utron is a lightweight MVC framework in Go(Golang) for building fast, scallable and robust database driven web applications.

• Postgres, MySQL and Foundation database support.
• Modular (you can choose which component to use)
• Middleware support. All alice compatible Middlewares works out of the box.
• Gopher spirit (write golang, use all the golang libraries you like)
• Lightweight. Only MVC.
• Multiple configuration files support (currently json, yaml and toml)

utron is a lightweight MVC framework. It is based on the premise of simplicity, relevance and elegancy.

• Simplicity. The design is simple, easy to understand and less layers from the standard library. It is in the spirit of the project that, users should understand the whole framework in a single day.

• Relevance. utron doesn't assume anything. We focus on things that matter, this way, we are able to achieve good maintenance and keeping the system well organized, well planned and sweet like.

• Elegancy. utron uses golang best practises. We are not afraid of heights, its just that we need a parachute in our backpack. The source code is heavily documented, any functionality should be well explained and well tested.

After two years of playing with golang. I have looked on some of my projects and asked myself, how golang is that?

So, utron is my reimagination of lightweight MVC, that maintains the golang spirit, and works seamlessly with the current libraries.

$ go get github.com/gernest/utron

There is nothing revolutionary about MVC that utron brings on the table.

• M is for models, it is the data structures that helps in data persistance, utron uses gorm an already established Object Relational Mapper for golang. So if you are familiar with gorm then you are good on the M part.

• V is for Views. Views are templates, that renders the final output. utron uses golang standard templates. so you don't have to learn anything new, just the text/template package to master views.

• C is for controllers. This is where the aplication logic stands, in order to achieve modularity, there are some facts that utron enforces to controllers. This subject is explained in more details below.

With the power of composition and inheritance, utron achieves a beautiful MVC workflow. I recommend you read the source code, it is well documented so as to demystify any magical unicorns.

We will create a TODO List application in utron to explore all components that makes utron MVC tick. The source code of the final application is included in this repository and can be found here utron todoMVC

This is the structure of the todo list application that will showcase how you can build web apps with utron.

todo
├── config
│   ├── app.json
│   ├── app.toml
│   └── app.yml
├── controllers
│   └── todo.go
├── models
│   └── todo.go
├── static
│   └── todo.css
├── views
│   ├── error.html
│   └── index.html
└── main.go

5 directories, 9 files

I have included three configuration files for clarity, but you are better off with just one.

utron support yaml, json and toml configurations files. In our todo app, we put the configuration files in the config directory. I have included all three formats for clarity, you can be just fine with either one of them.

utron searches for a file named app.json, or app.yml or app.toml in the config directory. The first to be found is the one to be used.

This is the content of config/app.json file:

{
	"app_name": "utron web app",
	"base_url": "http://localhost:8090",
	"port": 8090,
	"verbose": false,
	"static_dir": "static",
	"view_dir": "views",
	"database": "postgres",
	"database_conn": "postgres://postgres:postgres@localhost/todo"
}

You can overide the values from the config file by setting environment variables. The names of the environment variables are shown below (with their details)

If you haven't specified explicitly the location of the configuration directory, then it defaults to the directory named config in the current working directory.

utron uses gorm library as its Object Relational Mapper. So, you won't need to learn anything fancy. In our todo app, we need to define Todo model that will be used to store our todo details.

In the file models/todo.go we define our todo model like this

package models

import (
	"time"

	"github.com/gernest/utron"
)

type Todo struct {
	ID        int       `schema: "-"`
	Body      string    `schema:"body"`
	CreatedAt time.Time `schema:"-"`
	UpdatedAt time.Time `schema:"-"`
}

func init() {
	utron.RegisterModels(&Todo{})
}

Notice that, we need to register our model, by calling utron.RegisterModels(&Todo{}) in the init function otherwise utron won't be aware of the model.

utron will automatically create the table todos if it doesn't exist yet.

Don't be confused by the schema tag, I just added them since we will use the schema package to decode form values(this has nothing to do with utron, you can use whatever form library you fancy)

utron controllers are structs that implement the Controller interface. To help make utron usable, utron provides a BaseController which implements the Controller interface and offers additional conveniences to help in composing reusable code.

You get all the benefits of BaseController by embeding it in your struct. Our TODO Controller is in the controller/todo.go

package controllers

import (
	"net/http"
	"strconv"

	"github.com/gernest/utron"
	"github.com/gernest/utron/fixtures/todo/models"
	"github.com/gorilla/schema"
)

var decoder = schema.NewDecoder()

type TODO struct {
	*utron.BaseController
	Routes []string
}

func (t *TODO) Home() {
	todos := []*models.Todo{}
	t.Ctx.DB.Order("created_at desc").Find(&todos)
	t.Ctx.Data["List"] = todos
	t.Ctx.Template = "index"
	t.HTML(http.StatusOK)
}
func (t *TODO) Create() {
	todo := &models.Todo{}
	req := t.Ctx.Request()
	req.ParseForm()
	if err := decoder.Decode(todo, req.PostForm); err != nil {
		t.Ctx.Data["Message"] = err.Error()
		t.Ctx.Template = "error"
		t.HTML(http.StatusInternalServerError)
		return
	}

	t.Ctx.DB.Create(todo)
	t.Ctx.Redirect("/", http.StatusFound)
}

func (t *TODO) Delete() {
	todoID := t.Ctx.Params["id"]
	ID, err := strconv.Atoi(todoID)
	if err != nil {
		t.Ctx.Data["Message"] = err.Error()
		t.Ctx.Template = "error"
		t.HTML(http.StatusInternalServerError)
		return
	}
	t.Ctx.DB.Delete(&models.Todo{ID: ID})
	t.Ctx.Redirect("/", http.StatusFound)
}

func NewTODO() *TODO {
	return &TODO{
		Routes: []string{
			"get;/;Home",
			"post;/create;Create",
			"get;/delete/{id};Delete",
		},
	}
}

func init() {
	utron.RegisterController(NewTODO())
}

Note we registered our controller by calling utron.RegisterController(NewTODO()) in the init function so as to make utron aware of our controller. See Routing section below for more explanation of what the controller is doing.

