Golang Mongo Pagination For Package mongo-go-driver
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. View examples from here
Example api response of Normal Query click here.
Example api response of Aggregate Query click here.
View code used in this example from here
Install
$ go get -u -v github.com/gobeam/mongo-go-pagination
or with dep
$ dep ensure -add github.com/gobeam/mongo-go-pagination
For Aggregation Pipelines Query
package main
import (
"context"
"fmt"
. "github.com/gobeam/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{"$project": bson.M{"_id": 1, "qty": 1}}
// set collation if required
collation := options.Collation{
Locale: "en",
CaseLevel: true,
}
// you can easily chain function and pass multiple query like here we are passing match
// query and projection query as params in Aggregate function you cannot use filter with Aggregate
// because you can pass filters directly through Aggregate param
aggPaginatedData, err := New(collection).SetCollation(&collation).Context(ctx).Limit(limit).Page(page).Sort("price", -1).Aggregate(match, projectQuery)
if err != nil {
panic(err)
}
var aggProductList []Product
for _, raw := range aggPaginatedData.Data {
var product *Product
if marshallErr := bson.Unmarshal(raw, &product); marshallErr == nil {
aggProductList = append(aggProductList, *product)
}
}
// print ProductList
fmt.Printf("Aggregate Product List: %+v\n", aggProductList)
// print pagination data
fmt.Printf("Aggregate Pagination Data: %+v\n", aggPaginatedData.Data)
}
For Normal queries
func main() {
// Establishing mongo db connection
ctx, _ := context.WithTimeout(context.Background(), 10*time.Second)
client, err := mongo.Connect(ctx, options.Client().ApplyURI("mongodb://localhost:27017"))
if err != nil {
panic(err)
}
// Example for Normal Find query
filter := bson.M{}
var limit int64 = 10
var page int64 = 1
collection := client.Database("myaggregate").Collection("stocks")
projection := bson.D{
{"name", 1},
{"qty", 1},
}
// Querying paginated data
// Sort and select are optional
// Multiple Sort chaining is also allowed
// If you want to do some complex sort like sort by score(weight) for full text search fields you can do it easily
// sortValue := bson.M{
// "$meta" : "textScore",
// }
// aggPaginatedData, err := paginate.New(collection).Context(ctx).Limit(limit).Page(page).Sort("score", sortValue)...
var products []Product
paginatedData, err := New(collection).Context(ctx).Limit(limit).Page(page).Sort("price", -1).Select(projection).Filter(filter).Decode(&products).Find()
if err != nil {
panic(err)
}
// paginated data or paginatedData.Data will be nil because data is already decoded on through Decode function
// pagination info can be accessed in paginatedData.Pagination
// print ProductList
fmt.Printf("Normal Find Data: %+v\n", products)
// print pagination data
fmt.Printf("Normal find pagination info: %+v\n", paginatedData.Pagination)
}
Notice:
paginatedData.data //it will be nil incase of normal queries because data is already decoded on through Decode function
Running the tests
$ go test
Contributing
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.
Acknowledgments
MIT License
Copyright (c) 2021
