Use Node.js DDP Client on Arduino Yun to Access Meteor Server

Use Node.js DDP Client on Arduino Yun to Access Meteor Server

概述

在Arduino Yun上安装 Node.js, 并測试与 Meteor 通过 DDP Client 通讯。

所用硬件

• Arduino Yun
• SD Card（至少 2GB，我使用的是 8G ）

所用软件

PC 软件：

• Arduino IDE
• SSH Terminal（Putty / Screen）

升级 Arduino Yun固件

1. 从站点上下载 Arduino Yun 最新的 openWRT 固件, 当前升级包的版本号是 YunSysupgradeImage_v1.5.3.zip。

2. 选用 MS-DOS 方式格式化 SD Card，将所下载的 ZIP 文件展开出的 bin 文件复制到 SD Card 的根文件夹下。

3. 将 SD Card 插入 Arduino Yun, 并重新启动 Arduino Yun。正常情况下，应该能够在 Web Page 点按 “RESET” 按钮运行升级。

raw=true" alt="RESET" title="">

也能够用 SSH 登陆后，先检查一下 /mnt/sda1 文件夹下是否有升级文件，并运行下面命令。

    # ls /mnt/sda1
    openwrt-ar71xx-generic-yun-16M-squashfs-sysupgrade.bin

    # run-sysupgrade /mnt/sda1/openwrt-ar71xx-generic-yun-16M-squashfs-sysupgrade.bin

1. 升级完毕后。选择 ArduinoYun 的初始 WIFI。并通过 Web 页面訪问 192.168.240.1。设置 Arduino Yun 的网络连接。

利用 SD Card 扩展 Arduino Yun 空间

Arduino Yun 的板上存储仅有 16M，要想安装很多其它地东西就必须利用 SD Card 扩展磁盘空间。參考链接

1. 重新启动后，通过本地局域网。SSH 到 Arduino Yun上，检查现有的分区情况。

   # df
   Filesystem           1K-blocks      Used Available Use% Mounted on
   rootfs                    7104       364      6740   5% /
   /dev/root                 7680      7680         0 100% /rom
   tmpfs                    30560       148     30412   0% /tmp
   tmpfs                      512         0       512   0% /dev
   /dev/mtdblock3            7104       364      6740   5% /overlay
   overlayfs:/overlay        7104       364      6740   5% /
   /dev/sda1              7746772      1008   7745764   0% /mnt/sda1
   

2. 下载 YunDiskSpaceExpander.zip

3. 通过 USB 连接 Arduino Yun，打开 Arduino IDE 上传此 ino 文件, 然后打开 Serial Monitor。在屏幕右下方选择 “Newline”, 并依照提示进行操作。下面的操作记录了我为分区方式，供參考。须要注意的是，此处输入的 4096 的意思是，将 4G 的空间保留为 /mnt/sda1 下的数据存储，剩下的空间留给根文件夹。

   整个过程须要等待几分钟。

   Open the Serial Monitor and double check the dropdown menu "Newline" has been selected.
   
   This sketch will format your micro SD card and use it as additional disk space for your Arduino Yun.
   Please ensure you have ONLY your micro SD card plugged in: no pen drives, hard drives or whatever.
   Do you wish to proceed (yes/no)? yes
   
   Starting Bridge...
   
   Ready to install utility software. Please ensure your Arduino Yun is connected to internet.
   Ready to proceed (yes/no)?
   
   yes
   Updating software list...
   Software list updated. Installing software (this will take a while)...
   e2fsprogs mkdosfs fdisk rsync installed
   
   Proceed with partitioning micro SD card (yes/no)?
   
   yes
   Enter the size of the data partition in MB: 4096
   Partitioning (this will take a while)...
   Micro SD card correctly partitioned
   
   Creating 'arduino' folder structure...
   Copying files from Arduino Yun flash to micro SD card...
   Enabling micro SD as additional disk space... enabled
   
   We are done! Yeah! Now press the YUN RST button to apply the changes.
   

4. 按下 YUN RST 后等待系统全然重新启动，再次检查分区情况，能够看到，Root 文件夹已经被放置在 /dev/sda2 下了，大小已经被扩大。

   # df
   Filesystem           1K-blocks      Used Available Use% Mounted on
   rootfs                 3556712    120920   3257464   4% /
   /dev/root                 7680      7680         0 100% /rom
   tmpfs                    30560       100     30460   0% /tmp
   tmpfs                      512         0       512   0% /dev
   /dev/sda2              3556712    120920   3257464   4% /overlay
   overlayfs:/overlay     3556712    120920   3257464   4% /
   /dev/sda1              4186104        12   4186092   0% /mnt/sda1
   

