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Example of streamer for iOS

This streamer can be used to publish WebRTC video stream on Web Call Server.

...

• left - video from the camera
• right - the published video stream is played from the server

Work with code of the example

To analyze the code, let's take Streamer example version with hash c313c93, which can be downloaded with build build 2.5.2.4.

View class for the main view of the application: ViewController (header file ViewController.h; implementation file ViewController.m).

1. Import of API. ViewController.m, line 12 code

#import <FPWCSApi2/FPWCSApi2.h>

2. Connection to server.

ViewController method connect is called when Start button is tapped. ViewController.m, line 247

[self connect];

In the method,

- object with options for connection session is created (ViewController.m, line 36Session creation.

FPWCSApi2 createSession code

The options include:

• URL of WCS server
• appKey of internal server-side application (defaultApp)

FPWCSApi2SessionOptions *options = [[FPWCSApi2SessionOptions alloc] init];
.....NSURL *url =[[NSURL alloc] initWithString:_connectUrl.text];
options.urlServer = [NSString stringWithFormat:@"%@://%@:%@", url.scheme, url.host, url.port];
streamName = [url.....path.stringByDeletingPathExtension stringByReplacingOccurrencesOfString: @"/" withString:@""];
options.appKey = @"defaultApp";
NSError *error;

The options include URL of WCS server and appKey of internal server-side application.

...

session = [FPWCSApi2 createSession:options error:&error];

3. Connection to the server

FPWCSApi2Session connect code

[session connect];

4. Receiving the event confirming successful connection.

ViewController onConnected code

On this event, ViewController publishStream method is called to publish the stream

- (void)onConnected:(FPWCSApi2Session *)session = [FPWCSApi2 createSession:options error:&error];

...

 {
    [_connectButton setTitle:@"STOP" forState:UIControlStateNormal];
   // [self changeViewState:_connectButton enabled:YES];
    [self publishStream];
}

5. Stream publishing.

FPWCSApi2Session createStream, FPWCSApi2Stream publish code

Object with next stream options is passed to createStream method:

• stream name
• view to display video
• video constraints (for iPad for example)

[session on:kFPWCSSessionStatusEstablished callback:^(FPWCSApi2Session- (FPWCSApi2Stream *rSession)publishStream {
    FPWCSApi2Session *session = [FPWCSApi2 [self changeConnectionStatus:[rSession getStatus]]getSessions][0];
    FPWCSApi2StreamOptions *options = [[FPWCSApi2StreamOptions alloc] init];
    options.name = streamName;
    [self onConnected:rSession];
}];

[session on:kFPWCSSessionStatusDisconnected callback:^(FPWCSApi2Session *rSession){
    [self changeConnectionStatus:[rSession getStatus]];
    [self onDisconnected];
}];

[session on:kFPWCSSessionStatusFailed callback:^(FPWCSApi2Session *rSession){
    [self changeConnectionStatus:[rSession getStatus]];
    [self onDisconnected];
}];

Depending on the session status, corresponding ViewController method will be called to make appropriate changes in controls of the interface

• if connection is successfully established: onConnected
• in case of disconnection, or connection failure: onDisconnected

- FPWCSApi2Session method connect is called to establish connection to server (ViewController.m, line 75)

[session connect];

3. Stream publishing.

When connection to the server is established, ViewController method publishStream is called to publish the stream. ViewController.m, line 199

[self publishStream];

In the method,

- object with stream publish options is created (ViewController.m, line 81)

options.display = _videoView.local;
    if ( UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad ) {
        options.constraints = [[FPWCSApi2MediaConstraints alloc] initWithAudio:YES videoWidth:640 videoHeight:480 videoFps:15];
    }
    NSError *error;
    publishStream = [session createStream:options error:&error];
    ...
    if(![publishStream publish:&error]) {
        UIAlertController * alert = [UIAlertController
                                     alertControllerWithTitle:@"Failed to publish"
                                     message:error.localizedDescription
                                     preferredStyle:UIAlertControllerStyleAlert];
        
