For all your simple query to aggregation pipeline this is simple and easy to use Pagination driver with information like Total, Page, PerPage, Prev, Next, TotalPage and your actual mongo result.
$ go get -u -v github.com/dxtrleague/mongo-go-pagination
or with dep
$ dep ensure -add github.com/dxtrleague/mongo-go-pagination
package main
import (
"context"
"fmt"
. "github.com/dxtrleague/mongo-go-pagination"
"go.mongodb.org/mongo-driver/bson"
"go.mongodb.org/mongo-driver/bson/primitive"
"go.mongodb.org/mongo-driver/mongo"
"go.mongodb.org/mongo-driver/mongo/options"
"time"
)
type Product struct {
Id primitive.ObjectID `json:"_id" bson:"_id"`
Name string `json:"name" bson:"name"`
Quantity float64 `json:"qty" bson:"qty"`
Price float64 `json:"price" bson:"price"`
}
func main() {
// Establishing mongo db connection
ctx, _ := context.WithTimeout(context.Background(), 10*time.Second)
client, err := mongo.Connect(ctx, options.Client().ApplyURI("mongodb://localhost:27017"))
if err != nil {
panic(err)
}
var limit int64 = 10
var page int64 = 1
collection := client.Database("myaggregate").Collection("stocks")
//Example for Aggregation
//match query
match := bson.M{"$match": bson.M{"qty": bson.M{"$gt": 10}}}
//group query
projectQuery := bson.M{"$project": bson.M{"_id": 1, "qty": 1}}
// you can easily chain function and pass multiple query like here we are passing match
// query and projection query as params in Aggregate function you cannot use filter with Aggregate
// because you can pass filters directly through Aggregate param
aggPaginatedData, err := New(collection).Limit(limit).Page(page).Sort("price", -1).Aggregate(match, projectQuery)
if err != nil {
panic(err)
}
var aggProductList []Product
for _, raw := range aggPaginatedData.Data {
var product *Product
if marshallErr := bson.Unmarshal(raw, &product); marshallErr == nil {
aggProductList = append(aggProductList, *product)
}
}
// print ProductList
fmt.Printf("Aggregate Product List: %+v\n", aggProductList)
// print pagination data
fmt.Printf("Aggregate Pagination Data: %+v\n", aggPaginatedData.Data)
}
func main() {
// Establishing mongo db connection
ctx, _ := context.WithTimeout(context.Background(), 10*time.Second)
client, err := mongo.Connect(ctx, options.Client().ApplyURI("mongodb://localhost:27017"))
if err != nil {
panic(err)
}
// Example for Normal Find query
filter := bson.M{}
var limit int64 = 10
var page int64 = 1
collection := client.Database("myaggregate").Collection("stocks")
projection := bson.D{
{"name", 1},
{"qty", 1},
}
// Querying paginated data
// Sort and select are optional
paginatedData, err := New(collection).Limit(limit).Page(page).Sort("price", -1).Select(projection).Filter(filter).Find()
if err != nil {
panic(err)
}
// paginated data is in paginatedData.Data
// pagination info can be accessed in paginatedData.Pagination
// if you want to marshal data to your defined struct
var lists []Product
for _, raw := range paginatedData.Data {
var product *Product
if marshallErr := bson.Unmarshal(raw, &product); marshallErr == nil {
lists = append(lists, *product)
}
}
// print ProductList
fmt.Printf("Norm Find Data: %+v\n", lists)
// print pagination data
fmt.Printf("Normal find pagination info: %+v\n", paginatedData.Pagination)
}
$ go test
Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.
Please make sure to update tests as appropriate.
Copyright (c) 2020