broadcast
consumeExchange
consumeQueue
get
post
terminate
use
Create a Rabbit Response application. The rabbit-response function is a top-level function exported by the rabbit-response module.
const rabbitResponse = require('rabbit-response');
const rr = rabbitResponse({options});
| Param | Description | Required / Optional | Type | Default | Example |
|---|---|---|---|---|---|
| expiration | Message expiration time (ms) | optional | Number | 86,400,000 (24 Hours) | |
| host | IP or URL | optional | String | 'localhost' | Example |
| password | optional | String | 'guest' | Example | |
| port | optional | Number | 5672 | Example | |
| prefetchLimit | The max amount of messages to work on simultaneously from each queue | optional | Number | 100 | |
| protocol | 'amqp' / 'amqps' | optional | String | 'amqp' | Example |
| reconnectAttemptDelay | Reconnection time (ms) | optional | Number | 100 | |
| reQueueAttempts | In case of an error the message will be re-queued this many times(attempts). | optional | Number | 0 | |
| robust | Should Rabbit Response withstand RabbitMQ unavailability and errors | optional | Boolean | true | |
| username | optional | String | 'guest' | Example | |
| verbose | Should log be verbose | optional | Boolean | false | |
| logger | A function to log errors | optional | Function | console.log |
broadcast
consumeExchange
consumeQueue
get
post
terminate
use
rr.get(queueName, payload, options)
queueName (String) - The queue for processing the request.
payload (Null/Buffer/String/Number/Boolean/Object) - Any data needed to process the request.
| Param | Description | Required / Optional | Type | Default | Example |
|---|---|---|---|---|---|
| expiration | Message expiration time (ms) | optional | Number | 86,400,000 (24 Hours) | |
| masterId | An Id relating all messages for a specific task. used to terminate anything related to the task on all services. | optional | String / Number | --- | Example |
| progress | A function to be called on progress events | optional | Function | --- | Example |
| Example |
rr.post(queueName, payload, options)
queueName (String) - The queue to which you will post the message.
payload (Null/Buffer/String/Number/Boolean/Object) - The payload that will be posted to the queue.
| Param | Description | Required / Optional | Type | Default | Example |
|---|---|---|---|---|---|
| expiration | Message expiration time (ms) | optional | Number | 86,400,000 (24 Hours) | |
| masterId | An Id relating all messages for a specific task. Used to terminate anything related to the task on all services. | optional | String / Number | --- | Example |
rr.broadcast(exchangeName, payload, options)
exchangeName (String) - The exchange to which to broadcast the message.
payload (Null/Buffer/String/Number/Boolean/Object) - The payload that will be broadcasted.
| Param | Description | Required / Optional | Type | Default | Example |
|---|---|---|---|---|---|
| expiration | Message expiration time (ms) | optional | number | 86,400,000 (24 Hours) | |
| masterId | An Id relating all messages for a specific task. Used to terminate anything related to the task on all services. | optional | String / Number | --- | Example |
rr.consumeQueue(queueName, Middleware, Middleware, callback)
queueName (String) - The queue that receives the requests..
Middleware - Optional - as many as needed. these will be piped after the middleware used for the entire app (with use)
callback (Function) - A function that will be run for every Message in the queue. the function receives to arguments request and response.
returns: The following consumer object:
unSubscribe - Stops listening to new messages. Any message in process will finish normally.
rr.consumeQueue(exchangeName, Middleware, Middleware, callback)
exchangeName (String) - The exchange to register to.
Middleware - Optional - as many as needed. these will be piped after the middleware used for the entire app (with use)
callback (Function) - A function that will be run for every Message in the queue. the function receives to arguments request and response.
returns: The following consumer object:
unSubscribe - Stops listening to new messages. Any message in process will finish normally.
rr.consumeQueue(masterId)
masterId (String/Number) - ID by which to terminate all services.
Will terminate all services that share the "Master ID".
rr.use(Middleware)
Receives a Middleware function. Will add it at the beginning of all 'consumeQueue' and 'consumeExchange' declared after this call.
The consume methods (consumeQueue & consumeExchange) as well as any middleware they use, receive 2 objects. The first - request containing the data for the request.
The second - response - helps you handle replying to requests.
Both object can be extended by middleware.
An object containing the request data.
Main attributes:
| Attribute | Description |
|---|---|
| content | the request content in the same format as the original message (Null/Buffer/String/Number/Boolean/Object) |
| correlationId | An ID used by the source to identify the message and the response. |
| replyTo | The queue to which the requesting service is expecting to receive a response. |
| expiration | The max amount of the the requesting service is willing to wait for a response (from the moment the request was made). |
| payloadType | The type of payload can be on of: Null/Buffer/String/Number/Boolean/Object |
| failedAttempts | the number of times processing this message was attempted and failed. If it hasn't failed might be undefined |
| masterId | An Id relating all messages for a specific task. Used to terminate anything related to the task on all services. If a service receives a masterID it is usually recommended to pass it on to any subsequent service requests. |
| msgType | A number that represents the type of message sent (request/response/reject ETC). |
An object containing attributes and methods to assist in responding to a request.
| Attribute / Method | Description | Example | |
|---|---|---|---|
| replyTo | Attribute | Queue to which the sender of the message is listening. | |
| send | Method | Used to send a response to service that made the request. Receives one argument of type: Null/Buffer/String/Number/Boolean/Object | Example |
| reject | Method | Send a rejection to the requesting service. Receives a single argument that will be given as the error on the requesting side. supports types: Null/Buffer/String/Number/Boolean/Object | Example |
| progress | Method | Used to pass a response to sender while in the process of working on a request. These do not interfere with sending a reply/rejection and are not limited in number. Receives one argument of type: Null/Buffer/String/Number/Boolean/Object | Example |
- send and reject can only be sent once and are mutually exclusive.
Middleware is a great way to extend the capabilities of Rabbit Response. To use a middle ware all you need to do is import it and use the "use" function.
const middleware = require('superAmazingMiddleware');
rr.use(middleware);
Writing your own middleware is just as easy. A middleware is just a function that receives 3 things: request, response, next. Manipulate the request and response object as needed and call the next function when done.
const myMiddleware = (req,res,next) => {
// Do somthing to request.
// Do simthing else to response.
next();
}