Push Templates

All apps using push v2 or created after January 18, 2022 do not need to configure any template in general. However, some platforms might still need to add templates. This is a general description of templating. For templating in v2, see details here. For migrating to v2, see details here.

For both Firebase and APN, the payload that is being sent is rendered using the handlebars templating language, to ensure full configurability for your app.

Stream provides the following variables in the template rendering context:

Context Variables

Name	Type	Description
channel	object	Channel object. You can access the channel name and any other custom field you have defined for this channel
sender	object	Sender object. You can access the user name, id or any other custom field you have defined for the user
receiver	object	Receiver object. You can access the user name, id or any other custom field you have defined for the user
message	object	Message object. You can access the text of the message (or a preview of it if the message is too large) or any other custom field you have defined for the message
members	array	Channel members. You can access the user name, id and any other custom field of each member (i.e. excluding sender)
otherMembers	array	Like members but the user who will be receiving the notification is excluded (i.e. excluding sender and receiver)
unread_count	integer	Number of unread messages
unread_channels	integer	Number of unread channels for this user

members andotherMembers aren’t available in the v2 template context.

Defaults

v1

When editing APN/Firebase settings, if you leave the notification_template or data_template field empty, default templates will be used.

v2

Editing data template is forbidden. There is no default for notification_template, it’s sent only if set. apn_template is introduced for apn templating under firebase.

APN default (v1):

{
  "aps" : {
    "alert": {
      "title": "{{ sender.name }} @ {{ channel.name }}",
      "body": "{{ truncate message.text 2000 }}"
    },
    "badge": {{ unread_count }},
    "category": "NEW_MESSAGE"
  },
  "stream": {
    "sender": "stream.chat",
    "type": "message.new",
    "version": "v1",
    "id": "{{ message.id }}",
    "cid": "{{ channel.cid }}"
  }
}

Firebase default notification template (v1):

{
  "title": "{{ sender.name }} @ {{ channel.name }}",
  "body": "{{ truncate message.text 2000 }}",
  "click_action": "OPEN_ACTIVITY_1",
  "sound": "default"
}

Firebase default data template (v1):

{
  "sender": "{{ sender.id }}",
  "channel": {
    "type": "{{ channel.type }}",
    "id": "{{ channel.id }}"
  },
  "message": "{{ message.id }}"
}

APN default and Firebase default APN template (v2):

{
  "aps" : {
    "alert": {
      "title": "New message from {{ sender.name }}",
      "body": "{{ truncate message.text 2000 }}"
    },
    "mutable-content": 1,
    "category": "stream.chat"
  },
  "stream": {
    "sender": "stream.chat",
    "type": "message.new",
    "version": "v2",
    "id": "{{ message.id }}",
    "cid": "{{ channel.cid }}"
  }
}

Generic default data payload (v2):

{
 "sender": "stream.chat",
 "type": "message.new",
 "version": "v2",
 "message_id": "{{ message.id }}",
 "id": "{{ message.id }}",
 "channel_type": "{{ channel.type }}",
 "channel_id": "{{ channel.id }}",
 "cid": "{{ channel_cid }}"
}

Limitations

There are some limitations that Stream imposes on the push notification handlebars template to make sure no malformed payloads are being sent to push providers.

1: Custom Arrays Can’t Be Indexed

For example, given the context:

{
  "sender":{
    "name": "Bob",
    "some_array": ["foo","bar"]
  }
}

And the template:

"title": {{ sender.some_array.[0] }}

The rendered payload will be:

"title": ""

2: Interpolating Whole Lists and Objects Isn’t Allowed

For example, given the context:

{
  "sender":{
    "name": "bob",
    "some_array": ["foo","bar"],
    "address": {
      "street": "willow str"
    }
  }
}

And the template:

"title": "{{ sender.some_array }} {{ sender.address }}"

The rendered payload will be:

"title": "[] {}"

3: Unquoted fields that aren’t in the context will be rendered as empty strings

For example, given the context:

{
  "sender":{
    "name": "bob"
  }
}

And the template:

"title": {{ sender.missing_field }}

The rendered payload will be:

"title": ""

Advanced Use Cases

For advanced use cases (e.g. A list of channel members in the notification title, conditional rendering, etc), Stream provides some handlebars helper functions.

