非動態(tài)連接的“MQTT IN”不支持輸入，需要完整配置連接參數以及訂閱地址；
配置連接MQTT服務器認證參數；
復制下段JSON文本到Node-RED導入窗口，防止參數輸入錯誤導致連接失?。?/span>
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導入完成后會輸出成功日志如下圖。
打開剛才導入的“MQTT IN”節(jié)點，與常規(guī)連接一樣，使用動態(tài)連接也需要配置一個用于存儲動態(tài)連接參數的空間，需要配置一個空的“服務端”，可以像我一樣將IP地址配置為127.0.0.1，端口為8888（也可以為其他任意值，不能為空，其余參數可以為空），實際節(jié)點在連接時不會優(yōu)先使用輸入的參數而是使用傳入的參數連接（導入的“手動連接”JSON中對應的字段參數），缺少的參數會采用此處默認參數（根據說明得出，并未實際測試），需要注意使用動態(tài)連接節(jié)點應當通過上一節(jié)點驅動而不是底層自動驅動因此需要取消勾選“Connect automatically”屬性；
打開導入的“手動連接”，一共配置了兩個字段，一個用于存在請求信息（msg.action，相當于告知MQTT IN節(jié)點應當如何解析數據），一個用于存儲連接參數（msg.broker）；
msg.action支持一下功能：
“connect”，連接請求，用于告知MQTT IN節(jié)點使用msg.broker參數連接服務器；
“subscribe”，訂閱請求，用于告知MQTT IN節(jié)點使用msg.topic訂閱服務器的主題；
“unsubscribe”，取消訂閱，與“subscribe”對應使用，取消主題的訂閱；
“disconnect”，斷開服務器連接；
這里先說明“connect”方式需要的參數，需要見參數存在broker字段，因此需要選擇使用JOSN，如下圖所示：
“type”，用于標記參數，可以任意配置，也可缺?。?/span>
“broker”，用于存儲MQTT服務器地址；
“port”，用于存儲MQTT服務器端口；
“force”，強制斷開連接，一般使能，缺省為失能，可能返回錯誤（沒有斷開服務器連接時再次請求連接）；
“clientid”，MQTT連接三要素的客戶端ID；
“autoConnect”，自動連接使能，建議關閉，避免發(fā)生錯誤；
“protocolVersion”，MQTT連接的版本；
“keepalive”，MQTT的保活心跳，建議配置為120；
“username”，MQTT連接三要素的用戶名；
“password”，MQTT連接三要素的密鑰；
配置以上參數MQTT動態(tài)連接即可實現(xiàn)，下面是連接的服務器日志，由于添加了數據庫認證會比無認證的多幾個認證日志；
點擊觸發(fā)后“MQTT IN”節(jié)點會提示已連接；
斷開連接就要比連接要簡單的多，只要傳入請求方式“msg.action”等于“disconnect”，Node-RED上面會連接很多的MQTT服務器，斷開對應的連接就需要再次使用到上面配置的“空服務器”；
上面已經提到訂閱請求需要配置“msg.action”為“subscribe”，這是不在使用“broker”存儲參數，而是使用“topic”存儲，這里的topic需要存儲連個信息一個是訂閱的地址（msg.topic.topic），一個是訂閱的等級（msg.topic.qos），如下圖：
取消訂閱只需要令“msg.action”為“unsubscribe”，其余與訂閱一致；
使用動態(tài)連接方式連接自建MQTT服務器，并通過“123”主題回傳當前時間戳測試；
Debug調試窗口輸入時間戳，動態(tài)連接訂閱有效；
MQTT服務器調試日志：
筆者工程文件如下，導入Node-RED使用：
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