goexpress

goexpress

An Express JS Style HTTP server implementation in Golang with safe cleanup exit. The package make use of similar framework convention as there are in express-js. People switching from NodeJS to Golang often end up in a bad learning curve to start building their webapps, this project is meant to ease things up, its a light weight framework which can be extended to do any number of functionality.

Hello World

package main
import (
  express "github.com/DronRathore/goexpress"
)

func main (){
  var app = express.Express()
  app.Get("/", func(req express.Request, res express.Response){
    res.Write("Hello World")
    // you can skip closing connection
  })
  app.Start("8080")
}

Router

The router works in the similar way as it does in the express-js. You can have named parameters in the URL or named + regex combo.

func main (){
  var app = express.Express()
  app.Get("/:service/:object([0-9]+)", func(req express.Request, res express.Response){
    res.JSON(req.Params().Get("service"))
  })
  app.Start("8080")
}

Note: You can also adhoc an express.Router() instance too much like it is done in expressjs

package main
import (
  express "github.com/DronRathore/goexpress"
)
var LibRoutes = func (){
  // create a new Router instance which works in similar way as app.Get/Post etc
  var LibRouter = express.NewRouter()
  LibRouter.Get("/lib/:api_version", func(req express.Request, res express.Response){
    res.Json(req.Params.Get("api_version"))
  })
  return *LibRoutes
}() // immediate invocation
func main(){
  var app = express.Express()
  app.Use(LibRoutes) // attaches the Library Routes
  app.Start("8080")
}

Middleware

You can write custom middlewares, wrappers in the similar fashion. Middlewares can be used to add websocket upgradation lib, session handling lib, static assets server handler

func main (){
  var app = express.Express()
  app.Use(func(req *express.Request, res *express.Response){
    req.Params.Set("I-Am-Adding-Something", "something")
  })
  app.Get("/:service/:object([0-9]+)", func(req express.Request, res express.Response){
    // json will have the key added
    res.JSON(req.Params.Get("service"))
  })
  app.Start("8080")
}

ExpressInterface

You can pass around the instance of express struct across packages using this interface.

func main(){
  var app = express.Express()
  attachHandlers(app)
}
func attachHandlers(instance express.ExpressInterface){
  instance.Use(someMiddleware)
  instance.Set("logging", true)
}

Cookies

import (
  express "github.com/DronRathore/goexpress"
  http "net/http"
  Time "time"
)
func main (){
  var app = express.Express()
  app.Use(func(req express.Request, res express.Response){
    var cookie = &http.Cookie{
      Name: "name",
      Value: "value",
      Expires: Time.Unix(0, 0)
    }
    res.Cookie.Add(cookie)
    req.Params.Set("session_id", req.Cookies.Get("session_id"))
  })
  app.Get("/", func(req express.Request, res express.Response){
    res.Write("Hello World")
  })
  app.Start("8080")
}

Sending File

You can send a file by using the helper res.SendFile(url string, doNotSendCachedData bool)

func main (){
  var app = express.Express()

  app.Get("/public/:filename", func(req express.Request, res express.Response){
  res.SendFile(filename, false)
  })
  app.Start("8080")
}

Note: You can now also send an auto downloadable file too using res.Download api

/*
  @params:
    path: Full path to the file in local machine
    filename: The name to be sent to the client
*/
res.Download(path string, filename string)

Post Body

func main (){
  var app = express.Express()
  app.Use(func(req *express.Request, res *express.Response){
    res.Params.Set("I-Am-Adding-Something", "something")
  })
  app.Post("/user/new", func(req express.Request, res express.Response){
    type User struct {
      Name string `json:"name"`
      Email string `json:"email"`
    }
    var list = &User{Name: req.Body("name")[0], Email: req.Body("email")[0]}
    res.JSON(list)
  })
  app.Start("8080")
}

JSON Post

JSON Post data manipulation in golang is slightly different from JS. You have to pass a filler to the decoder, the decoder assumes the data to be in the same format as the filler, if it is not, it throws an error.

func main (){
  var app = express.Express()
  app.Use(func(req express.Request, res express.Response){
    res.Params["I-Am-Adding-Something"] = "something"
  })
  app.Post("/user/new", func(req express.Request, res express.Response){
    type User struct {
      Name string `json:"name"`
      Email string `json:"email"`
    }
    var list User
    err := req.JSON().Decode(&list)
    if err != nil {
      res.Error(400, "Invalid JSON")
    } else {
      res.JSON(list)
    }
  })
  app.Start("8080")
}

File Uploading

Form Data Post

If a request has content-type form-data with a valid bounday param than goexpress will automatically parse and load all the files in express.Files() array. It will also populate req.Body() if the post/put request contains any text key values.

func(req *express.Request, res *express.Response){
  if len(req.Files) > 0 {
    // do something
    for _, file := range req.Files() {
      name := file.FormName
      type := file.Mime["Content-Type"]
      res.Header().Set("Content-Type", type)
      content, err := ioutil.ReadAll(file.File)
      // save content or throw error
    }
  }
}

HTML Template

Use standard Golang http templates to render response page.

For example, you have a template file index.html in templates directory:

<h1>{{.Name}}</h1>

Fill the context and provide a path to the template file:

func(req *express.Request, res *express.Response){
  type TmplContext struct{
    Name string
  }
  data := TmplContext{"Rob"}
  res.Render("template.html", &data)
}

Safe Cleanup on exit

Newer version of goexpress provides three new methods namely express.ShutdownTimeout, express.BeforeShutdown and express.Shutdown, these methods can be utilised to do cleanup before the server shuts down.

• BeforeShutdown: This method takes a function as input which will be triggered before shutdown of the server is called
• ShutdownTimeout: This defines the time.Duration to spend while shutting down the server
• Shutdown: An explicit immediate shutdown call that can be made, this will not trigger shutdown hook at all

Testing

There are no testing added to this package yet, I am hoping to get my hands dirty in testing, if anyone can help me out with this, feel free to open a PR.

Contribution

• If you want some common must have middlewares support, please open an issue, will add them.
• Feel free to contribute. :)