tomcam/main.go

## main.go
// Minimalish, self-contained demo program for
// https://github.com/radovskyb/watcher
//
// Here's what this code does.
// 1. Creates a small tree of files for a minimal website.
// 2. Places those files in the directory WWW (configurable).
// 3. Watches the WWW directory and its childrens.
//
// To use it:
// 1. Open up a terminal
// 2. Change to the source directory, for example,
//    $ cd ~/go/watcher/main.go
// 3. Compile and run like this:
//    $ go run main.go
// 4. Open up another terminal
// 5. In the new terminal, change to the program directory
//    $ cd ~/go/watcher/main.go
// 6. Delete or add files in the demo directory, for example:
// 7. $ echo "hello" > WWW/hi.txt
// 8. $ rm WWW/hi.txt
// 9. Watch what happens in the first terminal window
//    when you make changes to files in the demo directory

// Run program, then try adding or deleting files from
// the WWW directory and its subdirectories.
//
// Based on:
// https://github.com/radovskyb/watcher#example
package main

import (
	"fmt"
	"github.com/radovskyb/watcher"
	"log"
	"os"
	"path/filepath"
	"time"
)

var (
	// Location for tree of test files
	baseDir = "WWW"

	// Contents for a tree of test files, generated right here.
	// Array of elements that each consist of
	// [0] a filename
	// [1] the contents of that file.
	testFiles = [][]string{

		// Very simple HTML file that links to
		// next two files, which are the stylesheets.
		// They're in different dirs at different levels
		// to make the test worthwhile.
		{"index.html", "<!doctype html><title>.</title><head><link rel='stylesheet' href='css/root.css'><link rel='stylesheet' href='assets/img/background.css'></head><h1>hello, world.</h1>"},

		// Tiny stylesheet
		{"css/root.css", "html {max-width:70ch;font-family:sans-serif;padding:3em 1em;margin:auto;line-height:1.75;font-size:1.25em;}"},

		// Repeated background image of a light grey star
		{"assets/img/background.css", "body { background-image: url('data:image/svg+xml;charset=utf-8,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%2240%22%20height%3D%2240%22%20viewBox%3D%220%200%2024%2024%22%3E%3Cpath%20fill%3D%22%23000000%22%20d%3D%22M12.86%2010.44L11%206.06l-1.86%204.39l-4.75.41L8%2014l-1.08%204.63L11%2016.17l4.09%202.46L14%2014l3.61-3.14l-4.75-.42m3.73%2010.26L11%2017.34L5.42%2020.7l1.46-6.35l-4.92-4.28l6.49-.57l2.55-6l2.55%206l6.49.57l-4.92%204.27l1.47%206.36Z%22%20style%3D%22fill%3A%20rgb(214%2C%20214%2C%20214)%3B%22%3E%3C%2Fpath%3E%3C%2Fsvg%3E');"},
	}
)

// Generate a small tree of files for the
// file preview test. That tree starts
// in location baseDir, which can be anywhere
func createTestDir(baseDir string, testFiles [][]string) {
	// Array contains a filename followed by its contents,
	// like this:
	//{"index.html", "<h1>hello, world.</h1>"},
	for _, row := range testFiles {
		// First element of the row contains a file path
		// designation. Strip the directory from path.
		// Append that directory to the base directory.
		// So css/root.css becomes WWW/css/root.css
		// for example.
		dir := filepath.Join(baseDir, filepath.Dir(row[0]))
		// Create the specified directory.
		if err := os.MkdirAll(dir, os.ModePerm); err != nil {
			panic(err)
		}
		// Extract the filename from the first element of the row.
		filename := filepath.Base(row[0])
		// Append it to the directory path to create a
		// fully qualified filename.
		filePath := filepath.Join(dir, filename)
		// Obtain the contents of the file
		// from the second element of the row.
		// Write the file contents out.
		stringToTextFile(filePath, row[1])
	}
}

