How Do i implement nodejs to the existing api proxy ?

[#1]

I have implemented an api proxy which calls a websevice. i need to make multiple similar callouts to a webservice. I would like:

• to trigger these in parallel, depending on data available from an existing service
• to implement this in nodejs, because using javascript callout i am able to make only sequential callout .

How do i implement this in nodejs? or is there better way to do it?

please help

[adas]

@arunpatcha

Yes nodejs would be the right way to go. You can use nodejs to make http callouts using frameworks like argo. Here's an example:

var argo = require('argo');
var express = require('express');
var app = express();
var proxy = argo()
             .target('http://example.com')
             .build();
app.get('/hello', function(req, res){ 
  res.send('Hello from Express');
});


app.all('*', proxy.run); 
app.listen(3000);   

Adding a nodejs target to an existing proxy is really simple. Once you have this nodejs script, in your TargetEndpoint instead of HTTPTargetConnection element, just refer to the nodejs as a ScriptTarget, like this:

<ScriptTarget>
  <ResourceURL>node://callout.js</ResourceURL>
  <Properties/>
</ScriptTarget>

[#3]

The requirement is like this i have implemented a mashup of two apis .

In that one api is called multiple no of time using a javascript and by getting values from first api and adding it in array and making multiple calls in sequence .

I want make these calls in parllel which can be achieved using nodejs.

I want to know where this nodejs has to added.

do i have to create a different target endpoint for it or can it be implemented in existing flow?

[#4]

You've just given me the info I was searching for. Thanks for the info, you made it easy to understand. Merging files is super easy with AltoMerge. Try it on your own here http://goo.gl/lHMuvo and you'll make sure how it's simple.

[ceber]

It is possible to make async requests with the standard javascript policy. Here's a sample that does that. https://github.com/apigee/api-platform-samples/tree/master/sample-proxies/async-callout

[#6]

In that sample the values are static. If my values are dynamic like i am having webservice that will give list of cities with zipcodes and for these each cities with zip codes i need get weather data for each city. how do i implement it so that i can call them async .

[ceber]

If the number of zip codes is dynamic, it gets more complicated to use javascript callouts. I think node.js might be a simpler way to implement things when you don't know how many callouts you're going to need to make. When you create a node.js proxy in Edge it's not handled the same as adding a javascript extension policy to an existing proxy. The node.js script becomes the "target" for the proxy. You can still apply policies to flows as you would with any other back-end target, but in addition you can use the apigee-access module to get access to flow variables directly from your node.js code.

I would start by building out a sample as described here: http://apigee.com/docs/api-services/content/getting-started-nodejs-apigee-edge

Then look at the apigee-access module: http://apigee.com/docs/api-services/content/using-apigee-access

I've used the async module to do something very similar to what you're describing. https://github.com/caolan/async

I can share code if it would help.