Account.needs_captcha: add hook, use live_config

This allows the minimum amount of karma needed to be exempt from the
captcha to be modified via live config. In addition, it adds the
ability to set a comment karma minimum, where previously it was required
to get link karma in order to be exempt from the captcha.

A hook has also been added to the function for private-code purposes.

r2/example.ini

@@ -708,6 +708,9 @@ proxy_gilding_accounts =
 cflag_min_votes = 7
 cflag_lower_bound = 0.4
 cflag_upper_bound = 0.6
+# Karma requirements to disable captchas - must meet at least one
+captcha_exempt_link_karma = 1
+captcha_exempt_comment_karma = 1
 
 #### Features
 # Availability for the "force HTTPS" option

r2/r2/lib/app_globals.py

@@ -301,6 +301,8 @@ class Globals(object):
             'frontend_logging',
         ],
         ConfigValue.int: [
+            'captcha_exempt_comment_karma',
+            'captcha_exempt_link_karma',
             'cflag_min_votes',
         ],
         ConfigValue.float: [

r2/r2/models/account.py

@@ -294,7 +294,21 @@ class Account(Thing):
         return ",".join((timestamp, signature))
 
     def needs_captcha(self):
-        return not g.disable_captcha and self.link_karma < 1
+        if g.disable_captcha:
+            return False
+
+        hook = hooks.get_hook("account.is_captcha_exempt")
+        captcha_exempt = hook.call_until_return(account=self)
+        if captcha_exempt:
+            return False
+
+        if self.link_karma >= g.live_config["captcha_exempt_link_karma"]:
+            return False
+
+        if self.comment_karma >= g.live_config["captcha_exempt_comment_karma"]:
+            return False
+
+        return True
 
     def modhash(self, rand=None, test=False):
         if c.oauth_user: