How to perform file system scanning

Question

1. I need to write a function which when given the path of a folder scans the files rooted at that folder.
2. And then I need to display the directory structure at that folder.

I know how to do 2 (I am going to use jstree to display it in the browser).

Answer 1

EDIT FOR 1.16: Enough people still hit this answer, that I thought I'd update it for Go 1.16.

The function filepath.WalkDir introduced in Go 1.16 has better performance than filepath.Walk mentioned in the previous edit. Here's a working example:

package main  import (     "flag"     "fmt"     "io/fs"     "path/filepath" )  func visit(path string, di fs.DirEntry, err error) error {     fmt.Printf("Visited: %s\n", path)     return nil }  func main() {     flag.Parse()     root := flag.Arg(0)     err := filepath.WalkDir(root, visit)     fmt.Printf("filepath.WalkDir() returned %v\n", err) } 

EDIT: Enough people still hit this answer, that I thought I'd update it for the Go1 API. This is a working example of filepath.Walk(). The original is below.

package main  import (   "path/filepath"   "os"   "flag"   "fmt" )  func visit(path string, f os.FileInfo, err error) error {   fmt.Printf("Visited: %s\n", path)   return nil }    func main() {   flag.Parse()   root := flag.Arg(0)   err := filepath.Walk(root, visit)   fmt.Printf("filepath.Walk() returned %v\n", err) } 

Please note that filepath.Walk walks the directory tree recursively.

This is an example run:

$ mkdir -p dir1/dir2 $ touch dir1/file1 dir1/dir2/file2 $ go run walk.go dir1 Visited: dir1 Visited: dir1/dir2 Visited: dir1/dir2/file2 Visited: dir1/file1 filepath.Walk() returned <nil> 

ORIGINAL ANSWER FOLLOWS: The interface for walking file paths has changed as of weekly.2011-09-16, see http://groups.google.com/group/golang-nuts/msg/e304dd9cf196a218. The code below will not work for release versions of GO in the near future.

There's actually a function in the standard lib just for this: filepath.Walk.

package main  import (     "path/filepath"     "os"     "flag" )  type visitor int  // THIS CODE NO LONGER WORKS, PLEASE SEE ABOVE func (v visitor) VisitDir(path string, f *os.FileInfo) bool {     println(path)     return true }   func (v visitor) VisitFile(path string, f *os.FileInfo) {     println(path) }  func main() {     root := flag.Arg(0)     filepath.Walk(root, visitor(0), nil) }