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The sample app contains a list of tasks in an entity that stores its data in a file. It is possible to add or delete tasks.

Step 1 : Define app settings

1-1 : Create app config file

First we create a folder named todo and in it we create a file named app.json containing :

{
	"name": "ToDo App"
}

1-2 : Define an entity

As a next step, we add the schema for an entity called tasks, in config file, to schemas array

{
	"name": "ToDo App",
	"schemas": [
		{
			"$id": "tasks",
			"properties": {
				"name": {
					"type": "string"
				},
				"status": {
					"type": "string",
					"enum": [
						"WAIT",
						"IN-PROGRESS",
						"DONE",
						"ARCHIVED"
					]
				},
				"progress": {
					"type": "number",
					"minimum": 0,
					"maximum": 100
				}
			}
		}
	]
}

1-3 : Config data storage

Then we define the storage settings. Here we decide to store data of entities in a json file named data.json next to the config file in the todo folder.

{
	"name": "ToDo App",
	"schemas": [],
	"storage": {
		"adapter": "file",
		"path": "./data.json"
	}
}

1-4 : Define an endpoint

To connect to this app we define an endpoint by type cli to send NoLang scripts to it and get responses from command line.

{
	"name": "ToDo App",
	"schemas": [],
	"storage": {},
	"endpoints": [
		{
			"type": "cli"
		}
	]
}

Step 2 : Run the app

In the command prompt, Run your app like below:

cd todo
nolang app.json

For more guides to run app see here

Step 3 : Contract with todo app

Add new task

Now we can send NoLang Scripts to the app and get its responses.

(out)//send script in one line:               
{"$$schema": "tasks", "$$header": {"action": "C"}, "name": "task1", "progress": 0, "status": "WAIT"} [ENTER]              
(out)//response:              
(out){"success": true, $$objid: 1 }

Retrieve tasks

To retrieve list of tasks, we can:

{"$$schema": "tasks", "$$header": {"action": "R"}} [ENTER]              
(out)[{ "name": "task1", "progress": 0, "status": "WAIT" }]

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Creating a RESTful API

To create a RESTful app it is enough to have endpoints with type http:

{
	"name": "a simple restfule app with Nolang",
	"entities": [],
	"endpoints": [
		{
			"type": "http",
			"static": "./public",
			"port": 8080,
			"routes": [
				{
					"path": "/",
					"method": "post"
				}
			]
		}
	]
}

this app listens to http port 8080 with POST method. we can send Nolang's scripts to it from a browser or any http client like bellow:

let command = {
	"$$schema": "products",
	"$$header": {
		"action": "C"
	},
	"productKey": "PROD-1",
	"productName": "Product 1",
	"address": "Address 1"
};               

fetch('http://localhost:8080', {
            method: 'POST',
            headers: {
                'Accept': 'application/json, text/plain, */*',
                'Content-Type': 'application/json'
            },
            body: JSON.stringify(command)
        }).then(res => res.json())        
.then(res => console.log(res)) //res is the final result       
.catch(err => console.error(err));

adding more methods

{
	"endpoints": [
		{
			"type": "http",
			"static": "./public",
			"port": 8080,
			"routes": [
				{
					"path": "/",
					"method": "post"
				},
				{
					"path": "/add",
					"method": "post",
					"return": {
						"$$schema": "tasks",
						"$$header": {
							"action": "C"
						},
						"name": "{{env.request.body.name}}",
						"progress": "{{env.request.body.progress}}"
					}
				},
				{
					"path": "/list",
					"method": "get",
					"return": {
						"$$schema": "tasks",
						"$$header": {
							"action": "R"
						}
					}
				},
				{
					"path": "/formSubmitTarget",
					"method": "post",
					"bodyParser": "urlencoded",
					"$$header": {
						"action": "C"
					},
					"Field1": "{{env.request.body.Input1}}",
					"Field2": "{{env.request.body.Input2}}"
				},
				{
					"path": "/redirectMe",
					"method": "get",
					"return": {
						"anything": "x",
						"$$res": {
							"redirect": "https://any.other.url"
						}
					}
				},
				{
					"path": "/responseManipulate",
					"method": "get",
					"return": {
						"anything": "x",
						"$$res": {
							"cookies": {
								"cookie1": "value1",
								"cookie2": {
									"value": "value2",
									"options": {}
								}
							},
							"clearCookie": {
								"name": {
									"path": "/admin"
								},
								"name2": {}
							},
							"headers": {
								"Set-Cookie": "foo=bar; Path=/; HttpOnly",
								"Link": [
									"",
									""
								]
							},
							"attachment": "path/to/logo.png",
							"download": "path/to/file.pdf",
							"links": {
								"next": "http://api.example.com/users?page=2",
								"last": "http://api.example.com/users?page=5"
							},
							"location": "http://example.com",
							"type": "jsonp",
							"vary": "User-Agent",
							"status": 404,
							"sendFile": "/absolute/path/to/404.png"
						}
					}
				}
			]
		}
	]
}

