为什么我的sailsjs服务会返回"undefined"?到调用控制器的动作? [英] Why does my sailsjs service return "undefined" to the calling controller action?

问题描述

我必须发布到其他人开发的API才能获得授权代码，并且由于必须在几个不同的上下文中这样做，我认为我应该将代码移到处理POST并获取响应的地方服务.

I have to POST to an API that someone else has developed in order to obtain an authorization code, and as I have to do it in several different contexts I thought I'd move the code for handling the POST and getting the response to a service.

此刻令人沮丧的是，我似乎正在从API中获得想要的值，但无法将其从服务器返回给调用的sails控制器.

The frustrating thing at the moment is that I seem to be getting back the value that I want from the API, but can't return it from the server to the calling sails controller.

这是服务源代码:

module.exports = {
  getVerifyCode: function(uuid, ip_addr) {
    console.log (uuid);
    console.log (ip_addr);
    var http = require('http'),
    querystring = require('querystring'),
    // data to send
    send_data = querystring.stringify({
      uuid : uuid,
      ip_addr : ip_addr 
    }),
    // options for posting to api
    options = {
      host: sails.config.api.host,
      port: sails.config.api.port,
      path: '/verifyCode/update',
      method: 'POST',
      headers: {
        'Content-Type': 'application/x-www-form-urlencoded',
        'Content-Length': Buffer.byteLength(send_data)
      }
    },
    json_output = "",
    // post request
    post_req = http.request(options, function(post_res) {
      post_res.on('data', function(chunk) {
        json_output += chunk;
      });
      post_res.on('end', function() {
        var json_data = JSON.parse(json_output),
        verify_code = json_data.verify_code;

        console.log("code="+verify_code);
        return ('vc='+verify_code);
      });
     });
    post_req.write(send_data);
    post_req.end();
  }
}

这是我的控制器操作中的两行相关内容:

And here's two relevant lines from my controller action:

    var vc = verify.getVerifyCode(req.session.uuid, req.connection.remoteAddress);
    console.log('vc='+vc);

奇怪的是，控制器控制台日志是在服务执行之前写入的:

The weird thing is that the controller console log gets written before the service one does:

vc=undefined
code=YoAr3ofWRIFGpoi4cRRehP3eH+MHYo3EogvDNcrNDTc=

有什么想法吗?我运行的服务要简单得多(只是一些字符串操作的东西)；我觉得这里的问题与API请求和响应的异步性质有关.

Any ideas? I have a much simpler service running (just some string manipulation stuff); I have a feeling the issue here relates to the asynchronous nature of the API request and response.

推荐答案

Jasper，您的正确假设是"API请求和响应的异步性质".

Jasper, your correct in your assumption that it is the " asynchronous nature of the API request and response".

当您在 verify 服务中执行http调用时，节点会进行该调用，然后它们继续处理其余代码 console.log('vc ='+ vc);.，并且不等待http调用结束.

When you execute your http call in your verify service, node makes that call and them moves on to the rest of the code console.log('vc='+vc); and does not wait for the http call to finish.

我不确定最终结果应该是什么，但是您可以重写控制器/服务以包含回调(这只是一个选项，当然有很多方法可以做到这一点，其他人应该建议其他人)

I'm not sure what your end result should be but you can rewrite your controller / service to include the callback (this is just one options, there are many ways to do this of course, other people should suggest others)

verify.js

verify.js

getVerifyCode: function(uuid, ip_addr, cb) {
    // Bunch of stuff
    return post_req = http.request(options, cb(post_res});
}

然后在您的控制器中controller.js

then in your controller controller.js

verify.getVerifyCode(req.session.uuid, req.connection.remoteAddress, function(resps){
    // code in here to execute when http call is finished
})

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