By registering a controller, there are two ways of assigning routes.

By registering a Controller, routes are autogenerated for the controller methods. The format is /:controler/:method where :controller is the lowercase name of the Controller, and :method is its method in lowercase.

so (*TODO) Hello() will map to /todo/hello

The user controller can define a field named Routes it should be of type []string, then you can assign routes by appending route string to the Routes field.

This is a better explation from comments on the router.go file.

		// if there is any field named Routes, and it is of signature []string
		// then  the field's value is used to overide the patterns  defined earlier.
		//
		// It is not necessary for every user implementation to define method named Routes
		// If we cant find it then we just ignore its use( fallback to defaults).
		//
		// Route strings, are of the form "httpMethods;path;method"
		// where httMethod: is a coma separated http method strings
		//                  e.g GET,POST,PUT.
		//                  The case does not matter, you can use lower case or upper case charaters
		//                  or even mixed case, that is get,GET,gET and GeT will all be treated as GET
		//
		//        path:     Is a url path or pattern, utron uses gorilla mux package. So, everything you can do
		//                  with gorilla mux url path then you can do here.
		//                  e.g /hello/{world}
		//                  Don't worry about the params, they will be accessibe via .Ctx.Params field in your
		//                  controller.
		//
		//        method:   The name of the user Controller method to execute for this route.

So, that explains much the following lines in our todo app in controllers/todo.go

func NewTODO() *TODO {
	return &TODO{
		Routes: []string{
			"get;/;Home",
			"post;/create;Create",
			"get;/delete/{id};Delete",
		},
	}
}

You can define routes in a file, the supported formats are json,toml and yaml. The routes file should be in the config directory.

utron will look for file named routes.json,or routes.toml or routes.yml in that order, the first to be found is the one to be used.

I have included a sample routes file in fixtures/config/routes.json

The difference with case 2 above is you will need to specify the name of the controller explictly. That is for TODO controler, we can define the home route string in routes file like get;/;TDODO.Home

We won't use this in our TODO list app, but you can find it useful in your use case.'

utron views are golang templates. This is the content of `views/index.html``

<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title>Utron Todo MVC</title>
	<link href="/static/todo.css" rel="stylesheet">
</head>
<body>
<form method="post" action="/create">
    <table>
        <tr>
           <th>
               Create A TODO
           </th>
        </tr>
        <tr>
            <td>
                <input name="body">
            </td>
            <td>
                <button type="submit">create</button>
            </td>
        </tr>
    </table>
</form>
<table>
    <tr>
        <th>
            My TODO LIST
        </th>
    </tr>
    {{range $k,$v:=.List}}
    <tr>
        <td>
            {{$v.ID}}
        </td>
        <td>
            {{$v.Body}}
        </td>
        <td>
            <a href="/delete/{{$v.ID}}">
                <button>Delete</button>
            </a>
        </td>
    </tr>
    {{end}}
</table>
</body>
</html>

Note that we have access to .List in our view. This is set in the controller, additionally you can access the application configuration via .Config context.

Above is a simple golang template to render our todo list application.

package main

import (
	"github.com/gernest/utron"
	_ "github.com/gernest/utron/fixtures/todo/controllers"
	_ "github.com/gernest/utron/fixtures/todo/models"
)

func main() {
	utron.Run()
}

In case you want to run the app we just created, it is included in this repository in fixtures/todo

• Prerequistite

• a working database connection (postres, mysql or foundation)
• golang toolchain installed and the go command is in your system PATH.

step 1 Install utron which will also include the todo app

$ go get github.com/gernest/utron

step 2 cd into the todo app directory

$ cd $GOPATH/src/github.com/gernest/utron/fixtures/todo

step 3 install dependency

$ go get github.com/gorilla/schema

step 4 edit config/app.json by setting database and database_conn to your values

step 5 run the app

go run main.go

If you see something like this

$ 2015/09/15 18:27:24 >>INFO>> staring server at http://localhost:8090

Then everything is okay, open http://localhost:8090 on your browser to start writing your todos. If you experience anything different, better open an issue.

Start with clicking the star button to make the author and his neighbors happy. Then fork it and submit a pull request for whatever change you want to be added to this project.

Or Open an issue for any questions.

Geofrey Ernest geofreyernest@live.com

Twitter : @gernesti

Facebook : Geofrey Ernest

I have 2 years experience working with golang and 5 years doing web developement. I don't have any juicy CV because I'm in Tanzania, and almost everyone i graduated with has no job, never had one and in doubts if he/she will ever land one(unless of course you are lucky which I'm not)

And if you are a recruiter, any tips on where I'm doing it wrong will be highly appreciated, because I have my full trust that code will get me out of this abysmal poverty.

These are amazing projects that made utron possible.

• gorilla mux
• ita
• gorm
• alice
• golang

• Fix a lot of typos(English is my third language).

This project is released under MIT licence see LICENCE for more details.