Context

The Context Object

The Context object is the “heart” of every request in Jazzy. It is passed to every route handler and middleware, providing a unified interface to interact with both the incoming request and the outgoing response.

Structure of Context

A Context object contains several key components:

• request: Access incoming data (headers, body, query params, etc.).
• response: Control the outgoing response (status, body, headers).
• auth: Manage user authentication and sessions.
• cache: Direct access to the application-level cache.
• requestId: A unique ID generated for every request (useful for logging).

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Accessing Information

Basic Helpers

• ctx.ip(): Automatically detects and returns the client’s IP address (respects TRUST_PROXY).
• ctx.param(key): Retrieves dynamic route parameters (e.g., /users/:id).
• ctx.input(key): Retrieves data from query strings or JSON bodies automatically.
• ctx.header(key): (Response) Sets a response header.
• ctx.status(code): (Response) Sets the HTTP status code.

Request Properties

You can access raw request data via ctx.request:

• ctx.request.headers: A table of incoming HTTP headers.
• ctx.request.httpMethod: The HTTP method (HttpGet, HttpPost, etc.).
• ctx.request.path: The requested URL path.
• ctx.request.body: The raw request body as a string.

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Generating Responses

Context provides fluent methods for sending different types of content:

proc handler(ctx: Context) {.async.} =
  ctx.status(200)
     .header("X-Powered-By", "Jazzy")
     .json(%*{"message": "Hello World"})

See the Responses documentation for more details.

Dependency Injection via Context

Because Context is passed everywhere, it serves as the primary way to access global services like Cache or Auth in a thread-safe manner:

proc dashboard(ctx: Context) {.async.} =
  if ctx.check(): # Check if user is logged in
    let user = ctx.user()
    let stats = ctx.cache.get("global_stats")
    ctx.json(%*{"user": user, "stats": stats})