// stringToTextFile creates a file called filename without checking to see if it
// exists, then writes contents to it.
// filePath is a fully qualified pathname.
// contents is the string to write. Appends a newline to that string.
func stringToTextFile(filePath, contents string) {
	var out *os.File
	var err error
	defer out.Close()
	if out, err = os.Create(filePath); err != nil {
		panic(err)
	}
	if _, err = out.WriteString(contents + "\n"); err != nil {
		panic(err)
	}
}

func main() {

	// Generate directory tree for website from the
	// testFiles strucure. Place it in the directory
	// specified by baseDir.
	createTestDir(baseDir, testFiles)

	// Allocate a single watcher.
	w := watcher.New()

	// SetMaxEvents to 1 allows at most 1 events to be received
	// on the Event channel per watching cycle.
	// Default is to send all events.
	// Not convinced this works.
	//w.SetMaxEvents(1)

	// Events to notify
	w.FilterOps(watcher.Create, watcher.Rename, watcher.Move, watcher.Remove)

	go func() {
		for {
			select {
			case event := <-w.Event:
				fmt.Println(event)
			case err := <-w.Error:
				panic(err)
			case <-w.Closed:
				return
			}
		}
	}()

	// Watch specified folder recursively for changes.
	if err := w.AddRecursive(baseDir); err != nil {
		log.Fatalln(err)
	}

	// Print a list of all of the files and folders currently
	// being watched and their paths.
	fmt.Println("Files being watched:")
	for path, f := range w.WatchedFiles() {
		if !f.IsDir() {
			fmt.Printf("%s: %s\n", path, f.Name())
		} else {
			fmt.Printf("DIR %s/\n", path)
		}
	}

	go func() {
		// TC: Not sure why this is necessary
		w.Wait()
	}()

	// Start the watching process - it'll check for changes every 100ms.
	if err := w.Start(time.Millisecond * 100); err != nil {
		log.Fatalln(err)
	}
}
	// Minimalish, self-contained demo program for
	// https://github.com/radovskyb/watcher
	//
	// Here's what this code does.
	// 1. Creates a small tree of files for a minimal website.
	// 2. Places those files in the directory WWW (configurable).
	// 3. Watches the WWW directory and its childrens.
	//
	// To use it:
	// 1. Open up a terminal
	// 2. Change to the source directory, for example,
	// $ cd ~/go/watcher/main.go
	// 3. Compile and run like this:
	// $ go run main.go
	// 4. Open up another terminal
	// 5. In the new terminal, change to the program directory
	// $ cd ~/go/watcher/main.go
	// 6. Delete or add files in the demo directory, for example:
	// 7. $ echo "hello" > WWW/hi.txt
	// 8. $ rm WWW/hi.txt
	// 9. Watch what happens in the first terminal window
	// when you make changes to files in the demo directory

	// Run program, then try adding or deleting files from
	// the WWW directory and its subdirectories.
	//
	// Based on:
	// https://github.com/radovskyb/watcher#example
	package main

	import (
	"fmt"
	"github.com/radovskyb/watcher"
	"log"
	"os"
	"path/filepath"
	"time"
	)

	var (
	// Location for tree of test files
	baseDir = "WWW"

	// Contents for a tree of test files, generated right here.
	// Array of elements that each consist of
	// [0] a filename
	// [1] the contents of that file.
	testFiles = [][]string{

	// Very simple HTML file that links to
	// next two files, which are the stylesheets.
	// They're in different dirs at different levels
	// to make the test worthwhile.
	{"index.html", "<!doctype html><title>.</title><head><link rel='stylesheet' href='css/root.css'><link rel='stylesheet' href='assets/img/background.css'></head><h1>hello, world.</h1>"},

	// Tiny stylesheet
	{"css/root.css", "html {max-width:70ch;font-family:sans-serif;padding:3em 1em;margin:auto;line-height:1.75;font-size:1.25em;}"},