安装 Node.js

确认 Arduino Yun 能够正常联网，然后运行下面安装 Node.js。 原文參考链接

# opkg update
# opkg install node

安装完毕之后，能够用下面命令检查 Node.js 成功安装

# node -e "console.log('Hello_Yun')"
Hello_Yun

Arduino Yun 可用的全部 Package 能够在这里找到。

您还能够依据须要，安装很多其它的 Node.js 基础包，比如：

# opkg install node-serialport
# opkg install node-noble

设置 Swap 区

Arduino Yun 提供的 Node.js 包非常有限。还须要通过 npm 安装很多其它可扩展包。可是由于 npm 所需的内存比較大，我们必须打开 Swap 才干够顺利运行，否则会报内存不足。

1. 检查现有的 Swap 设置

   # free -m
                total         used         free       shared      buffers
   Mem:         61116        31712        29404            0         8364
   -/+ buffers:              23348        37768
   Swap:            0            0            0
   

2. SSH 登陆后。创建 Swap 分区。这一步要等比較长的时间。

   # mkdir /swap
   
   # dd if=/dev/zero of=/swap/yunswapfile bs=1M count=1024
   1024+0 records in
   1024+0 records out
   

3. 设置 Swapon。此时已经能够看到 Swap 区正确创建了。

   # mkswap /swap/yunswapfile
   # swapon /swap/yunswapfile
   
   # free -m
               total         used         free       shared      buffers
   Mem:         61116        59704         1412            0         7676
   -/+ buffers:              52028         9088
   Swap:      1048572            0      1048572
   

4. 设置启动时自己主动载入 Swap。重新启动 Arduino Yun 后。Swap 区应该正常。

   # uci add fstab swap
   # uci set fstab.@swap[0].device=/swap/yunswapfile
   # uci set fstab.@swap[0].enabled=1
   # uci set fstab.@swap[0].fstype=swap
   # uci set fstab.@swap[0].options=default
   # uci set fstab.@swap[0].enabled_fsck=0
   # uci commit
   

安装 DDP Client

此时，我们再使用 npm 安装 DDP Client。

我使用的 DDP Client 是 https://www.npmjs.com/package/ddp

# npm install ddp
# npm install underscore

# npm list
    /root
    ├─┬ ddp@0.11.0
    │ ├── ddp-ejson@0.8.1-3
    │ ├── ddp-underscore-patched@0.8.1-2
    │ ├─┬ faye-websocket@0.9.4
    │ │ └─┬ websocket-driver@0.5.4
    │ │   └── websocket-extensions@0.1.1
    │ └─┬ request@2.53.0
    │   ├── aws-sign2@0.5.0
    │   ├─┬ bl@0.9.4
    │   │ └─┬ readable-stream@1.0.33
    │   │   ├── core-util-is@1.0.1
    │   │   ├── inherits@2.0.1
    │   │   ├── isarray@0.0.1
    │   │   └── string_decoder@0.10.31
    │   ├── caseless@0.9.0
    │   ├─┬ combined-stream@0.0.7
    │   │ └── delayed-stream@0.0.5
    │   ├── forever-agent@0.5.2
    │   ├─┬ form-data@0.2.0
    │   │ └── async@0.9.2
    │   ├─┬ hawk@2.3.1
    │   │ ├── boom@2.7.2
    │   │ ├── cryptiles@2.0.4
    │   │ ├── hoek@2.14.0
    │   │ └── sntp@1.0.9
    │   ├─┬ http-signature@0.10.1
    │   │ ├── asn1@0.1.11
    │   │ ├── assert-plus@0.1.5
    │   │ └── ctype@0.5.3
    │   ├── isstream@0.1.2
    │   ├── json-stringify-safe@5.0.1
    │   ├─┬ mime-types@2.0.13
    │   │ └── mime-db@1.11.0
    │   ├── node-uuid@1.4.3
    │   ├── oauth-sign@0.6.0
    │   ├── qs@2.3.3
    │   ├── stringstream@0.0.4
    │   ├── tough-cookie@1.2.0
    │   └── tunnel-agent@0.4.0
    └── underscore@1.8.3

使用 DDP Client 訪问 Meteor

下面的參考实现展示了怎样用 DDP Client 与 Meteor 交互。

var DDPClient = require("ddp"),
    _ = require('underscore');

var ddpclient = new DDPClient({
    // url: 'ws://192.168.199.240:3000/websocket'
    url: 'ws://mcotton-01.chinacloudapp.cn/websocket'
});

var useremail = "iasc@163.com";
var pwd = "123456";

var user_id = null, token = null;

var appkit_weather_station, myappkit_weather_station, my_app_kit_id;
var data_observer, control_observer;

