Scrape webpage using powershell - powershell

Question

I need to scrape a webpage.
I specifically need to extract the section "USDT Funding Market" on the page.
$WebExtract = Invoke-WebRequest -Uri "https://www.kucoin.com/margin/lend/USDT"
Although $WebExtract.content or $WebExtract.AllElements does not contain the "USDT Funding Market".

Answer 1

The reason for this is that your initial web request is only returning you the HTML of the page, however a lot of modern web applications like this have some JavaScript under the hood that will reach out to their API's and fill the page with data after the initial HTML is loaded.
The good news is, usually with public websites like this you can hit the underlying API's without worrying about authentication - which actually makes parsing the data easier, as it's typically in JSON format.
Try opening the debug console in your browser (usually F12), open the network tab and refresh the page - you can typically find these API requests/endpoints in there, e.g;
Simply copy that URL out and invoke the web request to the API instead, for example;
$request = Invoke-WebRequest -Uri 'https://www.kucoin.com/_api/currency/prices?base=USD&targets='
$json = $request.Content | ConvertFrom-Json
$json.data
This might not be the specific API endpoint/data you're after, but hopefully this points you in the right direction. If you poke around in the console you should be able to find the one you're looking for.
EDIT:
Apologies for the misleading information here, I didn't notice that these numbers were updating in real time on the site. The above is still pretty common for a lot of websites so I'll leave it, however on sites that are this responsive/live another common technology used is Web Sockets.
If you have a look at the last lines of the console, you should be able to see a request ending with 'transport=websocket' to a URL like this;
wss://ws-web.kucoin.com/socket.io/?token=...%3D%3D&format=json&acceptUserMessage=false&connectId=connect_welcome&EIO=3&transport=websocket
If you select this line and head over to the Messages tab in your browser console/debugger, you'll be able to see the web socket messages being returned;
This looks like the data you're after, but I'm not hugely familiar with querying Web Sockets through PowerShell.
Simply invoking a web request won't work here, as it's using the web sockets protocol to handle the communication. You would also need to find a way to get a valid token for opening a web sockets connection (likely just a web request for that).
Perhaps these posts will help;
http://wragg.io/powershell-slack-bot-using-the-real-time-messaging-api/
How to use a Websocket client to open a long-lived connection to a URL, using PowerShell V2?