Embedded Static Handler for Martini

gistfile1.go

package main

import (
	"bytes"
	"github.com/go-martini/martini"
	"log"
	"net/http"
	"path"
	"time"
	"strings"
)

type ReadAssetFn func(string) ([]byte, error)

func prepareStaticOptions(options []martini.StaticOptions) martini.StaticOptions {
	var opt martini.StaticOptions
	if len(options) > 0 {
		opt = options[0]
	}

	// Defaults
	if len(opt.IndexFile) == 0 {
		opt.IndexFile = "index.html"
	}
	// Normalize the prefix if provided
	if opt.Prefix != "" {
		// Ensure we have a leading '/'
		if opt.Prefix[0] != '/' {
			opt.Prefix = "/" + opt.Prefix
		}
		// Remove any trailing '/'
		opt.Prefix = strings.TrimRight(opt.Prefix, "/")
	}
	return opt
}

// EmbeddedStatic returns a middleware handler that serves static files in the given directory.
func EmbeddedStatic(fn ReadAssetFn, staticOpt ...martini.StaticOptions) martini.Handler {
	opt := prepareStaticOptions(staticOpt)
	lastMod := time.Now().Local()

	return func(res http.ResponseWriter, req *http.Request, log *log.Logger) {
		if req.Method != "GET" && req.Method != "HEAD" {
			return
		}
		if opt.Exclude != "" && strings.HasPrefix(req.URL.Path, opt.Exclude) {
			return
		}
		file := req.URL.Path[1:]
		// if we have a prefix, filter requests by stripping the prefix
		if opt.Prefix != "" {
			if !strings.HasPrefix(file, opt.Prefix) {
				return
			}
			file = file[len(opt.Prefix):]
			if file != "" && file[0] != '/' {
				return
			}
		}
		f, err := fn(file)
		if err != nil {
			if strings.HasSuffix(req.URL.Path, "/") {
				file = path.Join(file, opt.IndexFile)
				f, err = fn(file)
				if err != nil {
					return
				}
			} else {
				// try any fallback before giving up
				if opt.Fallback != "" {
					file = opt.Fallback // so that logging stays true
					f, err = fn(opt.Fallback)
					if err != nil {
						return
					}
				} else {
					return
				}
			}
		}

		if !opt.SkipLogging {
			log.Println("[Static] Serving " + file)
		}

		// Add an Expires header to the static content
		if opt.Expires != nil {
			res.Header().Set("Expires", opt.Expires())
		}

		content := bytes.NewReader(f)
		http.ServeContent(res, req, file, lastMod, content)
	}
}