Added example application lending protocol to academy #473

gitshreevatsa · 2025-03-05T15:58:44Z

This PR serves as an initiative to the Academy that will have all the dApp examples to help developers understand how to develop on top of =nil;. This particular PR adds an example dApp which is a lending protocol to the academy.

The lending protocol serves as a basic defi application which can be used to understand something's such as how to work with tokens, async methods and how to design smart contracts for a sharded network. It includes contracts and hardhat tasks required for working of the lending protocol. It also comes with a implementation guide for a deep dive into the implementation and a understanding lending protocol guide which explains the thesis of this application.

idea404

Great idea to add some examples from the team. A good first step in something folks will need. In my opinion, the most important goal behind this would be to offer coding patterns developers can easily copy into their application code, and not necessarily templates for production applications.

That being said I think this is too complex for a quickly digestible example of which the goal should be to teach programming patterns unique to =nil;.

I say we simplify this way further. In particular LendingPool.sol, we should keep the showcase of cross-shard calls with callbacks and isolated storage, but let's simplify the code and make it less about the lending protocol and more about the programming patterns being used, and explaining them and how to use them.

Let's also combine the Implementation Guide.md and Understanding-Lending-Protocol.md into a single markdown file, perhaps titled patterns.md that focuses on explaining:

a simple visual representation of how the contracts interact (step 1 here, step 2 there, etc.)
the nil-specific programming patterns seen in the example

idea404 · 2025-03-05T16:17:19Z

academy/README.md

+
+```sh
+git clone https://github.com/nilfoundation/nil
+cd nil/dapp-examples


Suggested change

cd nil/dapp-examples

cd academy/lending-protocol

idea404 · 2025-03-05T16:19:52Z

academy/lending-protocol/README.md

+   ```
+2. 📂 Navigate to the project root and install dependencies:
+   ```sh
+   cd nil/dapp-examples/lending-protocol


Suggested change

cd nil/dapp-examples/lending-protocol

cd nil/academy/lending-protocol

idea404 · 2025-03-05T16:25:06Z

academy/lending-protocol/README.md

+   ```
+4. 🚀 Run the end-to-end lending workflow:
+   ```sh
+   npx hardhat run-lending-protocol


This step gives me:

npx hardhat run-lending-protocol (node:42149) [DEP0040] DeprecationWarning: The `punycode` module is deprecated. Please use a userland alternative instead. (Use `node --trace-deprecation ...` to show where the warning was created) Faucet client created Deploying Wallet Deployer smart account generated at 0x0001f485a3f895138f387c1738131d0fcad30cc4 An unexpected error occurred: JSONRPCError: Do not know how to serialize a BigInt at new JSONRPCError (/Users/dennis/Documents/Code/nil/nil/academy/lending-protocol/node_modules/@open-rpc/client-js/build/Error.js:24:28) at HTTPTransport.<anonymous> (/Users/dennis/Documents/Code/nil/nil/academy/lending-protocol/node_modules/@open-rpc/client-js/build/transports/HTTPTransport.js:122:39) at step (/Users/dennis/Documents/Code/nil/nil/academy/lending-protocol/node_modules/@open-rpc/client-js/build/transports/HTTPTransport.js:46:23) at Object.next (/Users/dennis/Documents/Code/nil/nil/academy/lending-protocol/node_modules/@open-rpc/client-js/build/transports/HTTPTransport.js:27:53) at /Users/dennis/Documents/Code/nil/nil/academy/lending-protocol/node_modules/@open-rpc/client-js/build/transports/HTTPTransport.js:21:71 at new Promise (<anonymous>) at __awaiter (/Users/dennis/Documents/Code/nil/nil/academy/lending-protocol/node_modules/@open-rpc/client-js/build/transports/HTTPTransport.js:17:12) at HTTPTransport.sendData (/Users/dennis/Documents/Code/nil/nil/academy/lending-protocol/node_modules/@open-rpc/client-js/build/transports/HTTPTransport.js:84:16) at RequestManager.<anonymous> (/Users/dennis/Documents/Code/nil/nil/academy/lending-protocol/node_modules/@open-rpc/client-js/build/RequestManager.js:96:66) at step (/Users/dennis/Documents/Code/nil/nil/academy/lending-protocol/node_modules/@open-rpc/client-js/build/RequestManager.js:33:23) { code: 7979, data: TypeError: Do not know how to serialize a BigInt at JSON.stringify (<anonymous>) at HTTPTransport.<anonymous> (/Users/dennis/Documents/Code/nil/nil/academy/lending-protocol/node_modules/@open-rpc/client-js/build/transports/HTTPTransport.js:99:44) at step (/Users/dennis/Documents/Code/nil/nil/academy/lending-protocol/node_modules/@open-rpc/client-js/build/transports/HTTPTransport.js:46:23) at Object.next (/Users/dennis/Documents/Code/nil/nil/academy/lending-protocol/node_modules/@open-rpc/client-js/build/transports/HTTPTransport.js:27:53) at /Users/dennis/Documents/Code/nil/nil/academy/lending-protocol/node_modules/@open-rpc/client-js/build/transports/HTTPTransport.js:21:71 at new Promise (<anonymous>) at __awaiter (/Users/dennis/Documents/Code/nil/nil/academy/lending-protocol/node_modules/@open-rpc/client-js/build/transports/HTTPTransport.js:17:12) at HTTPTransport.sendData (/Users/dennis/Documents/Code/nil/nil/academy/lending-protocol/node_modules/@open-rpc/client-js/build/transports/HTTPTransport.js:84:16) at RequestManager.<anonymous> (/Users/dennis/Documents/Code/nil/nil/academy/lending-protocol/node_modules/@open-rpc/client-js/build/RequestManager.js:96:66) at step (/Users/dennis/Documents/Code/nil/nil/academy/lending-protocol/node_modules/@open-rpc/client-js/build/RequestManager.js:33:23) }

