Client Driver

Given the specific operation of the Database Web Gateway protocol, a Javascript client driver library MUST BE provided along with the server-side server systems. Java and Swift proxies SHOULD BE provided for mobile platforms. A Rustlang the RECOMMENDED platform to build client drivers, with its ability for compiling to WebAssembly+Javascript for web browsers, and language wrappers for Java and Swift.

Features

• MUST maintain a web socket connection, including initial establishment and reconnection

• MUST provide an async/promise API where communication failures and other errors are thrown for the awaiter to catch.

Simple select example :

var directory = Database.Start({host:"acme.net:91", token: this.token}); var db = directory.resolve(["cars"]); //resolve(readonlyArray, writeableArray). This creates an object with context, and internally it starts resolving. When the first query is executed, that resolution is awaited var result_set = await db.query(`select * from cars.colour_options C where car_id = $0;`, car_id); while (isInScope(result_set) && await result_set.gotNextBatch()) {  if (isInScope(result_set.current_batch) == false) //scope might have changed since query  continue;    optionsUI.apply(result_set); }

Simple composite insert example:

var directory = Database.Start({host:"acme.net:91", token: this.token}); var db = directory.resolve(["cars"]); //resolve(readonlyArray, writeableArray). This creates an object with context, and internally it starts resolving. When the first query is executed, that resolution is awaited var batch = db.createFixedQueryBatch(4); await batch.run("insert into orders (...) values (...);"); await batch.run("var @order_id = last_order_id();"); await batch.run("insert into order_item (...) values (@order_id...);"); await batch.query("select last_order_item_id();"); await batch.flush(); var order_item_id = await batch.result.single(); batch = null;

Advanced paged select context:

function CarsReadOnlyAdaptor() {  var directory = await Database.Start({host:"acme.net:91", token: this.token});  var db = directory.resolve(["cars", "brands"]); //resolve(readonlyArray, writeableArray). This creates an object with context, and internally it starts resolving. When the first query is executed, that resolution is awaited    return {  db: db,  viewPort: { fixed: 10 ... },  dataBuffer: { },  filters: [],  sorts: [],  fetchMissing: function() {   ...   var result_set = await db.query(`select * from cars.catalogue C join brands.vendors B on B.ID = C.vendor_id limit 100 offset {requiredOffset};`);  while (isInScope(result_set) && await result_set.gotNextBatch())  {  if (isInScope(result_set.current_batch) == false) //scope might have changed since query  continue;    dataBuffer.Store(result_set);  }  ...  },  trimDataBuffer: ...  hintViewPort: ...,  requireViewPort: ...,    }; }