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Encoding for General Proxy Parameters

The first component of an encoded proxy is a value of type Ice::Identity. If the proxy is a nil value, the category and name members are empty strings, and no additional data is encoded. The encoding for a non-null proxy consists of general parameters followed by endpoint parameters.

The general proxy parameters are encoded as if they were members of the following structure:

struct ProxyData {
    Ice::Identity id;
    Ice::StringSeq facet;
    byte mode;
    bool secure;
};

The general proxy parameters are described in the following table.

The facet field has either zero elements or one element. An empty sequence denotes the default facet, and a one-element sequence provides the facet name in its first member. If a receiver receives a proxy with a facet field with more than one element, it must throw a ProxyUnmarshalException.

Encoding for Endpoint Parameters

A proxy optionally contains an endpoint list or an adapter identifier, but not both.

• If a proxy contains endpoints, they are encoded immediately following the general parameters. A size specifying the number of endpoints is encoded first, followed by the endpoints. Each endpoint is encoded as a short specifying the endpoint type (1=TCP, 2=SSL, 3=UDP), followed by an encapsulation of type-specific parameters. The type-specific parameters for TCP, UDP, and SSL are presented in the sections that follow.
• If a proxy does not have endpoints, a single byte with value 0 immediately follows the general parameters and a string representing the object adapter identifier is encoded immediately following the zero byte.

Type-specific endpoint parameters are encapsulated because a receiver may not be capable of decoding them. For example, a receiver can only decode SSL endpoint parameters if it is configured with the IceSSL plug-in. However, the receiver must be able to re-encode the proxy with all of its original endpoints, in the order they were received, even if the receiver does not understand the type-specific parameters for an endpoint. Encapsulation of the parameters into an opaque endpoint allows the receiver to do this.

Encoding for TCP Endpoint Parameters

A TCP endpoint is encoded as an encapsulation containing the following structure:

struct TCPEndpointData {
    string host;
    int port;
    int timeout;
    bool compress;
};

The endpoint parameters are described in the following table.

Encoding for UDP Endpoint Parameters

A UDP endpoint is encoded as an encapsulation containing the following structure:

struct UDPEndpointData {
    string host;
    int port;
    byte protocolMajor;
    byte protocolMinor;
    byte encodingMajor;
    byte encodingMinor;
    bool compress;
};

The endpoint parameters are described in the following table.

Encoding for SSL Endpoint Parameters

An SSL endpoint is encoded as an encapsulation containing the following structure:

struct SSLEndpointData {
    string host;
    int port;
    int timeout;
    bool compress;
};

The endpoint parameters are described in the following table.

See Also

• Object Identity
• Facets and Versioning
• Basic Data Encoding
• IceSSL
• Using Connections
• Protocol Compression