Fix DingTalk robot error 310000 in Duaer

Post to a DingTalk robot from Duaer

HTTP Request: Method POST, URL the robot webhook, Send Body JSON, body {"msgtype":"text","text":{"content":{{ JSON.stringify($json.message) }}}}.

DingTalk returns HTTP 200 even on failure, so the Duaer node looks green. Read errcode in the output. Anything but 0 failed. Add If and Stop and Error to surface it.

Read errmsg for 310000

• keywords not in content: the robot has custom keywords and the message has none. Put a keyword at the start.
• sign not match or invalid timestamp: signing is on and the signature or timestamp is wrong. Use milliseconds, within one hour.
• ip … not in whitelist: an IP range is set and the Duaer egress IP is outside it. Self-hosted: add your server egress IP. Cloud: use keywords or signing.

Sign requests in Duaer

1. Add Edit Fields with a field ts set to {{ $now.toMillis() }} (milliseconds).
2. Add Crypto: Action Hmac, Type SHA256, Encoding BASE64, Property Name sign. Put the robot secret (starts with SEC) in the credential Hmac Secret.
3. Set Value to {{ $json.ts + "\n" + "SECyour-secret" }}, which is timestamp, newline, secret.
4. Append &timestamp={{ $json.ts }}&sign={{ encodeURIComponent($json.sign) }} to the HTTP Request URL.

The secret sits in the Crypto node. Keywords are simpler when you do not need signing. Each robot accepts up to 20 messages a minute, so batch them.