From 237e3cd889c063988c004b7a5f9bc3e2ccf27066 Mon Sep 17 00:00:00 2001
From: Jim Myhrberg <contact@jimeh.me>
Date: Thu, 15 Dec 2016 23:58:07 +0000
Subject: [PATCH] Add support for basic CLI flags

---
 kotaku-uk-rss.go | 44 +++---------------------------
 main.go          | 70 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+), 40 deletions(-)
 create mode 100644 main.go

diff --git a/kotaku-uk-rss.go b/kotaku-uk-rss.go
index 86ecab2..6b57d37 100644
--- a/kotaku-uk-rss.go
+++ b/kotaku-uk-rss.go
@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"log"
 	"net/http"
-	"os"
 	"sort"
 	"sync"
 	"time"
@@ -53,12 +52,14 @@ type RssCache struct {
 	body string
 }
 
+// Set allows setting the RssCache body.
 func (r *RssCache) Set(value string) {
 	r.Lock()
 	defer r.Unlock()
 	r.body = value
 }
 
+// Get allows getting the RssCache body.
 func (r *RssCache) Get() string {
 	r.RLock()
 	defer r.RUnlock()
@@ -134,7 +135,7 @@ func truncateString(s string, l int) string {
 	return s[:end]
 }
 
-func getArticlesFromUrl(url string) Articles {
+func getArticlesFromURL(url string) Articles {
 	doc := fetchDocument(url)
 	section := extractArticleSection(doc)
 	return parseArticleSection(section)
@@ -184,9 +185,7 @@ func updateRssLoop() {
 		articles := Articles{}
 		for _, url := range pageUrls {
 			fmt.Printf("fetching and parsing articles from: %s\n", url)
-			for _, article := range getArticlesFromUrl(url) {
-				articles = append(articles, article)
-			}
+			articles = append(articles, getArticlesFromURL(url)...)
 		}
 
 		fmt.Printf("building feed cache... ")
@@ -197,38 +196,3 @@ func updateRssLoop() {
 		time.Sleep(60 * time.Second)
 	}
 }
-
-/*
-  Configuration
-*/
-
-var rootURL = "http://www.kotaku.co.uk"
-
-var pageUrls = []string{
-	rootURL + "/",
-	rootURL + "/page/2/",
-	rootURL + "/page/3/",
-}
-
-/*
-  Main...
-*/
-
-var rssCache = RssCache{}
-
-func main() {
-	port := "80"
-	if os.Getenv("PORT") != "" {
-		port = os.Getenv("PORT")
-	}
-
-	http.HandleFunc("/rss", serveRss)
-
-	go updateRssLoop()
-
-	fmt.Println("Listing on port " + port + "...")
-	err := http.ListenAndServe(":"+port, nil)
-	if err != nil {
-		panic(err)
-	}
-}
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..8d2ae35
--- /dev/null
+++ b/main.go
@@ -0,0 +1,70 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+
+	"gopkg.in/alecthomas/kingpin.v2"
+)
+
+// Version gets populated with version at build-time.
+var Version string
+var defaultPort = "8080"
+
+var (
+	port = kingpin.Flag("port", "Port to listen to.").Short('p').
+		Default(defaultPort).String()
+	bind = kingpin.Flag("bind", "Bind address.").Short('b').
+		Default("0.0.0.0").String()
+	version = kingpin.Flag("version", "Print version info.").
+		Short('v').Bool()
+)
+
+/*
+  Configuration
+*/
+
+var rootURL = "http://www.kotaku.co.uk"
+
+var pageUrls = []string{
+	rootURL + "/",
+	rootURL + "/page/2/",
+	rootURL + "/page/3/",
+}
+
+/*
+  Main...
+*/
+
+var rssCache = RssCache{}
+
+func printVersion() {
+	fmt.Println("kotaku-uk-rss " + Version)
+}
+
+func startServer() {
+	if *port == defaultPort {
+		if envPort := os.Getenv("PORT"); envPort != "" {
+			*port = envPort
+		}
+	}
+
+	http.HandleFunc("/rss", serveRss)
+
+	address := *bind + ":" + *port
+	fmt.Println("Listening on " + address)
+	log.Fatal(http.ListenAndServe(address, nil))
+}
+
+func main() {
+	kingpin.Parse()
+
+	if *version {
+		printVersion()
+	} else {
+		go updateRssLoop()
+		startServer()
+	}
+}