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# sync-request
Make synchronous web requests with cross platform support.
**N.B.** You should **not** be using this in a production application. In a node.js application you will find that you are completely unable to scale your server. In a client application you will find that sync-request causes the app to hang/freeze. Synchronous web requests are the number one cause of browser crashes. For production apps, you should use [then-request](https://github.com/then/then-request), which is exactly the same except that it is asynchronous.
[](https://travis-ci.org/ForbesLindesay/sync-request)
[](https://david-dm.org/ForbesLindesay/sync-request)
[](https://www.npmjs.org/package/sync-request)
## Installation
npm install sync-request
## Usage
```js
request(method, url, options)
```
e.g.
- GET request without options
```js
var request = require('sync-request');
var res = request('GET', 'http://example.com');
console.log(res.getBody());
```
- GET request with options
```js
var request = require('sync-request');
var res = request('GET', 'https://example.com', {
'headers': {
'user-agent': 'example-user-agent'
}
});
console.log(res.getBody());
```
- POST request to a JSON endpoint
```js
var request = require('sync-request');
var res = request('POST', 'https://example.com/create-user', {
json: { username: 'ForbesLindesay' }
});
var user = JSON.parse(res.getBody('utf8'));
```
**Method:**
An HTTP method (e.g. `GET`, `POST`, `PUT`, `DELETE` or `HEAD`). It is not case sensitive.
**URL:**
A url as a string (e.g. `http://example.com`). Relative URLs are allowed in the browser.
**Options:**
- `qs` - an object containing querystring values to be appended to the uri
- `headers` - http headers (default: `{}`)
- `body` - body for PATCH, POST and PUT requests. Must be a `Buffer` or `String` (only strings are accepted client side)
- `json` - sets `body` but to JSON representation of value and adds `Content-type: application/json`. Does not have any affect on how the response is treated.
- `cache` - Set this to `'file'` to enable a local cache of content. A separate process is still spawned even for cache requests. This option is only used if running in node.js
- `followRedirects` - defaults to `true` but can be explicitly set to `false` on node.js to prevent then-request following redirects automatically.
- `maxRedirects` - sets the maximum number of redirects to follow before erroring on node.js (default: `Infinity`)
- `gzip` - defaults to `true` but can be explicitly set to `false` on node.js to prevent then-request automatically supporting the gzip encoding on responses.
- `timeout` (default: `false`) - times out if no response is returned within the given number of milliseconds.
- `socketTimeout` (default: `false`) - calls `req.setTimeout` internally which causes the request to timeout if no new data is seen for the given number of milliseconds. This option is ignored in the browser.
- `retry` (default: `false`) - retry GET requests. Set this to `true` to retry when the request errors or returns a status code greater than or equal to 400
- `retryDelay` (default: `200`) - the delay between retries in milliseconds
- `maxRetries` (default: `5`) - the number of times to retry before giving up.
These options are passed through to [then-request](https://github.com/then/then-request), so any options that work for then-request should work for sync-request (with the exception of custom and memory caching strategies, and passing functions for handling retries).
**Returns:**
A `Response` object.
Note that even for status codes that represent an error, the request function will still return a response. You can call `getBody` if you want to error on invalid status codes. The response has the following properties:
- `statusCode` - a number representing the HTTP status code
- `headers` - http response headers
- `body` - a string if in the browser or a buffer if on the server
It also has a method `res.getBody(encoding?)` which looks like:
```js
function getBody(encoding) {
if (this.statusCode >= 300) {
var err = new Error('Server responded with status code ' + this.statusCode + ':\n' + this.body.toString(encoding));
err.statusCode = this.statusCode;
err.headers = this.headers;
err.body = this.body;
throw err;
}
return encoding ? this.body.toString(encoding) : this.body;
}
```
## How is this possible?
Internally, this uses a separate worker process that is run using either [childProcess.spawnSync](http://nodejs.org/docs/v0.11.13/api/child_process.html#child_process_child_process_spawnsync_command_args_options) if available, or falling back to [spawn-sync](https://www.npmjs.org/package/spawn-sync) if not. The fallback will attempt to install a native module for synchronous execution, and fall back to doing busy waiting for a file to exist. All this ultimatley means that the module is totally cross platform and does not require native code compilation support.
The worker then makes the actual request using [then-request](https://www.npmjs.org/package/then-request) so this has almost exactly the same API as that.
This can also be used in a web browser via browserify because xhr has built in support for synchronous execution. Note that this is not recommended as it will be blocking.
## License
MIT
|