BBC-Coding-SETL-News-clock

BBC SETL Coding test: Control and update News lower thirds clock.

Setting up

You need a Java 17 development kit installed to compile the code. Instructions on how to do this are out-of-scope for this README, but there are several freely available builds of OpenJDK 17.

Whichever OS you are using probably has a prebuilt package installable from its package manager.

Further reading;

• OpenJDK (general information but emphasising Oracle's build);
  • About OpenJDK 17
  • Installing (Linux-heavy)
• Eclipse Temurin (AKA Adoptium)

Mock CasparCG Server

On many OSes, a CLI utility like Ncat can be used as a mock CasparCG Server, displaying the commands recieved and allowing you to type in responses. For example;

nc --listen 5250

When you see an incoming AMCP command like;

REQ 000000 CG 1 ADD 1 main/MAIN 1

... then you should type a suitable response like;

RES 000000 anything you like

The client code matches up the REQ and RES prefixes and the six hexadecimal digit identifier in them; the remainder of the line must be present, but is ignored. You'll see the command and response in the output of the control app.

The control app

To run the control app, at the command line;

./mvnw spring-boot:run

Among messages about the building of the app, you should see text like;

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.7.8)

2023-01-29 18:58:06.638  INFO 65934 --- [           main] uk.org.fwei.Application                  : Starting Application using Java 17.0.5 on mercury with PID 65934 (/home/dpc/Personal/Source/BBC-Coding-SETL-News-clock/target/classes started by dpc in /home/dpc/Personal/Source/BBC-Coding-SETL-News-clock)
2023-01-29 18:58:06.640  INFO 65934 --- [           main] uk.org.fwei.Application                  : No active profile set, falling back to 1 default profile: "default"
2023-01-29 18:58:07.305  INFO 65934 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2023-01-29 18:58:07.314  INFO 65934 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2023-01-29 18:58:07.314  INFO 65934 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.71]
2023-01-29 18:58:07.376  INFO 65934 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2023-01-29 18:58:07.376  INFO 65934 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 690 ms
Cannot send [CG 1 ADD 1 main/MAIN 1] to null:5250
Cannot send [CG 1 INVOKE 1 "leftTab('on', 'BBC News 18:58')"] to null:5250
2023-01-29 18:58:07.682  INFO 65934 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2023-01-29 18:58:07.694  INFO 65934 --- [           main] uk.org.fwei.Application                  : Started Application in 1.332 seconds (JVM running for 1.662)
Cannot send [CG 1 INVOKE 1 "leftTab('on', 'BBC News 18:59')"] to null:5250
Cannot send [CG 1 INVOKE 1 "leftTab('on', 'BBC News 19:00')"] to null:5250

Any messages about sending, not sending, or failing to send AMCP commands indicate that the control app is running as expected (even if it's having trouble connecting to a CasparCG Server).

If a problem occurs then a stack trace starting with text like;

Cannot send [CG 1 INVOKE 1 "leftTab('on', 'Beeb News 18:55')"] to ccgs01:55555
java.net.UnknownHostException: ccgs01
	at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:567)
	at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:327)

... will be output.

Settings

Several settings can be configured at the command line;

Setting	CLI option	Default value	Notes
CasparCG Server host	--casparCGServer.host	localhost	use null for console output
CasparCG Server port	--casparCGServer.port	5250
Left tab text prefix	--leftTab.textPrefix	'BBC News'	Use single quotes around values containing spaces

Examples

• The CasparCG Server host can be specified like this;

  ./mvnw spring-boot:run -Dspring-boot.run.arguments="--casparCGServer.host=ccgs01.fwei.org.uk"
  

• The Left tab's prefix text can be specified like this;

  ./mvnw spring-boot:run -Dspring-boot.run.arguments="--leftTab.textPrefix='British Broadcasting Corporation News'"
  

  (note that single quotes are used here because the prefix contains spaces)
• Multiple options can be specified together;

  ./mvnw spring-boot:run -Dspring-boot.run.arguments="--casparCGServer.host=ccgs01.fwei.org.uk --leftTab.textPrefix='Aunty Beeb News'"
  

Web UI

To use the control app, open your web browser and browse to;

• http://localhost:8080/

... to see some details of the app's internal state and a link to toggle the Left tab.