Node.js Stream API 泄​​漏

Question

在玩 Node 流时，我注意到几乎每个教程都讲授如下内容:

// Get Google's home page.
require('http').get("http://www.google.com/", function(response) {
  // The callback provides the response readable stream.
  // Then, we open our output text stream.
  var outStream = require('fs').createWriteStream("out.txt");

  // Pipe the input to the output, which writes the file.
  response.pipe(outStream);
});

但在我看来，这是一段相当危险的代码。如果文件流在某个时候抛出异常会怎样？我认为文件流可能会泄漏内存，因为根据文档，文件流显然没有关闭。

我应该关心吗？在我看来，node.js 流应该处理各种情况......

Answer 1

为避免文件描述符泄漏，您还需要:

var outStream = require('fs').createWriteStream("out.txt");

// Add this to ensure that the out.txt's file descriptor is closed in case of error.
response.on('error', function(err) {
  outStream.end();
});

// Pipe the input to the output, which writes the file.
response.pipe(outStream);

另一个未记录的方法是 outStream.destroy()，它也会关闭描述符，但似乎更喜欢 outStream.end()。