The CoreMedia system supports gRPC and CORBA for internal communication. While servers always offer both protocols for clients to connect, clients can be configured to use either gRPC or CORBA. The protocol can be chosen freely on each start of a component. Currently, CORBA is the default protocol.

Note that Content Servers and the Workflow Server also contain client parts for internal communication, e.g., for publication, replication, etc. Choosing a protocol on a server therefore does make a difference although services offered by the servers to their clients always cover both protocols.

For communicating via CORBA, CoreMedia applications require the IOR of the Content Server and Workflow Server which they want to communicate with. The IOR of a server is delivered via the HTTP protocol. The following diagram illustrates retrieval of the CORBA IOR from a server.

Figure 4.1. IOR inquiry and answer between CoreMedia Client and Server

For communicating via gRPC, CoreMedia applications require the gRPC endpoint and the HTTP base URI of the Content Server and Workflow Server which they want to communicate with. In addition to that, environment variable REPOSITORY_USEGRPC=true must be set.

Note

With release 2512.0 of the CoreMedia system, the Workflow Server does not yet offer gRPC services to its clients. Activating gRPC on clients (e.g., Studio Server or command line tools) won't do any harm as long as these are of release 2512.0, too. Future clients, though, will fail to connect to this Workflow Server if gRPC is active on them.

Due to the current lack of gRPC services in the Workflow Server, the IOR URL of the Content Management Server must always be specified when a client wants to connect to the Workflow Server.

The Content Management Server/Live Server embed their own host names into the IOR, which must be resolved by the client machines. If this is not possible by the client, you can configure the server to embed a numeric IP address into the IOR. To do so, set the property com.coremedia.corba.server.host. In the following example, the ORB is configured to embed its numeric address, by setting a system property:

-Dcom.coremedia.corba.server.host="10.1.3.253"

The Unified API takes care of detecting and cleaning up stale TCP connections at the CORBA level. This aids in reconnecting to the servers after a communication failure or a server downtime. If reconnects happen spuriously without an obvious cause, this feature can be disabled by setting the system property com.coremedia.corba.orb.reconnect=false.