Analyze requirement

The focus of this module is to serve static files. This means user, page related info should not include here. Here we should save chart's name, description, file's path or table for rendering.

erDiagram
    chart ||--|{ file: file_url
    chart {
        string id
        string name
        string description
        int userId
    }
    file {
        string url
        string name
        string info
        text data
    }

But during the further discussion, we notice in v3-v4, v6, 7, 10 contains shared files. Under the suggestions form the supervisor. We enhance old plan by extract file or database storage strategy logic into multi-table and do a many-to-many mapping between chart and file table.

Local storage table: should storage binding to local static file(or file storage server) Data storage table: should storage binding to a table.

erDiagram
    chart ||--|{ chart_files: chart_id
    chart {
        string id
        string name
        string description
        int userId
    }
    file ||--|{ chart_files: file_url
    file {
        string url
        string name
        enum strategy
        string info
        string owner
    }
    file ||--o| local: file_id
    file ||--o| database: file_id 

Behaviour

Storage(local/database) module

In the storage module, we should handle both local storage and database storage.

• Handles:

  • saveStorage: Save a storage and use models hooks for trigger IO and database handling. In IO handling, we will move exist file path to correct place(the path generate from chartId).

  • getStorage: Get a storage based on File model. Get both local and database storage.(we can create/get both local and database here).

  • updateStorage: Update a storage. In IO handling, replace correct path with new file; In database handling, calculate difference with different operation (Simple implement: drop old database and create new database).

  • deleteStorage: Remove a storage based on File model. Due to one-to-one relationship, this function have to remove this table because of cascade(In the further study, cascade not able to trigger model hooks. So, Here replace cascade by set null).

File module

In the file module we should handle file info and both local storage and database storage. It designs like an extender for storage, which has a one-to-one relationship.

• Handles:

  • saveFile: Alias for saveStorage.

  • getFileByUrl: Alias for getStorage.

  • updateFile: In update file handle, we should distinguish different strategy:

    • update the strategy -> remove old storage, and create new storage
    • same strategy -> use alias for updateStorage.

  • deleteFile: Alias for deleteStorage.

Chart module

In the chart module we should handle file and chart tables. However, we have to face a problem that multiple chart use a single file. So a many-to-many relationship should be used.

• Handles:

  • saveChart: We should insert both chart and file data into tables, if file have been created, we have to check did file exists before insert action;

  • getChartById: Chart should be found in this function with file data, which means we have to inner join all of ChartFile -> File -> Local/Database -> Database Linked file(optional).

  • updateChart: In this function we can insert, modified and delete chart and handle file by saveFile, updateFile and deleteFile.

  • deleteChart: Remove chart and try to delete files based on relationship.