August 2017
Intermediate to advanced
272 pages
5h 32m
Chinese
Content preview from Node.js物聯網裝置開發
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第十一章 飛向雲端
安裝 NodeRED
使用 npm 可輕鬆安裝 NodeRED，如下：
$ sudo npm install -g nodered
然後執行：
$ node-red
概念
NodeRED 的視覺化介面屬於 Web 形式，由預設連接埠 1880 提供。這麼一來，只要使用
熟悉的網站瀏覽器，便能著手設計系統。
如圖 11-4 所示，GUI 畫面裡，左方包含了一連串的 NodeRED 元素，右方有個除錯主控
台，以及「deploy（部署）」按鈕，按下後可讓目前設計的系統活起來。
圖 11-4 NodeRED 的 GUI 畫面，左方有著各種不同的元件
設計系統時，從畫面左方拖拉元件，放置到作用中的標籤頁裡。然後，拖拉元件之間的
連接線，制定元件之間的關係。以 NodeRED 的術語來說，程式被稱為 FLOW，而步驟
則稱為 NODE。
系統設計與 NodeRED
|
187
每個節點可以是輸入（INPUT）節點、輸出（OUTPUT）節點、或是處理（PROCESS）
節點。一般來說，輸入節點會啟動 FLOW，通常會從外部來源取得輸入，而且至少擁
有一個輸出。以圖 11-5 所示範例來說，其輸入是 Twitter 搜尋關鍵字「javascript」的
結果。
圖 11-5 不同的節點類型：輸入、處理、輸出 ...
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