What causes "context.hostname 不能被赋值" in YMFE/yapi?

Delete the hostname assignment from the script

context.hostname 不能被赋值

Error message

context.hostname 不能被赋值

What it means

context.hostname in the test-script sandbox is a read-only getter derived from the request URL. The setter exists solely to throw, preventing scripts from mutating the resolved host.

Solutions

Delete the hostname assignment from the script
Change the request URL/environment at the case level instead of in the script
Only read context.hostname in scripts

Example fix

// before
context.hostname = 'staging.api.com';
// after
// configure environment host in the case, then read it
const host = context.hostname;

Defensive patterns

Strategy: type-guard

Validate before calling

if (context.hostname !== expectedHost) console.warn('unexpected host; reconfigure environment instead of assigning');

Type guard

function isReadOnlyCtxProp(obj, key){ const d = Object.getOwnPropertyDescriptor(obj, key); return !!d && d.get && d.set && d.set.toString().includes('throw'); }

Try / catch

try {
  context.hostname = host;
} catch (e) {
  console.warn('hostname is derived from request URL and cannot be set');
}

Prevention

Never assign to context.* properties in scripts
Switch hosts via YApi environments, not scripts
Audit scripts for '=' assignments on context
Use getters for reads only

When it happens

Trigger: A case script executes context.hostname = 'api.example.com' during test/assert execution.

Common situations: Attempting to switch environments from inside a script; copying Postman snippets that mutate context; misunderstand that sandbox context is read-only.

Related errors

AI-assisted analysis of YMFE/yapi@59bade3a8a (2026-08-29). Data as JSON: /api/errors/b30ae4f4dc5bdc7c. Report an issue: GitHub.

Appendix: source

Thrown at common/postmanLib.js:266

async function crossRequest(defaultOptions, preScript, afterScript, commonContext = {}) {
  let options = Object.assign({}, defaultOptions);
  const taskId = options.taskId || Math.random() + '';
  let urlObj = URL.parse(options.url, true),
    query = {};
  query = Object.assign(query, urlObj.query);
  let context = {
    isNode,
    get href() {
      return urlObj.href;
    },
    set href(val) {
      throw new Error('context.href 不能被赋值');
    },
    get hostname() {
      return urlObj.hostname;
    },
    set hostname(val) {
      throw new Error('context.hostname 不能被赋值');
    },

    get caseId() {
      return options.caseId;
    },

    set caseId(val) {
      throw new Error('context.caseId 不能被赋值');
    },

    method: options.method,
    pathname: urlObj.pathname,
    query: query,
    requestHeader: options.headers || {},
    requestBody: options.data,
    promise: false,
    storage: await getStorage(taskId)
  };

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