对于我的（开放源代码）Node.js项目bundeszirkus.de，我需要实现一个搜索和下载URL的Web抓取工具。目前，我正在像这样使用Nightmare.js：链接到完整文件
exports.scrape = function(cb) {
_callback = cb
_downloadedLinks = 0
let nightmare = new Nightmare({ show: false })
const url = 'https://www.bundestag.de/services/opendata'
// we request nightmare to browse to the bundestag.de url and extract the whole inner html
nightmare
.goto(url)
.wait('body')
.evaluate(() => document.querySelector('body').innerHTML)
.end()
.then(response => {
_downloadedLinks = 0
let validLinks = extractLinks(response)
_foundLinks = validLinks.length
logger.info("[scraper] found " + validLinks.length + " valid links.")
if(validLinks.length > 0){
validLinks.forEach(href => {
downloadFileFromHref(BT_LINK + href)
});
} else {
logger.info("[scraper] did not download any files.")
_callback()
}
}).catch(err => {
logger.info("[scraper] did not download any files.")
_callback()
});
// Extracting the links we need
let extractLinks = html => {
data = [];
const $ = cheerio.load(html);
$('.bt-link-dokument').each(function() {
data.push(this.attribs.href);
});
return data.filter(checkDocumentLink)
}
}
在我的本地计算机上运行时，这非常正常。但是，在我的ubuntu服务器（AWS）上运行它时似乎出现了问题。我已经读到这是由于服务器上没有可用的图形界面这一事实造成的，因此我尝试在其上运行Xvfb。
这是我的ecosystem.config.js文件。
运行时，pm2 ls我可以看到Xvfb和我的服务器都在运行：
ubuntu@ip-XXX-XX-XX-XXX:~/bundeszirkus-server/current$ pm2 ls
┌─────────────────────┬────┬─────────┬──────┬───────┬────────┬─────────┬────────┬─────┬────────────┬────────┬──────────┐
│ App name │ id │ version │ mode │ pid │ status │ restart │ uptime │ cpu │ mem │ user │ watching │
├─────────────────────┼────┼─────────┼──────┼───────┼────────┼─────────┼────────┼─────┼────────────┼────────┼──────────┤
│ Xvfb │ 1 │ N/A │ fork │ 26063 │ online │ 6 │ 14m │ 0% │ 17.5 MB │ ubuntu │ disabled │
│ bundeszirkus-server │ 0 │ 1.0.0 │ fork │ 26057 │ online │ 6 │ 14m │ 0% │ 246.4 MB │ ubuntu │ disabled │
└─────────────────────┴────┴─────────┴──────┴───────┴────────┴─────────┴────────┴─────┴────────────┴────────┴──────────┘
Use `pm2 show <id|name>` to get more details about an app
据我所知，一切似乎都已正确设置，但是服务器的日志条目显示没有文件正在下载：
{"message":"Starting server!","level":"info","timestamp":"2020-01-11 11:56:38"}
{"message":"Starting initial scraping.","level":"info","timestamp":"2020-01-11 11:56:38"}
{"message":"[scraper] found 0 valid links.","level":"info","timestamp":"2020-01-11 11:56:42"}
{"message":"[scraper] did not download any files.","level":"info","timestamp":"2020-01-11 11:56:42"}
{"message":"Loading data.","level":"info","timestamp":"2020-01-11 11:56:42"}
{"message":"[loader] loading data ...","level":"info","timestamp":"2020-01-11 11:56:42"}
同时，在我的本地（Ubuntu）计算机上运行时，它可以工作：
{"message":"Starting server!","level":"info","timestamp":"2020-01-11 12:52:47"}
{"message":"Starting initial scraping.","level":"info","timestamp":"2020-01-11 12:52:47"}
{"message":"[scraper] found 5 valid links.","level":"info","timestamp":"2020-01-11 12:52:49"}
{"message":"[scraper] downloading file: 19138-data.xml from href: http://www.bundestag.de/resource/blob/674998/86249f57e79b8308e820d6581e7e2a95/19138-data.xml","level":"info","timestamp":"2020-01-11 12:52:49"}
{"message":"[scraper] downloading file: 19136-data.xml from href: http://www.bundestag.de/resource/blob/674328/0e9d258d50d08923fe6d6ad1381bdb3f/19136-data.xml","level":"info","timestamp":"2020-01-11 12:52:49"}
{"message":"[scraper] downloading file: 19137-data.xml from href: http://www.bundestag.de/resource/blob/674730/2bc751b619488227c9267e3cbe12c4c3/19137-data.xml","level":"info","timestamp":"2020-01-11 12:52:49"}
{"message":"[scraper] downloading file: 19135-data.xml from href: http://www.bundestag.de/resource/blob/673576/147b80c74d6d681833568cfcf36f9670/19135-data.xml","level":"info","timestamp":"2020-01-11 12:52:49"}
{"message":"[scraper] downloading file: 19134-data.xml from href: http://www.bundestag.de/resource/blob/673116/982f9d0ec845b85bddd289ede4a589fd/19134-data.xml","level":"info","timestamp":"2020-01-11 12:52:49"}
{"message":"[scraper] finished downloading all 5 files.","level":"info","timestamp":"2020-01-11 12:52:51"}
{"message":"Loading data.","level":"info","timestamp":"2020-01-11 12:52:51"}
我在这里迷失了如何寻找缺失的部分。任何帮助是极大的赞赏！
在执行以下操作后，它现在可以工作：
xvfb像这样添加到代码中：let xvfb = new Xvfb();
try {
xvfb.startSync();
}
catch (e) {
console.log(e);
}
// scraping
xvfb.stopSync();
.wait('body')对.wait(2000)。本文收集自互联网，转载请注明来源。
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我来说两句