joeljames / nigroni-mgo-session

nigroni-mgo-session

nigroni-mgo-session is a simple Negroni middleware/handler for easy mgo session management in requests. It handles creating a new mongo session in the begning of a request and handles closing the mongo session at the end of request.

Getting Started

1. Before getting started make sure we have a copy of MongoDB running and is accessible. Running it locally would be recommended, but if thats not an option you can run on a remote server. Makes sure the mongo server is accessible, and you have a Mongo collection created within the database. If you haven't installed nigroni-mgo-session, you can run the below command to install it.

   go get github.com/joeljames/nigroni-mgo-session

2. This package will be used with nigroni and mgo. If you haven't installed the dependencies you could install run the below command.

   • To install Nigroni run the command below.

     go get github.com/codegangsta/negroni

   • To install mgo run the command below.

     go get gopkg.in/mgo.v2
     

3. Now lets add an example which demonstrates the usage of this middleware. I have added comments to the example to explain the usage.

   • Now, that you have a running instance of MongoDB you can Shell into mongo by running the command below.

     mongo

   • Create your database and collection and insert some data into the collection.

     use db
     db.createCollection("widget");
     db.widget.insert({'id': '123'});
     db.widget.insert({'id': '456'});
     

   • Set your DATABASE_URL and DATABASE_NAME environment variable.

     export DATABASE_URL=mongodb://username:password@localhost:27017/db
     export DATABASE_NAME=db

   • If you have the package and dependency downloaded, you could simple copy the above example to a file example.go and then run the command go run example.go to start up the server.

       package main
   
       import (
           "fmt"
           "net/http"
           "os"
   
           "github.com/codegangsta/negroni"
           nigronimgosession "github.com/joeljames/nigroni-mgo-session"
       )
   
       func main() {
           // Use the MongoDB `DATABASE_URL` from the env
           dbURL := os.Getenv("DATABASE_URL")
           // Use the MongoDB `DATABASE_NAME` from the env
           dbName := os.Getenv("DATABASE_NAME")
           // Set the MongoDB collection name
           dbColl := "widget"
   
           fmt.Println("Connecting to MongoDB: ", dbURL)
           fmt.Println("Database Name: ", dbName)
           fmt.Println("Collection Name: ", dbColl)
   
           // Creating the database accessor here.
           // Pointer to this database accessor will be passed to the middleware.
           dbAccessor, err := nigronimgosession.NewDatabaseAccessor(dbURL, dbName, dbColl)
           if err != nil {
               panic(err)
           }
   
           n := negroni.Classic()
   
           // Registering the middleware here.
           n.Use(nigronimgosession.NewDatabase(*dbAccessor).Middleware())
   
           mux := http.NewServeMux()
           mux.HandleFunc("/", func(writer http.ResponseWriter, request *http.Request) {
               // You can access the nms object from the request context.
               // The nms object is stored in key `nigronimgosession.KEY`.
               ctx := request.Context()
               nms := ctx.Value(nigronimgosession.KEY).(*nigronimgosession.NMS)
               // Now lets perform a count query using mgo db object.
               count, _ := nms.DB.C("widget").Find(nil).Count()
   
               fmt.Fprintf(writer, "Determining the count in the collection using the db object. \n\n")
               fmt.Fprintf(writer, "Total number of object in the mongo database: %d  \n\n", count)
   
               // You can access the mgo session object from the request object.
               // The session object is stored in key `mgoSession`.
               count2, _ := nms.Session.DB(dbName).C("widget").Find(nil).Count()
               fmt.Fprintf(writer, "Determining the count in the collection using the session object. \n\n")
               fmt.Fprintf(writer, "Total number of object in the mongo database: %d  \n\n", count2)
           })
   
           n.UseHandler(mux)
           n.Run(":3000")
       }

4. Assuming you are running the server locally, you can hit http://localhost:3000/ to see the output.

Contribution

1. Fork the package on Github

   git clone https://github.com/joeljames/nigroni-mgo-session.git
   cd nigroni-mgo-session

2. Create a new local branch to submit a pull request.

   git checkout -b name-of-feature

3. Commit your changes

   git commit -m "Detailed commit message"
   git push origin name-of-feature

4. Submit a pull request.