Golang : How to tell if a file is compressed either gzip or zip ?
Sometimes it is good to check if a file is really in compressed form or not by examining the actual data bytes and not relying on the file extension alone. This tutorial will show you how to use http.DetectContentType() function to determine if a file is really compressed or not.
Here are the codes:
package main
import (
"flag"
"fmt"
"net/http"
"os"
)
func main() {
flag.Parse() // get the arguments from command line
sourcefile := flag.Arg(0)
// open a file that you wish to check
// if it is compressed or not
if sourcefile == "" {
fmt.Println("Usage : detectcompress sourcefile")
os.Exit(1)
}
file, err := os.Open(sourcefile)
if err != nil {
fmt.Println(err)
os.Exit(1)
}
defer file.Close()
buff := make([]byte, 512)
// why 512 bytes ? see http://golang.org/pkg/net/http/#DetectContentType
_, err = file.Read(buff)
if err != nil {
fmt.Println(err)
os.Exit(1)
}
filetype := http.DetectContentType(buff)
fmt.Println(filetype) // for info
switch filetype {
case "application/x-gzip", "application/zip":
fmt.Println("File is compressed with gzip or zip")
default:
fmt.Println("File is not compressed")
}
}
Sample output :
./detectzip testfile.sql
text/plain; charset=utf-8
File is not compressed
./detectzip testfile.unknown
application/zip
File is compressed with gzip or zip
Reference :
See also : Golang : How to verify uploaded file is image or allowed file types
By Adam Ng
IF you gain some knowledge or the information here solved your programming problem. Please consider donating to the less fortunate or some charities that you like. Apart from donation, planting trees, volunteering or reducing your carbon footprint will be great too.
Advertisement
Tutorials
+9.3k Golang : How to get ECDSA curve and parameters data?
+6.1k Golang : Measure execution time for a function
+11.6k Android Studio : Create custom icons for your application example
+19.6k Golang : Close channel after ticker stopped example
+8.1k Golang : Multiplexer with net/http and map
+10.9k Golang : Sieve of Eratosthenes algorithm
+5.4k Golang : How to deal with configuration data?
+7.3k Golang : How to iterate a slice without using for loop?
+15.1k Golang : package is not in GOROOT during compilation
+28.2k Golang : Connect to database (MySQL/MariaDB) server
+9.6k Javascript : Read/parse JSON data from HTTP response