Open / Create File

OpenFile

package main

import (
	"log"
	"os"
	"path"
)

func main() {

	fd := Open("a/b/c/d.txt")
	if _, err := fd.Write([]byte("This is a test.\nThis is only a test.\n")); err != nil {
		log.Fatal(err)
	}
	if err := fd.Close(); err != nil {
		log.Fatal(err)
	}

}

// open a file; create path and file if not exist, else return file descriptor
func Open(filepath string) *os.File {
	// split path and file from filepath
	dir, file := path.Split(filepath)
	// if there are any nested directories...
	if dir != "" {
		// check to see if directories already exist...
		if _, err := os.Stat(dir); err != nil && os.IsNotExist(err) {
			log.Println("Creating all dirs:", dir)
			// if not, make all nested directories...
			if err := os.MkdirAll(dir, 0755); err != nil {
				log.Fatal(err)
			}
		}
		log.Println("Directory exists:", dir)
	}
	// if the file param isn't empty...
	if file != "" {
		// check to see if file already exists...
		if _, err := os.Stat(filepath); err != nil && os.IsNotExist(err) {
			log.Println("Creating file:", filepath)
			// if not, create file...
			if _, err := os.Create(filepath); err != nil {
				log.Fatal(err)
			}
		}
		log.Println("File exists:", file)
	}
	// all directories and files should exist, or have been created by now
	fd, err := os.OpenFile(filepath, os.O_APPEND|os.O_RDWR, 0644)
	if err != nil {
		log.Fatal(err)
	}
	if err := fd.Sync(); err != nil {
		log.Fatal(err)
	}
	log.Println("Opening and return file:", fd.Fd())
	// return file descriptor
	return fd
}