Initializing the server
Let’s pretend you’ve just initialized a new Fresh project. You want to do some
complicated setup that runs once, before the server is started. This is,
fortunately, quite easy. Here’s how. Modify your fresh.config.ts like this:
import twindConfig from "./twind.config.ts";
+import { Context } from "./routes/_middleware.ts";
+
+await Context.init();
export default defineConfig({
plugins: [twindPlugin(twindConfig)],So your full fresh.config.ts should look like this:
import { defineConfig } from "$fresh/server.ts";
import twindPlugin from "$fresh/plugins/twind.ts";
import twindConfig from "./twind.config.ts";
import { Context } from "./routes/_middleware.ts";
await Context.init();
export default defineConfig({
plugins: [twindPlugin(twindConfig)],
});But what’s going on in this new _middleware.ts we’ve created?
import { FreshContext } from "$fresh/server.ts";
export interface State {
context: Context;
}
export class Context {
private static context: Context;
private complicatedStartupValue: number;
public constructor() {
console.log("i'm logged during initialization, and not during handling!");
// presumably this involves connecting to a
// database or doing some heavy computation
this.complicatedStartupValue = 42;
}
public static async init() {
Context.context = new Context();
}
public static instance() {
if (this.context) return this.context;
else throw new Error("Context is not initialized!");
}
}
export async function handler(
_req: Request,
ctx: FreshContext<State>,
) {
ctx.state.context = Context.instance();
if (ctx.destination === "route") {
console.log("i'm logged during a request!");
console.log(ctx.state.context);
}
const resp = await ctx.next();
return resp;
}So now in this handler (or any other handler functions you create) you can
have access to the complicated initialization step by calling
Context.instance().
Proving it out
Dev
When you run deno task start you should see the following output:
Task start deno run -A --watch=static/,routes/ dev.ts
Watcher Process started.
i'm logged during initialization, and not during handling!
The manifest has been generated for 6 routes and 1 islands.
🍋 Fresh ready
Local: http://localhost:8000/Going to http://localhost:8000/ should produce:
i'm logged during a request!
Context { complicatedStartupValue: 42 }Build
When you run deno task build you should see:
Task build deno run -A dev.ts build
i'm logged during initialization, and not during handling!
The manifest has been generated for 6 routes and 1 islands.
Assets written to: /path/to/my/project/_freshThere’s no handling of routes associated with this, but note that the initialization occurred.
Preview
Finally when you run deno task preview you should see:
Task preview deno run -A main.ts
i'm logged during initialization, and not during handling!
Using snapshot found at /Users/reed/code/temp/1763/_fresh
🍋 Fresh ready
Local: http://localhost:8000/Going to http://localhost:8000/ should produce:
i'm logged during a request!
Context { complicatedStartupValue: 42 }