Mongo Pagination

Pagination is a package providing a function (Paginate) that queries the mongo database and return results by pages. It is useful to avoid the processing of too much data.

The pagination follow the rules explained in the Scalingo pagination documentation

How to use it

First, set the default value of number of items per page and the maximum of item by page as the following snippet:

pageService := pagination.NewPaginationService(pagination.ServiceOpts{
	PerPageDefault: 5,
	MaxPerPage:     15,
})

Then call the Paginate as follow:

resultObject := []*ResultObject{}
dbQuery := bson.M{"searched_field": "field_1"}

paginateOpts := PaginateOpts{
    PageNumber:  5,         // Number of the requested page (can be empty, default 1)
    AmountItems: 10,        // Amount of items by page (can be empty)
    Query:       dbQuery,   // Query which will be executed on the database (can be nil)
    SortOrder:   "-_id",    // The field for the sort order (by default "_id")
}

meta, err := pageService.Paginate(
    ctx,                    // A context (required)
    "RequestedCollection",  // Name of the collection (required)
    &resultObject,          // The object that will contain the data (must be an array)
    paginateOpts)

The returned meta object contains pagination metadata that could be used in the request answer.