shared.ts

import { deserializeJSONStream, deserializeJSStream } from "./serialization.ts";

export const BODY_FORMAT_KEY = "X-Start-Type";

export const BODY_FORMAL_FILE = "__START__";

export const enum BodyFormat {
  Seroval = "0",
  String = "1",
  FormData = "2",
  URLSearchParams = "3",
  Blob = "4",
  File = "5",
  ArrayBuffer = "6",
  Uint8Array = "7",
}

export function getHeadersAndBody(body: any):
  | {
      headers?: HeadersInit;
      body: BodyInit;
    }
  | undefined {
  switch (true) {
    case typeof body === "string":
      return {
        headers: {
          "Content-Type": "text/plain",
          [BODY_FORMAT_KEY]: BodyFormat.String,
        },
        body,
      };
    case body instanceof FormData:
      return {
        headers: {
          [BODY_FORMAT_KEY]: BodyFormat.FormData,
        },
        body,
      };
    case body instanceof URLSearchParams:
      return {
        headers: {
          "Content-Type": "application/x-www-form-urlencoded",
          [BODY_FORMAT_KEY]: BodyFormat.URLSearchParams,
        },
        body,
      };
    case body instanceof File: {
      const formData = new FormData();
      formData.append(BODY_FORMAL_FILE, body, body.name);
      return {
        headers: {
          [BODY_FORMAT_KEY]: BodyFormat.File,
        },
        body: formData,
      };
    }
    case body instanceof Blob:
      return {
        headers: {
          [BODY_FORMAT_KEY]: BodyFormat.Blob,
        },
        body,
      };
    case body instanceof ArrayBuffer:
      return {
        headers: {
          [BODY_FORMAT_KEY]: BodyFormat.ArrayBuffer,
        },
        body,
      };
    case body instanceof Uint8Array:
      return {
        headers: {
          [BODY_FORMAT_KEY]: BodyFormat.Uint8Array,
        },
        body: new Uint8Array(body),
      };
    default:
      return undefined;
  }
}

export async function extractBody(instance: string, client: boolean, source: Request | Response) {
  const contentType = source.headers.get("content-type");
  const startType = source.headers.get(BODY_FORMAT_KEY);
  const clone = source.clone();

  switch (true) {
    case startType === BodyFormat.Seroval:
      if (client && import.meta.env.SEROVAL_MODE === "js") {
        return await deserializeJSStream(instance, clone);
      }
      return await deserializeJSONStream(clone);
    case startType === BodyFormat.String:
      return await clone.text();
    case startType === BodyFormat.File: {
      const formData = await clone.formData();
      return formData.get(BODY_FORMAL_FILE);
    }
    case startType === BodyFormat.FormData:
    case contentType?.startsWith("multipart/form-data"):
      return await clone.formData();
    case startType === BodyFormat.URLSearchParams:
    case contentType?.startsWith("application/x-www-form-urlencoded"):
      return new URLSearchParams(await clone.text());
    case startType === BodyFormat.Blob:
      return await clone.blob();
    case startType === BodyFormat.ArrayBuffer:
      return await clone.arrayBuffer();
    case startType === BodyFormat.Uint8Array:
      return new Uint8Array(await clone.arrayBuffer());
  }

  return undefined;
}