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http#

Probe a JSON service and prove an API key against it.

Functions#

  • http_probe_json URL PATH [TIMEOUT]
  • Purpose: GET URL/PATH once and print the body.
  • Args: URL (http:// or https:// only; curl refuses any other scheme; a trailing / is dropped), PATH (a leading / is added when missing), TIMEOUT whole seconds, default 5, used for both the connect and the total deadline.
  • Returns: 0 and the body on a 2xx with a body; 1 when nothing answers, the status is not 2xx or the body is empty, or an argument is missing or bad.

  • Read a field from the body with json_get_field (json module).

  • http_check_key URL PATH HEADER KEY

  • Purpose: Prove KEY, sent as HEADER: KEY, against an authenticated read at URL/PATH.
  • Returns: 0 accepted (200 with a JSON media type, application/json or application/*+json); 2 refused (401 or 403); 1 nothing answered, any other status, a 200 that is not JSON (a web app or captive portal answers every path that way), or bad arguments.
  • Behavior: the key reaches curl on stdin as a config line (-K -), never in argv, where other users could read it with ps. A key containing CR or LF is refused (header injection), and so is a header name that is not [A-Za-z0-9-]+. Only http:// and https:// URLs are contacted.

Example#

source ./helpers.sh
shlib_import logging json http
body="$(http_probe_json "$URL" /v1/info)" || { log_error "not answering"; exit 1; }
echo "version $(json_get_field "$body" version)"
rc=0; http_check_key "$URL" "/v1/items?limit=1" X-API-Key "$KEY" || rc=$?
case $rc in 0) echo ok ;; 2) echo "wrong key" ;; *) echo "not serving" ;; esac

Dependencies#

  • curl; logging for messages.