initial commit

README.md

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+GzipDate
+========
+
+Simple command line app for the specific creation and handling of Gzip archives.
+
+
+Features
+--------
+
+* Create gzip archives for each of a list of files, adding a file system safe ISO-601 datatime value to the filename when creating the archive
+* Extract the archived file from Gzip archives restoring their original names if available. The original name is always available for archives created by GzipDate.
+* Does not delete source files by default. Though they can be automatically deleted with a command line switch.
+* Always uses maximum compression when creating archives
+* 100% compatible with gzip and gunzip tools
+
+
+Rational
+--------
+
+I like making archives with the date in the name. Especially for game saves that get auto deleted like in Roguelike type games. It's also supper annoying to me that `gunzip` doesn't use the stored filename within the archive by default. I also like my tools to be smart about if a file is already compressed or not. Gzip will give an error if you try to recompress a file that already ends in `.gz`. GzipDate just uncompresses the file instead.
+
+

go.mod

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+module github.com/runeimp/gzipdate
+
+go 1.14

main.go

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+package main
+
+import (
+	"bytes"
+	"compress/gzip"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	"path"
+	"time"
+)
+
+/*
+ * CONSTANTS
+ */
+const (
+	AppName         = "GzipDate"
+	AppVersion      = "1.0.0"
+	argDeleteUsage  = "Delete the source file after successful processing"
+	argHelpUsage    = "Display this help info"
+	argVersionUsage = "Display this apps version number"
+)
+
+/*
+ * DERIVED CONSTANTS
+ */
+var (
+	AppLabel = fmt.Sprintf("%s v%s", AppName, AppVersion)
+)
+
+/*
+ * VARIABLES
+ */
+var (
+	deleteSource = false
+	files        []string
+	showHelp     = false
+)
+
+func main() {
+
+	// Bespoke CLI Handler because flags is lame
+	for _, arg := range os.Args[1:] {
+		switch arg {
+		case "-d", "-del", "-delete":
+			deleteSource = true
+		case "-h", "-help":
+			helpOutput()
+			os.Exit(0)
+		case "-v", "-ver", "-version":
+			fmt.Println(AppLabel)
+			os.Exit(0)
+		default:
+			files = append(files, arg)
+		}
+	}
+
+	if len(os.Args[1:]) == 0 {
+		helpOutput()
+		os.Exit(1)
+	}
+
+	// fmt.Printf("Delete Source File? %t\n", deleteSource)
+
+	var err error
+
+	if len(files) > 0 {
+		for _, filename := range files {
+			// j := i + 1
+			// fmt.Printf("%-3d %s\n", j, filename)
+			if path.Ext(filename) == ".gz" {
+				// fmt.Printf("File #%-3d gunzip %q\n", j, filename)
+				content, err := ioutil.ReadFile(filename)
+				if err != nil {
+					log.Fatal(err)
+				}
+				err = gzipDecode(content)
+				if err == nil && deleteSource {
+					fmt.Printf("    Deleting source: %q\n", filename)
+					os.Remove(filename)
+				}
+			} else {
+				// fmt.Printf("File #%-3d gzip %q\n", j, filename)
+				err = gzipEncode(filename)
+				if err == nil && deleteSource {
+					fmt.Printf("    Deleting source: %q\n", filename)
+					os.Remove(filename)
+				}
+			}
+		}
+	}
+}
+
+func gzipDecode(content []byte) error {
+	newFilename := "filename.unknown"
+
+	zr, err := gzip.NewReader(bytes.NewReader(content))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	if err := zr.Close(); err != nil {
+		log.Fatal(err)
+	}
+
+	// fmt.Printf("Name: %s\nComment: %s\nModTime: %s\n\n", zr.Name, zr.Comment, zr.ModTime.UTC())
+	// if _, err := io.Copy(os.Stdout, zr); err != nil {
+	// 	log.Fatal(err)
+	// }
+
+	if len(zr.Name) > 0 {
+		newFilename = zr.Name
+	}
+	destination, err := os.Create(newFilename)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer destination.Close()
+
+	nBytes, err := io.Copy(destination, zr)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	mtime := zr.ModTime.UTC()
+	atime := zr.ModTime.UTC()
+	if err := os.Chtimes(newFilename, atime, mtime); err != nil {
+		log.Fatal(err)
+	}
+
+	fmt.Printf("%d B written to %q\n", nBytes, zr.Name)
+
+	return err
+}
+
+func gzipEncode(filename string) error {
+	var (
+		destination *os.File
+		err         error
+		file        *os.File
+		fileinfo    os.FileInfo
+		nBytes      int64
+	)
+	// content, err := ioutil.ReadFile(filename)
+	file, err = os.Open(filename)
+	if err != nil {
+		log.Fatal(err)
+	}
+	fileinfo, err = file.Stat()
+	content := make([]byte, fileinfo.Size())
+	_, err = file.Read(content)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	now := time.Now()
+	datetime := now.Format("2006-01-02_150405")
+	newFilename := fmt.Sprintf("%s_%s.gz", filename, datetime)
+	// fmt.Printf("gzipEncode() | filename = %q | content length = %d B | newFilename = %q\n", filename, len(content), newFilename)
+
+	var buf bytes.Buffer
+	zw, zwError := gzip.NewWriterLevel(&buf, gzip.BestCompression)
+	if zwError != nil {
+		log.Fatal(zwError)
+	}
+
+	// Setting the Header fields is optional.
+	zw.Name = filename
+	zw.Comment = fmt.Sprintf("Compressed with %s", AppLabel)
+	zw.ModTime = fileinfo.ModTime()
+
+	if _, err := zw.Write(content); err != nil {
+		log.Fatal(err)
+	}
+
+	if err := zw.Close(); err != nil {
+		log.Fatal(err)
+	}
+
+	destination, err = os.Create(newFilename)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer destination.Close()
+
+	nBytes, err = buf.WriteTo(destination)
+	fmt.Printf("Saving %d bytes from %q to %q\n", nBytes, filename, newFilename)
+
+	return err
+}
+
+func helpOutput() {
+	// flag.Usage()
+	// fmt.Println("----")
+	fmt.Printf("USAGE: gzipdate [OPTIONS] FILENAMES\n\nOPTIONS:\n")
+	// flag.PrintDefaults()
+	// fmt.Println()
+
+	fmt.Printf("  -d | -del | -delete   %s\n", argDeleteUsage)
+	fmt.Printf("  -h | -help            %s\n", argHelpUsage)
+	fmt.Printf("  -v | -ver | -version  %s\n", argVersionUsage)
+	fmt.Println()
+	fmt.Printf("Options may be interspersed with file names if so desired.\nThey are not position dependent.\n\n")
+}