From 088dcb4dff60df39785df13d0a33d3ceaa1dff38 Mon Sep 17 00:00:00 2001
From: Damien Arrachequesne <damien.arrachequesne@gmail.com>
Date: Thu, 10 Mar 2022 14:01:40 +0100
Subject: [PATCH] feat: add the "maxPayload" field in the handshake details

So that clients in HTTP long-polling can decide how many packets they
have to send to stay under the maxHttpBufferSize value.

This is a backward compatible change which should not mandate a new
major revision of the protocol (we stay in v4), as we only add a field
in the JSON-encoded handshake data:

```
0{"sid":"lv_VI97HAXpY6yYWAAAC","upgrades":["websocket"],"pingInterval":25000,"pingTimeout":5000,"maxPayload":1000000}
```

Related: https://github.com/socketio/socket.io-client/issues/1531
---
 lib/socket.ts  | 3 ++-
 test/server.js | 5 +++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/lib/socket.ts b/lib/socket.ts
index c3a81619..73b9b0f1 100644
--- a/lib/socket.ts
+++ b/lib/socket.ts
@@ -90,7 +90,8 @@ export class Socket extends EventEmitter {
         sid: this.id,
         upgrades: this.getAvailableUpgrades(),
         pingInterval: this.server.opts.pingInterval,
-        pingTimeout: this.server.opts.pingTimeout
+        pingTimeout: this.server.opts.pingTimeout,
+        maxPayload: this.server.opts.maxHttpBufferSize
       })
     );
 
diff --git a/test/server.js b/test/server.js
index fff27d58..906bdb6b 100644
--- a/test/server.js
+++ b/test/server.js
@@ -449,6 +449,7 @@ describe("server", () => {
           expect(obj.sid).to.be.a("string");
           expect(obj.pingTimeout).to.be.a("number");
           expect(obj.upgrades).to.be.an("array");
+          expect(obj.maxPayload).to.eql(1000000);
           done();
         });
       });
@@ -3356,7 +3357,7 @@ describe("server", () => {
             expect(res.headers["set-cookie"].length).to.be(2);
             expect(res.headers["set-cookie"][1]).to.be("mycookie=456");
 
-            const sid = JSON.parse(res.text.substring(4)).sid;
+            const sid = JSON.parse(res.text.substring(5)).sid;
 
             request
               .post(`http://localhost:${port}/engine.io/`)
@@ -3393,7 +3394,7 @@ describe("server", () => {
             expect(res.headers["set-cookie"].length).to.be(2);
             expect(res.headers["set-cookie"][1]).to.be("mycookie=456");
 
-            const sid = JSON.parse(res.text.substring(4)).sid;
+            const sid = JSON.parse(res.text.substring(5)).sid;
 
             request
               .post(`http://localhost:${port}/engine.io/`)