README.md

Query Server

Description

Only read requests are allowed unconditionally.

export type RouteItem = {
  method: "get";
  path: string;
  action: Function;
};

Soft Delete
When the Command server performs soft delete processing on the record, the Query server processes it in advance.

PostSchema.pre("find", function () {
  this.where({ deleted: false });
});

PostSchema.pre("findOne", function () {
  this.where({ deleted: false });
});

QueryEntityHandler
It is in charge of synchronizing to MongoDB according to the domain, entity, and CUD type delivered to the subscription section in Event Bus.

/**
 * @description
 * In the Event Sourcing pattern, any unnecessary entities held by the Command Server are excluded.
 */
export const excludeFieldsHelper = (entity: any, excludeFields: string[]) => {
  const _entity = { ...entity };

  excludeFields.forEach((excludeField) => {
    delete _entity[excludeField];
  });

  return _entity;
};

type SelectCollectionModel = typeof PostModel;

const selectCudAction = (cudAction: CUDAction) => {
  const cudActions = {
    CREATE: async (Collection: SelectCollectionModel, entity: any) => {
      const document = new Collection({
        ...entity,
        updated_at: entity.created_at,
      });
      await document.save();
    },
    UPDATE: async (Collection: SelectCollectionModel, entity: any) => {
      await Collection.updateOne(
        { post_id: entity.post_id },
        { ...excludeDateField(entity), updated_at: new Date() },
      );
    },
    DELETE: async (Collection: SelectCollectionModel, entity: any) => {
      await Collection.updateOne(
        { post_id: entity.post_id },
        { ...excludeDateField(entity), updated_at: new Date() },
      );
    },
  };

  return cudActions[cudAction];
};

const QueryEntityHandler = async ({
  domainName,
  cudAction,
  entity,
}: EventHandleParams): Promise<void> => {
  const collection = selectCollection(domainName);

  if (!collection) throw new Error(ErrorStatusMessage.IS_EMPTY_COLLECTION);

  console.log("============== QueryEntityHandler Work Start ==============");
  const action = selectCudAction(cudAction);
  await action(collection, entity);

  printWorkJob({ domainName, cudAction, entity });
  console.log("============== QueryEntityHandler Work End ==============");
};