April 24, 2018

sfpark api

I recently came to learn of the SFpark API, which lets one make queries like: LAT=37.787702 LONG=-122.407796 curl "http://api.sfpark.org/sfpark/rest/availabilityservice?lat=${LAT}&long=${LONG}&radius=0.25&uom=mile&response=json" | pbcopy pbpaste | jq '.AVL[] | select (.TYPE | contains("OFF"))' and get a response including records like: { "TYPE": "OFF", "OSPID": "950", "NAME": "Union Square Garage", "DESC": "333 Post Street", "INTER": "Geary between Stockton & Powell", "TEL": "(415) 397-0631", "OPHRS": { "OPS": { "FROM": "7 Days/Wk", "BEG": "24 Hrs/Day" } }, "OCC": "381", "OPER": "670", "PTS": "1", "LOC": "-122.

February 23, 2018

regex in java

I can never remember how to do java regexes with Pattern. Pattern pattern = Pattern.compile("x_(yy|zz)"); String input = "x_yy"; boolean m = pattern.asPredicate().test(input); System.out.println("matches: " + m); Matcher matcher = pattern.matcher(input); while (matcher.find()) { System.out.println("whole matched string: " + matcher.group(0)); System.out.println("matched group: " + matcher.group(1)); } I also learned a really cool thing IntelliJ can do with pattern matches! ![java regex]({{ site.baseurl }}/assets/java-regex.png)

January 26, 2018

guava RangeMap

We had some code like this: NavigableMap<Double, Integer> PRIORITY_MULTIPLIERS = new TreeMap<Double, Integer>() {{ "{{ " }} put(LOW_THRESHOLD, 1); // (20k..40k) => 1 put(MEDIUM_THRESHOLD, 2); // [40k..100k) => 2 put(HIGH_THRESHOLD, 3); // [100k..+∞) => 3 }}; Integer getPriorityMultiplier(Double v) { if (v < LOW_THRESHOLD) { return 0; } return PRIORITY_MULTIPLIERS.floorEntry(v).getValue() } I replaced with a [RangeMap][RangeMap] that uses [Range][Range] instances as keys: [RangeMap]: https://google.github.io/guava/releases/16.0/api/docs/com/google/common/collect/RangeMap.html [Range]: https://google.github.io/guava/releases/16.0/api/docs/com/google/common/collect/Range.html RangeMap<Double, Integer> PRIORITY_MULTIPLIERS = ImmutableRangeMap.

January 12, 2018

osquery

I’ve known about [osquery][] for a while, but recently spent some time digging around in it. [osquery]: https://osquery.io The basic idea is to provide a consistent SQL interface to a bunch of system data, instead of learning idiosyncrasies of individual commands (which themselves vary across operating systems). My hacker buddy Sharvil has worked on osquery a fair bit and explained to me a couple years ago that it actually uses [sqlite][]’s [virtual table functionality][vtab] to provide the interface – it’s a fascinating and brilliant project!

January 9, 2018

profitably wrong

I’ve come to realize that my career so far has been built on being “profitably wrong.” I think this is interesting because the usual approaches are being “profitably fast” (optimizing) or “profitably better” (improving), and most people think of any kind of wrongness as being a terrible thing. But sometimes the best way to optimize or improve is approximating! The definitions of “profitably” has changed as I’ve worked on different things, as has the specific type of “wrongness”.

January 5, 2018

todobackend.com

TodoBackend.com defines a simple API and has a frontend that works given any backend URL. Particularly interesting to me: haskell super concise! whoa, 6 different backends! spock backend is crazy concise. python + flask seems like it would greatly benefit from a Store object scala + akka crazy pattern matching in routes definition java + mangooio + jOOQ especially the distinction between Todo and TodoPatch also really glad I don’t have to write routes config separately from the code!

January 4, 2018

dancing bull pricing structure

Dancing Bull is a great Korean BBQ restaurant that opened nearby recently. They have this pricing scheme: Note that the unlimited bulgogi is \$23/person, but the bulgogi a la carte is \$25/grill (with each additional orders after that costing \$9). This raises an obvious question: which is the better deal? Spoiler: it depends on both how many people you have and how hungry they are. First, we had to clarify how it actually worked.

January 3, 2018

everything has a failure rate

I was happily riding in to work this morning on my motorcycle. Periodically while riding, a spark of terror that I’ve forgotten to buckle my backpack to the bike’s frame hits me. So frequently, in fact, that I’ve grown used to reaching behind me to feel for the backpack in a spare second when I don’t need to clutch. Today was different: I reached for the backpack but felt nothing.

January 2, 2018

extracting the last few dollars from Visa/MC gift cards

Once in a while, I get a prepaid gift card like this: They’re – like money – great! But they do have one downside: it’s hard to spend the change once you’ve bought off most of the value. Originally this was going to be a quick “just redeem it with Amazon’s gift card” post, but a bit of study revealed that it isn’t quiet that simple: the authorized amount can prevent the full transaction from going through, so if it’s the first transaction at Amazon, you might need to leave $1.

January 1, 2018

things you don't learn in grad school

oncall exists. the data is never available how you need it. unit tests matter. pushing code after 3pm is risky if you’re not willing to work all night. (courtesy Paul Joos)