Explicit Request Contexts

Request contexts allow a client to send additional data to the server without having to include this data as input parameters in the operation’s Slice definition. They provide a lightweight mechanism for passing metadata alongside normal request arguments.

The Ice context demo provides a complete example of using request context in JavaScript.

Using the Slice greeter definitions once again:

module VisitorCenter
{
    interface Greeter
    {
        string greet(string name);
    }
}

A client application can set a request context to send additional metadata:

// We request a French greeting by setting the context parameter.
let greeting = await greeter.greet(name, new Map([["language", "fr"]]));

On the server side, the request context is available through the ctx member of the Ice.Current parameter:

greet(name: string, current: Ice.Current): string | Promise<strng> {
    // We retrieve the value for the language entry in the context.
    const language: string = current.ctx.get("language") || "";
    ...
}