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Test Info:
- This WPT test may be referenced by the following Test IDs:
- /websockets/send-data-isolation.sub.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<meta charset="utf-8">
<title>WebSocket send() data isolation</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
"use strict";
// These tests verify that `send()` on a WebSocket correctly copies its input data,
// so that subsequent modifications to the input do not affect what gets sent.
// We use an echo server that sends back what it receives.
promise_test(async () => {
const ws = new WebSocket(echoURL);
await new Promise((resolve, reject) => {
ws.onopen = resolve;
ws.onerror = () => reject(new Error("WebSocket connection failed"));
});
const input = new Uint8Array([1, 2, 3, 4]);
const messagePromise = new Promise((resolve, reject) => {
ws.onmessage = e => {
const reader = new FileReader();
reader.onload = () => resolve(new Uint8Array(reader.result));
reader.onerror = () => reject(reader.error);
reader.readAsArrayBuffer(e.data);
};
ws.onerror = () => reject(new Error("WebSocket error"));
});
ws.send(input);
input[0] = 99;
const result = await messagePromise;
ws.close();
assert_array_equals(
Array.from(result),
[1, 2, 3, 4],
"Sent data should not be affected by modifying the input Uint8Array"
);
}, "Modifying a Uint8Array after send() does not affect the sent data");
promise_test(async () => {
const ws = new WebSocket(echoURL);
await new Promise((resolve, reject) => {
ws.onopen = resolve;
ws.onerror = () => reject(new Error("WebSocket connection failed"));
});
const input = new Uint8Array([5, 6, 7, 8]);
const inputBuffer = input.buffer;
const messagePromise = new Promise((resolve, reject) => {
ws.onmessage = e => {
const reader = new FileReader();
reader.onload = () => resolve(new Uint8Array(reader.result));
reader.onerror = () => reject(reader.error);
reader.readAsArrayBuffer(e.data);
};
ws.onerror = () => reject(new Error("WebSocket error"));
});
ws.send(inputBuffer);
input[0] = 99;
const result = await messagePromise;
ws.close();
assert_array_equals(
Array.from(result),
[5, 6, 7, 8],
"Sent data should not be affected by modifying the underlying ArrayBuffer"
);
}, "Modifying an ArrayBuffer after send() does not affect the sent data");
promise_test(async () => {
const ws = new WebSocket(echoURL);
await new Promise((resolve, reject) => {
ws.onopen = resolve;
ws.onerror = () => reject(new Error("WebSocket connection failed"));
});
// Test with a view into a larger buffer (exercises offset handling)
const largerBuffer = new ArrayBuffer(16);
const view = new Uint8Array(largerBuffer, 4, 4);
view.set([10, 11, 12, 13]);
const messagePromise = new Promise((resolve, reject) => {
ws.onmessage = e => {
const reader = new FileReader();
reader.onload = () => resolve(new Uint8Array(reader.result));
reader.onerror = () => reject(reader.error);
reader.readAsArrayBuffer(e.data);
};
ws.onerror = () => reject(new Error("WebSocket error"));
});
ws.send(view);
view[0] = 99;
const result = await messagePromise;
ws.close();
assert_array_equals(
Array.from(result),
[10, 11, 12, 13],
"Sent data should not be affected by modifying a typed array view"
);
}, "Modifying a typed array view after send() does not affect the sent data");
</script>