public async stageBlock()

in src/blob/handlers/BlockBlobHandler.ts [169:266]
83 lines of code
9 McCabe index (conditional complexity)

  public async stageBlock(
    blockId: string,
    contentLength: number,
    body: NodeJS.ReadableStream,
    options: Models.BlockBlobStageBlockOptionalParams,
    context: Context
  ): Promise<Models.BlockBlobStageBlockResponse> {
    const blobCtx = new BlobStorageContext(context);
    const accountName = blobCtx.account!;
    const containerName = blobCtx.container!;
    const blobName = blobCtx.blob!;
    const date = blobCtx.startTime!;

    // stageBlock operation doesn't have blobHTTPHeaders
    // https://learn.microsoft.com/en-us/rest/api/storageservices/put-block
    // options.blobHTTPHeaders = options.blobHTTPHeaders || {};
    const contentMD5 = context.request!.getHeader("content-md5")
      || context.request!.getHeader("x-ms-blob-content-md5")
      ? options.transactionalContentMD5 ||
      context.request!.getHeader("content-md5")
      : undefined;

    this.validateBlockId(blockId, blobCtx);

    await this.metadataStore.checkContainerExist(
      context,
      accountName,
      containerName
    );

    const persistency = await this.extentStore.appendExtent(
      body,
      context.contextId
    );
    if (persistency.count !== contentLength) {
      // TODO: Confirm error code
      throw StorageErrorFactory.getInvalidOperation(
        blobCtx.contextId!,
        `The size of the request body ${persistency.count} mismatches the content-length ${contentLength}.`
      );
    }

    // Calculate MD5 for validation
    const stream = await this.extentStore.readExtent(
      persistency,
      context.contextId
    );
    const calculatedContentMD5 = await getMD5FromStream(stream);
    if (contentMD5 !== undefined) {
      if (typeof contentMD5 === "string") {
        const calculatedContentMD5String = Buffer.from(
          calculatedContentMD5
        ).toString("base64");
        if (contentMD5 !== calculatedContentMD5String) {
          throw StorageErrorFactory.getInvalidOperation(
            context.contextId!,
            "Provided contentMD5 doesn't match."
          );
        }
      } else {
        if (!Buffer.from(contentMD5).equals(calculatedContentMD5)) {
          throw StorageErrorFactory.getInvalidOperation(
            context.contextId!,
            "Provided contentMD5 doesn't match."
          );
        }
      }
    }

    const block: BlockModel = {
      accountName,
      containerName,
      blobName,
      isCommitted: false,
      name: blockId,
      size: contentLength,
      persistency
    };

    // TODO: Verify it.
    await this.metadataStore.stageBlock(
      context,
      block,
      options.leaseAccessConditions
    );

    const response: Models.BlockBlobStageBlockResponse = {
      statusCode: 201,
      contentMD5: undefined, // TODO: Block content MD5
      requestId: blobCtx.contextId,
      version: BLOB_API_VERSION,
      date,
      isServerEncrypted: true,
      clientRequestId: options.requestId
    };

    return response;
  }