Proof of concept for an aircraft metadata DB.

2015-02-24 21:51:30 +00:00 · 2015-02-24 21:51:30 +00:00 · da2fff8531
commit da2fff8531
parent d7c5047fd3
6 changed files with 219 additions and 1 deletions
--- a/public_html/dbloader.js
+++ b/public_html/dbloader.js
@ -0,0 +1,118 @@
+// -*- mode: javascript; indent-tabs-mode: nil; c-basic-offset: 8 -*-
+
+// Part of dump1090, a Mode S message decoder for RTLSDR devices.
+//
+// dbloader.js: load aircraft metadata from static json files
+//
+// Copyright (c) 2014,2015 Oliver Jowett <oliver@mutability.co.uk>
+//
+// This file is free software: you may copy, redistribute and/or modify it
+// under the terms of the GNU General Public License as published by the
+// Free Software Foundation, either version 2 of the License, or (at your
+// option) any later version.
+//
+// This file is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"use strict";
+
+var _aircraft_cache = {};
+
+function getAircraftData(icao) {
+        var defer;
+
+        icao = icao.toUpperCase();
+
+        if (icao in _aircraft_cache) {
+                defer = _aircraft_cache[icao];
+        } else {
+                // load from blocks:
+                defer = _aircraft_cache[icao] = $.Deferred();
+                request_from_db(icao, 1, defer);
+        }
+
+        return defer;
+}
+
+function request_from_db(icao, level, defer) {
+        var bkey = icao.substring(0, level);
+        var dkey = icao.substring(level);
+        var req = db_ajax(bkey);
+
+        req.done(function(data) {
+                var subkey;
+
+                if ("children" in data) {
+                        subkey = bkey + dkey.substring(0,1);
+                        if (data.children.indexOf(subkey) == -1) {
+                                defer.reject();
+                        } else {
+                                request_from_db(icao, level+1, defer);
+                        }
+                } else {
+                        if (dkey in data) {
+                                defer.resolve(data[dkey]);
+                        } else {
+                                defer.reject();
+                        }
+                }
+        });
+
+        req.fail(function(jqXHR,textStatus,errorThrown) {
+                defer.reject();
+        });
+}
+
+var _request_count = 0;
+var _request_queue = [];
+var _request_cache = {};
+
+var MAX_REQUESTS = 2;
+
+function db_ajax(bkey) {
+        var defer;
+
+        if (bkey in _request_cache) {
+                return _request_cache[bkey];
+        }
+
+        if (_request_count < MAX_REQUESTS) {
+                // just do ajax directly
+                ++_request_count;
+                defer = _request_cache[bkey] = $.ajax({ url: 'db/' + bkey + '.json',
+                                                        cache: true,
+                                                        timeout: 5000,
+                                                        dataType : 'json' });
+                defer.always(db_ajax_request_complete);
+        } else {
+                // put it in the queue
+                defer = _request_cache[bkey] = $.Deferred();
+                defer.bkey = bkey;
+                _request_queue.push(defer);
+        }
+
+        return defer;
+}
+
+function db_ajax_request_complete() {
+        var req;
+        var ajaxreq;
+
+        if (_request_queue.length == 0) {
+                --_request_count;
+        } else {
+                req = _request_queue.shift();
+                ajaxreq = $.ajax({ url: 'db/' + req.bkey + '.json',
+                                   cache: true,
+                                   timeout: 5000,
+                                   dataType : 'json' });
+                ajaxreq.done(function(data) { req.resolve(data); });
+                ajaxreq.fail(function(jqxhr, status, error) { req.reject(jqxhr, status, error); });
+                ajaxreq.always(db_ajax_request_complete);
+        }
+}