How to read headers from file using cURL? - linux

Question

I found this.
And I wrote this variant:
#!/bin/bash
while read line ; do
headers="$headers -H '$line'"
done < public/headers.txt
echo $headers
curl -X PUT \
$headers \
-d #'public/example.json' \
echo.httpkit.com
In headers.txt I have:
X-PAYPAL-SECURITY-USERID:123
X-PAYPAL-SECURITY-PASSWORD:123
But when I run ./public/curl.sh I am not getting the headers I am sending.
I isolated the issue with an env var:
$ x='-H some:asd'
$ curl $x echo.httpkit.com
=> header was NOT present
$ curl -H 'some:asd' echo.httpkit.com
=> header was present
$ curl -H some:asd echo.httpkit.com
=> header was present
How can I correctly insert a variable in the header section?

Answer 1

Let's ask shellcheck:
In yourscript line 3:
headers="$headers -H '$line'"
^-- SC2089: Quotes/backslashes will be treated literally.
Use an array.
Ok, then let's do that:
#!/bin/bash
while read line ; do
headers=("${headers[#]}" -H "$line")
done < public/headers.txt
echo "${headers[#]}"
curl -X PUT \
"${headers[#]}" \
-d #'public/example.json' \
echo.httpkit.com
Result:
{
"method": "PUT",
"uri": "/",
"path": {
"name": "/",
"query": "",
"params": {}
},
"headers": {
"host": "echo.httpkit.com",
"user-agent": "curl/7.35.0",
"accept": "*/*",
"x-paypal-security-userid": "123", // <----- Yay!!
"x-paypal-security-password": "123",
"content-length": "32",
"content-type": "application/x-www-form-urlencoded"
},
"body": "\"This is text from example.json\"",
"ip": "127.0.0.1",
"powered-by": "http://httpkit.com",
"docs": "http://httpkit.com/echo"
}

Answer 2

If you don't want to put the HTTP headers on a command line (perhaps for security reasons), you can still have curl read them directly from a file.
curl -H #headerfile.txt https://www.google.com/ # requires curl >=7.55.0
If your curl is older than 7.55.0:
Use the option -K/--config <config file>, and put several -H/--header <header> lines in the text file.
For more details, please see my answer in the original article:
https://stackoverflow.com/a/48762561/5201675