restaurant-search/server.go

/*
 * Copyright (c) 2015 Alex Yatskov <alex@foosoft.net>
 * Author: 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.
 */

package main

import (
	"database/sql"
	"encoding/json"
	"flag"
	"fmt"
	"log"
	"math"
	"net/http"
	"os"
	"os/signal"
	"runtime/pprof"
	"strings"
	"sync"
	"syscall"
	"time"

	"github.com/GaryBoone/GoStats/stats"
	_ "github.com/mattn/go-sqlite3"
)

var db *sql.DB

func prepareColumn(steps int, minScore float64, allEntries, matchedEntries []record, features map[string]float64, modes map[string]modeType, name string, col *column, wg *sync.WaitGroup) {
	defer wg.Done()

	*col = column{
		Bracket: bracket{Max: -1.0, Min: 1.0},
		Mode:    modes[name].String(),
		Steps:   steps,
		Value:   features[name]}

	col.Hints = project(
		allEntries,
		features,
		modes,
		name,
		minScore,
		steps)

	var d stats.Stats
	for _, record := range matchedEntries {
		if feature, ok := record.features[name]; ok {
			d.Update(feature)
		}
	}

	if d.Count() > 0 {
		var dev float64
		if d.Count() > 1 {
			dev = d.SampleStandardDeviation() * 3
		}

		mean := d.Mean()

		col.Bracket.Max = math.Min(mean+dev, d.Max())
		col.Bracket.Min = math.Max(mean-dev, d.Min())
	}
}

func handleExecuteQuery(rw http.ResponseWriter, req *http.Request) {
	startTime := time.Now()

	var (
		request struct {
			Features    map[string]float64 `json:"features"`
			Geo         *geoData           `json:"geo"`
			MaxResults  int                `json:"maxResults"`
			MinScore    float64            `json:"minScore"`
			Modes       map[string]string  `json:"modes"`
			Profile     map[string]float64 `json:"profile"`
			Resolution  int                `json:"resolution"`
			SortAsc     bool               `json:"sortAsc"`
			SortKey     string             `json:"sortKey"`
			WalkingDist float64            `json:"walkingDist"`
		}

		response struct {
			Columns     map[string]*column `json:"columns"`
			Count       int                `json:"count"`
			MinScore    float64            `json:"minScore"`
			Records     []record           `json:"records"`
			ElapsedTime int64              `json:"elapsedTime"`
		}
	)

	if err := json.NewDecoder(req.Body).Decode(&request); err != nil {
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}

	var geo *geoData
	if request.Geo != nil {
		geo = &geoData{request.Geo.Latitude, request.Geo.Longitude}
	}

	allEntries := getRecords(queryContext{geo, request.Profile, request.WalkingDist})
	features := fixFeatures(request.Features)
	modes := fixModes(request.Modes)

	matchedEntries := findRecords(allEntries, features, modes, request.MinScore)
	sorter := recordSorter{entries: matchedEntries, key: request.SortKey, ascending: request.SortAsc}
	sorter.sort()

	var wg sync.WaitGroup
	wg.Add(len(features))

	response.Columns = make(map[string]*column)
	for name := range features {
		response.Columns[name] = new(column)
		go prepareColumn(
			request.Resolution,
			request.MinScore,
			allEntries,
			matchedEntries,
			features,
			modes,
			name,
			response.Columns[name],
			&wg)
	}

	wg.Wait()

	response.Count = len(matchedEntries)
	response.MinScore = request.MinScore
	response.ElapsedTime = time.Since(startTime).Nanoseconds()

	if len(matchedEntries) > request.MaxResults {
		response.Records = matchedEntries[:request.MaxResults]
	} else {
		response.Records = matchedEntries
	}

	js, err := json.Marshal(response)
	if err != nil {
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}

	rw.Header().Set("Content-Type", "application/json")
	rw.Write(js)
}

func handleGetCategories(rw http.ResponseWriter, req *http.Request) {
	categoryRows, err := db.Query("SELECT description, id FROM categories")
	if err != nil {
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}
	defer categoryRows.Close()

	type category struct {
		Description string `json:"description"`
		Id          int    `json:"id"`
	}

	var response []category
	for categoryRows.Next() {
		var (
			description string
			id          int
		)

		if err := categoryRows.Scan(&description, &id); err != nil {
			http.Error(rw, err.Error(), http.StatusInternalServerError)
			return
		}

		response = append(response, category{description, id})
	}

	if err := categoryRows.Err(); err != nil {
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}

	js, err := json.Marshal(response)
	if err != nil {
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}

	rw.Header().Set("Content-Type", "application/json")
	rw.Write(js)
}

func handleAddCategory(rw http.ResponseWriter, req *http.Request) {
	var (
		request struct {
			Description string `json:"description"`
		}

