Ok so I am trying to make two or more requests to API endpoints using the request module. I am rendering a HTML file and passing the returned JSON to a handlebars template using the below code:
res.render('list.html', {
title: 'List',
data: returnedJSON
}
I can then iterate over this JSON within my handlebars template fairly easily.
The problem I have, is that I am now needing to use multiple data sources where a category list will be built from a categories JSON response and a Staff list from a staff JSON response. I would like a simple solution where I can do this, but expand it to use any number of data sources.
Below is a full code snippet of what I have with one data source:
request({
url: 'https://api.com/categories',
headers: {
'Bearer': 'sampleapitoken'
}
}, function(error, response, body) {
if(error || response.statusCode !== 200) {
// handle error
} else {
var json = JSON.parse(body);
res.render('list.html', {
title: 'Listing',
data: json
});
}
});
This works great for one endpoint, but as mentioned before I now need to use multiple requests and have multiple data sources for example:
request({
url: ['https://api.com/categories','https://api.com/staff'],
headers: {
'Bearer': 'sampleapitoken'
}
}, function(error, response, body1, body2) {
if(error || response.statusCode !== 200) {
// handle error
} else {
var json1 = JSON.parse(body1);
var json2 = JSON.parse(body2);
res.render('list.html', {
title: 'Listing',
staff: json1,
categories: json2
});
}
});
I appreciate the above doesn't work like that, but I hope this can help convey what I am trying to achieve.
Thanks in advance :)
You can use the async library to map your request objects and pass them to an actual request and return all results in one callback.
var async = require("async");
var request = require("request");
// create request objects
var requests = [{
url: 'https://api.com/categories',
headers: {
'Bearer': 'sampleapitoken'
}
}, {
url: 'https://api.com/staff',
headers: {
'Bearer': 'sampleapitoken'
}
}];
async.map(requests, function(obj, callback) {
// iterator function
request(obj, function(error, response, body) {
if (!error && response.statusCode == 200) {
// transform data here or pass it on
var body = JSON.parse(body);
callback(null, body);
} else {
callback(error || response.statusCode);
}
});
}, function(err, results) {
// all requests have been made
if (err) {
// handle your error
} else {
console.log(results);
for (var i = 0; i < results.length; i++) {
// request body is results[i]
}
}
});
However a simpler way would to leverage promises, this can be done with bluebird and promisifying the request lib, or use the already promisified request lib request-promise. You'll still want to include a promise/A+ lib to map the results asynchronously.
var Promise = require("bluebird");
var request = require('request-promise');
// create request objects
var requests = [{
url: 'https://api.com/categories',
headers: {
'Bearer': 'sampleapitoken'
}
}, {
url: 'https://api.com/staff',
headers: {
'Bearer': 'sampleapitoken'
}
}];
Promise.map(requests, function(obj) {
return request(obj).then(function(body) {
return JSON.parse(body);
});
}).then(function(results) {
console.log(results);
for (var i = 0; i < results.length; i++) {
// access the result's body via results[i]
}
}, function(err) {
// handle all your errors here
});
It's important to note that all latest versions of node and browsers support Promises out of the box and this can be implemented without external libraries.