allow client to suggest diff in password field "d=1234"

src/models/StratumV1Client.ts

@@ -217,6 +217,9 @@ export class StratumV1Client {
 
                 if (errors.length === 0) {
                     this.clientAuthorization = authorizationMessage;
+                    if (this.clientSuggestedDifficulty == null && this.clientAuthorization.startingDiff != null && this.clientAuthorization.startingDiff > this.sessionDifficulty) {
+                        this.sessionDifficulty = this.clientAuthorization.startingDiff;
+                    }
                     const success = await this.write(JSON.stringify(this.clientAuthorization.response()) + '\n');
                     if (!success) {
                         return;

src/models/stratum-messages/AuthorizationMessage.ts

@@ -1,5 +1,5 @@
 import { Expose, Transform } from 'class-transformer';
-import { ArrayMaxSize, ArrayMinSize, IsArray, IsOptional, IsString, MaxLength } from 'class-validator';
+import { ArrayMaxSize, ArrayMinSize, IsArray, IsNumber, IsOptional, IsString, MaxLength } from 'class-validator';
 
 import { eRequestMethod } from '../enums/eRequestMethod';
 import { IsBitcoinAddress } from '../validators/bitcoin-address.validator';
@@ -8,7 +8,7 @@ import { StratumBaseMessage } from './StratumBaseMessage';
 export class AuthorizationMessage extends StratumBaseMessage {
 
     @IsArray()
-    @ArrayMinSize(2)
+    @ArrayMinSize(1)
     @ArrayMaxSize(2)
     params: string[];
 
@@ -24,11 +24,28 @@ export class AuthorizationMessage extends StratumBaseMessage {
     @IsString()
     @MaxLength(64)
     @Transform(({ value, key, obj, type }) => {
-        return obj.params[0].split('.')[1] == null ? 'worker' : obj.params[0].split('.')[1];
+        const workerName = obj.params[0].split('.')[1];
+        if (workerName == null) {
+            return 'worker';
+        }
+        return workerName;
     })
     public worker: string;
 
 
+    @Expose()
+    @IsNumber()
+    @Transform(({ value, key, obj, type }) => {
+        const password: string | null = obj.params[1];
+        if (password?.includes('d=')) {
+            return parseInt(password.split('d=')[1]);
+        }
+        return null;
+    })
+    @IsOptional()
+    public startingDiff: number;
+
+
     @Expose()
     @IsString()
     @Transform(({ value, key, obj, type }) => {