Add uastats, a tool to summarise user agents. (avct#31)

* Add uastats, a tool to summarise user agents.

uastats reads from stdin expecting one useragent per line. When the
input finishes it will print a summary similar to the following:

Read 319356 useragents

Browsers
BrowserChrome      183682 (57.52%)
BrowserSafari      64062 (20.06%)
BrowserIE          38184 (11.96%)
BrowserFirefox     25561 (8.00%)
BrowserSilk        3541 (1.11%)
BrowserOpera       2543 (0.80%)
BrowserAndroid     954 (0.30%)
BrowserUnknown     625 (0.20%)
BrowserBlackberry  132 (0.04%)
BrowserSpotify     69 (0.02%)
BrowserUCBrowser   3 (0.00%)

Operating Systems
OSWindows       143500 (44.93%)
OSAndroid       84930 (26.59%)
OSiOS           56519 (17.70%)
OSMacOSX        24116 (7.55%)
OSKindle        3878 (1.21%)
OSChromeOS      2804 (0.88%)
OSLinux         1629 (0.51%)
OSWindowsPhone  1206 (0.38%)
OSPlaystation   262 (0.08%)
OSUnknown       262 (0.08%)
OSXbox          125 (0.04%)
OSBlackberry    118 (0.04%)
OSNintendo      7 (0.00%)

Device Types
DeviceComputer  170833 (53.49%)
DevicePhone     114783 (35.94%)
DeviceTablet    32994 (10.33%)
DeviceConsole   393 (0.12%)
DeviceUnknown   246 (0.08%)
DeviceTV        107 (0.03%)

* Remove Go 1.7 from Travis.

.travis.yml

@@ -5,7 +5,6 @@ language: go
 go:
   - 1.9.x
   - 1.8.x
-  - 1.7.x
 
 script:
   - go test

cmd/uastats/main.go

@@ -0,0 +1,101 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"sort"
+	"text/tabwriter"
+
+	"code.avct.io/uasurfer"
+)
+
+func main() {
+	var count int
+	ua := &uasurfer.UserAgent{}
+	stats := stats{
+		BrowserNames: make(map[uasurfer.BrowserName]int),
+		OSNames:      make(map[uasurfer.OSName]int),
+		DeviceTypes:  make(map[uasurfer.DeviceType]int),
+	}
+
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		count++
+		ua.Reset()
+		uasurfer.ParseUserAgent(scanner.Text(), ua)
+		stats.BrowserNames[ua.Browser.Name]++
+		stats.OSNames[ua.OS.Name]++
+		stats.DeviceTypes[ua.DeviceType]++
+	}
+	if err := scanner.Err(); err != nil {
+		fmt.Fprintln(os.Stderr, "reading standard input:", err)
+	}
+	fmt.Printf("Read %d useragents\n", count)
+	fmt.Println()
+	stats.Summary(count, os.Stdout)
+}
+
+type stats struct {
+	OSNames      map[uasurfer.OSName]int
+	BrowserNames map[uasurfer.BrowserName]int
+	DeviceTypes  map[uasurfer.DeviceType]int
+}
+
+func (s *stats) Summary(total int, dest io.Writer) {
+	browserCounts := make([]stringCount, 0, len(s.BrowserNames))
+	for k, v := range s.BrowserNames {
+		browserCounts = append(browserCounts, stringCount{name: k.String(), count: v})
+	}
+	sort.Slice(browserCounts, func(i, j int) bool { return browserCounts[j].count < browserCounts[i].count }) // by count reversed
+	fmt.Fprintf(dest, "Browsers\n")
+	err := writeTable(browserCounts, total, dest)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "writing summary: %v", err)
+		return
+	}
+
+	fmt.Fprintln(dest)
+	osCounts := make([]stringCount, 0, len(s.OSNames))
+	for k, v := range s.OSNames {
+		osCounts = append(osCounts, stringCount{name: k.String(), count: v})
+	}
+	sort.Slice(osCounts, func(i, j int) bool { return osCounts[j].count < osCounts[i].count }) // by count reversed
+	fmt.Fprintf(dest, "Operating Systems\n")
+	err = writeTable(osCounts, total, dest)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "writing summary: %v", err)
+		return
+	}
+
+	fmt.Fprintln(dest)
+	deviceCounts := make([]stringCount, 0, len(s.DeviceTypes))
+	for k, v := range s.DeviceTypes {
+		deviceCounts = append(deviceCounts, stringCount{name: k.String(), count: v})
+	}
+	sort.Slice(deviceCounts, func(i, j int) bool { return deviceCounts[j].count < deviceCounts[i].count }) // by count reversed
+	fmt.Fprintf(dest, "Device Types\n")
+	err = writeTable(deviceCounts, total, dest)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "writing summary: %v", err)
+		return
+	}
+}
+
+func writeTable(counts []stringCount, total int, dest io.Writer) error {
+	tw := tabwriter.NewWriter(dest, 10, 1, 2, ' ', 0)
+	for i := range counts {
+		fmt.Fprintf(tw, "%s\t%d (%.2f%%)\n", counts[i].name, counts[i].count, percent(counts[i].count, total))
+	}
+	return tw.Flush()
+}
+
+type stringCount struct {
+	name  string
+	count int
+}
+
+func percent(num, den int) float64 {
+	return float64(num) / float64(den) * 100.0
+}