使用 google 云函数进行抓取，状态码为：304

Question

我正在试用 google 云功能，它可以工作，但以状态代码 304 结束，不确定是什么原因。下面是代码，

//gcloud beta functions deploy scrapeGitCollection --trigger-http
var cheerio = require('cheerio');
var request = require('request');

function getDateTime() {

    var date = new Date();

    var hour = date.getHours();
    hour = (hour < 10 ? "0" : "") + hour;

    var min  = date.getMinutes();
    min = (min < 10 ? "0" : "") + min;

    var sec  = date.getSeconds();
    sec = (sec < 10 ? "0" : "") + sec;

    var year = date.getFullYear();

    var month = date.getMonth() + 1;
    month = (month < 10 ? "0" : "") + month;

    var day  = date.getDate();
    day = (day < 10 ? "0" : "") + day;

    return year + "/" + month + "/" + day + " " + hour + ":" + min + ":" + sec;

  }  

var scrape = new Promise((resolve, reject) =>{
    var text;
    var array = [];

    request({
        method: 'GET',
        url: 'https://github.com/collections'
    }, function(err, response, body) {
        if (err) return reject(err);

        // Tell Cherrio to load the HTML
        $ = cheerio.load(body);
        $('.col-10 h2 a').each(function(i, element) {
            var node = $(this);
            text = node.text();
            //console.log(text);
            array.push(text);
        });

        text = JSON.stringify(array);
        console.log(text);
        resolve(text);
    });     
});

// [START functions_helloworld_http]
/**
 * HTTP Cloud Function.
 * @param {Object} req Cloud Function request context.
 * @param {Object} res Cloud Function response context.
 *
*/
exports.scrapeGitCollection = (req, res) => {
    console.log('Triggered @ '+getDateTime());
    scrape.then((data) =>{
        res.send(`Hello ${data || 'World'}!`);
    }).catch( (errorMessage) =>{
        console.error(errorMessage);
    });

  };
// [END functions_helloworld_http]

这是我在 stackdriver 中看到的日志

2018-07-05 22:19:39.181 IST
scrapeGitCollection
x6mbdi17rdj7
Function execution took 7 ms, finished with status code: 304
{
 insertId:  "000000-4f8925ba-a5a5-4f0e-9c32-906e91374e32"  
 labels: {…}  
 logName:  "projects/btd-in-16062018/logs/cloudfunctions.googleapis.com%2Fcloud-functions"  
 receiveTimestamp:  "2018-07-05T16:49:45.425756526Z"  
 resource: {…}  
 severity:  "DEBUG"  
 textPayload:  "Function execution took 7 ms, finished with status code: 304"  
 timestamp:  "2018-07-05T16:49:39.181731257Z"  
}

出于调试目的，我在 scrape() 函数中添加了以下行，它没有出现在日志中。

console.log(text);

如果我强行如下说，我会得到上面的 console.log 文本和结果。

res.status(200).send(`Hello ${data || 'World'}!`);

不想强行说status(200)。想解决我之前得到的 304。

Answer 1

根据 Mozilla 的文档，the 304 status code 表示请求已重定向，很可能是缓存的资源。我相信这与响应主体始终相同有关，因为如果您将响应更改为

res.send(`Hello ${data || 'World'}!` + getDateTime());

然后你会看到每次响应代码都是200。

请注意，304 不是错误。错误状态代码为 400 and above.

使用 google 云函数进行抓取，状态码为：304

Scraping using google cloud function it finished with status code: 304

node.js

cheerio

google-cloud-functions