        UIAlertAction* okButton = [UIAlertAction
                                    actionWithTitle:@"Ok"
                                    style:UIAlertActionStyleDefault
                                    handler:^(UIAlertAction * action) {
                                        [self onUnpublished];
                                    }];
        
        [alert addAction:okButton];
        [self presentViewController:alert animated:YES completion:nil];
    }
    return publishStream;
}

6. Receiving the event confirming successful stream publishing.

ViewController onPublishing code

On this event, ViewController playStream method is called to play preview stream

- (void)onPublishing:(FPWCSApi2Stream *)stream {
    [self playStream];
}

7. Preview stream playback.

FPWCSApi2Session createStream, FPWCSApi2Stream play code

Object with next stream options is passed to createStream method:

• stream name
• view to display video

- (FPWCSApi2Stream *)playStream {
    FPWCSApi2Session *session = [FPWCSApi2 getSessions][0];
    FPWCSApi2StreamOptions *options = [[FPWCSApi2StreamOptions alloc] init];
    options.name = streamName;
    options.display = _videoView.local;

The required options are stream name and view for displaying video.
Also, video constraints can be specified. E.g., in the example, constraints are added in case the iOS device is iPad:

if ( UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad ) {
    options.constraints = [[FPWCSApi2MediaConstraints alloc] initWithAudio:YES videoWidth:640 videoHeight:480 videoFps:15];
}

- new stream is created with FPWCSApi2Session method createStream, which returns FPWCSApi2Stream object (ViewController.m, line 88)

publishStream = [session createStream:options error:&error];

- callback functions for processing stream statuses are added (ViewController.m, line 106)

[publishStream on:kFPWCSStreamStatusPublishing callback:^(FPWCSApi2Stream *rStream){
    [self changeStreamStatus:rStream];
    [self onPublishing:rStream];
}];

Depending on the stream status, corresponding ViewController method will be called to make appropriate changes in controls of the interface

• if stream is successfully published: onPublishing
• in case of failure, or when stream is unpublished: onUnpublished

- FPWCSApi2Stream method publish is called to publish the stream (ViewController.m, line 120)

[publishStream publish:&error]

4. Disconnection. ViewController.m, line 239

FPWCSApi2Session method disconnect is called to close connection to the server when Stop button is tapped.

[session disconnect];remote;
    NSError *error;
    playStream = [session createStream:options error:nil];
    ...
    if(![playStream play:&error]) {
        UIAlertController * alert = [UIAlertController
                                     alertControllerWithTitle:@"Failed to play"
                                     message:error.localizedDescription
                                     preferredStyle:UIAlertControllerStyleAlert];
        
        UIAlertAction* okButton = [UIAlertAction
                                   actionWithTitle:@"Ok"
                                   style:UIAlertActionStyleDefault
                                   handler:^(UIAlertAction * action) {
                                       
                                   }];
        
        [alert addAction:okButton];
        [self presentViewController:alert animated:YES completion:nil];
    }
    return playStream;
}

8. Disconnection

FPWCSApi2Session disconnect code

- (void)connectButton:(UIButton *)button {
    [self changeViewState:button enabled:NO];
    if ([button.titleLabel.text isEqualToString:@"STOP"]) {
        if ([FPWCSApi2 getSessions].count) {
            FPWCSApi2Session *session = [FPWCSApi2 getSessions][0];
            NSLog(@"Disconnect session with server %@", [session getServerUrl]);
            [session disconnect];
        } else {
            NSLog(@"Nothing to disconnect");
            [self onDisconnected];
        }
    } else {
        //todo check url is not empty
        [self changeViewState:_connectUrl enabled:NO];
        [self connect];
    }
}

9. Receiving the event confirming successful disconnection.

ViewController onDisconnected code

- (void)onDisconnected {
    [_connectButton setTitle:@"START" forState:UIControlStateNormal];
    [self changeViewState:_connectButton enabled:YES];
    [self changeViewState:_connectUrl enabled:YES];
    [self onUnpublished];
    [self onStopped];
}