curl error when using url string from string - json

Question

I'm now testing some restful APIs using bash shell script.
I want to read url from file then make a json data string with the url in file.
For the test, below codes work fine. It's not reading from file.
#!/bin/bash
URL=http://test.com/test.jpg
curl -X POST \
-H "Content-Type:application/json" \
-H "accept:application/json" \
--data '{"url":"'"$URL"'"}' \
http://api.test.com/test
But, it returns some error when I'm using the codes like below.
#!/bin/bash
FILE=./url.txt
cat $FILE | while read line; do
echo $line # or whaterver you want to do with the $line variable
curl -X POST \
-H "Content-Type:application/json" \
-H "accept:application/json" \
--data '{"url":"'"$line"'"}' \
http://api.test.com/test
done
But, it returns error when I use the string from reading file.
This is error message.
Illegal unquoted character ((CTRL-CHAR, code 13)): has to be escaped using backslash to be included in string value
at [Source: org.apache.catalina.connector.CoyoteInputStream#27eb679c; line: 1, column: 237]
How to solve this issue?
Why it returns error when I use the string from file reading?

Answer 1

It appears that your file is in dos format with \n\r line terminators. Try running dos2unix on it to strip the \rs. Additionally, no need to cat the file, use redirection, like so
while read -r line; do
echo $line # or whaterver you want to do with the $line variable
curl -X POST \
-H "Content-Type:application/json" \
-H "accept:application/json" \
--data '{"url":"'"$line"'"}' \
http://api.test.com/test
done < "$FILE"
Also, pass -r to read to prevent backslash escaping