Freeswitch sip Push notifications

不管是安卓还是ios现在多数的app都无法长时间在后台运行（特殊权限以及应用除外）,如果要想在app没有激活或者被冻结的情况下接收到来电，那么就需要先推送一条通知。

搜了一下有这么个插件：https://github.com/sem32/freeswitch-PushNotificator 尝试了一下发现编译起来比较麻烦，后来发现了这篇文章：https://www.zoiper.com/en/tutorials/push-notifications参考里面的关键代码，包含一个push.sh,代码如下：

#!/bin/bash

printResult() {
    echo "<root>"
    echo -e "\t<code>"$1"</code>"
    echo -e "\t<X_NotificationStatus>"$2"</X_NotificationStatus>"
    echo -e "\t<X_DeviceConnectionStatus>"$3"</X_DeviceConnectionStatus>"
    echo -e "\t<X_SubscriptionStatus>"$4"</X_SubscriptionStatus>"
    echo "</root>"
}

CURL=`which curl`

if [ -z $CURL ]; then
    echo "Curl not found"
    exit 1
fi

if [ -z $1 ]; then
    echo "Url is not set"
    exit 1
fi

URL=$1

i=0
max_i=3
while [ 1 ]
    do
        if [ $i -ge $max_i ]; then
            exit 0;
        fi
        let i++

        headers=`$CURL -s --data '
<?xml version="1.0" encoding="utf-8"?>
<root>
<Value1>Zoiper</Value1>
<Value2>Incoming</Value2>
<Value3>Call</Value3>
</root>
' -D - $URL --header "Content-Type: text/xml" --header "X-NotificationClass: 4" | tr -d '\r' `


        code=`echo "$headers" | head -n 1`
        X_NotificationStatus=`echo "$headers" | grep "X-NotificationStatus" | sed 's#X-NotificationStatus: ##' | sed -e 's/^\s*//g' -e 's/\s*$//g' `
        X_DeviceConnectionStatus=`echo "$headers" | grep "X-DeviceConnectionStatus"  | sed 's#X-DeviceConnectionStatus: ##' | sed -e 's/^\s*//g' -e 's/\s*$//g' `
        X_SubscriptionStatus=`echo "$headers" | grep "X-SubscriptionStatus"  | sed 's#X-SubscriptionStatus: ##'  | sed -e 's/^\s*//g' -e 's/\s*$//g' `

        if [ "$code" != "HTTP/1.1 200 OK" ]; then
            break;
        fi

        if [ "$X_NotificationStatus" != "Suppressed" ]; then
            break;
        fi

        if [ "$X_DeviceConnectionStatus" != "Connected" ]; then
            break;
        fi

        if [ "$X_SubscriptionStatus" != "Active" ]; then
            break;
        fi

    done

printResult "$code" "$X_NotificationStatus" "$X_DeviceConnectionStatus" "$X_SubscriptionStatus" 

除此之外freeswitch还需要配置dialplan逻辑：

<action application="set" data="result=${sofia_contact(1001)}"/>
<action application="set" data="push=${regex(${result}|^(?:.*)X-PUSH-URI=(.*)|%1)}"/>"
<action application="set" data="result=${system /usr/bin/push.sh ${push}}"/>
<action application="sleep" data="2000"/>
                

所以整体的一个逻辑就是修改拨号逻辑，在接收到呼叫的时候首先发送通知，2s之后开始正式呼叫。但是单纯基于上面的逻辑是无法进行push的，需要第三方推送服务支持，可以使用个推等服务。如果要通知呼叫号码，目标号码等，可以使用下面的代码：

 <action application="set" data="result=${system /root/sh/push_notice.sh ${caller_id_number} ${destination_number}}"/>
<action application="sleep" data="2000"/>