feat: add context to pubsub notification callbacks

web3.js/module.d.ts

@@ -37,10 +37,12 @@ declare module '@solana/web3.js' {
   /* TODO */
 
   // === src/connection.js ===
+  export type Context = {
+    slot: number;
+  };
+
   export type RpcResponseAndContext<T> = {
-    context: {
+    context: Context;
-      slot: number;
-    };
     value: T;
   };
 
@@ -115,13 +117,18 @@ declare module '@solana/web3.js' {
     root: 'number';
   };
 
-  export type AccountChangeCallback = (accountInfo: AccountInfo) => void;
+  export type AccountChangeCallback = (
+    accountInfo: AccountInfo,
+    context: Context,
+  ) => void;
   export type ProgramAccountChangeCallback = (
     keyedAccountInfo: KeyedAccountInfo,
+    context: Context,
   ) => void;
   export type SlotChangeCallback = (slotInfo: SlotInfo) => void;
   export type SignatureResultCallback = (
     signatureResult: SignatureStatusResult,
+    context: Context,
   ) => void;
 
   export type SignatureSuccess = {

web3.js/module.flow.js

@@ -50,10 +50,12 @@ declare module '@solana/web3.js' {
   /* TODO */
 
   // === src/connection.js ===
+  declare export type Context = {
+    slot: number,
+  };
+
   declare export type RpcResponseAndContext<T> = {
-    context: {
+    context: Context,
-      slot: number,
-    },
     value: T,
   };
 
@@ -130,13 +132,18 @@ declare module '@solana/web3.js' {
     root: 'number',
   };
 
-  declare type AccountChangeCallback = (accountInfo: AccountInfo) => void;
+  declare type AccountChangeCallback = (
+    accountInfo: AccountInfo,
+    context: Context,
+  ) => void;
   declare type ProgramAccountChangeCallback = (
     keyedAccountInfo: KeyedAccountInfo,
+    context: Context,
   ) => void;
   declare type SlotChangeCallback = (slotInfo: SlotInfo) => void;
   declare type SignatureResultCallback = (
     signatureResult: SignatureStatusResult,
+    context: Context,
   ) => void;
 
   declare export type SignatureSuccess = {|

web3.js/src/connection.js

@@ -21,17 +21,25 @@ import type {TransactionSignature} from './transaction';
 
 type RpcRequest = (methodName: string, args: Array<any>) => any;
 
+/**
+ * Extra contextual information for RPC responses
+ *
+ * @typedef {Object} Context
+ * @property {number} slot
+ */
+type Context = {
+  slot: number,
+};
+
 /**
  * RPC Response with extra contextual information
  *
  * @typedef {Object} RpcResponseAndContext
- * @property {{slot: number}} context
+ * @property {Context} context
  * @property {T} value response
  */
 type RpcResponseAndContext<T> = {
-  context: {
+  context: Context,
-    slot: number,
-  },
   value: T,
 };
 
@@ -67,6 +75,18 @@ function jsonRpcResult(resultDescription: any) {
   ]);
 }
 
+/**
+ * @private
+ */
+function notificationResultAndContext(resultDescription: any) {
+  return struct({
+    context: struct({
+      slot: 'number',
+    }),
+    value: resultDescription,
+  });
+}
+
 /**
  * The level of commitment desired when querying state
  *   'max':    Query the most recent block which has reached max voter lockout
@@ -330,7 +350,7 @@ const GetAccountInfoAndContextRpcResult = jsonRpcResultAndContext(
  */
 const AccountNotificationResult = struct({
   subscription: 'number',
-  result: AccountInfoResult,
+  result: notificationResultAndContext(AccountInfoResult),
 });
 
 /**
@@ -346,7 +366,7 @@ const ProgramAccountInfoResult = struct({
  */
 const ProgramAccountNotificationResult = struct({
   subscription: 'number',
-  result: ProgramAccountInfoResult,
+  result: notificationResultAndContext(ProgramAccountInfoResult),
 });
 
