From 3504ecd19621697b0e23abc5423d7047d36c3749 Mon Sep 17 00:00:00 2001
From: Brandon Dyck <brandon@dyck.us>
Date: Wed, 1 Apr 2020 00:09:49 -0600
Subject: [PATCH] Move config constants into environment variables

---
 http/server.go | 58 ++++++++++++++++++++++++++++++++------------------
 1 file changed, 37 insertions(+), 21 deletions(-)

diff --git a/http/server.go b/http/server.go
index 34e5c17..0b04c4d 100644
--- a/http/server.go
+++ b/http/server.go
@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"crypto/rand"
+	"flag"
 	"fmt"
 	"io"
 	"log"
@@ -19,11 +20,6 @@ import (
 	_ "gitlab.codemonkeysoftware.net/b/henwen"
 )
 
-const Addr = ":8080"
-const Title = "Henwen"
-const baseURL = "http://localhost:8080"
-const dbFileName = "./henwen.db"
-
 const (
 	pathRoot     = "/"
 	pathCreate   = "/create"
@@ -32,14 +28,24 @@ const (
 )
 
 type handler struct {
-	mux   *http.ServeMux
-	store *henwen.Store
+	mux     *http.ServeMux
+	store   *henwen.Store
+	title   string
+	baseURL string
 }
 
-func NewHandler(store *henwen.Store) http.Handler {
+type HandlerParams struct {
+	Title   string
+	Store   *henwen.Store
+	BaseURL string
+}
+
+func NewHandler(params HandlerParams) http.Handler {
 	h := &handler{
-		store: store,
-		mux:   http.NewServeMux(),
+		store:   params.Store,
+		title:   params.Title,
+		baseURL: params.BaseURL,
+		mux:     http.NewServeMux(),
 	}
 	h.mux.HandleFunc(pathRoot, h.handleRoot)
 	h.mux.HandleFunc(pathCreate, h.handleCreate)
@@ -55,7 +61,7 @@ func (h *handler) handleRoot(w http.ResponseWriter, r *http.Request) {
 			hm.Text("Create event"),
 		),
 	}
-	_ = writePage(w, body)
+	_ = h.writePage(w, body)
 }
 
 func (h *handler) handleCreate(w http.ResponseWriter, r *http.Request) {
@@ -77,7 +83,7 @@ func (h *handler) handleCreate(w http.ResponseWriter, r *http.Request) {
 			e.Input(a.Type("submit")),
 		),
 	}
-	_ = writePage(w, body)
+	_ = h.writePage(w, body)
 }
 
 func (h *handler) handleDoCreate(w http.ResponseWriter, r *http.Request) {
@@ -111,7 +117,7 @@ func (h *handler) handleDoCreate(w http.ResponseWriter, r *http.Request) {
 	var adminQuery = make(url.Values)
 	adminQuery.Add(keyEventID, event.AlphaID)
 	adminQuery.Add(keyAdminCode, event.AdminCode)
-	adminURL := baseURL + pathAdmin + "?" + adminQuery.Encode()
+	adminURL := h.baseURL + pathAdmin + "?" + adminQuery.Encode()
 
 	const dateDisplayFmt = "Monday, January 2, 2006"
 
@@ -135,7 +141,7 @@ func (h *handler) handleDoCreate(w http.ResponseWriter, r *http.Request) {
 		e.H3()(hm.Text("Latest date")),
 		hm.Text(latest.Format(dateDisplayFmt)),
 	}
-	_ = writePage(w, body)
+	_ = h.writePage(w, body)
 }
 
 func (h *handler) handleAdmin(w http.ResponseWriter, r *http.Request) {
@@ -182,20 +188,20 @@ func (h *handler) handleAdmin(w http.ResponseWriter, r *http.Request) {
 			e.Input(a.Type("submit")),
 		),
 	}
-	_ = writePage(w, body)
+	_ = h.writePage(w, body)
 }
 
 func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	h.mux.ServeHTTP(w, r)
 }
 
-func writePage(w io.Writer, contents hm.Term) error {
+func (h *handler) writePage(w io.Writer, contents hm.Term) error {
 	page := e.Html()(
 		e.Head()(
-			e.Title()(hm.Text(Title)),
+			e.Title()(hm.Text(h.title)),
 		),
 		e.Body()(
-			e.H1()(hm.Text(Title)),
+			e.H1()(hm.Text(h.title)),
 			e.Div()(contents),
 		),
 	)
@@ -237,14 +243,24 @@ func genString() (string, error) {
 const dateFmt = "2006-01-02"
 
 func main() {
-	store, err := henwen.NewStore(dbFileName, genString)
+	addr := flag.String("address", ":8080", "bind address for HTTP server as host:port")
+	title := flag.String("title", "Henwen", "website title")
+	baseURL := flag.String("baseURL", "http://localhost:8080", "base URL for HTTP routes")
+	dbFileName := flag.String("db", "./henwen.db", "name of database file")
+	flag.Parse()
+
+	store, err := henwen.NewStore(*dbFileName, genString)
 	if err != nil {
 		log.Fatal(err)
 	}
 
 	srv := http.Server{
-		Addr:    Addr,
-		Handler: NewHandler(store),
+		Addr: *addr,
+		Handler: NewHandler(HandlerParams{
+			Store:   store,
+			Title:   *title,
+			BaseURL: *baseURL,
+		}),
 	}
 	log.Println(srv.ListenAndServe())
 }