Paid QA

OpenSquare Paid-QA is a paid Q&A platform that allow user to create topics and fund the valuable answers. It saves users' collaboration interactions to blockchain and stores collaboration content to IPFS. This repository is the Node.js implementation of the OpenSquare QA Specification standard 1.0.

Code structure

The code is organized with yarn workspaces and make sure yarn is installed before running it. There are 9 packages backend-common, common, node-api, scan, server, site, spec and ui under the packages folder.

backend-common

This package maintains the common database models and business logics shared by server and scan packages.

common

This package maintains the common UI utilities, used by site package.

spec

It implements several utility functions and classes to help decode/encode qa-spec specification, used by server and site packages.

ui

It contains common OpenSquare styled UI components, used by site package and other collaboration products like off-chain voting.

scan

It implements a scanner which is used to scan the history qa-spec related extrinsics on different substrate chains. It also provides scripts to fetch qa collaboration data from IPFS and sync it to business database. So the key components includes:

• A scanner to scan remark/batch extrinsics from supported chains.
• Scripts to fetch topic/answer content from IPFS and store to scan database.
• Scripts to sync topic related data from scan database to business database.

node-api

This package maintains multiple @polkadot/api instances for different chains in case of a single endpoint failure. It is in charge of interaction with chain nodes and provides restful apis for caller to fetch on-chain data. The apis include:

• [chain]/remark/block/[blockHash]/extrinsic/[extrinsicIndex]: get the remark at a block extrinsic(by block hash and extrinsic index).
• [chain]/remark/batch_send: submit answers by batch transactions to the chain.
• [chain]/token/native/info: get native token metadata of the chain.
• [chain]/token/[assetId]/info: get asset token metadata defined in Statemine/Statemint/Westmint assets pallet.
• [chain]/token/[assetId]/[blockHash]/info: get asset token metadata at a block.

server

It integrates koa.js as the server, and you can find the code under packages/server folder. The server provides apis for topics, supports, funds and resolves, check them under packages/server/features folder.

It depends on MongoDB and related topics and interaction data are stored. All interaction data are signed with polkadot keys and submitted to blockchain, where topic contents are uploaded to IPFS too. We use infura as the IPFS service provider, so make sure to register an account, create an IPFS project and get the corresponding infura project id and secret.

This package also depends on the node-api package to fetch on-chain info. So don't forget to config the required NODE_API_ENDPOINT environment variable.

Generally, Its features include:

• Providing restful apis for site page.
• Managing business data with MongoDB.
• Querying chain data from node-api package.

site

Site package depends on React and renders the fronted pages.

How to run it

Prerequisites

MongoDB

Make sure mongodb is installed, while corresponding url is required to config in the server package. Check here to find a way to install it natively.

Note
We require a MongoDB replica set to keep some business transactional. Please refer here for how to convert it to a replica set.

Infura api key and secret

Register an infura account, crate and IPFS project and get the project ID and secret.

Run

1. Dependency installation

yarn

2. Run node-api

cd packages/node-api
cat .env.example > .env

The default environment variables will work, but if you want to change some, just edit the '.env' file.

# You can change the chain endpoints, separated by ';'.
DOT_ENDPOINTS=wss://rpc.polkadot.io;wss://polkadot.api.onfinality.io/public-ws;wss://polkadot-rpc.dwellir.com
KSM_ENDPOINTS=wss://kusama-rpc.polkadot.io;wss://kusama.api.onfinality.io/public-ws;wss://kusama-rpc.dwellir.com
WND_ENDPOINTS=wss://westend-rpc.polkadot.io;wss://westend.api.onfinality.io/public-ws
STATEMINE_ENDPOINTS=wss://statemine.api.onfinality.io/public-ws;wss://statemine-rpc.polkadot.io
STATEMINT_ENDPOINTS=wss://statemint-rpc.polkadot.io;wss://statemint.api.onfinality.io/public-ws;wss://statemint-rpc.dwellir.com
WESTMINT_ENDPOINTS=wss://westmint-rpc.polkadot.io;wss://westmint-rpc.dwellir.com

# You need a polkadot key mnemonic to call the batch transations to submit answers remarks
POLKADOT_ACCOUNT_PHRASE=xxx

SERVER_PORT=3223 # keep it

Then run

node src/index.js

Well, the node-api should be ready.

3. Run server for the restful api server

Come back to the project root dir and run

cd packages/server
cat .env.example > .env

Open the '.env' file and do necessary configuration

PORT=5050
MONGODB_URI=mongodb://localhost:27017/paid-qa
NODE_API_ENDPOINT=http://localhost:3223

INFURA_PROJECT_ID=xxx
INFURA_PROJECT_SECRET=xxx
LOCAL_IPFS_NODE_URL=http://localhost:5001

# Indicate that to use Infura or local IPFS node
USE_LOCAL_IPFS_NODE=false

Run following scripts to start API server

node src/index.js

The restful api server will be ready.

4. Run site package for the fronted

Come back to the project root dir and run

cd packages/site
cat .env.example > .env

Open the '.env' file and do necessary configuration

# QA server restful API endpoint
VITE_APP_QA_API_SERVER=http://127.0.0.1:5050/
VITE_APP_SOCKET_IO_URL=http://127.0.0.1:5050/

VITE_APP_IDENTITY_SERVER_HOST=https://id.statescan.io

Then run

cd ../.. # go back to the root directory
yarn start

5. Run scan package(optional)

Note: you don't have to run this package unless you want to sync the history topic collaboration data which maybe uploaded by other deployments.

Come back to the project root dir and run

cd packages/scan
cat .env.example > .env

Open the '.env' file and do necessary configuration

WS_ENDPOINT=wss://westmint-rpc.polkadot.io

MONGODB_URI=mongodb://localhost:27017/paid-qa
SCAN_MONGODB_URI=mongodb://localhost:27017/qa-scan

# polkadot|kusama|statemine|westend|westmint
CHAIN=westmint

SCAN_STEP=20

# Turn on it when we scan the block meta data first
USE_META=false
MONGO_META_URL=mongodb://127.0.0.1:27017
MONGO_DB_META_NAME=meta-westmint

LOG_LEVEL=info
NODE_ENV=production

IPFS_GATEWAY_URL=https://ipfs.infura.io/ipfs/

Then start on-chain scanner;

node src/index.js

Run the content IPFS sync script. You may also run it with pm2 with a --cron-restart setting, check here for an example.

node src/ipfs/index.js

Run the scan database to business database sync script. You may also run it with pm2 with a --cron-restart setting, check here for an example.

node src/sync/index.js

Do everything work well? Join OpenSquare matrix room if any problems.