server.go

package main

import (
	"fmt"
	"github.com/gokyle/webshell"
	"github.com/russross/blackfriday"
	"html/template"
	"io/ioutil"
	"net/http"
	"os"
	"path/filepath"
	"regexp"
)

var (
	server_port   = "8080"
	page_tpl      = webshell.MustCompileTemplate("templates/page.html")
	htmlToMd      = regexp.MustCompile("^(.+)\\.html$")
	extRegex      = regexp.MustCompile("^(.+)\\.(\\w+)$")
	slash_replace = regexp.MustCompile("/")
)

type Page struct {
	HomeActive  bool
	AboutActive bool
	Title       string
	Body        template.HTML
}

func init() {
	port := os.Getenv("PORT")
	if port != "" {
		server_port = port
	}
}

func getMdFilename(file string) string {
	if file == "" {
		file = "index.html"
	}

	var md_file string
	if extRegex.MatchString(file) {
		if ext := extRegex.ReplaceAllString(file, "$2"); ext == "html" {
			md_file = "pages/" + htmlToMd.ReplaceAllString(file,
				"$1.md")
		}
	} else {
		md_file = "pages/" + file + ".md"
	}
	return md_file
}

func getPageTitle(pagename string) string {
	title := extRegex.ReplaceAllString(filepath.Base(pagename), "$1")
	title = slash_replace.ReplaceAllString(title, " ")
	return title
}

func servePage(w http.ResponseWriter, r *http.Request) {
	md_file := getMdFilename(r.URL.Path[1:])
	title := getPageTitle(md_file)
	out, err := loadMarkdown(md_file)
	if err != nil {
		webshell.Error404("Page not found.", "text/plain", w, r)
		return
	}
	page := Page{false, false, title, template.HTML(string(out))}
	active := extRegex.ReplaceAllString(filepath.Base(md_file), "$1")
	if active == "index" {
		page.HomeActive = true
	} else if active == "about" {
		page.AboutActive = true
	}
	body, err := webshell.BuildTemplate(page_tpl, page)
	if err != nil {
		webshell.Error500(err.Error(), "text/plain", w, r)
		return
	}
	w.Write(body)
}

func loadMarkdown(file string) (out []byte, err error) {
	var in []byte
	in, err = ioutil.ReadFile(file)
	if err != nil {
		return
	}
	out = blackfriday.MarkdownCommon(in)
	return
}

func main() {
	app := webshell.NewApp("webshell tutorial", "", server_port)
	app.AddRoute("/", servePage)
	app.StaticRoute("/assets/", "assets/")
	app.StaticRoute("/examples/", "examples/")
	fmt.Println("[!] ", app.Serve())
}