api_docs: Add /captcha to api docs.

r2/r2/controllers/api_docs.py

@@ -168,6 +168,7 @@ class ApidocsController(RedditController):
         # controllers to gather docs from.
         from r2.controllers.api import ApiController, ApiminimalController
         from r2.controllers.apiv1 import APIv1Controller
+        from r2.controllers.captcha import CaptchaController
         from r2.controllers.front import FrontController
         from r2.controllers.wiki import WikiApiController
         from r2.controllers import listingcontroller
@@ -177,6 +178,7 @@ class ApidocsController(RedditController):
             (ApiController, '/api'),
             (ApiminimalController, '/api'),
             (WikiApiController, '/api/wiki'),
+            (CaptchaController, ''),
             (FrontController, '')
         ]
         for name, value in vars(listingcontroller).iteritems():

r2/r2/controllers/captcha.py

@@ -25,8 +25,16 @@ import StringIO
 import r2.lib.captcha as captcha
 from pylons import c, response
 
+from r2.controllers.api_docs import api_doc, api_section
+
 class CaptchaController(RedditController):
+    @api_doc(api_section.captcha, uri='/captcha/{iden}')
     def GET_captchaimg(self, iden):
+        """Request a captcha image given an iden.
+
+        Responds with an image/png.
+
+        """
         image = captcha.get_image(iden)
         f = StringIO.StringIO()
         image.save(f, "PNG")