fsStorage mixin #

Introduction #

fsStorege mixin implements a CRUID operation for entity, whose data is stored in the file system (in opposite to mStorage mixin what stores data into DB).

WARNING Mixin designed for storing rather "configurations" when "data" and expect what data files are subject of version control system. Limitations:

• transactions are NOT supported
• concurrent access to data files based on "last win" strategy and should be avoided

Mixin expects data to be located:

• in a single location specified by dataPath property;
• in the models sub-folders when modelBased: true. In this case dataPath is joined with each model public folder location, and data will be loaded from each model what contains such a folder. Entities with modelBased fsStorage MUST contain a "model" attribute;

Each entity with fsStorage MUST contain a natural unique key attribute ("code" by default). The row ID is calculated as crc32(naturalKeyValue).

Mixin persist data as:

• if filePerRow is true then dataPath expected to be a folder and each row stored as s separate naturalKeyValue.ubrow file;
• if filePerRow is false then all rows is persisted in one file (or models file if modelBased true) specified by dataPath;

Entity attributes of type "Document" should use a "mdb" BLOB store. Content of BLOBS stored in the same folder as row

{
  "dataPath": "reports",
  "modelBased": true,
  "filePerRow": true,
  "naturalKey": "code",
  "allowOverride": false
}

For per-model storage sets allowOverride property to true allows row with the same natural key to be present in several models. In this case last model (in order they defined in ubConfig) win.