Removing usage of BigInt() in faucet methods fixed this in the task file

idea404 · 2025-03-05T16:25:27Z

academy/lending-protocol/README.md

+1. 📥 Clone the repository:
+   ```sh
+   git clone https://github.com/NilFoundation/nil.git
+   ```


Would help to include here to set RPC and Private Key in .env

idea404 · 2025-03-05T16:39:15Z

academy/lending-protocol/task/run-lending-protocol.ts

+    {
+      smartAccountAddress: deployerWallet.address,
+      faucetAddress: process.env.USDT as `0x${string}`,
+      amount: BigInt(3000),


This will error when deps are installed with current package.json config.

Once removed in all uses of this function the task execution runs as expected

idea404 · 2025-03-05T17:35:42Z

academy/lending-protocol/Understanding-Lending-Protocol.md

+
+This project illustrates the power of **sharded smart contract design** in building decentralized finance applications. By isolating different tasks into specialized contracts, we achieve:
+
+- **Better performance:** Contracts can handle specific tasks independently and concurrently, reducing delays.


Again, not entirely true if the trx is dependent on callbacks

Concurrently, yes because, I can send 2 to 3 messages in the same function like lets say, I can use asyncCall and sendTokens and both happen on their respective shards concurrently, afaiu

idea404 · 2025-03-05T17:36:22Z

academy/lending-protocol/Understanding-Lending-Protocol.md

+
+- **Better performance:** Contracts can handle specific tasks independently and concurrently, reducing delays.
+- **Lower gas costs:** Gas fees are minimized by avoiding unnecessary state changes in contracts that don’t need to be updated.
+- **Easier upgrades and maintenance:** With separate contracts, you can upgrade one piece of the system without disrupting the entire protocol.


This isn't shown in this example

idea404 · 2025-03-05T17:37:35Z

academy/lending-protocol/Understanding-Lending-Protocol.md

This file focuses too much on a theoretical dApp design and could better be left out

idea404 · 2025-03-05T17:40:47Z

academy/lending-protocol/Implementation Guide.md

+- **GlobalLedger** (Shard 3)
+- **Oracle** (Shard 4)
+- **LendingPool** (Shard 1)
+


we should be clear that we deploy on different shards to illustrate the programming patterns you can implement with =nil;. App design recommendations are case-specific and out-of-scope here anyway

idea404 · 2025-03-05T17:45:28Z

academy/lending-protocol/Implementation Guide.md

+
+When a user deposits tokens into the **LendingPool**, the following steps occur:
+
+1.  **Deposit Transaction**:


A step-by-step walkthrough through a call on the contract is not really necessary here, or helpful IMO.

It's more valuable to highlight in a visual how the contracts call each other and what the method names called are in this visual. In code you can show the nil-specific syntax, like sendRequest() and explain how that works, what the params are for.

Again, the purpose of the examples is:

To showcase nil-specific programming patterns

Give devs easy to find and copy for use code snippets for their own purposes

gitshreevatsa temporarily deployed to prod March 5, 2025 15:58 — with GitHub Actions Inactive

gitshreevatsa requested a review from 0xAleksaOpacic March 5, 2025 16:01

idea404 reviewed Mar 5, 2025

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gitshreevatsa force-pushed the dapp-examples branch 3 times, most recently from 47c8bc9 to 5fb065e Compare March 6, 2025 16:18

gitshreevatsa temporarily deployed to prod March 6, 2025 16:18 — with GitHub Actions Inactive

gitshreevatsa requested a review from idea404 March 6, 2025 16:28

gitshreevatsa force-pushed the dapp-examples branch from 5fb065e to ed23827 Compare March 10, 2025 07:53

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add lending protocol example to academy

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gitshreevatsa force-pushed the dapp-examples branch from ed23827 to fbdd62d Compare March 10, 2025 08:00

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Added example application lending protocol to academy #473

Added example application lending protocol to academy #473

gitshreevatsa commented Mar 5, 2025

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gitshreevatsa Mar 5, 2025

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idea404 Mar 5, 2025

	cd nil/dapp-examples/lending-protocol
	cd nil/academy/lending-protocol


		This project illustrates the power of sharded smart contract design in building decentralized finance applications. By isolating different tasks into specialized contracts, we achieve:

		- Better performance: Contracts can handle specific tasks independently and concurrently, reducing delays.


		When a user deposits tokens into the LendingPool, the following steps occur:

		1. Deposit Transaction:

Added example application lending protocol to academy #473

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Added example application lending protocol to academy #473

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