Import sql file in node.js and execute against PostgreSQL

I've written the following function which works for my case. It would have been much more simpler if it weren't for:

• Using batch to manage concurrency
• Having the tricky PostgreSQL COPY case to consider

Code snippet:

function processSQLFile(fileName) {

  // Extract SQL queries from files. Assumes no ';' in the fileNames
  var queries = fs.readFileSync(fileName).toString()
    .replace(/(\r\n|\n|\r)/gm," ") // remove newlines
    .replace(/\s+/g, ' ') // excess white space
    .split(";") // split into all statements
    .map(Function.prototype.call, String.prototype.trim)
    .filter(function(el) {return el.length != 0}); // remove any empty ones

  // Execute each SQL query sequentially
  queries.forEach(function(query) {
    batch.push(function(done) {
      if (query.indexOf("COPY") === 0) { // COPY - needs special treatment
        var regexp = /COPY\ (.*)\ FROM\ (.*)\ DELIMITERS/gmi;
        var matches = regexp.exec(query);
        var table = matches[1];
        var fileName = matches[2];
        var copyString = "COPY " + table + " FROM STDIN DELIMITERS ',' CSV HEADER";
        var stream = client.copyFrom(copyString);
        stream.on('close', function () {
          done();
        });
        var csvFile = __dirname + '/' + fileName;
        var str = fs.readFileSync(csvFile);
        stream.write(str);
        stream.end();
      } else { // Other queries don't need special treatment
        client.query(query, function(result) {
          done();
        });
      }
    });
  });
}

Beware that this would fail if you used semicolons anywhere except to terminate SQL statements.

You can just separate consequent queries with a semicolon when passed to client.query

That works:

var pg = require('pg');

pg.connect('postgres://test:test@localhost/test', function(err, client, done){
        client.query('CREATE TABLE test (test VARCHAR(255)); INSERT INTO test VALUES(\'test\') ');
        done();
});

And consequently, that works too:

var pg = require('pg');
var fs = require('fs');

var sql = fs.readFileSync('init_database.sql').toString();

pg.connect('postgres://test:test@localhost/test', function(err, client, done){
    if(err){
        console.log('error: ', err);
        process.exit(1);
    }
    client.query(sql, function(err, result){
        done();
        if(err){
            console.log('error: ', err);
            process.exit(1);
        }
        process.exit(0);
    });
});