V Vant Docs

Network

Network layer for external connections (lib/network.js).

What

The network layer handles HTTP/HTTPS communication:

Quick Start

Import network:

const network = require('./lib/network');

Fetch

Make HTTP requests - fetch resolves to the response BODY STRING on 2xx and rejects on non-2xx (there is no { json, status } wrapper):

const body = await network.fetch('https://api.example.com/data');
// body is a string; parse JSON yourself or use fetchJson

const data = await network.fetchJson('https://api.example.com/data');
// fetchJson: JSON.parse with a string fallback

Options

Configure fetch:

const response = await network.fetch('https://api.example.com/data', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ key: 'value' }),
    timeout: 30000,          // per-request timeout
    cache: true,             // GET responses are cached (default)
    circuit: true,           // route through the circuit breaker (default)
    system: false            // true opts system-initiated calls out of
                             // the per-call sandbox canNetwork gate
});

Redirects (3xx + Location) are followed automatically.

Retry

Retry is a separate export that wraps any function with exponential backoff (there is no fetchWithRetry):

const result = await network.retry(
    () => network.fetch('https://api.example.com/data'),
    { retries: 3, backoff: 1000, maxBackoff: 30000 }  // 1s, 2s, 4s...
);
// throws the last error when retries are exhausted

Latency

Track API latency:

const stats = network.getLatencyStats();
console.log(stats);  // latency record set by measureLatency()

await network.measureLatency('https://api.example.com');

Online Check

Check if online:

const online = await network.checkOnline();
console.log(online); // true | false

(isOnline() reads the cached flag; checkOnline() probes.)

Domain Restrictions

Whitelist allowed domains:

network.setAllowedDomains(['api.github.com', 'api.openai.com']);

const allowed = network.isDomainAllowed('https://api.github.com/user');
console.log(allowed);      // true
console.log(network.getAllowedDomains());

Circuit Breaker

Network routes external calls through a circuit breaker (shared with QoS):

const stats = network.getCircuitStatus();
console.log(stats.state);  // CLOSED | OPEN (time-based recovery)

After repeated failures the circuit opens to prevent cascade; it closes again after the timeout elapses. Internal/reserved addresses are additionally guarded by resolveAndCheckIP (SSRF gate).

Integration

Network integrates with sandbox: when the sandbox denies canNetwork, per-call fetches are refused (system-initiated calls can opt out with system: true). Domain restrictions are enforced inside network.js on every request plus an IP-resolution SSRF gate:

network.setAllowedDomains(['api.github.com']);

await network.fetch('https://evil.com');
// refused by the domain whitelist

See Security for details.