first commit

plugins/sqlite/reader.js

@@ -0,0 +1,169 @@
+var _ = require('lodash');
+var util = require('../../core/util.js');
+var config = util.getConfig();
+var log = require(util.dirs().core + 'log');
+
+var sqlite = require('./handle');
+var sqliteUtil = require('./util');
+
+var Reader = function() {
+  _.bindAll(this);
+  this.db = sqlite.initDB(true);
+}
+
+
+// returns the most recent window complete candle
+// windows within `from` and `to`
+Reader.prototype.mostRecentWindow = function(from, to, next) {
+  to = to.unix();
+  from = from.unix();
+
+  var maxAmount = to - from + 1;
+
+  this.db.all(`
+    SELECT start from ${sqliteUtil.table('candles')}
+    WHERE start <= ${to} AND start >= ${from}
+    ORDER BY start DESC
+  `, function(err, rows) {
+    if(err) {
+
+      // bail out if the table does not exist
+      if(err.message.split(':')[1] === ' no such table')
+        return next(false);
+
+      log.error(err);
+      return util.die('DB error while reading mostRecentWindow');
+    }
+
+    // no candles are available
+    if(rows.length === 0) {
+      return next(false);
+    }
+
+    if(rows.length === maxAmount) {
+
+      // full history is available!
+
+      return next({
+        from: from,
+        to: to
+      });
+    }
+
+    // we have at least one gap, figure out where
+    var mostRecent = _.first(rows).start;
+
+    var gapIndex = _.findIndex(rows, function(r, i) {
+      return r.start !== mostRecent - i * 60;
+    });
+
+    // if there was no gap in the records, but
+    // there were not enough records.
+    if(gapIndex === -1) {
+      var leastRecent = _.last(rows).start;
+      return next({
+        from: leastRecent,
+        to: mostRecent
+      });
+    }
+
+    // else return mostRecent and the
+    // the minute before the gap
+    return next({
+      from: rows[ gapIndex - 1 ].start,
+      to: mostRecent
+    });
+
+  })
+}
+
+Reader.prototype.tableExists = function(name, next) {
+
+  this.db.all(`
+    SELECT name FROM sqlite_master WHERE type='table' AND name='${sqliteUtil.table(name)}';
+  `, function(err, rows) {
+    if(err) {
+      console.error(err);
+      return util.die('DB error at `get`');
+    }
+
+    next(null, rows.length === 1);
+  });
+}
+
+Reader.prototype.get = function(from, to, what, next) {
+  if(what === 'full')
+    what = '*';
+
+  this.db.all(`
+    SELECT ${what} from ${sqliteUtil.table('candles')}
+    WHERE start <= ${to} AND start >= ${from}
+    ORDER BY start ASC
+  `, function(err, rows) {
+    if(err) {
+      console.error(err);
+      return util.die('DB error at `get`');
+    }
+
+    next(null, rows);
+  });
+}
+
+Reader.prototype.count = function(from, to, next) {
+  this.db.all(`
+    SELECT COUNT(*) as count from ${sqliteUtil.table('candles')}
+    WHERE start <= ${to} AND start >= ${from}
+  `, function(err, res) {
+    if(err) {
+      console.error(err);
+      return util.die('DB error at `get`');
+    }
+
+    next(null, _.first(res).count);
+  });
+}
+
+Reader.prototype.countTotal = function(next) {
+  this.db.all(`
+    SELECT COUNT(*) as count from ${sqliteUtil.table('candles')}
+  `, function(err, res) {
+    if(err) {
+      console.error(err);
+      return util.die('DB error at `get`');
+    }
+
+    next(null, _.first(res).count);
+  });
+}
+
+Reader.prototype.getBoundry = function(next) {
+
+  this.db.all(`
+    SELECT
+    (
+      SELECT start
+      FROM ${sqliteUtil.table('candles')}
+      ORDER BY start LIMIT 1
+    ) as 'first',
+    (
+      SELECT start
+      FROM ${sqliteUtil.table('candles')}
+      ORDER BY start DESC
+      LIMIT 1
+    ) as 'last'
+  `, function(err, rows) {
+    if(err) {
+      console.error(err);
+      return util.die('DB error at `get`');
+    }
+
+    next(null, _.first(rows));
+  });
+}
+
+Reader.prototype.close = function() {
+  this.db.close();
+  this.db = null;
+}
+
+module.exports = Reader;