UnhandledPromiseRejectionWarning：错误：协议错误（Runtime.callFunctionOn）：目标已关闭。 （木偶师）

Question

我是 Puppeteer 和 Node 的新手，在尝试执行以下代码时出现此错误：

 'use strict';

const puppeteer = require('puppeteer');
const evalLib = require('./oaa_a11y_evaluation.js');

function evaluateRules() {
  var ruleset = OpenAjax.a11y.RulesetManager.getRuleset("ARIA_STRICT");
  var evaluator_factory = OpenAjax.a11y.EvaluatorFactory.newInstance();
  evaluator_factory.setParameter('ruleset', ruleset);
  evaluator_factory.setFeature('eventProcessing', 'fae-util');
  evaluator_factory.setFeature('groups', 7);
  var evaluator = evaluator_factory.newEvaluator();
  var evaluation = evaluator.evaluate(window.document, document.title, document.location.href);
  // var out = evaluation.toJSON(true);
  return;
}

(async() => {
  const browser = await puppeteer.launch();
  var page = await browser.newPage();
  await page.goto('http://mihirkumar.com/', {waitUntil: 'load'});
  page.evaluate(evaluateRules);
  await browser.close();
})();

这是详细的错误消息：

 (node:27876) UnhandledPromiseRejectionWarning: Error: Protocol error (Runtime.callFunctionOn): Target closed.
at Promise (C:\Users\Mihir\fae\node_modules\puppeteer\lib\Connection.js:200:56)
at new Promise (<anonymous>)
at CDPSession.send (C:\Users\Mihir\fae\node_modules\puppeteer\lib\Connection.js:199:12)
at ExecutionContext.evaluateHandle (C:\Users\Mihir\fae\node_modules\puppeteer\lib\ExecutionContext.js:79:75)
at ExecutionContext.evaluate (C:\Users\Mihir\fae\node_modules\puppeteer\lib\ExecutionContext.js:46:31)
at Frame.evaluate (C:\Users\Mihir\fae\node_modules\puppeteer\lib\FrameManager.js:326:20)
at <anonymous>
at process._tickCallback (internal/process/next_tick.js:188:7)
(node:27876) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:27876) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

来自 https://github.com/GoogleChromeLabs/puppeteer-examples 的其他示例运行得非常好，所以我认为我不需要使用 此处 提到的修复程序。谢谢您的帮助。

原文由 Mihir Kumar 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

感谢您的回复。使函数异步绝对是一个更好的改变。我的问题是我没有将 OpenAjax javascript 库注入加载的页面。一旦我用 puppeteer 的 page.addScriptTag 函数做到了这一点，事情就很好了。

原文由 Mihir Kumar 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 2

正如 Sven 在评论中提到的那样，您应该在每个 page 函数上使用 await 在关闭浏览器之前返回一个承诺（几乎是所有承诺）的函数。

尝试这个：

 'use strict';

const puppeteer = require('puppeteer');
const evalLib = require('./oaa_a11y_evaluation.js');

async function evaluateRules() {
  var ruleset = OpenAjax.a11y.RulesetManager.getRuleset("ARIA_STRICT");
  var evaluator_factory = OpenAjax.a11y.EvaluatorFactory.newInstance();
  evaluator_factory.setParameter('ruleset', ruleset);
  evaluator_factory.setFeature('eventProcessing', 'fae-util');
  evaluator_factory.setFeature('groups', 7);
  var evaluator = evaluator_factory.newEvaluator();
  var evaluation = evaluator.evaluate(window.document, document.title, document.location.href);
  // var out = evaluation.toJSON(true);
  return;
}

(async() => {
  const browser = await puppeteer.launch();
  var page = await browser.newPage();
  await page.goto('http://mihirkumar.com/', {waitUntil: 'load'});
  await page.evaluate(evaluateRules); // <-- await here
  await browser.close();
})();

原文由 Nicolás A. 发布，翻译遵循 CC BY-SA 4.0 许可协议