrate-developer-hub/awesome-substrate

---

## `subxt`

- Something analogous to `PJS` for Rust.
- The real magic is that it generates the types by fetching the metadata at compile time, or linking
it statically.
- ..It might need manual updates when the code, and therefore the metadata changes.

Notes:
Listen to James Wilson introducing subxt: https://www.youtube.com/watch?v=aFk6We_Ke1I
---

## Additional Resources! 😋

> Check speaker notes (click "s" 😉)
Notes:

- see "Client Libraries" here: https://project-awesome.org/substrate-developer-hub/awesome-substrate
- https://paritytech.github.io/json-rpc-interface-spec/introduction.html
- Full subxt guide: https://docs.rs/subxt/latest/subxt/book/index.html

---

### JSON-RPC: Mini Activity

In Kusama:

- Find the genesis hash..
- Number of extrinsics at block 10,000,000.
- The block number is stored under `twox128("System") ++ twox128("Number")`.
- Find it now, and at block 10,000,000.
- Find it now, and at block 10,000,000.

<br/>

Expand All @@ -349,27 +385,4 @@ wscat -c wss://kusama-rpc.polkadot.io -x '{"jsonrpc":"2.0", "id":72, "method":"s
wscat -c wss://kusama-rpc.polkadot.io -x '{"jsonrpc":"2.0", "id":72, "method":"state_getStorage", "params": ["0x26aa394eea5630e07c48ae0c9558cef702a5c1b19ab7a04f536c519aca4983ac", "0xdcbaa224ab080f2fbf3dfc85f3387ab21019355c392d79a143d7e50afba3c6e9"] }' | jq
```

Notice that this number that we get back is the little endian (SCALE) encoded value that we passed in at first.
---
## `subxt`
- Something analogous to `PJS` for Rust.
- The real magic is that it generates the types by fetching the metadata at compile time, or linking
it statically.
- ..It might need manual updates when the code, and therefore the metadata changes.
Notes:
Listen to James Wilson introducing subxt: https://www.youtube.com/watch?v=aFk6We_Ke1I
---
## Additional Resources! 😋
> Check speaker notes (click "s" 😉)
Notes:
- see "Client Libraries" here: https://project-awesome.org/substrate-developer-hub/awesome-substrate
- https://paritytech.github.io/json-rpc-interface-spec/introduction.html
- Full subxt guide: https://docs.rs/subxt/latest/subxt/book/index.html
Notice that this number that we get back is the little endian (SCALE) encoded value that we passed in at first.

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