feat(koa): simpleMiddleWare for koa

affects: @tao.js/koa

ISSUES CLOSED: #23

packages/koa-tao/src/index.js

@@ -1,3 +1,6 @@
 import taoHttpMiddleware from './tao-http-middleware';
+import simpleMiddleware from './simple-middleware';
 
 export default taoHttpMiddleware;
+
+export { taoHttpMiddleware, simpleMiddleware };

packages/koa-tao/src/simple-middleware.js

@@ -0,0 +1,79 @@
+// import { AppCtx } from '@tao.js/core';
+import cartesian from 'cartesian';
+import { Channel, Transponder } from '@tao.js/utils';
+import { noop, normalizeAC, cleanInput } from './helpers';
+
+const DEFAULT_CHANNEL_NAME = 'koa-simple-middleware';
+const CHANNEL_NAME_TYPE = 'channel';
+const TRANSPONDER_NAME_TYPE = 'transponder';
+const DEFAULT_TIMEOUT = 3000;
+
+function getNameId(type, name) {
+  return newId => {
+    return `${name}-${type}-${newId}`;
+  };
+}
+
+function buildCtxTao(transponder) {
+  return {
+    setCtx({ t, term, a, action, o, orient }, data) {
+      return transponder.setCtx({ t, term, a, action, o, orient }, data);
+    },
+    setAppCtx(ac) {
+      return transponder.setAppCtx(ac);
+    }
+  };
+}
+
+/**
+ * Use the `simpleMiddleware` to build koa apps that work with your TAO Signal Network on the
+ * koa app server.
+ *
+ * @export
+ * @param {Kernel} TAO
+ * @param {Object} [opt={}]
+ * @param {string} [opt.name] - name to prepend to the TAO Channel and Transponder names that will be generated
+ * @param {number} [opt.timeout=3000] - timeout in Milliseconds to wait on completing a TAO chain before the Transponder rejects the Promise
+ * @param {Promise} [opt.promise=Promise] - Promise constructor used to create promises returned by `setCtx` and `setAppCtx`
+ * @returns {Object} - an Object instantiated to attach a `middleware` to a koa app and add/remove response handlers
+ */
+export default function simpleMiddleware(TAO, opt = {}) {
+  const namer = getNameId(CHANNEL_NAME_TYPE, opt.name || DEFAULT_CHANNEL_NAME);
+  const channel = new Channel(TAO, namer);
+  return {
+    middleware() {
+      return (ctx, next) => {
+        const transponder = new Transponder(
+          channel,
+          getNameId(TRANSPONDER_NAME_TYPE, opt.name),
+          opt.timeout || DEFAULT_TIMEOUT,
+          opt.promise
+        );
+        ctx.tao = buildCtxTao(transponder);
+        next();
+        transponder.detach();
+        ctx.tao = null;
+        transponder = null;
+      };
+    },
+    addResponseHandler({ t, term, a, action, o, orient }, handler = noop) {
+      const trigrams = cleanInput(
+        normalizeAC({ t, term, a, action, o, orient })
+      );
+      const permutations = cartesian(trigrams);
+      for (let trigram of permutations) {
+        console.log('@tao.js/koa::addResponseHandler::trigram:', trigram);
+        channel.addInlineHandler(trigram, handler);
+      }
+    },
+    removeResponseHandler({ t, term, a, action, o, orient }, handler = noop) {
+      const trigrams = cleanInput(
+        normalizeAC({ t, term, a, action, o, orient })
+      );
+      const permutations = cartesian(trigrams);
+      for (let trigram of permutations) {
+        channel.removeInlineHandler(trigram, handler);
+      }
+    }
+  };
+}

packages/tao-utils/src/Transceiver.js

@@ -18,7 +18,7 @@ function transceiverControl(transceiverId, resolve, reject) {
 }
 
 /**
- * Like a Transponder, a Transceiver converts Signnals on a Network to Promises.
+ * Like a Transponder, a Transceiver converts Signals on a Network to Promises.
  * Unlike a Transponder, a Transceiver allows the handlers attached to it to control
  * the behavior of the Promise.
  *