Server-Sent Events for React Native

EventSource.m

#import "RCTBridge.h"
#import "RCTConvert.h"
#import "RCTEventDispatcher.h"
#import "EventSource/EventSource.h"

#import "EventSourceClient.h"

@implementation EventSourceClient

@synthesize eventSource;
@synthesize bridge = _bridge;

RCT_EXPORT_MODULE();

- (void)dealloc{
  [self.eventSource close];
}

RCT_EXPORT_METHOD(connectWithURL:(NSString *)URLString){
  NSURL *serverURL = [NSURL URLWithString:URLString];
  
  self.eventSource = [EventSource eventSourceWithURL:serverURL];
  
  [self.eventSource onOpen: ^(Event *e) {
    RCTLogInfo(@"EventSource: Connected");
    
    [self.bridge.eventDispatcher sendDeviceEventWithName:@"EventSourceConnected"
                                                    body:@{@"event": @"connected",
                                                           // Guard against null values as NSMutableDictionary
                                                           // expects objects
                                                           @"data": e.data ? e.data : [NSNull null]}];
  }];
  
  [self.eventSource onError: ^(Event *e) {
    RCTLogInfo(@"EventSource: Error %@: %@", e.event, e.data);
    
    [self.bridge.eventDispatcher sendDeviceEventWithName:@"EventSourceError"
                                                    body:@{@"event": @"error",
                                                           // Guard against null values as NSMutableDictionary
                                                           // expects objects
                                                           @"data": e.data ? e.data : [NSNull null]}];
  }];
  
  [self.eventSource onMessage: ^(Event *e) {
    RCTLogInfo(@"%@: %@", e.event, e.data);
    
    [self.bridge.eventDispatcher sendDeviceEventWithName:@"EventSourceMessage"
                                                 body:@{@"event": e.event,
                                                        // Guard against null values as NSMutableDictionary
                                                        // expects objects
                                                        @"data": e.data ? e.data : [NSNull null]}];
  }];

}

@end

EventSourceClient.h

#import "RCTBridgeModule.h"
#import "EventSource/EventSource.h"

@interface EventSourceClient : NSObject <RCTBridgeModule> {
  EventSource *eventSource;
}

@property (nonatomic, retain) EventSource *eventSource;
@end

index.ios.js

var React = require('react-native');
var {
  AppRegistry,
  StyleSheet,
  Text,
  View,
  TouchableHighlight,
  AlertIOS,
  VibrationIOS,
  DeviceEventEmitter,
} = React;

var EventSource = require('NativeModules').EventSourceClient;

var MyFancyApp = React.createClass({
  getDefaultProps: function() {
    return {
      url: "https://sse/url"
    };
  },
  componentDidMount: function() {
    var subscription = DeviceEventEmitter.addListener(
      'EventSourceMessage', function(message) {
        console.log(message.event);
       });

    EventSource.connectWithURL(this.props.url);
  },
  componentDidUmnount: function() {
    subscription.remove();
  },
  render: function() {
    return (<View></View>)
  }
});