Custom Messages

Content beyond text and images, such as an order card or shared location, can be a WKMessageContent subclass. Every client must use the same type number and JSON fields for the same content.

1. Define the content

This example uses an order card. 10001 is only an example; maintain a shared registry of type numbers so product messages do not collide.

@interface OrderMessageContent : WKMessageContent
@property (nonatomic, copy) NSString *orderID;
@property (nonatomic, copy) NSString *title;
@end

@implementation OrderMessageContent

+ (NSNumber *)contentType {
    return @(10001);
}

- (NSDictionary *)encodeWithJSON {
    return @{
        @"order_id": self.orderID ?: @"",
        @"title": self.title ?: @""
    };
}

- (void)decodeWithJSON:(NSDictionary *)json {
    self.orderID = [json[@"order_id"] isKindOfClass:[NSString class]]
        ? json[@"order_id"] : @"";
    self.title = [json[@"title"] isKindOfClass:[NSString class]]
        ? json[@"title"] : @"";
}

- (NSString *)conversationDigest {
    return [NSString stringWithFormat:@"[Order] %@", self.title];
}

- (NSString *)searchableWord {
    return self.title;
}

@end

Validate types and missing fields while decoding network data. Clients may not all run the same application version.

2. Register before reading messages

[[WKSDK shared] registerMessageContent:[OrderMessageContent class]];

Register once while configuring the SDK at app startup, before connecting or reading local messages. Unregistered content cannot be restored as your product type.

3. Send and render

OrderMessageContent *content = [OrderMessageContent new];
content.orderID = @"order-2026-001";
content.title = @"Coffee beans";

WKChannel *channel = [WKChannel personWithChannelID:@"bob"];
[[WKSDK shared].chatManager sendMessage:content channel:channel];

Render known types and show a safe placeholder for unknown content:

if ([message.content isKindOfClass:[OrderMessageContent class]]) {
    OrderMessageContent *order = (OrderMessageContent *)message.content;
    [self showOrderWithID:order.orderID title:order.title];
} else {
    [self showUnsupportedMessage];
}

Keep schema changes backward compatible: give new fields defaults, do not reuse an old field for a new meaning, and never change a published type number.

iOS Custom Messages

1. Define the content

2. Register before reading messages

3. Send and render

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