bash - How to urlencode data for curl command?

Question

I am trying to write a bash script for testing that takes a parameter and sends it through curl to web site. I need to url encode the value to make sure that special characters are processed properly. What is the best way to do this?

Here is my basic script so far:

#!/bin/bash
host=${1:?'bad host'}
value=$2
shift
shift
curl -v -d "param=${value}" http://${host}/somepath $@

Answer 1

Use curl --data-urlencode; from man curl:

This posts data, similar to the other --data options with the exception that this performs URL-encoding. To be CGI-compliant, the <data> part should begin with a name followed by a separator and a content specification.

Example usage:

curl 
    --data-urlencode "paramName=value" 
    --data-urlencode "secondParam=value" 
    http://example.com

See the man page for more info.

This requires curl 7.18.0 or newer (released January 2008). Use curl -V to check which version you have.

You can as well encode the query string:

curl -G 
    --data-urlencode "p1=value 1" 
    --data-urlencode "p2=value 2" 
    http://example.com
    # http://example.com?p1=value%201&p2=value%202