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restaurant-search/server/search.js

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#!/usr/bin/env node
/*
* Copyright (c) 2015 Alex Yatskov <alex@foosoft.net>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
'use strict';
var _ = require('underscore');
var async = require('async');
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var geolib = require('geolib');
var mysql = require('mysql');
var pool = null;
function innerProduct(values1, values2) {
var result = 0.0;
for (var feature in values1) {
if (feature in values2) {
result += values1[feature] * values2[feature];
}
}
return result;
}
function walkMatches(data, features, minScore, callback) {
for (var i = 0, count = data.length; i < count; ++i) {
var record = data[i];
var score = innerProduct(features, record.features);
if (score >= minScore) {
callback(record, score);
}
}
}
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function statRecords(data, features, minScore) {
var compatibility = 0;
var count = 0;
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walkMatches(data, features, minScore, function(record, score) {
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compatibility += record.compatibility * score;
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++count;
});
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return {
compatibility: compatibility,
count: count
};
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}
function findRecords(data, features, minScore) {
var results = [];
walkMatches(data, features, minScore, function(record, score) {
results.push({
name: record.name,
score: score,
distanceToUser: record.distanceToUser / 1000.0,
distanceToStn: record.distanceToStn / 1000.0,
closestStn: record.closestStn,
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accessCount: record.accessCount,
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id: record.id
});
});
results.sort(function(a, b) {
return b.score - a.score;
});
return results;
}
function step(range, steps, callback) {
var stepSize = (range.max - range.min) / steps;
for (var i = 0; i < steps; ++i) {
var stepMax = range.max - stepSize * i;
var stepMin = stepMax - stepSize;
var stepMid = (stepMin + stepMax) / 2;
callback(stepMid);
}
}
function project(data, features, feature, minScore, range, steps) {
var sample = _.clone(features);
var results = [];
step(range, steps, function(position) {
sample[feature] = position;
results.push({
sample: position,
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stats: statRecords(data, sample, minScore)
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});
});
return results;
}
function buildHints(data, features, feature, minScore, range, steps) {
var projection = project(
data,
features,
feature,
minScore,
range,
steps
);
var hints = [];
_.each(projection, function(result) {
hints.push({
sample: result.sample,
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stats: result.stats
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});
});
return hints;
}
function loadDb(params) {
pool = mysql.createPool(params);
}
function getRecords(context, callback) {
pool.query('SELECT * FROM reviews', function(err, rows) {
if (err) {
throw err;
}
var records = _.map(rows, function(row) {
return {
name: row.name,
id: row.id,
closestStn: row.closestStn,
distanceToStn: row.distanceToStn,
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accessCount: row.accessCount,
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geo: {
latitude: row.latitude,
longitude: row.longitude
},
features: {
delicious: row.delicious,
accomodating: row.accomodating,
affordable: row.affordable,
atmospheric: row.atmospheric
},
};
});
computeRecordGeo(records, context);
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computeRecordPopularity(records, context, callback);
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});
}
function computeRecordGeo(records, context) {
var distUserMin = Number.MAX_VALUE;
var distUserMax = Number.MIN_VALUE;
_.each(records, function(record) {
record.distanceToUser = 0.0;
if (context.geo) {
record.distanceToUser = geolib.getDistance(record.geo, context.geo);
}
distUserMin = Math.min(distUserMin, record.distanceToUser);
distUserMax = Math.max(distUserMax, record.distanceToUser);
});
var distUserRange = distUserMax - distUserMin;
_.each(records, function(record) {
record.features.nearby = -((record.distanceToUser - distUserMin) / distUserRange - 0.5) * 2.0;
record.features.accessible = 1.0 - (record.distanceToStn / context.walkingDist);
record.features.accessible = Math.min(record.features.accessible, 1.0);
record.features.accessible = Math.max(record.features.accessible, -1.0);
});
}
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function computeRecordPopularity(records, context, callback) {
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async.each(
records,
function(record, callback) {
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pool.query(
'SELECT * FROM history WHERE reviewId = (?)',
[record.id],
function(err, rows) {
async.map(
rows,
function(row, callback) {