Helper Functions

name	type	description
implodemembers	function	takes the list of channel members and implodes it into a single string, using a custom limit, separator and suffix.
json	function	renders passed parameter as JSON (e.g {“channel”:{{{ json channel }}}} )
each	function	For loop. Use this to access the current variable, @index for the current index and @first and @last as convenience booleans to determine if the iteration is at its first/last element
if	function	If function. Tests trueness of given parameter. Supports else statement. (e.g {{#if sender.name}}{{ sender.name }}{{/if}} )
unless	function	Unless function. Tests falseness of given parameter. Supports else statement. (e.g {{#unless sender.name}}Missing name{{/unless}} )
equal	function	Equality check function. Tests equality of the given 2 parameters. Supports else statement. (e.g {{#equal channel.type “messaging” }}This is the messaging channel{{else}}This is another channel{{/equal}} )
unequal	function	Inequality check function. Tests inequality of the given 2 parameters. Supports else statement. (e.g {{#unequal channel.type “messaging” }}This is another channel{{else}}This is the messaging channel{{/unequal}} )
ifLt	function	If less than. Supports else statement.
ifLte	function	If less than or equal. Supports else statement.
ifGt	function	If greater than. Supports else statement.
ifGte	function	If greater than or equal. Supports else statement.
remainder	function	Calculates the difference between the length of an array and an integer (e.g {{remainder otherMembers 2}}
truncate	function	Truncate given text to given length (e.g {{ truncate message.text 2000 }})

Most of the functions above are straight forward, except for implodeMembers, which will be detailed further.

The full function signature is: {{implodeMembers otherMembers|members [limit=] [separator=] [nameField=] [suffixFmt=]}}

Function Parameters

name	type	description	default
otherMembers	members	array	Which member array to implode
limit	integer	How many member names to show before adding the suffix	3
nameField	string	Field name from which field to retrieve the member’s name. Note: does not support nesting	name
separator	string	Separator to use for channel members	,
suffixFmt	string	Format string to use for the suffix. Note: only %d is allowed for formatting	and %d other(s)

Examples

Let’s put these helpers to use in a few examples:

Example 1

Rendering channel members in the notification title. Each member’s name is stored in the fullName field.

What we want to achieve:

{
  "aps": {
    "alert": {
      "title": "Bob Jones, Jessica Wright, Tom Hadle and 4 other(s)",
      "body": "Bob Jones: Hello there fellow channel members"
    },
    "badge": 0
  }
}

How we will achieve it: using implodeMembers with a custom name field (leaving others empty so that defaults will be used):

{
  "aps": {
    "alert": {
      "title": "{{implodeMembers otherMembers nameField="fullName"}}",
      "body": "{{ sender.fullName }}: {{ message.text }}"
    },
    "badge": {{ unread_count }}
  }
}

Example 2

Rendering channel members in the notification title. Each member’s name is stored in the nested details.name field.

What we want to achieve:

{
  "aps": {
    "alert": {
      "title": "Bob Jones, Jessica Wright, Tom Hadle and 4 other(s)",
      "body": "Bob Jones: Hello there fellow channel members"
    },
    "badge": 0
  }
}

How we will achieve it: since implodeMembers doesn’t support nested fields, we need to use a bunch of helpers such as each, ifLte. Note how the use of ~ will trim the whitespaces so that the title in rendered in a single row:

{
  "aps": {
    "alert": {
      "title": "
      {{~#each otherMembers}}
        {{#ifLte @index 2}}
          {{~this.details.name}}{{#ifLt @index 2 }}, {{/ifLt~}}
        {{~else if @last~}}
          {{{ " " }}} and {{remainder otherMembers 3}} other(s)
        {{~/ifLte~}}
      {{/each~}}",
      "body": "{{ sender.details.name }}: {{ message.text }}"
    },
    "badge": {{ unread_count }}
  }

Push Devices

Push Templates in v2