Relaunching @edent_solar. Part 5 - Getting data out of Fronius Solarweb

Mostly notes to myself. My solar panels have an open API. But it's only available if I'm on the same network as the Fronius inverter. I can connect my system to https://www.solarweb.com/ so I can access it anywhere in the world - if I have the right password.

SolarWeb has an (optional) guest mode. You can view the panels' performance if you know the secret URl. It looks something like this:

https://www.solarweb.com/Home/GuestLogOn?pvSystemid=123-456-789

Visiting that URl sets some cookies and then redirects you to something like this:

https://www.solarweb.com/PvSystems/PvSystem?pvSystemId=abc-def-hij

And the live performance data is at: https://www.solarweb.com/ActualData/GetCompareDataForPvSystem?pvSystemId=abc-def-hij

In order to make a request to the data URl, you need the cookies from the first URl. Here's some horrible PHP which will do just that.

 PHP<?php



$ch = curl_init();

//  Get the loging URl

curl_setopt($ch, CURLOPT_URL, "https://www.solarweb.com/Home/GuestLogOn?pvSystemid=123-456-789");

curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true); //  It redirects

curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);



//  Store and use cookies

curl_setopt($ch, CURLOPT_COOKIEJAR,  '/tmp/cookies.txt');

curl_setopt($ch, CURLOPT_COOKIEFILE, '/tmp/cookies.txt');



//  Get the page

curl_exec($ch);



//  Find redirect URL

$redirect_url    = curl_getinfo($ch)["url"];

//  It is in the form https://www.solarweb.com/PvSystems/PvSystem?pvSystemId=abc-def-hij

//  Get the System ID

$system_id_query = parse_url($redirect_url, PHP_URL_QUERY);

parse_str($system_id_query, $params);

$system_id = $params["pvSystemId"];



//  Finish up this request

curl_close($ch);



//  2nd request

$ch = curl_init();

//  URl of the data

curl_setopt($ch, CURLOPT_URL, "https://www.solarweb.com/ActualData/GetCompareDataForPvSystem?pvSystemId={$system_id}");

curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

//  Use cookies

curl_setopt($ch, CURLOPT_COOKIEJAR,  '/tmp/cookies.txt');

curl_setopt($ch, CURLOPT_COOKIEFILE, '/tmp/cookies.txt');

$output = curl_exec($ch);



//  Output JSON

// header("Content-Type: application/json");

echo $output;

//  Clean up

curl_close($ch);

And, hey presto, out pops a scrap of JSON:

 JSON{

   "Datasources":"n/a",

   "IsOnline":true,

   "P_PV":402.0

}