A very simple HTTP file server - no security, customize directory to serve and customize listening IP:port via envvars (that's it)

httpfileserv.go

////////////////////////////////////////////////////////////////////////////////
// The MIT License (MIT)
//
// Copyright (c) 2015 Mark LaPerriere
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
////////////////////////////////////////////////////////////////////////////////
package main

import (
    "flag"
    "fmt"
    "log"
    "net/http"
    "os"
    "path/filepath"
)

func main() {
    flag.Usage = func() {
        fmt.Println(`usage: httpfileserv

export HTTPFS_WORKINGDIR=<dir>       sets the working dir of the HTTP file server [default: .]
export HTTPFS_BINDADDRESS=<ip:port>  sets the listening IP address and port [default ':8080']
`)
    }
    flag.Parse()

    workingDir := os.Getenv("HTTPFS_WORKINGDIR")
    if workingDir == "" {
        workingDir, _ = filepath.Abs(".")
    }

    bindAddress := os.Getenv("HTTPFS_BINDADDRESS")
    if bindAddress == "" {
        bindAddress = ":8080"
    }

    log.Println(fmt.Sprintf("Serving files in '%s' on '%s'", workingDir, bindAddress))
    log.Fatal(http.ListenAndServe(bindAddress, http.FileServer(http.Dir(workingDir))))
}