synology 自动更新IP同步阿里云脚本

场景

需要使用域名指向自己的NAS的场景，达到域名动态的指定自己的IP的目的，但是家庭宽带IP不固定，每次重启路由IP会变，所以写一个脚本来自动查询IP，并更新到阿里云的域名上。

脚本

NAS 中配置定时任务是可以执行脚本的，本身也是Linux，如查开ssh的话，直接就能上去操作，不过不安全就是，全身如果IP对外暴露，就会有被人恶意连接上的危险。
很多文章放脚本需要开ssh之后，通过FTP工具上传脚本，不要这么做，轻易不要开启ssh登陆，除非你已经很熟悉了。

shell 脚本

建一个目录，创建一个文件aliyun.sh，然后右键--属性查看文件路径：

查看文件路径

脚本内容如下：

#!/bin/sh

set -e

if [ $1 ]; then
    ApiId=$1
fi

if [ $2 ]; then
    ApiKey=$2
fi

if [ $3 ]; then
    Domain=$3
fi

if [ -z "$ApiId" -o -z "$ApiKey" -o -z "$Domain" ]; then
    echo "参数缺失"
    exit 1
fi

if [ $4 ]; then
    SubDomain=$4
fi

if [ -z "$SubDomain" ]; then
    SubDomain="@"
fi

Nonce=$(date -u "+%N")        # 有bug?
Timestamp=$(date -u "+%Y-%m-%dT%H%%3A%M%%3A%SZ")        # SB 阿里云, 什么鬼时间格式
Nonce=$Timestamp

urlencode() {
    local raw="$1";
    local len="${#raw}"
    local encoded=""

    for i in `seq 1 $len`; do
        local j=$((i+1))
        local c=$(echo $raw | cut -c$i-$i)

        case $c in [a-zA-Z0-9.~_-]) ;;
            *)
            c=$(printf '%%%02X' "'$c") ;;
        esac

        encoded="$encoded$c"
    done

    echo $encoded
}

# $1 = query string
getSignature() {
    local encodedQuery=$(urlencode $1)
    local message="GET&%2F&$encodedQuery"
    local sig=$(echo -n "$message" | openssl dgst -sha1 -hmac "$ApiKey&" -binary | openssl base64)
    echo $(urlencode $sig)
}

sendRequest() {
    local sig=$(getSignature $1)
    local result=$(wget -qO- --no-check-certificate --content-on-error "https://alidns.aliyuncs.com?$1&Signature=$sig")
    echo $result
}

getRecordId() {
    echo "获取 $SubDomain.$Domain 的 IP..." >&2
    local queryString="AccessKeyId=$ApiId&Action=DescribeSubDomainRecords&Format=JSON&SignatureMethod=HMAC-SHA1&SignatureNonce=$Nonce&SignatureVersion=1.0&SubDomain=$SubDomain.$Domain&Timestamp=$Timestamp&Type=A&Version=2015-01-09"
    local result=$(sendRequest "$queryString")
    local code=$(echo $result | sed 's/.*,"Code":"\([A-z]*\)",.*/\1/')
    local recordId=$(echo $result | sed 's/.*,"RecordId":"\([0-9]*\)",.*/\1/')

    if [ "$code" = "$result" ] && [ ! "$recordId" = "$result" ]; then
        local ip=$(echo $result | sed 's/.*,"Value":"\([0-9\.]*\)",.*/\1/')

        if [ "$ip" == "$NewIP" ]; then
            echo "IP 无变化, 退出脚本..." >&2
            echo "quit"
        else
            echo $recordId
        fi
    else
        echo "null"
    fi
}

# $1 = record ID, $2 = new IP
updateRecord() {
    local queryString="AccessKeyId=$ApiId&Action=UpdateDomainRecord&DomainName=$Domain&Format=JSON&RR=$SubDomain&RecordId=$1&SignatureMethod=HMAC-SHA1&SignatureNonce=$Nonce&SignatureVersion=1.0&Timestamp=$Timestamp&Type=A&Value=$2&Version=2015-01-09"
    local result=$(sendRequest $queryString)
    local code=$(echo $result | sed 's/.*,"Code":"\([A-z]*\)",.*/\1/')

    if [ "$code" = "$result" ]; then
        echo "$SubDomain.$Domain 已指向 $NewIP." >&2
    else
        echo "更新失败." >&2
        echo $result >&2
    fi
}

# $1 = new IP
addRecord() {
    local queryString="AccessKeyId=$ApiId&Action=AddDomainRecord&DomainName=$Domain&Format=JSON&RR=$SubDomain&SignatureMethod=HMAC-SHA1&SignatureNonce=$Nonce&SignatureVersion=1.0&Timestamp=$Timestamp&Type=A&Value=$1&Version=2015-01-09"
    local result=$(sendRequest $queryString)
    local code=$(echo $result | sed 's/.*,"Code":"\([A-z]*\)",.*/\1/')

    if [ "$code" = "$result" ]; then
        echo "$SubDomain.$Domain 已指向 $NewIP." >&2
    else
        echo "添加失败." >&2
        echo $result >&2
    fi
}

# Get new IP address
echo "获取当前 IP..."
NewIP=$(wget -qO- --no-check-certificate "http://members.3322.org/dyndns/getip")
echo "当前 IP 为 $NewIP."

# Get record ID of sub domain
recordId=$(getRecordId)

if [ ! "$recordId" = "quit" ]; then
    if [ "$recordId" = "null" ]; then
        echo "域名记录不存在, 添加 $SubDomain.$Domain 至 $NewIP..."
        addRecord $NewIP
    else
        echo "域名记录已存在, 更新 $SubDomain.$Domain 至 $NewIP..."
        updateRecord $recordId $NewIP
    fi
fi