CartoDB-SQL-API/app/services/stream_copy.js
2018-06-21 14:49:38 +02:00

82 lines
2.2 KiB
JavaScript

const PSQL = require('cartodb-psql');
const copyTo = require('pg-copy-streams').to;
const copyFrom = require('pg-copy-streams').from;
const { Client } = require('pg');
const ACTION_TO = 'to';
const ACTION_FROM = 'from';
module.exports = class StreamCopy {
constructor(sql, userDbParams) {
this.pg = new PSQL(userDbParams);
this.sql = sql;
this.connectionClosedByClient = false;
this.copyToStream = null;
this.copyFromStream = null;
}
static get ACTION_TO() {
return ACTION_TO;
}
static get ACTION_FROM() {
return ACTION_FROM;
}
to(cb) {
this.pg.connect((err, client, done) => {
if (err) {
return cb(err);
}
this.copyToStream = copyTo(this.sql);
const pgstream = client.query(this.copyToStream);
pgstream
.on('end', () => done())
.on('error', err => done(err))
.on('cancelQuery', err => {
// See https://www.postgresql.org/docs/9.5/static/protocol-flow.html#PROTOCOL-COPY
const cancelingClient = new Client(client.connectionParameters);
cancelingClient.cancel(client, pgstream);
// see https://node-postgres.com/api/pool#releasecallback
done(err);
});
cb(null, pgstream);
});
}
from(cb) {
this.pg.connect((err, client, done) => {
if (err) {
return cb(err);
}
this.copyFromStream = copyFrom(this.sql);
const pgstream = client.query(this.copyFromStream);
pgstream
.on('end', () => done())
.on('error', err => done(err))
.on('cancelQuery', () => {
client.connection.sendCopyFail('CARTO SQL API: Connection closed by client');
});
cb(null, pgstream);
});
}
getRowCount(action = ACTION_TO) {
if (action === ACTION_TO && this.copyToStream) {
return this.copyToStream.rowCount;
}
if (action === ACTION_FROM && this.copyFromStream) {
return this.copyFromStream.rowCount;
}
}
};