REST HTTP Controllers
A REST HTTP controller is a code layer which handles incoming HTTP requests to a specific server resource. For example /api/DemoUser
It implements and export functions/methods that supports multiple HTTP Methods like GET, POST, PUT, DEL, PATCH to offer different actions/operations against a server resource.
Commonly in a application, the database operations are performed in a REST HTTP controller. But this will not be the standard here.
Every controller method receives two paramaters by default: req and res, which stands for Request and Response HTTP objects.
The HTTP Request Message, which is a plain text Message received by the Controller is then translated into a message format which is the standard used to perform communication between HTTP (REST APIs) and AQMP (Workers) based micro services
After formating the incoming HTTP Request Message, we can use it to directly consume a Service Layer Action, or send it to a specific RabbitMQ Queue.
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How to create a REST HTTP controller to handle the DemoUser Data Entity related Remote Procedure Calls?
Please check the DemoUser example related files at ./src/lib/api/controllers/DemoUser.js.
DemoUser REST HTTP controller
/**
import REST response functions
*/
import { result, notFound, errorResponse, accepted, created } from '../../response';
/**
Import RabbitEnvelop message composer class
*/
import RabbitEnvelop from '../../RabbitEnvelop'
/**
Import application running instance to be able to use it RPC Mapper
*/
import app from '../../../app'
const
/**
Data Entity name which this controller handler out
*/
entity = "DemoUser",
/**
Queue Name which this controller sends out RabbitMQ message for WRITE operations
*/
queue = `JumentiX.${entity}`,
/**
Primary key name for this Data Entity. _id is Mongo default
*/
primaryKeyName = '_id';
/**
HTTP Method: GET
HTTP route: /api/DemoUser
SERVER PROCEDURE: List all Entities by consuming it service layer
*/
export async function list(req, res)
{
try {
const
// set Service Procedure name
action = "getAll",
// set who asked for the job
from = req.user,
// create a job request message
job = new RabbitEnvelop( { from, entity, action }),
/**
RPC - application.mapperRPC.services.DemoUser.getAll( job )
execute the job
*/
{ error, data, count, pages, limit, page } = await app.mapperRPC.services[ entity ][ action ]( job ),
// set job message
message = ( error.message || error, ( action + " " + entity ) );
// check if is there a error executing the job
if( error ) return errorResponse(res, { error, message })
// respond job result
return result(res, { data, count, pages, limit, page, message })
} catch (error) {
return errorResponse(res, { error, message: error.message })
}
}
/**
HTTP Method: GET
HTTP route: /api/DemoUser/{id}
SERVER PROCEDURE: Read a specific Entity by consuming it service layer
*/
export async function read(req, res) {
try {
const
// set Service Procedure name
action = "getById",
// set who asked for the job
from = req.user,
// set payload to execute the job
payload = {
[ primaryKeyName ]: req.swagger.params.id.value,
},
// create a job request message
job = new RabbitEnvelop( { from, entity, action, payload }),
/**
RPC - application.mapperRPC.services.DemoUser.getById( job )
execute the job
*/
{ error, data } = await app.mapperRPC.services[ entity ][ action ]( job ),
// set job message
message = ( error.message || error, ( action + " " + entity ) );
// check if is there a error executing the job
if( error ) return errorResponse(res, { error, message })
// respond job result
return result(res, { data, message })
} catch (error) {
return errorResponse(res, { error, message: error.message })
}
}
/**
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Following WRITE operations are performed by sending messages to Entity's queue
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
*/
/**
Create an entity by sending a message to it queue.
*/
export async function create(req, res)
{
try {
const
// set Service Procedure name
action = "create",
// set who asked for the job
from = req.user,
// set payload to execute the job
payload = req.body,
// create a job request message
job = new RabbitEnvelop( { from, entity, action, payload }),
// set job message
message = 'Your request is being processed and you be notified coming soon.',
// set message to Entity's queue
{ sent, error } = app.sender.send.messageToQueue( queue, job );
// check if is there a error executing the job
if( error ) return errorResponse(res, { error, message: error.message })
// respond
return accepted(res, { data: job, message })
} catch (error) {
return errorResponse(res, { error, message: error.message })
}
}
/**
Update an entity by sending a message to it queue.
*/
export async function update(req, res) {
try {
const
// set Service Procedure name
action = "update",
// set who asked for the job
from = req.user,
// set payload to execute the job
payload = copy( req.body, { [ primaryKeyName ]: req.swagger.params.id.value }),
// create a job request message
job = new RabbitEnvelop( { from, entity, action, payload }),
// set job message
message = 'Your request is being processed and you be notified coming soon.',
// set message to Entity's queue
{ sent, error } = app.sender.send.messageToQueue( queue, job );
// check if is there a error executing the job
if( error ) return errorResponse(res, { error, message: error.message })
// respond
return accepted(res, { data: job, message })
} catch (error) {
return errorResponse(res, { error, message: error.message })
}
}
/**
Delete an entity by sending a message to it queue.
*/
export async function destroy(req, res) {
try {
const
// set Service Procedure name
action = "delete",
// set who asked for the job
from = req.user,
// set payload to execute the job
payload = {
[ primaryKeyName ]: req.swagger.params.id.value,
},
// create a job request message
job = new RabbitEnvelop( { from, entity, action, payload }),
// set job message
message = 'Your request is being processed and you be notified coming soon.',
// set message to Entity's queue
{ sent, error } = app.sender.send.messageToQueue( queue, job );
// check if is there a error executing the job
if( error ) return errorResponse(res, { error, message: error.message })
// respond
return accepted(res, { data: job, message })
} catch (error) {
return errorResponse(res, { error, message: error.message })
}
}