使while循环同步 [英] Making the while loop synchronous

问题描述

我有一段代码

var page = 2;
var last_page = 100;
while(page <= last_page) {
  request("http://some_json_server.com/data?page=" + page, function (error, response, body) {
    if (!error && response.statusCode == 200) {
      store_data(body)
    }
    page++;
  });                
}

我已经完成了以下操作，但实际上并没有检索任何内容。我这样做是否正确？

I've done the following, but it is actually not retrieving anything. Am I doing this correctly?

var page = 2;
var last_page = 100;
while(page <= last_page) {
var async_arr = [];
async_arr.push(
  function(next) {
    request("http://some_api_url?page=" + page, function (error, response, body) {
      if (!error && response.statusCode == 200) {
        store_data(body);
      }
    });
  }
);

async.series(
  async_arr, done
);

推荐答案

您正在寻找 async.whilst（）。这个解决方案假设您实际上想要在另一个之后执行每个请求。正如@UpTheCreek提到的那样（编辑：我提到的评论被编辑过），很可能会异步进行，并使用 async.parallel 。

You're looking for async.whilst(). This solution is assuming you actually want to do each request after the other. As @UpTheCreek mentions (edit: the comment I referred to was edited) it would likely be possible to do it asynchronously and keep track of each result using async.parallel.

var page = 2,
    lastPage = 100;

async.whilst(function () {
  return page <= lastPage;
},
function (next) {
  request("http://some_json_server.com/data?page=" + page, function (error, response, body) {
    if (!error && response.statusCode == 200) {
      store_data(body)
    }
    page++;
    next();
  });
},
function (err) {
  // All things are done!
});

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