feat: Add sse handler

Author: relekang

src/db.js

@@ -1,4 +1,5 @@
 const promise = require('promise')
+const Observable = require("zen-observable")
 
 let adapter
 const adapterName = `micro-analytics-adapter-${process.env.DB_ADAPTER || 'flat-file-db'}`
@@ -17,10 +18,20 @@ try {
   }
 }
 
+const observable = new Observable((observer) => {
+  let timer = setInterval(_ => {
+    observer.next("hello")
+  }, 1000)
+
+  return _ => clearTimeout(timer)
+});
+
+
 module.exports = {
   get: adapter.get,
   getAll: adapter.getAll,
   put: adapter.put,
   has: adapter.has,
   keys: adapter.keys,
+  subscribe: adapter.subscribe,
 }

src/handler.js

@@ -0,0 +1,51 @@
+const url = require('url')
+const { send, createError, sendError } = require('micro')
+
+const db = require('./db')
+const { pushView } = require('./utils')
+
+module.exports = async function (req, res) {
+  const { pathname, query } = url.parse(req.url, /* parseQueryString */ true)
+  res.setHeader('Access-Control-Allow-Origin', '*')
+  // Send all views down if "?all" is true
+  if (String(query.all) === 'true') {
+    try {
+      const data = {
+        data: await db.getAll({
+          pathname: pathname,
+          before: parseInt(query.before, 10),
+          after: parseInt(query.after, 10),
+        }),
+        time: Date.now()
+      }
+      send(res, 200, data)
+      return
+    } catch (err) {
+      console.log(err)
+      throw createError(500, 'Internal server error.')
+    }
+  }
+  // Check that a page is provided
+  if (pathname.length <= 1) {
+    throw createError(400, 'Please include a path to a page.')
+  }
+  if (req.method !== 'GET' && req.method !== 'POST') {
+    throw createError(400, 'Please make a GET or a POST request.')
+  }
+  const shouldIncrement = String(query.inc) !== 'false'
+  try {
+    const currentViews = await db.has(pathname) ? (await db.get(pathname)).views.length : 0
+    // Add a view and send the total views back to the client
+    if (shouldIncrement) {
+      await pushView(pathname, { time: Date.now() })
+    }
+    if (req.method === 'GET') {
+      send(res, 200, { views: shouldIncrement ? currentViews + 1 : currentViews })
+    } else {
+      send(res, 200)
+    }
+  } catch (err) {
+    console.log(err)
+    throw createError(500, 'Internal server error.')
+  }
+}

src/index.js

@@ -1,51 +1,11 @@
-const url = require('url')
-const { send, createError, sendError } = require('micro')
+const micro = require('micro')
+const SSE = require('sse')
 
-const db = require('./db')
-const { pushView } = require('./utils')
+const handler = require('./handler')
+const sseHandler = require('./sse')
 
-module.exports = async function (req, res) {
-  const { pathname, query } = url.parse(req.url, /* parseQueryString */ true)
-  res.setHeader('Access-Control-Allow-Origin', '*')
-  // Send all views down if "?all" is true
-  if (String(query.all) === 'true') {
-    try {
-      const data = {
-        data: await db.getAll({
-          pathname: pathname,
-          before: parseInt(query.before, 10),
-          after: parseInt(query.after, 10),
-        }),
-        time: Date.now()
-      }
-      send(res, 200, data)
-      return
-    } catch (err) {
-      console.log(err)
-      throw createError(500, 'Internal server error.')
-    }
-  }
-  // Check that a page is provided
-  if (pathname.length <= 1) {
-    throw createError(400, 'Please include a path to a page.')
-  }
-  if (req.method !== 'GET' && req.method !== 'POST') {
-    throw createError(400, 'Please make a GET or a POST request.')
-  }
-  const shouldIncrement = String(query.inc) !== 'false'
-  try {
-    const currentViews = await db.has(pathname) ? (await db.get(pathname)).views.length : 0
-    // Add a view and send the total views back to the client
-    if (shouldIncrement) {
-      await pushView(pathname, { time: Date.now() })
-    }
-    if (req.method === 'GET') {
-      send(res, 200, { views: shouldIncrement ? currentViews + 1 : currentViews })
-    } else {
-      send(res, 200)
-    }
-  } catch (err) {
-    console.log(err)
-    throw createError(500, 'Internal server error.')
-  }
-}
+const server = micro(handler)
+const sse = new SSE(server)
+sse.on('connection', sseHandler)
+
+server.listen(3000)

src/sse.js

@@ -0,0 +1,17 @@
+const db = require('./db')
+
+module.exports = function handleSseConnection(connection) {
+  console.log('new connection')
+  const subscription = db.subscribe((event) => {
+  console.log('new event', event)
+    connection.send({
+      event: 'new-event',
+      data: JSON.stringify(event),
+    })
+  })
+
+  connection.on('close', function () {
+    console.log('closing connection')
+    subscription.unsubscribe()
+  })
+}