How to escape a JSON variable posted with curl in bash script?
I'm submitting a message to Mandrill in a bash script via their API and the content of the 'message' variable is causing the API call to come back with an error:
An error occured: {"status":"error","code":-1,"name":"ValidationError","message":"You must specify a key value"}
The content of the $message_body variable is:
Trigger: Network traffic high on 'server'
Trigger status: PROBLEM
Trigger severity: Average
Trigger URL:
Item values:
1. Network traffic inbound (server:net.if.in[eth0,bytes]): 3.54 MBytes
2. Network traffic outbound (server:net.if.out[eth0,bytes]): 77.26 KBytes
3. *UNKNOWN* (*UNKNOWN*:*UNKNOWN*): *UNKNOWN*
Original event ID: 84
I'm not sure what part of the string is throwing it off, but it seems that something is causing the JSON to be invalid when submitted to Mandrill's API.
If I change the above message to something simple such as "Testing 123" the message gets submitted successfully.
The code that does the POST is as follows:
#!/bin/bash
...
message_body = `cat message.txt`
msg='{ "async": false, "key": "'$key'", "message": { "from_email": "'$from_email'", "from_name": "'$from_name'", "headers": { "Reply-To": "'$reply_to'" }, "auto_html": false, "return_path_domain": null, "subject": "'$2'", "text": "'$message_body'", "to": [ { "email": "'$1'", "type": "to" } ] } }'
results=$(curl -A 'Mandrill-Curl/1.0' -d "$msg" 'https://mandrillapp.com/api/1.0/messages/send.json' -s 2>&1);
echo "$results"
What can I do to make sure the $message_body variable is prepared and ready to be submitted as valid JSON?
I suspect the problem is the lack of quoting around your variables
msg='{ "async": false, "key": "'$key'", "message": { "from_email": "'$from_email'", "from_name": "'$from_name'", "headers": { "Reply-To": "'$reply_to'" }, "auto_html": false, "return_path_domain": null, "subject": "'$2'", "text": "'$message_body'", "to": [ { "email": "'$1'", "type": "to" } ] } }'
# ..............................^^^^ no quotes around var ...........^^^^^^^^^^^...................^^^^^^^^^^...............................^^^^^^^^^...................................................................^^..............^^^^^^^^^^^^^.........................^^
Try this instead: any double quote in each variable is escaped.
escape_quotes() { echo "${1//"/"}"; }
msg=$(
printf '{ "async": false, "key": "%s", "message": { "from_email": "%s", "from_name": "%s", "headers": { "Reply-To": "%s" }, "auto_html": false, "return_path_domain": null, "subject": "%s", "text": "%s", "to": [ { "email": "%s", "type": "to" } ] } }'
"$(escape_quotes "$key")"
"$(escape_quotes "$from_email")"
"$(escape_quotes "$from_name")"
"$(escape_quotes "$reply_to")"
"$(escape_quotes "$2")"
"$(escape_quotes "$message_body")"
"$(escape_quotes "$1")"
)