Write JSON to mysql database with node.js - mysql

Question

I'm trying to write a JSON object (or string, unsure) to my mysql database using node.js. I first retrieved the JSON via an xml url using xml2js. I am able to log the json string result in my console via JSON.stringify, but I am unsure how to proceed from here.
Here is the url I took the xml from: https://water.weather.gov/ahps2/hydrograph_to_xml.php?gage=deld1&output=xml
I would like to write each instance from the JSON string to a row, with the columns as the name of the data. It would look something like this:
Here is my code in index.js, which I enact with node index.js on the console:
var parseString = require('xml2js').parseString;
var http = require('http');
var https = require('https');
var mysql = require('mysql');
var con = mysql.createConnection({
host: "localhost",
user: "root",
password: "password",
database: "mydb"
});
function xmlToJson(url, callback) {
var req = https.get(url, function(res) {
var xml = '';
res.on('data', function(chunk) {
xml += chunk;
});
res.on('error', function(e) {
callback(e, null);
});
res.on('timeout', function(e) {
callback(e, null);
});
res.on('end', function() {
parseString(xml, function(err, result) {
callback(null, result);
});
});
});
}
var url = "https://water.weather.gov/ahps2/hydrograph_to_xml.php?gage=deld1&output=xml"
xmlToJson(url, function(err, data) {
if (err) {
return console.err(err);
}
strungout = JSON.stringify(data, null, 1);
console.log(strungout);
//strungout contains my json string
})
con.connect(function(err) {
if (err) throw err;
//below is where I might make an insert statement to insert my values into a mysql table
var sql = someinsertstatement
con.query(sql, function (err, result) {
if (err) throw err;
console.log("records inserted");
res.end();
});
});
As mentioned, when I run the above code in my console, the console returns the JSON, though I am unsure how to assign this to a variable that I can then write into my mysql database.
Alternatively, if there is an easier way to write xml from a website directly to my mysql database, I would certainly appreciate any pointers. I feel like it should be easier than this, but I am new to pretty much all of it.
EDIT:
Adding the JSON. I removed the line breaks to consolidate it. Trying to assign the result '4.68' to a variable.
data = {"site": {"observed": [{"datum": [{"valid": [{"_": "2019-02-21T19:42:00-00:00","$": {"timezone": "UTC"}}],"primary": [{"_": "4.68","$": {"name": "Stage","units": "ft"}}]}]}]}};
Thank you.

Answer 1

This worked on my end. Found that the main data you seek is site.observed.datum
const parser = require('xml2json');
const request = require("request");
var mysql = require('mysql');
var con = mysql.createConnection({
host: "localhost",
user: "root",
password: "password",
database: "mydb"
});
var api_url = 'https://water.weather.gov/ahps2/hydrograph_to_xml.php?gage=deld1&output=xml';
function xmlToJson(url, callback){
return request({
method: 'GET',
url: api_url,
}, function (error, response, body) {
if (error) {
return callback({
errorResponse: error,
rowsToInsert: false
});
}else{
let jsonRes = JSON.parse(parser.toJson(body));
let datumResult = jsonRes.site.observed.datum;//I had to log Object.keys multple time to get the
const readyForDB = datumResult.map(x => {
let timeOfReading = x.valid.$t;
let stage = x.primary.$t;
let flow = x.secondary.$t;
return [
timeOfReading, stage, flow
]
});
return callback({
errorResponse: false,
rowsToInsert: readyForDB
});
}
})
}
return xmlToJson(api_url, ({errorResponse, rowsToInsert}) => {
if(errorResponse){
throw callback.errorResponse;
}
return con.connect(function(err) {
if (err) throw err;
//below is where I might make an insert statement to insert my values into a mysql table
var sql = "INSERT INTO forecast (timeOfReading, stage, flow) VALUES ?"
con.query(sql, [rowsToInsert], function (err, result) {
if (err) throw err;
console.log(result.affectedRows + " rows inserted");
});
});
});

Answer 2

Sounds like you have the JSON you want but are unsure how to access data within it. Correct me if I'm wrong.
Lets say you have this JSON object called "test":
{
a:1
b:{
x:2
}
}
You can access the value of 1 by calling test.a, and similarly access the value of 2 by calling test.b.x