Function waitForServer

javascript/selenium-webdriver/http/util.js:56–99

* Waits for a WebDriver server to be healthy and accepting requests. * @param {string} url Base URL of the server to query. * @param {number} timeout How long to wait for the server. * @param {Promise=} opt_cancelToken A promise used as a cancellation signal: * if resolved before the server

(url, timeout, opt_cancelToken)

 *     if the wait is cancelled.
 */
function waitForServer(url, timeout, opt_cancelToken) {
  return new Promise((onResolve, onReject) => {
    let start = Date.now()

    let done = false
    let resolve = (status) => {
      done = true
      onResolve(status)
    }
    let reject = (err) => {
      done = true
      onReject(err)
    }

    if (opt_cancelToken) {
      opt_cancelToken.then((_) => reject(new CancellationError()))
    }

    checkServerStatus()

    function checkServerStatus() {
      return getStatus(url).then((status) => resolve(status), onError)
    }

    function onError(e) {
      // Some servers don't support the status command. If they are able to
      // response with an error, then can consider the server ready.
      if (e instanceof error.UnsupportedOperationError) {
        resolve({})
        return
      }

      if (Date.now() - start > timeout) {
        reject(Error('Timed out waiting for the WebDriver server at ' + url))
      } else {
        setTimeout(function () {
          if (!done) {
            checkServerStatus()
          }
        }, 50)
      }
    }
  })
}

/**
 * Polls a URL with GET requests until it returns a 2xx response or the