Protect against hard to catch date corruption

real_date.clj

(defn date?
  "Ensure a date string is a date and after a cutoff date. This protects against technically valid but corrupt dates like from a century ago or in the future."
  ([s]
   ;; store the year 10 years from now so we don't have to compute it every call
   (date? s 2010 `~(+ 10 (clj-time.core/year (clj-time.core/now)))))
  ([s past-cutoff future-cutoff]
   (try
     (if-let [d
              (clj-time.format/parse
               (clj-time.format/formatter "YYYYMMDD") s)]
       (and d  (> future-cutoff (clj-time.core/year d) past-cutoff)))
     (catch java.lang.IllegalArgumentException  e
       false)
     (catch org.joda.time.IllegalFieldValueException e
       false))))

(comment
  (date? "10001111") ;;=> false
  (date? "20111111") ;;=> true
  (date? "23111111") ;;=> false

)