mihomo-party-org/clash-party · error

Request headers too large

Error message

Request headers too large

What it means

validateHeaders() enforces limits before sending: at most MAX_HEADERS entries per request. Exceeding the count throws 'Request headers too large' — a guard keeping outgoing requests small and predictable for the gateway/proxy chain.

Source

Thrown at src/main/resolve/plugin/http-client.ts:32

  // 走代理时由代理负责解析/连接目标，本地 SSRF guarded lookup 不再适用（安全保证降级）
  proxy?: { host: string; port: number }
}

export interface PluginResponse {
  status: number
  headers: http.IncomingHttpHeaders
  body: string
}

const FORBIDDEN_HEADERS = new Set(['host', 'content-length', 'connection', 'transfer-encoding'])
const MAX_HEADERS = 32
const MAX_HEADER_NAME_LEN = 128
const MAX_HEADER_VALUE_LEN = 4096
const MAX_HEADER_BYTES = 16 * 1024

function validateHeaders(input: Record<string, string>): Record<string, string> {
  const entries = Object.entries(input)
  if (entries.length > MAX_HEADERS) throw new Error('Request headers too large')

  const headers: Record<string, string> = {}
  let total = 0
  for (const [k, v] of entries) {
    if (FORBIDDEN_HEADERS.has(k.toLowerCase())) {
      throw new Error(`Forbidden header: ${k}`)
    }
    const nameBytes = Buffer.byteLength(k, 'utf-8')
    const valueBytes = Buffer.byteLength(v, 'utf-8')
    if (nameBytes > MAX_HEADER_NAME_LEN || valueBytes > MAX_HEADER_VALUE_LEN) {
      throw new Error('Request headers too large')
    }
    total += nameBytes + valueBytes
    headers[k] = v
  }
  if (total > MAX_HEADER_BYTES) throw new Error('Request headers too large')
  return headers
}

View on GitHub (pinned to 911e090537)

Solutions

1. Trim the header set to only what the gateway requires.
2. Deduplicate/merge headers before calling — many come from default header sets.
3. Move bulk data into the request body instead of headers.

Example fix

// before
headers: { ...incomingHeaders, ...defaultHeaders } // may exceed MAX_HEADERS
// after
const allowed = ['content-type', 'accept', 'user-agent']
const headers = Object.fromEntries(
  Object.entries(incomingHeaders).filter(([k]) => allowed.includes(k.toLowerCase()))
)

const MAX_HEADERS = 16
if (Object.keys(headers).length > MAX_HEADERS) {
  throw new Error(`Too many headers: ${Object.keys(headers).length} > ${MAX_HEADERS}`)
}

try {
  return await request(url, { headers })
} catch (e) {
  if ((e as Error).message === 'Request headers too large') {
    // rebuild a minimal header set and retry once
  } else throw e
}

When it happens

Trigger: Calling the HTTP client (via requestOnce) with a headers record containing more than MAX_HEADERS entries (e.g. >16 headers).

Common situations: Programmatically forwarding all incoming request headers, merging default headers repeatedly so they accumulate, or signing code that adds many metadata headers.

Related errors

• Forbidden header: ${k}
• Subscription failed: Profile missing proxies or providers
• Empty URL
• Unsupported ruleset behavior: ${behavior}
• Invalid core path: directory traversal detected

AI-assisted analysis of mihomo-party-org/clash-party@911e090537 (2026-08-30). Data as JSON: /api/errors/e09d16b6f9705fee. Report an issue: GitHub.