stats_handler.go

package main

import (
	"encoding/json"
	"net/http"
	"strconv"
	"strings"
	"time"

	"github.com/pilu/traffic"
	"google.golang.org/appengine"
	"google.golang.org/appengine/datastore"
	"google.golang.org/appengine/log"
	"google.golang.org/appengine/memcache"
	"google.golang.org/appengine/user"
)

type StatsData struct {
	Posts        int
	WordsPerPost float64
	PostsPerDay  float64
	WordsPerDay  float64
	DaysSince    float64
	IsAdmin      bool
	LinksPerPost float64
	LinksPerDay  float64
	Years        []string
	YearData     map[string][]float64
}

func StatsWorkHandler(w traffic.ResponseWriter, r *traffic.Request) {
	c := appengine.NewContext(r.Request)

	var data *StatsData
	entries, err := AllPosts(c)
	if err != nil {
		log.Errorf(c, "Error loading posts: %+v", err)
		http.Error(w, err.Error(), 500)
		return
	}

	postCount := len(*entries)
	oldestPost := (*entries)[postCount-1]
	dayCount := time.Since(oldestPost.Datetime).Hours() / 24.0
	oldestYear := oldestPost.Datetime.Year()

	years := []string{}
	yearData := make(map[string][]float64)
	for i := time.Now().Year(); i >= oldestYear; i-- {
		years = append(years, strconv.Itoa(i))
		yearData[strconv.Itoa(i)] = []float64{0.0, 0.0, 0.0}
	}

	words := 0
	for _, p := range *entries {
		words += len(strings.Fields(p.Content))
		words += len(strings.Fields(p.Title))
		yearData[strconv.Itoa(p.Datetime.Year())][0] += 1
	}

	for _, y := range years {
		yearData[y][1] = yearData[y][0] / 52.0
	}

	readLinks := 0
	q := LinkQuery(c, 10000, true)
	for t := q.Run(c); ; {
		var l Link
		_, err := t.Next(&l)
		if err == datastore.Done {
			break
		}
		if err != nil {
			log.Errorf(c, "Error loading link: %+v", err)
		} else {
			readLinks += 1
			yearPosted := l.Posted.Year()
			// Don't want to record stats for years we don't have posts.
			if yearPosted >= oldestYear {
				yearData[strconv.Itoa(yearPosted)][2] += 1
			}
		}
	}

	data = &StatsData{
		Posts:        postCount,
		PostsPerDay:  float64(postCount) / dayCount,
		WordsPerPost: float64(words) / float64(postCount),
		WordsPerDay:  float64(words) / dayCount,
		DaysSince:    dayCount,
		LinksPerDay:  float64(readLinks) / dayCount,
		Years:        years,
		YearData:     yearData,
	}

	b, err := json.Marshal(data)
	if err != nil {
		log.Errorf(c, err.Error())
		http.Error(w, err.Error(), 500)
		return
	}
	item := &memcache.Item{
		Key:   "stats-data",
		Value: b,
	}

	// Set the item, unconditionally
	if err := memcache.Set(c, item); err != nil {
		log.Errorf(c, "error setting item: %v", err)
	}
}

func StatsHandler(w traffic.ResponseWriter, r *traffic.Request) {
	c := appengine.NewContext(r.Request)

	data := &StatsData{}
	if json_data, err := memcache.Get(c, "stats-data"); err == memcache.ErrCacheMiss {
		log.Errorf(c, "stats-data is empty")
	} else if err != nil {
		log.Errorf(c, "error getting item: %v", err)
	} else {
		err := json.Unmarshal(json_data.Value, &data)
		if err != nil {
			log.Errorf(c, err.Error())
			http.Error(w, err.Error(), 500)
			return
		}
	}

	data.IsAdmin = user.IsAdmin(c)
	w.Render("stats", data)
}

func StatsHistoryJsonHandler(w traffic.ResponseWriter, r *traffic.Request) {
	c := appengine.NewContext(r.Request)
	entries, err := AllPostsJson(c)
	if err != nil {
		log.Errorf(c, "Error loading posts: %+v", err)
		http.Error(w, err.Error(), 500)
		return
	}
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.Header().Set("Access-Control-Allow-Origin", "*")
	w.WriteJSON(entries)
}