Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/debitoor/multifetch
Express middleware for performing internal batch requests
https://github.com/debitoor/multifetch
Last synced: 12 days ago
JSON representation
Express middleware for performing internal batch requests
- Host: GitHub
- URL: https://github.com/debitoor/multifetch
- Owner: debitoor
- Created: 2013-12-29T14:28:22.000Z (almost 11 years ago)
- Default Branch: master
- Last Pushed: 2020-10-27T09:59:40.000Z (about 4 years ago)
- Last Synced: 2024-10-31T18:14:01.866Z (17 days ago)
- Language: JavaScript
- Size: 40 KB
- Stars: 85
- Watchers: 42
- Forks: 7
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
multifetch [](https://travis-ci.org/debitoor/multifetch)
==========
Express middleware for performing internal batch GET requests. It allows the client to send a single HTTP request, which in turn can fetch multiple JSON resources in the app, without performing any further requests.
npm install multifetch
Developed and tested with `node 0.10`. Versions above `1.0.0` of this module are tested with `express 4`, while previous versions used `express 3`.
Usage
-----
It can be used without any configuration.
```javascript
var multifetch = require('multifetch');
var express = require('express');
var app = express();
app.get('/api/multifetch', multifetch());
app.get('/api/user', function(request, response) {
response.json({
name: 'user_1',
associates: ['user_2', 'user_3']
});
});
app.listen(8080);
```
Performing a GET request to `/api/multifetch?user=/api/user`, will return the user and some meta information. The query parameter should have a resource name as key and the relative path as value. The path can have its own query, as long it's encoded correctly. Furthermore the endpoint must return `application/json` or `text/json` (with or without character encoding) in the `content-type` header, or else the content will be ignored.
```javascript
// Response JSON object
{
user: {
statusCode: 200, // Response code returned by the user route
headers: { // All response headers
'content-type': 'application/json',
...
},
body: { // The actual json body
name: 'user_1',
associates: ['user_2', 'user_3']
}
},
_error: false // _error will be true if one of the requests failed
}
```
This way we can fetch multiple resources, by adding them to the query. If we had more routes defined, it would be possible to do.
GET /api/multifetch?user=/api/user&albums=/api/users/user_1/albums&files=/api/files
And the response will contain all the resources as described above.
```javascript
{
user: {
statusCode: 200,
headers: { ... },
body: { ... }
},
albums: {
statusCode: 200,
headers: { ... },
body: [ ... ]
},
files: {
statusCode: 200,
headers: { ... },
body: [ ... ]
},
_error: false
}
```
We don't perform any additional HTTP requests, instead express' internal routing is used to get the resources and send them back to client. The JSON is streamed to client one requests at the time.
It is also possible to configure `multifetch` to ignore some of the query parameters, or call a provided callback function before performing any internal routing, which makes it possible to set any required headers on the internal request, e.g. api access tokens (the `cookie` header is set by default).
```javascript
// Ignore access_token and token in the query
app.get('/api/multifetch', multifetch({ ignore: ['access_token', 'token'] }));
// Callback function run before each internal request.
// The serverRequest argument, is the original request to multifetch,
// while internalRequest is the fake request generated to get the actual resource.
app.get('/api/multifetch', multifetch(function(serverRequset, internalRequest, next) {
if(serverRequest.hasAccess) {
// Calling next with a truthy value, skips this internal request.
return next(true);
}
// Copy token
internRequest.headers.token = serverRequest.headers.token || serverRequest.query.token;
next();
}));
```
If `request.body` is available and is a JSON object, resources will also be included from there (body object with resource names as keys, and paths as values). This
can de bone by using a `post` route with the `bodyParse` middleware.
Requesting non JSON resources, where `content-type` doesn't contain `json`, returns `null` as body.
Passing `headers: false` as an option, excludes `statusCode` and `headers` from the response, only the resource content is returned (the `_error` property is still available).
```javascript
app.get('/api/multifetch', multifetch({ headers: false }));
```
Response with content only.
```javascript
{
user: {
name: 'user_1',
associates: ['user_2', 'user_3']
},
_error: false
}
```
### Concurrency
By default, `multifetch` will process each request sequentially, waiting until a request has been processed and fully piped out before it processes the next request.
If the response to each of your requests is small but takes a long time to fetch (e.g. heavy database queries), `multifetch` supports concurrently processing requests.
Passing `concurrency: N` as an option allows you to control the number of concurrent requests being processed at any one time:
```javascript
app.get('/api/multifetch', multifetch({ concurrency: 5 }));
```
In the above case, 5 requests would be routed through express concurrently, and the response of each is placed in a queue to be streamed out to the client sequentially.
License
-------
[MIT](http://opensource.org/licenses/MIT)