Plugin

go mongox supports plugin programming, providing a flexible way to insert custom logic before and after database operations, thereby enhancing the scalability and maintainability of applications.

Enabling Built-in Plugins (Hooks)

The go mongox library comes with three useful built-in hook plugins (implemented based on plugins):

• field hook: Automates the update of the default field field
• model hook: Sets up hook functions for models (structs), which are called before and after collection operations in MongoDB.
• validator hook: Uses struct tags (tag) to validate field values.

The go mongox library does not activate these hooks by default. If you want to activate them, you can refer to the following code:

mongox.InitPlugin(&mongox.PluginConfig{
    EnableDefaultFieldHook: true,
    EnableModelHook:        true,
    EnableValidationHook:   true,
    // Override the default validator, effective when EnableValidationHook is true
    Validate: nil,
})

Plugin Registration and Removal

go mongox provides the RegisterPlugin and UnregisterPlugin methods to register and remove plugins.

// Register Plugin
mongox.RegisterPlugin("after find", func(ctx context.Context, opCtx *operation.OpContext, opts ...any) error {
    if user, ok := opCtx.Doc.(*User); ok {
        fmt.Println(user)
    }
    if users, ok := opCtx.Doc.([]*User); ok {
        fmt.Println(users)
    }
    return nil
}, operation.OpTypeAfterFind)

// Remove Plugin
mongox.RemovePlugin("after find", operation.OpTypeAfterFind)

The function signature of mongox.RegisterPlugin is as follows:

func RegisterPlugin(name string, cb callback.CbFn, opType operation.OpType)

This function takes three parameters:

• name: The name of the plugin

• cb: The callback function of the plugin, the signature of which is as follows:

  type CbFn func(ctx context.Context, opCtx *operation.OpContext, opts ...any) error

  This function takes three parameters:

  • ctx: The context object

  • opCtx: The operation context object opCtx has the following structure:

        type OpContext struct {
           Col *mongo.Collection `opt:"-"`
           Doc any
           // filter also can be used as query
           Filter       any
           Updates      any
           Replacement  any
           MongoOptions any
           ModelHook    any
        }

    When opType is operation.OpTypeBeforeInsert or operation.OpTypeAfterInsert, the value of opCtx.Doc may not be nil, and its type may be *struct or []*struct.

    When opType is operation.OpTypeBeforeUpdate or operation.OpTypeAfterUpdate, the values of opCtx.Filter and opCtx.Updates may not be nil.

    When opType is operation.OpTypeBeforeDelete or operation.OpTypeAfterDelete, the value of opCtx.Filter may not be nil.

    When opType is operation.OpTypeBeforeUpsert or operation.OpTypeAfterUpsert, the values of opCtx.Filter and opCtx.Updates may not be nil.

    When opType is operation.OpTypeBeforeFind or operation.OpTypeAfterFind, the value of opCtx.Filter may not be nil, and if it is the latter, the value of opCtx.Doc may not be nil.

    The MongoOptions and ModelHook being nil depends on whether the user sets them during the execution of the MongoDB operations.

  • opts: Optional parameters

• opType: The type of the plugin, the supported types are as follows:

  type	description
  operation.OpTypeBeforeInsert	Execute before inserting the document
  operation.OpTypeAfterInsert	Execute after inserting the document
  operation.OpTypeBeforeUpdate	Execute before updating the document
  operation.OpTypeAfterUpdate	Execute after updating the document
  operation.OpTypeBeforeDelete	Execute before deleting the document
  operation.OpTypeAfterDelete	Execute after deleting the document
  operation.OpTypeBeforeUpsert	Execute before saving the document
  operation.OpTypeAfterUpsert	Execute after saving the document
  operation.OpTypeBeforeFind	Execute before finding the document
  operation.OpTypeAfterFind	Execute after finding the document