/*
 * Connect to the Meteor Server
 */
ddpclient.connect(function (error, wasReconnect) {
    // If autoReconnect is true, this callback will be invoked each time
    // a server connection is re-established

    if (error) {
        console.log("DDP connection error!");
        return;
    }

    if (wasReconnect) {
        console.log("Reestablishment of a connection.");
    }

    console.log("connected!");

    ddpclient.call("login", [
        {user: {email: useremail}, password: pwd}
    ], function (err, result) {
        console.log(result);
        user_id = result.id;
        token = result.token;

        if (token) {
            console.log("Logined!", user_id, token);

            //var observer = ddpclient.observe("appkits");

            /*
             * Subscribe to a Meteor Collection
             */
            ddpclient.subscribe(
                "appkits",                  // name of Meteor Publish function to subscribe to
                [],                       // any parameters used by the Publish function
                function () {             // callback when the subscription is complete
                    console.log("appkits all ==> ", ddpclient.collections.appkits);

                    appkit_weather_station = _(ddpclient.collections.appkits).findWhere({name: 'Weather Station'});
                    console.log("appkits weather_station  ==> ", appkit_weather_station);
                    console.log("appkits weather_station id ==> ", appkit_weather_station._id);

                    // Create myAppKit

                    var myAppKit = ddpclient.call(
                        'myAppKitInsert',
                        [{
                            name: 'My Weather Station',
                            app_kit_id: appkit_weather_station._id
                        }],
                        function (err, result) {
                            console.log('myAppKitInsert, error: ' + error);
                            console.log('myAppKitInsert, result: ' + result._id);

                            my_app_kit_id = result._id;

                            /*
                             * Subscribe to a Meteor Collection
                             */
                            ddpclient.subscribe(
                                "myappkits",                  // name of Meteor Publish function to subscribe to
                                [user_id],          // any parameters used by the Publish function
                                function () {             // callback when the subscription is complete
                                    console.log("myappkits all ==> ", ddpclient.collections.myappkits);

                                    console.log("appkit_weather_station id ==> ", appkit_weather_station._id);

                                    myappkit_weather_station = _(ddpclient.collections.myappkits).filter({_id: my_app_kit_id});
                                    console.log("myappkits weather_station  ==> ", myappkit_weather_station);
                                }
                            );

                            ddpclient.subscribe(
                                "dataevents",                  // name of Meteor Publish function to subscribe to
                                [user_id],          // any parameters used by the Publish function
                                function () {             // callback when the subscription is complete
                                    console.log("dataevents all ==> ", ddpclient.collections.dataevents);
                                }
                            );

                            ddpclient.subscribe(
                                "controlevents",                  // name of Meteor Publish function to subscribe to
                                [user_id],          // any parameters used by the Publish function
                                function () {             // callback when the subscription is complete
                                    console.log("controlevents all ==> ", ddpclient.collections.controlevents);
                                }
                            );

                            /*
                             * observe DataEvents
                             */
                            data_observer = ddpclient.observe("dataevents");

                            data_observer.added = function (id) {
                                console.log("[ADDED] to " + data_observer.name + ":  " + id);

                                var event = _(ddpclient.collections.dataevents).findWhere({_id: id});
                                console.log("[ADDED] dataevents ", event)
                            };

                            /*
                             * observe ControlEvents
                             */
                            control_observer = ddpclient.observe("controlevents");

                            control_observer.added = function (id) {
                                console.log("[ADDED] to " + control_observer.name + ":  " + id);

                                var event = _(ddpclient.collections.controlevents).findWhere({_id: id});
                                console.log("[ADDED] controlevents ", event)
                            };

                            /*
                             * Send new Control Event to Server
                             * */
                            var newControlEvent = ddpclient.call(
                                'controlEventInsert',
                                [{
                                    my_app_kit_id: my_app_kit_id,
                                    control_name: "Status",
                                    control_value: "true"
                                }],
                                function (err, result) {
                                    console.log('controlEventInsert, error: ' + error);
                                    console.log('controlEventInsert, result: ' + result._id);
                                });
                        }
                    );
                }
            );
        }
    });

    ////Debug information
    //
    //ddpclient.on('message', function (msg) {
    //    console.log("ddp message: " + msg);
    //});

    /*
     ddpclient.on('socket-close', function (code, message) {
     console.log("Close: %s %s", code, message);
     });

     ddpclient.on('socket-error', function (error) {
     console.log("Error: %j", error);
     });
     */

    // close

    setTimeout(function () {
        // observer.stop();
        ddpclient.close();
    }, 5000);

});

---

代码地址

https://github.com/iascchen/arduino_study/tree/master/src/yun_ddp

---

转载请注明出处

Author : iascchen(at)gmail(dot)com

Date : 2015-6-3

Github : https://github.com/iascchen/arduino_study

新浪微博 : @问天鼓

---