pool.query(
'SELECT * FROM historyGroups WHERE historyId = (?)',
[row.id],
function(err, historyGroupRows) {
var reviewFeatures = {};
_.each(historyGroupRows, function(historyGroupRow) {
reviewFeatures[historyGroupRow.categoryId] = historyGroupRow.categoryValue;
});
var groupScore = innerProduct(context.profile, reviewFeatures);
callback(err, groupScore);
}
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);
},
function(err, groupScores) {
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var scoreAvg = 0;
if (groupScores.length > 0) {
var scoreSum = _.reduce(groupScores, function(a, b) { return a + b; });
scoreAvg = scoreSum / groupScores.length;
}
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record.compatibility = scoreAvg;
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callback(err);
}
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);
}
);
},
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function(err) {
if (err) {
throw err;
}
callback(records);
}
);
}
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function fixupProfile(profile) {
var fixed = {};
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_.each(JSON.parse(profile || '{}'), function(value, key) {
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if (parseFloat(value) !== 0) {
fixed[key] = value;
}
});
return fixed;
}
function fixupFeatures(features) {
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var keys = [
'delicious',
'accomodating',
'affordable',
'atmospheric',
'nearby',
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'accessible'
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];
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if (!features) {
features = {};
}
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var fixed = {};
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_.each(keys, function(key) {
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fixed[key] = features[key] || 0;
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});
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return fixed;
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}
function getCategories(callback) {
pool.query('SELECT * FROM categories', function(err, rows) {
if (err) {
throw err;
}
var categories = _.map(rows, function(row) {
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return {
id: row.id,
description: row.description
};
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});
callback(categories);
});
}
function addCategory(query, callback) {
var description = query.description.trim();
if (description) {
pool.query('INSERT INTO categories(description) VALUES(?)', [description], function(err, info) {
if (err) {
throw err;
}
callback({
id: info.insertId,
description: description,
success: true
});
});
}
else {
callback({success: false});
}
}
function removeCategory(query, callback) {
pool.query('DELETE FROM categories WHERE id = (?)', [query.id], function(err, info) {
if (err) {
throw err;
}
callback({success: info.affectedRows > 0});
});
}
function accessReview(query, callback) {
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query.profile = fixupProfile(query.profile);
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pool.query('SELECT url FROM reviews WHERE id = (?) LIMIT 1', [query.id], function(err, rows) {
if (err) {
throw err;
}
var results = {
success: rows.length > 0
};
if (results.success) {
results.url = 'http://www.tripadvisor.com' + rows[0].url;
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pool.query('UPDATE reviews SET accessCount = accessCount + 1 WHERE id = (?)', [query.id], function(err, info) {
if (_.keys(query.profile).length > 0) {
pool.query('INSERT INTO history(date, reviewId) VALUES(NOW(), ?)', [query.id], function(err, info) {
if (err) {
throw err;
}
for (var categoryId in query.profile) {
pool.query(
'INSERT INTO historyGroups(categoryId, categoryValue, historyId) VALUES(?, ?, ?)',
[categoryId, query.profile[categoryId], info.insertId]
);
}
});
}
});
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}
callback(results);
});
}
function runQuery(query, callback) {
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query.profile = fixupProfile(query.profile);
query.features = fixupFeatures(query.features);
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var context = {
geo: query.geo,
profile: query.profile,
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walkingDist: query.walkingDist * 1000.0
};
getRecords(context, function(data) {
var searchResults = findRecords(
data,
query.features,
query.minScore
);
var graphColumns = {};
for (var feature in query.features) {
var searchHints = buildHints(
data,
query.features,
feature,
query.minScore,
query.range,
query.hintSteps
);
graphColumns[feature] = {
value: query.features[feature],
hints: searchHints,
steps: query.hintSteps
};
}
callback({
columns: graphColumns,
items: searchResults.slice(0, query.maxResults),
count: searchResults.length
});
});
}
module.exports = {
loadDb: loadDb,
runQuery: runQuery,
getCategories: getCategories,
addCategory: addCategory,
removeCategory: removeCategory,
accessReview: accessReview
};