The http endpoint has five routes:
The first is a POST method for sending Nolang scripts.
The second, at /add, accepts a JSON body containing name and progress keys.
The /list route retrieves a list of tasks via a GET request.
The /formSubmitTarget route allows submission of an HTML form with the action set to /formSubmitTarget, pay attention to using the bodyParser attribute.
/redirectMe route shows if the response of a request contains redirect key, the request will be redirected to its value. For example if you call a method in request, that method can reply an object contains $$res includes a redirect key.
Finally the /responseManipulate route shows all options to how to manipulate the response of http using $$res keyword. For more information see Express Response Methods.

from the browser or any js client, we can use the API like below:

//using /add
fetch('https://localhost:8080/add', {
    method: 'POST',
    headers: {
        'Accept': 'application/json, text/plain, */*',
        'Content-Type': 'application/json'
    },
    body: {
        name: "new task",
        status: "IN-PROGRESS"
    }
}).then(res => res.json())
    .then(res => console.log(res)) //res is the final result
    .catch(err => console.error(err));


//using /list
fetch('https://localhost:8080/list', {
    method: 'GET',
    headers: {
        'Accept': 'application/json, text/plain, */*',
        'Content-Type': 'application/json'
    }
}).then(res => res.json())
    .then(res => document.getElementById('list').innerText = res) //res is the final result
    .catch(err => console.error(err));

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Web Socket sample

add a route like bellow in app.json file in the http endpoint

{
	"routes": [
		{
			"path": "/ws",
			"method": "ws"
		}
	]
}

connect to the websocket server from browser:

if ("WebSocket" in window) {
    
    const ws = new WebSocket("ws://localhost:1100/ws");

    //to send Nolang scripts via websocket to the server:
    var sendRequest = function (script){
        ws.send(script);
    }

    //To receive Nolang server's responses:
    ws.onmessage = function (evt) {
        let response = evt.data.toString();
        console.log(response);
    };
} 

 sendRequest('..a Nolang script..')

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Server Sent Events sample

add a route like bellow in app.json file in the http endpoint

{
	"routes": [
		{
			"path": "/done_tasks",
			"method": "get",
			"return": {
				"$$schema": "tasks",
				"$$header": {
					"action": "R",
					"listen": true,
					"filter": {
						"status": "DONE"
					}
				}
			}
		}
	]
}

get live list of done tasks

const source = new EventSource('/done_tasks');
source.onmessage = (event)=>{
    console.log(event.data)
}

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Uploading files

To upload files we can use file or image type properties in entities:

{
	"$id": "entity3",
	"properties": {
		"name": {
			"type": "string"
		},
		"photo": {
			"type": "image"
		}
	}
}

config app

In app.json5 config file the http endpoints must have some items:

{
	"endpoints": [
		{
			"type": "http",
			"upload": {
				"root": "./uploads",
				"maxSize": 5000000
			},
			"port": 8080,
			"routes": [
				{
					"path": "/",
					"method": "post"
				}
			]
		}
	]
}

Uploading file from browser to server

Unlike ordinary scripts, when uploading a file it is needed to use html forms to upload, so the script must be encapsulated in command property like below:

document.querySelector('#fileInput').addEventListener('change', event => {
        handleImageUpload(event)
    })

    const handleImageUpload = event => {
        const files = event.target.files
        const formData = new FormData()
        formData.append('photo', files[0]) //photo is equal to the name of the image field
        formData.append('command', JSON.stringify({ //command contains the script
            $$schema: 'user_proxy',
            $$header: {
                action: 'C'
            },
            name: document.getElementById('Name').value,
        }))

        fetch('/', {
            method: 'POST',
            body: formData
        })
            .then(response => response.json())
            .then(data => {
                console.log(data)
            })
            .catch(error => {
                console.error(error)
            })
    }

