You signed in with another tab or window. Reload to refresh your session.You signed out in another tab or window. Reload to refresh your session.You switched accounts on another tab or window. Reload to refresh your session.Dismiss alert
[![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/#https://github.com/subsquid/squid-evm-template)
# Minimal EVM squid
This is a starter template of a squid indexer for EVM networks (Ethereum, Polygon, BSC, etc.). See [Squid SDK docs](https://docs.subsquid.io/) for a complete reference.
To extract EVM logs and transactions by a topic or a contract address, use `EvmBatchProcessor.addLog()` and `EvmBatchProcessor.addTransaction()` methods of the `EvmBatchProcessor` instance defined in `src/processor.ts`.
The requested data is transformed in batches by a single handler provided to the `processor.run()` method.
For a full list of supported networks and config options,
check the [`EvmBatchProcessor` overview](https://docs.subsquid.io/develop-a-squid/evm-processor/) and the [configuration page](https://docs.subsquid.io/develop-a-squid/evm-processor/configuration/).
For a step-by-step migration guide from TheGraph, see [the dedicated docs page](https://docs.subsquid.io/migrate/migrate-subgraph/).
Dependencies: Node.js, Docker.
## Quickstart
```bash
# 0. Install @subsquid/cli a.k.a. the sqd command globally
npm i -g @subsquid/cli
# 1. Retrieve the template
sqd init my_squid_name -t evm
cd my_squid_name
# 2. Install dependencies
npm ci
# 3. Start a Postgres database container and detach
sqd up
# 4. Build and start the processor
sqd process
# 5. The command above will block the terminal
# being busy with fetching the chain data,
# transforming and storing it in the target database.
#
# To start the graphql server open the separate terminal
# and run
sqd serve
```
A GraphiQL playground will be available at [localhost:4350/graphql](http://localhost:4350/graphql).
## Dev flow
### 1. Define database schema
Start development by defining the schema of the target database via `schema.graphql`.
Schema definition consists of regular graphql type declarations annotated with custom directives.
Full description of `schema.graphql` dialect is available [here](https://docs.subsquid.io/basics/schema-file).
### 2. Generate TypeORM classes
Mapping developers use TypeORM [EntityManager](https://typeorm.io/#/working-with-entity-manager)
to interact with target database during data processing. All necessary entity classes are
generated by the squid framework from `schema.graphql`. This is done by running `sqd codegen`
command.
### 3. Generate database migrations
All database changes are applied through migration files located at `db/migrations`.
`squid-typeorm-migration(1)` tool provides several commands to drive the process.
```bash
## drop create the database
sqd down
sqd up
## replace any old schemas with a new one made from the entities
sqd migration:generate
```
See [docs on database migrations](https://docs.subsquid.io/basics/db-migrations) for more details.
### 4. Import ABI contract and generate interfaces to decode events
It is necessary to import the respective ABI definition to decode EVM logs. One way to generate a type-safe facade class to decode EVM logs is by placing the relevant JSON ABIs to `./abi`, then using `squid-evm-typegen(1)` via an `sqd` script:
```bash
sqd typegen
```
See more details on the [`squid-evm-typegen` doc page](https://docs.subsquid.io/evm-indexing/squid-evm-typegen).
## Project conventions
Squid tools assume a certain [project layout](https://docs.subsquid.io/basics/squid-structure):
* All compiled js files must reside in `lib` and all TypeScript sources in `src`.
The layout of `lib` must reflect `src`.
* All TypeORM classes must be exported by `src/model/index.ts` (`lib/model` module).
* Database schema must be defined in `schema.graphql`.
* Database migrations must reside in `db/migrations` and must be plain js files.
* `sqd(1)` and `squid-*(1)` executables consult `.env` file for environment variables.
# ERC721_Token_Indexer-