	// Repeated background image of a light grey star
	{"assets/img/background.css", "body { background-image: url('data:image/svg+xml;charset=utf-8,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%2240%22%20height%3D%2240%22%20viewBox%3D%220%200%2024%2024%22%3E%3Cpath%20fill%3D%22%23000000%22%20d%3D%22M12.86%2010.44L11%206.06l-1.86%204.39l-4.75.41L8%2014l-1.08%204.63L11%2016.17l4.09%202.46L14%2014l3.61-3.14l-4.75-.42m3.73%2010.26L11%2017.34L5.42%2020.7l1.46-6.35l-4.92-4.28l6.49-.57l2.55-6l2.55%206l6.49.57l-4.92%204.27l1.47%206.36Z%22%20style%3D%22fill%3A%20rgb(214%2C%20214%2C%20214)%3B%22%3E%3C%2Fpath%3E%3C%2Fsvg%3E');"},
	}
	)

	// Generate a small tree of files for the
	// file preview test. That tree starts
	// in location baseDir, which can be anywhere
	func createTestDir(baseDir string, testFiles [][]string) {
	// Array contains a filename followed by its contents,
	// like this:
	//{"index.html", "<h1>hello, world.</h1>"},
	for _, row := range testFiles {
	// First element of the row contains a file path
	// designation. Strip the directory from path.
	// Append that directory to the base directory.
	// So css/root.css becomes WWW/css/root.css
	// for example.
	dir := filepath.Join(baseDir, filepath.Dir(row[0]))
	// Create the specified directory.
	if err := os.MkdirAll(dir, os.ModePerm); err != nil {
	panic(err)
	}
	// Extract the filename from the first element of the row.
	filename := filepath.Base(row[0])
	// Append it to the directory path to create a
	// fully qualified filename.
	filePath := filepath.Join(dir, filename)
	// Obtain the contents of the file
	// from the second element of the row.
	// Write the file contents out.
	stringToTextFile(filePath, row[1])
	}
	}

	// stringToTextFile creates a file called filename without checking to see if it
	// exists, then writes contents to it.
	// filePath is a fully qualified pathname.
	// contents is the string to write. Appends a newline to that string.
	func stringToTextFile(filePath, contents string) {
	var out *os.File
	var err error
	defer out.Close()
	if out, err = os.Create(filePath); err != nil {
	panic(err)
	}
	if _, err = out.WriteString(contents + "\n"); err != nil {
	panic(err)
	}
	}

	func main() {

	// Generate directory tree for website from the
	// testFiles strucure. Place it in the directory
	// specified by baseDir.
	createTestDir(baseDir, testFiles)

	// Allocate a single watcher.
	w := watcher.New()

	// SetMaxEvents to 1 allows at most 1 events to be received
	// on the Event channel per watching cycle.
	// Default is to send all events.
	// Not convinced this works.
	//w.SetMaxEvents(1)

	// Events to notify
	w.FilterOps(watcher.Create, watcher.Rename, watcher.Move, watcher.Remove)

	go func() {
	for {
	select {
	case event := <-w.Event:
	fmt.Println(event)
	case err := <-w.Error:
	panic(err)
	case <-w.Closed:
	return
	}
	}
	}()

	// Watch specified folder recursively for changes.
	if err := w.AddRecursive(baseDir); err != nil {
	log.Fatalln(err)
	}

	// Print a list of all of the files and folders currently
	// being watched and their paths.
	fmt.Println("Files being watched:")
	for path, f := range w.WatchedFiles() {
	if !f.IsDir() {
	fmt.Printf("%s: %s\n", path, f.Name())
	} else {
	fmt.Printf("DIR %s/\n", path)
	}
	}

	go func() {
	// TC: Not sure why this is necessary
	w.Wait()
	}()

	// Start the watching process - it'll check for changes every 100ms.
	if err := w.Start(time.Millisecond * 100); err != nil {
	log.Fatalln(err)
	}
	}