Added markdown middleware

config/dispenser.go

@@ -105,10 +105,10 @@ func (d *dispenser) Val() string {
 	}
 }
 
-// ArgErr generates an argument error, meaning that another
-// argument was expected but not found. The error is saved
-// within the dispenser, but this function returns nil for
-// convenience in practice.
+// ArgErr returns an argument error, meaning that another
+// argument was expected but not found. In other words,
+// a line break or open curly brace was encountered instead of
+// an argument.
 func (d *dispenser) ArgErr() error {
 	if d.Val() == "{" {
 		return d.Err("Unexpected token '{', expecting argument")
@@ -117,12 +117,6 @@ func (d *dispenser) ArgErr() error {
 }
 
 // Err generates a custom parse error with a message of msg.
-// TODO: Update the docs of all these Err methods!
-// This function returns nil for convenience, but loads the
-// error into the dispenser so it can be reported. The caller
-// of the middleware preparator is responsible for checking
-// the error in the dispenser after the middleware preparator
-// is finished.
 func (d *dispenser) Err(msg string) error {
 	msg = fmt.Sprintf("%s:%d - Parse error: %s", d.filename, d.tokens[d.cursor].line, msg)
 	return errors.New(msg)

config/middleware.go

@@ -7,6 +7,7 @@ import (
 	"github.com/mholt/caddy/middleware/gzip"
 	"github.com/mholt/caddy/middleware/headers"
 	"github.com/mholt/caddy/middleware/log"
+	"github.com/mholt/caddy/middleware/markdown"
 	"github.com/mholt/caddy/middleware/proxy"
 	"github.com/mholt/caddy/middleware/redirect"
 	"github.com/mholt/caddy/middleware/rewrite"
@@ -26,6 +27,7 @@ func init() {
 	register("proxy", proxy.New)
 	register("fastcgi", fastcgi.New)
 	register("websocket", websockets.New)
+	register("markdown", markdown.New)
 }
 
 var (

middleware/markdown/markdown.go

+// Package markdown is middleware to render markdown files as HTML
+// on-the-fly.
+package markdown
+
+import (
+	"io/ioutil"
+	"net/http"
+	"path"
+	"strings"
+
+	"github.com/mholt/caddy/middleware"
+	"github.com/russross/blackfriday"
+)
+
+// New creates a new instance of Markdown middleware that
+// renders markdown to HTML on-the-fly.
+func New(c middleware.Controller) (middleware.Middleware, error) {
+	md, err := parse(c)
+	if err != nil {
+		return nil, err
+	}
+
+	md.Root = c.Root()
+	md.Renderer = blackfriday.HtmlRenderer(0, "", "")
+
+	return func(next http.HandlerFunc) http.HandlerFunc {
+		md.Next = next
+		return md.ServeHTTP
+	}, nil
+}
+
+// Markdown stores the configuration necessary to serve the Markdown middleware.
+type Markdown struct {
+	// Server root
+	Root string
+
+	// Next HTTP handler in the chain
+	Next http.HandlerFunc
+
+	// Markdown renderer
+	Renderer blackfriday.Renderer
+
+	// Base path to match
+	PathScope string
+
+	// List of extensions to consider as markdown files
+	Extensions []string
+
+	// List of style sheets to load for each markdown file
+	Styles []string
+
+	// List of JavaScript files to load for each markdown file
+	Scripts []string
+}
+
+// ServeHTTP implements the http.Handler interface.
+func (m Markdown) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if middleware.Path(r.URL.Path).Matches(m.PathScope) {
+		for _, ext := range m.Extensions {
+			if strings.HasSuffix(r.URL.Path, ext) {
+				fpath := m.Root + r.URL.Path
+
+				body, err := ioutil.ReadFile(fpath)
+				if err != nil {
+					panic(err) // TODO
+				}
+
+				content := blackfriday.Markdown(body, m.Renderer, 0)
+
+				var scripts, styles string
+				for _, style := range m.Styles {
+					styles += strings.Replace(cssTemplate, "{{url}}", style, 1) + "\r\n"
+				}
+				for _, script := range m.Scripts {
+					scripts += strings.Replace(jsTemplate, "{{url}}", script, 1) + "\r\n"
+				}
+
+				html := htmlTemplate
+				html = strings.Replace(html, "{{title}}", path.Base(fpath), 1)
+				html = strings.Replace(html, "{{css}}", styles, 1)
+				html = strings.Replace(html, "{{js}}", scripts, 1)
+				html = strings.Replace(html, "{{body}}", string(content), 1)
+
+				w.Write([]byte(html))
+				return
+			}
+		}
+	}
+
+	m.Next(w, r)
+}
+
+// parse fills up a new instance of Markdown middleware.
+func parse(c middleware.Controller) (Markdown, error) {
+	var md Markdown
+
+	for c.Next() {
+		// Get the path scope
+		if !c.NextArg() {
+			return md, c.ArgErr()
+		}
+		md.PathScope = c.Val()
+
+		// Load any other configuration parameters
+		for c.NextBlock() {
+			switch c.Val() {
+			case "ext":
+				exts := c.RemainingArgs()
+				if len(exts) == 0 {
+					return md, c.ArgErr()
+				}
+				md.Extensions = append(md.Extensions, exts...)
+			case "css":
+				if !c.NextArg() {
+					return md, c.ArgErr()
+				}
+				md.Styles = append(md.Styles, c.Val())
+			case "js":
+				if !c.NextArg() {
+					return md, c.ArgErr()
+				}
+				md.Scripts = append(md.Scripts, c.Val())
+			default:
+				return md, c.Err("Expected valid markdown configuration property")
+			}
+		}
+
+	}
+
+	return md, nil
+}
+
+const (
+	htmlTemplate = `<!DOCTYPE html>
+<html>
+	<head>
+		<title>{{title}}</title>
+		<meta charset="utf-8">
+		{{css}}
+		{{js}}
+	</head>
+	<body>
+		{{body}}
+	</body>
+</html>`
+	cssTemplate = `<link rel="stylesheet" href="{{url}}">`
+	jsTemplate  = `<script src="{{url}}"></script>`
+)