index.ts

import {
  ChecksumConstructor,
  Decoder,
  Encoder,
  HashConstructor,
  InitializeHandler,
  InitializeHandlerArguments,
  InitializeHandlerOptions,
  InitializeHandlerOutput,
  InitializeMiddleware,
  MetadataBearer,
  Pluggable,
  SourceData,
} from "@aws-sdk/types";
interface PreviouslyResolved {
  base64Encoder: Encoder;
  md5: ChecksumConstructor | HashConstructor;
  utf8Decoder: Decoder;
}

export function ssecMiddleware(options: PreviouslyResolved): InitializeMiddleware<any, any> {
  return <Output extends MetadataBearer>(next: InitializeHandler<any, Output>): InitializeHandler<any, Output> =>
    async (args: InitializeHandlerArguments<any>): Promise<InitializeHandlerOutput<Output>> => {
      let input = { ...args.input };
      const properties = [
        {
          target: "SSECustomerKey",
          hash: "SSECustomerKeyMD5",
        },
        {
          target: "CopySourceSSECustomerKey",
          hash: "CopySourceSSECustomerKeyMD5",
        },
      ];

      for (const prop of properties) {
        const value: SourceData | undefined = (input as any)[prop.target];
        if (value) {
          const valueView: Uint8Array = ArrayBuffer.isView(value)
            ? new Uint8Array(value.buffer, value.byteOffset, value.byteLength)
            : typeof value === "string"
            ? options.utf8Decoder(value)
            : new Uint8Array(value);
          const encoded = options.base64Encoder(valueView);
          const hash = new options.md5();
          hash.update(valueView);
          input = {
            ...(input as any),
            [prop.target]: encoded,
            [prop.hash]: options.base64Encoder(await hash.digest()),
          };
        }
      }

      return next({
        ...args,
        input,
      });
    };
}

export const ssecMiddlewareOptions: InitializeHandlerOptions = {
  name: "ssecMiddleware",
  step: "initialize",
  tags: ["SSE"],
  override: true,
};

export const getSsecPlugin = (config: PreviouslyResolved): Pluggable<any, any> => ({
  applyToStack: (clientStack) => {
    clientStack.add(ssecMiddleware(config), ssecMiddlewareOptions);
  },
});