I am quite newbie with node.js. What i am trying to achieve is the following:
- Connect to my postgresql database and get info of three places (id, coordinates). For each place obtained i need:
- Call a weather api and get the info of that spot using the coordinates obtained in the previous step.
- Insert the returned json in the database. I get 8 hourly objects, with the weather info every 3 hours (0,3,6,9,12,15,18,21). I need to iterate through this objects and then store them in 8 records in the database.
I have written the following code so far:
function insert_forecast_spot(id, body, client) {
var date = body.data.weather[0].date;
var callbacks = 0;
for (var i=0; i < 8; i++) {
var hourly = body.data.weather[0].hourly[i];
client.query('INSERT into parte (id, date, time) VALUES($1, $2, $3)',
[id, date, hourly.time],
function(err, result) {
if (err) {
console.log(err);
} else {
console.log('row inserted: ' + id + ' iteration ' + i);
callbacks++;
if (callbacks === 8) {
console.log('All callbacks done!from id '+id);
}
}
});
} //for
} // function
app.get('/getapi', function(req, res, next){
//------------ BBDD CONNECTION----------------
pg.connect(conString, function(err, client, done) {
if(err) {
// example how can you handle errors
console.error('could not connect to postgres',err);
return next(new Error('Database error'));
}
client.query('SELECT * from places where id>3274 and id<3278', function(err, result) {
if(err) {
console.error('error running query',err);
done();
return next(new Error('Database error'));
}
done();
var first_callback = 0;
for (var y=0; y<result.rows.length; y++) {
console.log('y'+y);
var coords = JSON.parse(result.rows[y].json).coordinates;
var id = result.rows[y].id;
var input = {
query: coords[1] + ',' + coords[0] ,
format: 'JSON',
fx: ''
};
var url = _PremiumApiBaseURL + "marine.ashx?q=" + input.query + "&format=" + input.format + "&fx=" + input.fx + "&key=" + _PremiumApiKey;
request(url,function (err, resp, body){
body = JSON.parse(body);
if (!err && resp.statusCode == 200) {
insert_forecast_spot(id,body, client);
}
else {
console.error(err);
done(); // done(); is rough equivalent of client.end();
}
});
first_callback++;
if (first_callback === result.rows.length-1) {
console.log('All global callbacks done!');
done(); // done(); is rough equivalent of client.end();
res.send("done");
}}
}); // SELECT
}); // CONNECT
}); // app.get
What it does is try to insert the id=3277 spot's forecast three times!
The console logs is as follows:
y0
y1
All global callbacks done!
GET /getapi 200 40ms - 4b
y2
row inserted: 3277 iteration 8
row inserted: 3277 iteration 8
row inserted: 3277 iteration 8
row inserted: 3277 iteration 8
row inserted: 3277 iteration 8
row inserted: 3277 iteration 8
row inserted: 3277 iteration 8
row inserted: 3277 iteration 8
All callbacks done!from id 3277
{ [error: duplicate key value violates unique constraint "parte_pkey"]
name: 'error',
length: 178,
severity: 'ERROR',
code: '23505',
detail: 'Key (id, date, "time")=(3277, 2013-11-22, 0) already exists.',
hint: undefined,
position: undefined,
internalPosition: undefined,
internalQuery: undefined,
where: undefined,
file: 'nbtinsert.c',
line: '397',
routine: '_bt_check_unique' }
this final error repeats 16 times as it tries to insert again the 8 records of the place two times.
