Linux Check Image Exists at Apache URL

Question

I'm writing a program that uses a Linux command to check if a file exists on the local server.

The program executes a command with a supplied argument

ls *ARG_GOES_HERE* &> /dev/null

and then checks the status if it was able to find the file or not.

The problem is that sometimes the file is not a straight forward path like

/var/www/html/images/myImage.jpg

Sometimes the image location is stored using the web location

http://192.168.1.2/images/myImage.jpg

Which fails in the linux command.

Is it possible to check if an image exists on a local apache location using bash?

Answer 1

You can use the curl command to check that the file exists and can be accessed via HTTP. Something like this should work for you:

path_to_file=images/myImage.jpg
if curl --head --location --silent --fail "http://192.168.1.2/$path_to_file" > /dev/null
then
    printf "%s exists\n" "$path_to_file"
else
    printf "%s does not exist\n" "$path_to_file"
fi

The following curl options are used:

• --head – only fetch the HTTP headers (there’s no need for the body)
• --location – follow any HTTP redirects
• --silent – don’t show progress meter or error messages
• --fail – the curl commands fails with an error status if the HTTP request fails, e.g., if the web server responded with a 404, the curl commands exits with a status of 22 (error) instead of 0 (success).