runtimes/js: Added middleware functionality

[fredr]

Adds a way to set custom status codes and an api for passing data from middlewares to the handler.

const mw = middleware(async (req, next) => {
  // add data that can be read from the handler
  req.data.myMiddlewareData = { some: "data" };

  const resp = await next(req);

  // change the status code on the response
  resp.status = 418;

  return resp
});

To access data in the handler

export const get = api(
  { expose: true, method: "GET", path: "/hello/:name" },
  async ({ name }: { name: string }): Promise<Response> => {
    const callMeta = currentRequest() as APICallMeta;
    const myData = callMeta.middlewareData?.myMiddlewareData;

    return { message: "Hello " + name };
  },
);

[encore-cla]

All committers have signed the CLA.

[solarsoft0]

any luck on this PR, cc @fredr @eandre, I actually need a way to set context/data from an handler too; after hook could benefit from this to determine behavior, or is there another alternative way to do this aside from raw?

seems blocking my effort on this, and i'm avoiding forklift migration. solarsoft0/encore-better-auth#1

[solarsoft0]

any luck on this PR, cc @fredr @eandre, I actually need a way to set context/data from an handler too; after hook could benefit from this to determine behavior, or is there another alternative way to do this aside from raw?

seems blocking my effort on this, and i'm avoiding forklift migration. solarsoft0/encore-better-auth#1

without this, i would need to resort to handling middleware manually like its currently being done, which makes it less of encore, if that makes sense.

[fredr]

hey @solarsoft0, this PR stalled over Christmas and new years vacation, but I'm back now and we should soon get this merged. We are exploring some different approaches for the implementation first

[solarsoft0]

hey @solarsoft0, this PR stalled over Christmas and new years vacation, but I'm back now and we should soon get this merged. We are exploring some different approaches for the implementation first

thank you! I can see it's reaaaaady!