reader

###Reader usage

You can create Reader instance using constructor method. If all of your Views that uses reader are initialized by calling View#Init method, or by using View loaded by NewResourceFromUrl method, you can pass emptry Resource:

emptyResource := data.EmptyResource()
service := reader.New(emptyResource)

Resource is needed only to try to initialize View unless View was initialized earlier.

In order to read data you need data.Session:

var fooView *data.View 

session := &data.Session{
	Dest: new(interface{}),
	View: fooView, 
	AllowUnmapped: true,
	
	Selectors:     Selectors{},
	Subject:     "",
	HttpRequest: *http.Request{},
	MatchedPath: "",
}

• Dest is required. It has to be a pointer to interface{} or pointer to slice of T or *T
• View is required. Due to optimization reasons it is important to create one instance, share it across the system and provide fully initialized View. For View creation see: create programmatically or load from file
• Selectors are not used when datly is used only to communicate with database, but may be used when datly is configured also as request handler (see TODO)
• AllowUnmapped is optional, by default is set to false. It is being used when some database table columns doesn't match View.Schema type.
• Subject is optional. It is being used to build criteria and represents logged user.
• HttpRequest is optional, needed only if any of Parameter location is path, query, cookie, header or if datly is used as request handler.
• MatchedPath is optional, needed only if any of Parameter location is path or if datly is used as request handler. You can now read data from database using the reader instance.

You should let reader initialize the session. New session has to be created for each time you call reader.Read. Having reader and session you can fetch data from database:

err := service.Read(context.TODO(), session)
if err != nil {
	// ... handle error
}

toolbox.DumpIndent(session.Dest, false) //prints view fetched from database