Google chat: Invalid JSON payload received. Closing quote expected in string.\n\n^

Question

I am trying to send a google chat message using bash script. When I define a local variable or using simple text, it works. But when I source a file, and use variables defined in that file, I get error.

This works:

#!/bin/bash
MSG="Data"
curl -H 'Content-Type: application/json' -X POST "$CHAT_URL" --data @<(cat <<EOF
{
  "cards": [
    {
      "sections": [
        {
          "widgets": [
            {
                "textParagraph": {
                    "text": "Msg: $MSG"
                }
            }]}]}]}
EOF
)

This does not:

#!/bin/bash
source file.txt      # contents: MSG=Data
echo $MSG            # variable defined in file.txt
curl -H 'Content-Type: application/json' -X POST "$CHAT_URL" --data @<(cat <<EOF
{
  "cards": [
    {
      "sections": [
        {
          "widgets": [
            {
                "textParagraph": {
                    "text": "Msg: $MSG"
                }
            }]}]}]}
EOF
)

Output:

Data
{
  "error": {
    "code": 400,
    "message": "Invalid JSON payload received. Closing quote expected in string.\n\n^",
    "status": "INVALID_ARGUMENT"
  }
}

Answer 1

This question is basically a duplicate of Are shell scripts sensitive to encoding and line endings? and Are multi-line strings allowed in JSON?

Your file has windows line endings (\r\n). Therefore the string loaded from your file ends with \r. JSON strings are not allowed to contain control characters, hence the error message.

To fix the problem, convert your file using dos2unix file.txt.