I am intending to design a Rest API, which receives user request and do heavy putation and return the result.

I am new to web programming. so just get familiar with basic API service.

what I know:

1) request sent by post method with JSON, because data is not so simple. 2) I followed some examples and been successful with basics.

so I think I better start writing the heavy putation part.

I want it as following.

1) receive post request, and start to pute

2) just after puting send "working msg" (I think I can just do re.send("MSG"))

my questions

1)but where should I put my heavy puting?

2)since I already responded with "MSG", how can I send another content when there is no request?

3) I have read about middleware, and feels like middleware handles things between receiving request and sending response. am I right?

It would be great if you could show me a simple examples.

I am intending to design a Rest API, which receives user request and do heavy putation and return the result.

I am new to web programming. so just get familiar with basic API service.

what I know:

1) request sent by post method with JSON, because data is not so simple. 2) I followed some examples and been successful with basics.

so I think I better start writing the heavy putation part.

I want it as following.

1) receive post request, and start to pute

2) just after puting send "working msg" (I think I can just do re.send("MSG"))

my questions

1)but where should I put my heavy puting?

2)since I already responded with "MSG", how can I send another content when there is no request?

3) I have read about middleware, and feels like middleware handles things between receiving request and sending response. am I right?

It would be great if you could show me a simple examples.

• javascript
• json
• node.js

• REST is all about "resources" and what you're doing to them, it might help get better answers if you provided some context as to what the putation you're doing is. As a starting point though, HTTP 202 (Accepted) is a useful status code if you're just taking some input to process, but don't want to guarantee anything is going to work yet. – Tom Davies Commented Dec 15, 2016 at 17:01
• 1 Do it in background as this.lau said. Node.js is ONE THREAD ONLY, therefore if you do heavy processing in it, it blocks all the ining messages. – libik Commented Dec 15, 2016 at 17:07
• @TomDavies thx, I will look for how to do background jobs now – arslan Commented Dec 15, 2016 at 17:10
• @libik can you show me any example code of something like this? – arslan Commented Dec 15, 2016 at 17:11
• 2 @alim - example of what? If yuo google "node.js single thread" you find a lot information about it. – libik Commented Dec 15, 2016 at 17:23

1 Answer 1

Probably the best way to implement this is to do the heavy processing server-side in the background, and provide a way for the client to check if the job is pleted or not.

For example, let's say you want to run some heavy calculation. You could create a resource like this:

POST /calculator

The client POST a calculation, then the resource queue the calculation job for later processing (maybe by some cron job on the server) and respond with a job resource:

{ "id": 123456, "status": "pending" }

Then the clients can check at any time if the job is pleted by checking the /jobs resource:

GET /jobs/123456

which initially might respond with this again:

{ "id": 123456, "status": "pending" }

Then when it's in progress:

{ "id": 123456, "status": "in_progress" }

And when it's done:

{ "id": 123456, "status": "done", "result": <some object that contains the result of the calculation> }