Add get minimal fees method (#549)

* Add get minimal fees method

* Use fromMAS instead of custom conversion

* Fix doc getMinimalFees

packages/massa-web3/src/interfaces/INodeStatus.ts

@@ -71,4 +71,5 @@ export interface INodeStatus {
   pool_stats: { endorsement_count: number; operation_count: number }
   version: string
   chain_id: bigint
+  minimal_fees?: string
 }

packages/massa-web3/src/interfaces/IPublicApiClient.ts

@@ -115,4 +115,11 @@ export interface IPublicApiClient extends BaseClient {
   getGraphInterval(
     graphInterval: IGetGraphInterval
   ): Promise<Array<IGraphInterval>>
+
+  /**
+   * Get the minimal fees required for your operation to be accepted by the API provider
+   *
+   * @returns The minimal fees as bigint (in nano-MAS).
+   */
+  getMinimalFees(): Promise<bigint>
 }

packages/massa-web3/src/web3/PublicApiClient.ts

@@ -15,7 +15,7 @@ import { IDatastoreEntryInput } from '../interfaces/IDatastoreEntryInput'
 import { IGetGraphInterval } from '../interfaces/IGetGraphInterval'
 import { IGraphInterval } from '../interfaces/IGraphInterval'
 import { IBlockcliqueBlockBySlot } from '../interfaces/IBlockcliqueBlockBySlot'
-import { ISlot } from '@massalabs/web3-utils'
+import { ISlot, fromMAS } from '@massalabs/web3-utils'
 
 /**
  * Public API client for interacting with a Massa node.
@@ -41,6 +41,7 @@ export class PublicApiClient extends BaseClient implements IPublicApiClient {
 
     // public api methods
     this.getNodeStatus = this.getNodeStatus.bind(this)
+    this.getMinimalFees = this.getMinimalFees.bind(this)
     this.getAddresses = this.getAddresses.bind(this)
     this.getBlocks = this.getBlocks.bind(this)
     this.getEndorsements = this.getEndorsements.bind(this)
@@ -130,6 +131,30 @@ export class PublicApiClient extends BaseClient implements IPublicApiClient {
     return { ...nodeStatus, chain_id: BigInt(nodeStatus.chain_id) }
   }
 
+  /**
+   * Retrieves the minimal fees for operations to be accepted by the API provider.
+   *
+   * @returns The minimal fees as a bigint (in nano-MAS).
+   */
+  public async getMinimalFees(): Promise<bigint> {
+    const jsonRpcRequestMethod = JSON_RPC_REQUEST_METHOD.GET_STATUS
+    let fees: string = '0'
+    if (this.clientConfig.retryStrategyOn) {
+      let result = await trySafeExecute<INodeStatus>(this.sendJsonRPCRequest, [
+        jsonRpcRequestMethod,
+        [],
+      ])
+      fees = result.minimal_fees || '0'
+    } else {
+      let result = await this.sendJsonRPCRequest<INodeStatus>(
+        jsonRpcRequestMethod,
+        []
+      )
+      fees = result.minimal_fees || '0'
+    }
+    return fromMAS(fees)
+  }
+
   /**
    * Retrieves data about a list of addresses, such as their balances and block creation details.
    *