 /**
@@ -371,7 +391,7 @@ const SlotNotificationResult = struct({
  */
 const SignatureNotificationResult = struct({
   subscription: 'number',
-  result: SignatureStatusResult,
+  result: notificationResultAndContext(SignatureStatusResult),
 });
 
 /**
@@ -589,7 +609,10 @@ type KeyedAccountInfo = {
 /**
  * Callback function for account change notifications
  */
-export type AccountChangeCallback = (accountInfo: AccountInfo) => void;
+export type AccountChangeCallback = (
+  accountInfo: AccountInfo,
+  context: Context,
+) => void;
 
 /**
  * @private
@@ -610,6 +633,7 @@ type AccountSubscriptionInfo = {
  */
 export type ProgramAccountChangeCallback = (
   keyedAccountInfo: KeyedAccountInfo,
+  context: Context,
 ) => void;
 
 /**
@@ -639,6 +663,7 @@ type SlotSubscriptionInfo = {
  */
 export type SignatureResultCallback = (
   signatureResult: SignatureStatusResult,
+  context: Context,
 ) => void;
 
 /**
@@ -1472,20 +1497,23 @@ export class Connection {
     if (res.error) {
       throw new Error(res.error.message);
     }
-
+    assert(typeof res.result !== 'undefined');
     const keys = Object.keys(this._accountChangeSubscriptions).map(Number);
     for (let id of keys) {
       const sub = this._accountChangeSubscriptions[id];
       if (sub.subscriptionId === res.subscription) {
         const {result} = res;
-        assert(typeof result !== 'undefined');
+        const {value, context} = result;
 
-        sub.callback({
+        sub.callback(
-          executable: result.executable,
+          {
-          owner: new PublicKey(result.owner),
+            executable: value.executable,
-          lamports: result.lamports,
+            owner: new PublicKey(value.owner),
-          data: bs58.decode(result.data),
+            lamports: value.lamports,
-        });
+            data: bs58.decode(value.data),
+          },
+          context,
+        );
         return true;
       }
     }
@@ -1536,7 +1564,7 @@ export class Connection {
     if (res.error) {
       throw new Error(res.error.message);
     }
-
+    assert(typeof res.result !== 'undefined');
     const keys = Object.keys(this._programAccountChangeSubscriptions).map(
       Number,
     );
@@ -1544,17 +1572,20 @@ export class Connection {
       const sub = this._programAccountChangeSubscriptions[id];
       if (sub.subscriptionId === res.subscription) {
         const {result} = res;
-        assert(typeof result !== 'undefined');
+        const {value, context} = result;
 
-        sub.callback({
+        sub.callback(
-          accountId: result.pubkey,
+          {
-          accountInfo: {
+            accountId: value.pubkey,
-            executable: result.account.executable,
+            accountInfo: {
-            owner: new PublicKey(result.account.owner),
+              executable: value.account.executable,
-            lamports: result.account.lamports,
+              owner: new PublicKey(value.account.owner),
-            data: bs58.decode(result.account.data),
+              lamports: value.account.lamports,
+              data: bs58.decode(value.account.data),
+            },
           },
-        });
+          context,
+        );
         return true;
       }
     }
@@ -1608,7 +1639,6 @@ export class Connection {
     }
     assert(typeof res.result !== 'undefined');
     const {parent, slot, root} = res.result;
-
     const keys = Object.keys(this._slotSubscriptions).map(Number);
     for (let id of keys) {
       const sub = this._slotSubscriptions[id];
@@ -1672,7 +1702,6 @@ export class Connection {
       throw new Error(res.error.message);
     }
     assert(typeof res.result !== 'undefined');
-
     const keys = Object.keys(this._signatureSubscriptions).map(Number);
     for (let id of keys) {
       const sub = this._signatureSubscriptions[id];
@@ -1681,7 +1710,7 @@ export class Connection {
         // no need to explicitly send an unsubscribe message
         delete this._signatureSubscriptions[id];
         this._updateSubscriptions();
-        sub.callback(res.result);
+        sub.callback(res.result.value, res.result.context);
         return;
       }
     }