Merge pull request 'implement /hit API endpoint' (#18) from hit-endpoint into main

Reviewed-on: 9pfs/countify#18

index.js

@@ -68,6 +68,55 @@ async function get_counter_value(ns_name, key) {
   }
 }
 
+async function counter_increment(ns_name, key, offset, create = false) {
+  var nsid = await get_namespace_id(ns_name);
+  return await sql.begin(async (sql) => {
+    if (offset == 0) return true;
+    if (create) {
+      var existence_res =
+        await sql`SELECT value FROM keys WHERE name = ${key} AND namespace_id = ${nsid}`;
+      if (existence_res.length == 0) {
+        if (
+          !(await add_counter({
+            namespace: ns_name,
+            key: key,
+            value: 1,
+            enable_reset: false,
+            update_lowerbound: 0,
+            update_upperbound: 1,
+          }))
+        )
+          return null;
+        else return 1; // We know the key value will be 1 here, just return it explicitly (Ending early to save some SQL calls)
+      }
+    }
+    var sql_res = await sql`UPDATE keys SET value = value + ${offset} WHERE
+      namespace_id = ${nsid} AND
+      name = ${key} AND
+      ${offset < 0 ? sql`update_lowerbound <= ${offset}` : sql`update_upperbound >= ${offset}`}
+      RETURNING value`;
+    if (sql_res.length == 1) return parseInt(sql_res[0].value);
+    else return null;
+  });
+}
+
+app.get("/hit/:ns/:key", async function (req, res) {
+  var counter_res = await counter_increment(
+    req.params.ns,
+    req.params.key,
+    1,
+    true,
+  );
+  return res
+    .status(counter_res == null ? 403 : 200)
+    .json({ value: counter_res });
+});
+app.get("/hit/:key", async function (req, res) {
+  var counter_res = await counter_increment("default", req.params.key, 1, true);
+  return res
+    .status(counter_res == null ? 403 : 200)
+    .json({ value: counter_res });
+});
 app.get("/get/:ns/:key", async function (req, res) {
   var e = await get_counter_value(req.params.ns, req.params.key);
   return res.status(e == null ? 404 : 200).json({ value: e });