## How to add a new connector

You can create a new PR to add a new connector. To get the PR merged, certain requirements needs to be met which will be explained here.

### New connector should follow the current directory structure

Common files for all connectors are in `contracts/common` directory.

* `math.sol` has methods for mathematical operations (`DSMath`)
* `interfaces.sol` contains the common interfaces
  * `TokenInterface` for ERC-20 interface including WETH
* `stores.sol` contains the global constants as well as methods `getId` & `setId` (`Stores`)
* `basic.sol` inherits `DSMath` & `Stores` contracts. This contains few details explained below
  * Wrapping & unwrapping ETH (`convertEthToWeth` & `convertWethToEth`)
  * Getting token & ETH balance of DSA

Connectors are under `contracts/connectors` directory, and should be formatted as follows:

* Connector events should be in a separate contract: `events.sol`
* Interfaces should be defined in a seperate file: `interface.sol`
* If the connector has helper methods & constants (including interface instances), this should be defined in a separate file: `helpers.sol`
  * `Helpers` contract should inherit `Basic` contract from common directory
  * If the connector doesn't have any helper methods, the main contract should inherit `Basic` contract
* The main logic of the contract should be under `main.sol`, and the contract should inherit `Helpers` (if exists, otherwise `Basic`) & `Events`

Few things to consider while writing the connector:

* Connector should have a public string declared `name`, which will be the name of the connector. This will be versioned. Ex: `Compound-v1`
* User interacting methods (`external` methods) will not be emitting events, rather the methods will be returning 2 variables:
  * `_eventName` of `string` type: This will be the event signture defined in the `Events` contract. Ex: `LogDeposit(address,address,uint256,uint256,uint256)`
  * `_eventParam` of `bytes` type: This will be the abi encoded event parameters
* The contracts should not have `selfdestruct()`
* The contracts should not have `delegatecall()`
* Use `uint(-1)` for maximum amount everywhere
* Use `ethAddr` (declared in `Stores`) to denote Ethereum (non-ERC20)
* Use `address(this)` instead of `msg.sender` for fetching balance on-chain, etc
* Only `approve()` limited amount while giving ERC20 allowance, which strictly needs to be 0 by the end of the spell.
* Use `getUint()` (declared in `Stores`) for getting value that saved from previous spell
* Use `setUint()` (declared in `Stores`) for setting value to save for the future spell

### Support

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