mgo

Documentation

Overview

Package mongocursorpagination eases the computation of pagination information of a find mongo query by augmenting the base query with cursor information and returning a cursor.

Index

• type Cursor
  • func Find(p FindParams, results interface{}) (Cursor, error)
• type CursorError
  • func (e *CursorError) Error() string
• type FindParams
• type MgoDb
• type MgoQuery

Types

type Cursor

type Cursor struct {
	// The URL safe previous page cursor to pass in a Find call to get the previous page.
	// This is set to the empty string if there is no previous page.
	Previous string
	// The URL safe next page cursor to pass in a Find call to get the next page.
	// This is set to the empty string if there is no next page.
	Next string
	// true if there is a previous page, false otherwise
	HasPrevious bool
	// true if there is a next page, false otherwise
	HasNext bool
	// Total count of documents matching filter - only computed if CountTotal is True
	Count int
}

Cursor holds the pagination data about the find mongo query that was performed.

func Find

func Find(p FindParams, results interface{}) (Cursor, error)

Find executes a find mongo query by using the provided FindParams, fills the passed in result slice pointer and returns a Cursor.

type CursorError

type CursorError struct {
	// contains filtered or unexported fields
}

func (*CursorError) Error

func (e *CursorError) Error() string

type FindParams

type FindParams struct {
	// The mongo database to use
	DB MgoDb
	// The name of the mongo collection to query
	CollectionName string
	// The find query to augment with pagination
	Query bson.M
	// The number of results to fetch, should be > 0
	Limit int
	// true, if the results should be sort ascending, false otherwise
	SortAscending bool
	// The name of the mongo collection field being paginated and sorted on. This field must:
	// 1. Be orderable. We must sort by this value. If duplicate values for paginatedField field
	//    exist, the results will be secondarily ordered by the _id
	// 2. Be indexed. For large collections, this should be indexed for query performance
	// 3. Be immutable. If the value changes between paged queries, it could appear twice
	// 4. Match the bson field name the result struct. e.g.:
	//
	//    PaginatedField would be "name" when paginating employees by name
	//
	//    type Employee struct {
	//        ID          bson.ObjectId `bson:"_id"`
	//        Name        string        `bson:"name"`
	//    }
	//
	PaginatedField string
	// The collation to use for the sort ordering.
	// See https://docs.mongodb.com/manual/reference/collation-locales-defaults/#supported-languages-and-locales
	// This is ignored if PaginatedField is empty
	Collation *mgo.Collation
	// The value to start querying the page
	Next string
	// The value to start querying previous page
	Previous string
	// Whether or not to include total count of documents matching filter in the cursor
	// Specifying true makes an additionnal query
	CountTotal bool
}

FindParams holds the parameters to be used in a paginated find mongo query that will return a Cursor.

type MgoDb

type MgoDb interface {
	C(string) *mgo.Collection
}

type MgoQuery

type MgoQuery interface {
	All(result interface{}) error
	Sort(fields ...string) MgoQuery
	Limit(n int) MgoQuery
	Count() (n int, err error)
	Collation(*mgo.Collation) MgoQuery
}