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
+12.8k Golang : How to determine if a year is leap year?
+8.2k Golang : Write multiple lines or divide string into multiple lines
+7k Golang : get the current working directory of a running program
+7.8k Golang : Set or add headers for many or different handlers
+11.6k Golang : Arithmetic operation with numerical slices or arrays example
+4.7k Golang : Intercept, inject and replay HTTP traffics from web server
+9.2k Golang : Edge detection with Sobel method
+18.8k Golang : Set or Add HTTP Request Headers
+13k Golang : Get current time
+19k Golang : Accept input from user with fmt.Scanf skipped white spaces and how to fix it
+13.3k How to automatically restart your crashed Golang server
+8.6k Golang : Accessing content anonymously with Tor