film42/hn-follow

Follow the interactions of up to 10 HN users

HN Follow

Follow friends on Hacker News

hn-follow's Issues

Null pointer exception in tree-template

I'm getting a null pointer exception with the following code,
(interaction-feed (get-user "grellas"))
It works with other users, like qzcx and film42.

Stack Trace:
java.lang.NullPointerException: null
/Users/Jon/fall2014/hn-follow/src/hn_follow/core/api.clj:55 hn-follow.core.api/tree-template
            core.clj:2559 clojure.core/map[fn]
          LazySeq.java:40 clojure.lang.LazySeq.sval
          LazySeq.java:49 clojure.lang.LazySeq.seq
             Cons.java:39 clojure.lang.Cons.next
              RT.java:598 clojure.lang.RT.next
              core.clj:64 clojure.core/next
            core.clj:2884 clojure.core/nthnext
        core_print.clj:48 clojure.core/print-sequential
       core_print.clj:147 clojure.core/fn
         MultiFn.java:231 clojure.lang.MultiFn.invoke
            core.clj:3392 clojure.core/pr-on
            core.clj:3404 clojure.core/pr
             AFn.java:154 clojure.lang.AFn.applyToHelper
          RestFn.java:132 clojure.lang.RestFn.applyTo
             core.clj:624 clojure.core/apply
            core.clj:4373 clojure.core/pr-str
          RestFn.java:408 clojure.lang.RestFn.invoke
              eval.clj:69 lighttable.nrepl.eval/clean-serialize
          RestFn.java:423 clojure.lang.RestFn.invoke
              eval.clj:82 lighttable.nrepl.eval/->result
             AFn.java:156 clojure.lang.AFn.applyToHelper
             AFn.java:144 clojure.lang.AFn.applyTo
             core.clj:626 clojure.core/apply
            core.clj:2468 clojure.core/partial[fn]
          RestFn.java:408 clojure.lang.RestFn.invoke
            core.clj:2557 clojure.core/map[fn]
          LazySeq.java:40 clojure.lang.LazySeq.sval
          LazySeq.java:49 clojure.lang.LazySeq.seq
              RT.java:484 clojure.lang.RT.seq
             core.clj:133 clojure.core/seq
            core.clj:2595 clojure.core/filter[fn]
          LazySeq.java:40 clojure.lang.LazySeq.sval
          LazySeq.java:49 clojure.lang.LazySeq.seq
              RT.java:484 clojure.lang.RT.seq
             core.clj:133 clojure.core/seq
            core.clj:2855 clojure.core/dorun
            core.clj:2871 clojure.core/doall
             eval.clj:126 lighttable.nrepl.eval/eval-clj
          RestFn.java:442 clojure.lang.RestFn.invoke
             eval.clj:192 lighttable.nrepl.eval/eval2476[fn]
             AFn.java:152 clojure.lang.AFn.applyToHelper
             AFn.java:144 clojure.lang.AFn.applyTo
             core.clj:624 clojure.core/apply
            core.clj:1862 clojure.core/with-bindings*
          RestFn.java:425 clojure.lang.RestFn.invoke
             eval.clj:177 lighttable.nrepl.eval/eval2476[fn]
             eval.clj:176 lighttable.nrepl.eval/eval2476[fn]
         MultiFn.java:227 clojure.lang.MultiFn.invoke
              core.clj:98 lighttable.nrepl.core/queued[fn]
            core.clj:2402 clojure.core/comp[fn]
interruptible_eval.clj:138 clojure.tools.nrepl.middleware.interruptible-eval/run-next[fn]
              AFn.java:22 clojure.lang.AFn.run
ThreadPoolExecutor.java:1142 java.util.concurrent.ThreadPoolExecutor.runWorker
ThreadPoolExecutor.java:617 java.util.concurrent.ThreadPoolExecutor$Worker.run
          Thread.java:744 java.lang.Thread.run

Road to Pagination

I have a first round implementation of updates coming in realtime from the HN API running in production. If we can abstract the 10 parallel async requests on a profile load, we can probably start to implement pagination, which is a feature on the radar. I'll try prototyping something and checking performance. My biggest concern is load time when we need to cache a new user to the system. On the other hand, it might reduce the amount of time spent waiting for that first byte to be sent.

Other optimizations:

• Only send a list of rendered items; stop sending the whole tree for each user over the wire.