		response struct {
			Description string `json:"description"`
			Id          int    `json:"id"`
			Success     bool   `json:"success"`
		}
	)

	if err := json.NewDecoder(req.Body).Decode(&request); err != nil {
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}

	response.Description = strings.TrimSpace(request.Description)

	if len(response.Description) > 0 {
		result, err := db.Exec("INSERT INTO categories(description) VALUES(?)", request.Description)
		if err != nil {
			http.Error(rw, err.Error(), http.StatusInternalServerError)
			return
		}

		insertId, err := result.LastInsertId()
		if err != nil {
			http.Error(rw, err.Error(), http.StatusInternalServerError)
			return
		}

		affectedRows, err := result.RowsAffected()
		if err != nil {
			http.Error(rw, err.Error(), http.StatusInternalServerError)
			return
		}

		response.Success = affectedRows > 0
		response.Id = int(insertId)
	}

	js, err := json.Marshal(response)
	if err != nil {
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}

	rw.Header().Set("Content-Type", "application/json")
	rw.Write(js)
}

func handleRemoveCategory(rw http.ResponseWriter, req *http.Request) {
	var (
		request struct {
			Id int `json:"id"`
		}

		response struct {
			Success bool `json:"success"`
		}
	)

	if err := json.NewDecoder(req.Body).Decode(&request); err != nil {
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}

	if _, err := db.Exec("DELETE FROM categories WHERE id = (?)", request.Id); err == nil {
		response.Success = true
	}

	js, err := json.Marshal(response)
	if err != nil {
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}

	rw.Header().Set("Content-Type", "application/json")
	rw.Write(js)
}

func handleAccessReview(rw http.ResponseWriter, req *http.Request) {
	var request struct {
		Id      int                `json:"id"`
		Profile map[string]float64 `json:"profile"`
	}

	if err := json.NewDecoder(req.Body).Decode(&request); err != nil {
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}

	reviewsResult, err := db.Exec("UPDATE reviews SET accessCount = accessCount + 1 WHERE id = (?)", request.Id)
	if err != nil {
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}

	rowsAffected, err := reviewsResult.RowsAffected()
	if err != nil {
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}

	if rowsAffected == 0 || len(request.Profile) == 0 {
		return
	}

	historyResult, err := db.Exec("INSERT INTO history(date, reviewId) VALUES(NOW(), ?)", request.Id)
	if err != nil {
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}

	insertId, err := historyResult.LastInsertId()
	if err != nil {
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}

	for id, value := range request.Profile {
		catRow := db.QueryRow("SELECT EXISTS(SELECT NULL FROM categories WHERE id = ?)", id)

		var catExists int
		if err := catRow.Scan(&catExists); err != nil {
			http.Error(rw, err.Error(), http.StatusInternalServerError)
			return
		}

		if catExists == 0 {
			continue
		}

		if _, err := db.Exec("INSERT INTO historyGroups(categoryId, categoryValue, historyId) VALUES(?, ?, ?)", id, value, insertId); err != nil {
			http.Error(rw, err.Error(), http.StatusInternalServerError)
			return
		}
	}
}

func handleClearHistory(rw http.ResponseWriter, req *http.Request) {
	if _, err := db.Exec("DELETE FROM historyGroups"); err != nil {
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}

	if _, err := db.Exec("DELETE FROM history"); err != nil {
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}

	rw.Header().Set("Content-Type", "text/plain")
	fmt.Fprint(rw, "History tables cleared")
}

func main() {
	staticDir := flag.String("static", "static", "static files path")
	portNum := flag.Int("port", 8080, "port to serve content on")
	dataSrc := flag.String("db", "build/data/db.sqlite3", "database path")
	profile := flag.String("profile", "", "write cpu profile to file")
	flag.Parse()

	var err error
	if db, err = sql.Open("sqlite3", *dataSrc); err != nil {
		log.Fatal(err)
	}
	defer db.Close()

	if *profile != "" {
		f, err := os.Create(*profile)
		if err != nil {
			log.Fatal(err)
		}

		pprof.StartCPUProfile(f)

		c := make(chan os.Signal, 1)
		signal.Notify(c, os.Interrupt, syscall.SIGINT, syscall.SIGTERM)

		go func() {
			<-c
			pprof.StopCPUProfile()
			os.Exit(1)
		}()
	}

	http.HandleFunc("/query", handleExecuteQuery)
	http.HandleFunc("/categories", handleGetCategories)
	http.HandleFunc("/learn", handleAddCategory)
	http.HandleFunc("/forget", handleRemoveCategory)
	http.HandleFunc("/access", handleAccessReview)
	http.HandleFunc("/clear", handleClearHistory)
	http.Handle("/", http.FileServer(http.Dir(*staticDir)))

	log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", *portNum), nil))
}