Inngest - Encryption middleware

encryption-middleware.ts

import { InngestMiddleware } from "inngest";

export const encryptionMiddleware = (
  key: string = process.env.INNGEST_ENCRYPTION_KEY || ""
) => {
  if (!key) {
    throw new Error("Must provide an encryption key");
  }

  const prefix = "__ENCRYPTED__";

  // Change `encrypt` to whatever implementation you want - obviously not this.
  const encrypt = <T = string>(value: unknown): T => {
    return `${prefix}${JSON.stringify(value)
      .split("")
      .reverse()
      .join("")}` as T;
  };

  // Change `decrypt` to whatever implementation you want - obviously not this.
  const decrypt = <T>(value: T): T => {
    if (typeof value === "string" && value.startsWith(prefix)) {
      return JSON.parse(
        value.slice(prefix.length).split("").reverse().join("")
      );
    }

    // Assume the value is not encrypted, e.g. sent from the UI or something.
    return value;
  };

  return new InngestMiddleware({
    name: "Encryption",
    init: () => {
      return {
        onSendEvent: () => {
          return {
            transformInput: ({ payloads }) => {
              return {
                payloads: payloads.map((payload) => ({
                  ...payload,
                  data: payload.data ? encrypt(payload.data) : undefined,
                })),
              };
            },
          };
        },
        onFunctionRun: () => {
          return {
            transformInput: ({ ctx, steps }) => {
              return {
                steps: steps.map((step) => ({
                  ...step,
                  data: step.data ? decrypt(step.data) : undefined,
                })),
                ctx: {
                  event: ctx.event ? decrypt(ctx.event) : undefined,
                  events: ctx.events ? ctx.events.map(decrypt) : undefined,
                } as {},
              };
            },
            transformOutput: (ctx) => {
              return {
                result: {
                  data: ctx.result.data ? encrypt(ctx.result.data) : undefined,
                },
              };
            },
          };
        },
      };
    },
  });
};