Use this library to export a Postgres database to JSON and then import it to HTML5 IndexedDB. Makes use of streams to handle I/O for databases larger than available RAM.
Both importer and exporter will return RxJS Observable objects, which will emit useful progress messages.
Note: exporter will be unavailable in non-node.js environments and importer will be unavailable in non-browser environments.
var exporter = require('postgres-indexed-db').Exporter;
//exporter config.db is fed into pg.Pool https://www.npmjs.com/package/pg
var observable = exporter({
db: {
database: "dvdrental_sample"
},
output_path: "test/exported_data",
results_per_page: 5000
});
observable.subscribe(function(msg_o){
switch(msg_o.message){
case "success":
console.log('finished');
//Data is output to JSON in the output_path;
//one .json file per db table.
break;
case "progress":
console.log("%" (msg_o.value*100).toFixed(2) " done...");
break;
}
}); //Import
var Importer = require('postgres-indexed-db').Importer;
//path to data from exporter as 1st param, IndexedDB name as 2nd
var observable = Importer.import( "test/exported_data", 'test_db' );
observable.subscribe(function(msg_o){
switch (msg_o.message){
case "success":
console.log('finished');
//Schema data has been imported to IndexedDB. Indices from Postgres have
//also been migrated.
break;
case "progress":
console.log((msg_o.value * 100).toFixed(2) '% done...');
break;
case "manifest":
manifest = msg_o.value;
break;
}
});
//idbImported can be used to query whether a database has been successfully imported.
//uses localStorage, can be used to avoid a re-import when undesirable
Importer.idbImported('test_db'); //returns trueTo run the tests, first create a postgres database called 'dvdrental_sample' and extract test/test_db.zip and use the resulting .sql file to populate the database with test data.
Run test/test.js to test the exporter, and then open test/test.html in a browser to test the importer.