After uploading file(s) and the command, the file will be stored in [upload-dir]/[entity's $id]/[id of new record]/[name of image filed] , for example ./uploads/entity3/2341/photo.png

In the database where data of the entity is stored, in the photo field, a json data will be saved containing these information: `{fileName: file.name, size: file.size, ext: fileExt}`

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How to consider user roles

If you want to create a Nolang app which considers user's roles it needs:

Add user section in the app.json config file, with authenticate: true
Have an entity containing users' info
For any entity required to consider the user access rights, have $$roles in the entity definition
In scripts that are sent to app, add user information

1- In app.json config file

{
	"user": {
		"authenticate": true,
		"schema": "users",
		"usernameField": "username",
		"passwordField": "password",
		"rolesField": "roles",
		"jwt": {
			"secret": "5Tyh&8%$S-=@",
			"expiredIn": "2h"
		},
		"directRoles": false
	}
}

2- Define an entity for users' information

To store information of users

{
	"$id": "users",
	"properties": {
		"username": {
			"type": "string"
		},
		"password": {
			"type": "string"
		},
		"roles": {
			"type": "array"
		},
		"extraField": {
			"type": "string"
		}
	},
	"$$storage": {
		"adapter": "inline",
		"data": [
			{
				"username": "admin1",
				"password": "1234",
				"roles": [
					"ADMIN"
				]
			},
			{
				"username": "user1",
				"password": "11123",
				"roles": [
					"USER"
				]
			},
			{
				"username": "superuser",
				"password": "2314",
				"roles": [
					"ADMIN",
					"USER"
				]
			}
		]
	}
}

3- Add `$$roles` in entity

{
	"$id": "tasks",
	"properties": {
		"name": {},
		"status": {},
		"progress": {}
	},
	"$$roles": [
		{
			"roleId": "ADMIN",
			"permissions": [
				{
					"access": [
						"A"
					]
				}
			]
		},
		{
			"roleId": "USER",
			"permissions": [
				{
					"access": [
						"C",
						"U",
						"R"
					]
				}
			]
		},
		{
			"roleId": "*",
			"permissions": [
				{
					"access": [
						"R"
					]
				}
			]
		}
	]
}

4- User info in `$$header.user` in Nolang scripts

To introduce to user in script it needs to define it in $$header like below:

{
	"$$schema": "tasks",
	"$$header": {
		"action": "R",
		"user": {
			"username": "admin1",
			"password": "1234"
		}
	}
}

If in step 1, a jwt is set in user section of app config file, after sending the above script to the server, a token will be generated and returned. that token must be saved in the client side and used in next scripts like below:

{
	"$$schema": "tasks",
	"$$header": {
		"action": "R",
		"user": {
			"token": "yHSIDhsljHD1GE4U5DHL7JHu&43h3ewjkdjdfhlajfd="
		}
	}
}

If in step 1, directRoles : true is set in user section of app config file, roles of users can be sent directly in script. It is not a secure way and must be used just in development not in production.

{
	"$$schema": "tasks",
	"$$header": {
		"action": "R",
		"user": {
			"roles": [
				"ADMIN"
			]
		}
	}
}

Step 1 : Define app settings

1-1 : Create app config file

1-2 : Define an entity

1-3 : Config data storage

1-4 : Define an endpoint

Step 2 : Run the app

Step 3 : Contract with todo app

Add new task

Retrieve tasks

Creating a RESTful API

adding more methods

Web Socket sample

Server Sent Events sample

Uploading files

config app

Uploading file from browser to server

After uploading file(s) and the command, the file will be stored in [upload-dir]/[entity's $id]/[id of new record]/[name of image filed] , for example ./uploads/entity3/2341/photo.png

In the database where data of the entity is stored, in the photo field, a json data will be saved containing these information: {fileName: file.name, size: file.size, ext: fileExt}

How to consider user roles

1- In app.json config file

2- Define an entity for users' information

3- Add $$roles in entity

4- User info in $$header.user in Nolang scripts

In the database where data of the entity is stored, in the photo field, a json data will be saved containing these information: `{fileName: file.name, size: file.size, ext: fileExt}`

3- Add `$$roles` in entity

4- User info in `$$header.user` in Nolang scripts