苹果推送通知消息，使用SNS有效载荷长度

Question

I am using AWS SNS for pushing notification to apple devices. However, I am facing a lot of issue regarding the length of the message that can be passed to the SNS. Eg.

If i'm using the following message, it gets delivered:

{
    "default":"This is the default message",
    "APNS":"{
              \"aps\":{
                        \"badge\":9,
                        \"alert\":\"The ninth season of supernatural, an American paranormal drama television series created by Eric Kripke, premiered on October 8, 2013, concluded on May 20, 2014, and contained 23 episodes. On February 14, 201\",
                        \"sound\":\"default\"
                      }
            }"
}

with alert's value(which is the actual message) : 208 characters
Total characters : 319 characters

But if I add 1 more character in the message(alert's value), it doesn't work.

Again, If I use the following json with reduced message length(by 25 characters) and 1 extra parameter along aps the working lengths are as follows:

{
       "default":"This is the default message",
       "APNS":"{
                 \"aps\":{
                           \"badge\":9,
                           \"alert\":\"The ninth season of supernatural, an American paranormal drama television series created by Eric Kripke, premiered on October 8, 2013, concluded on May 20, 2014, and contained 23 epis\",
                           \"sound\":\"default\"
                         },
                 \"sound\":\"newMessage.aif\"
               }"
}

with alert's value(which is the actual message) : 183 characters
Total characters : 324 characters

However, if I add 1 more character to message(alert's value), it doesn't work.

I can't seem to figure out the amount of trimming I need to do, before sending the messages, so that it doesn't fail. Any body got any idea?

Answer 1

The payload of your message is :

{
     "aps":{
        "badge":9,
        "alert":"The ninth season of supernatural, an American paranormal drama television series created by Eric Kripke, premiered on October 8, 2013, concluded on May 20, 2014, and contained 23 epis",
        "sound":"default"
      },
      "sound":"newMessage.aif"
}

The total length of all the characters you see above, including the quotes and the brackets, should be <= 256 bytes (not just the content of the alert property). You should avoid any spaces and new-lines that are not part of the alert message, because those are also counted toward the 256 bytes limit.

Note that your second example contains an additional parameter "sound":"newMessage.aif" . That's why you have less remaining space for your alert.

BTW, I don't understand why you send the sound parameter twice. Is it a mistake? It should only appear inside the aps dictionary.

Relevant quotes from the APNS guide :

Each push notification includes a payload. The payload contains information about how the system should alert the user as well as any custom data you provide. The maximum size allowed for a notification payload is 256 bytes; Apple Push Notification Service refuses any notification that exceeds this limit.

The examples are formatted with whitespace and line breaks for readability. In practice, omit whitespace and line breaks to reduce the size of the payload, improving network performance.