Overview

This module is a very simple wrapper around Node's built-in http library for making HTTP requests. It provides an easy way to send an HTTP GET or POST, including things like support for HTTPS (SSL), file uploads and JSON REST style API calls. Compressed responses are also handled automatically.

Usage
Method List
Request Types
Default Headers
Handling Timeouts
Automatic Redirects
Automatic Errors
Automatic Retries
Compressed Responses
Rate Limiting
Abort Signals
Performance Metrics
DNS Caching
- Flushing the Cache
SSL Certificate Validation
License

Usage

Use npm to install the module:

npm install pixl-request

Then use require() to load it in your code:

const PixlRequest = require('pixl-request');

Instantiate a request object and pass in an optional user agent string (you can also set this later via a header):

let request = new PixlRequest( "My Custom Agent 1.0" );

Here is a simple HTTP GET example:

try {
	let { data } = await request.get('https://www.bitstamp.net/api/ticker/');
	console.log("Success: " + data);
}
catch (err) {
	throw err;
}

The result object actually contains other properties besides data. Here is an example using all of them:

try {
	let { resp, data, perf } = await request.get('https://www.bitstamp.net/api/ticker/');
	console.log("Status: " + resp.statusCode + " " + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.get( 'https://www.bitstamp.net/api/ticker/', function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + " " + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
} );

And here is a simple JSON REST API request:

try {
	let { resp, data, perf } = await request.json('http://myserver.com/api', { 
		"foo": "test", 
		"bar": 123 
	});
	console.log("Status: " + resp.statusCode + " " + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.json( 'http://myserver.com/api', { "foo": "test", "bar": 123 }, function(err, resp, data, perf) {
	if (err) throw(err);
	console.log("Status: " + resp.statusCode + " " + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
} );

Method List

Here are all the methods available in the request library:

Method Name	Description
get()	Performs an HTTP GET request.
head()	Performs an HTTP HEAD request.
post()	Performs an HTTP POST request.
put()	Performs an HTTP PUT request.
delete()	Performs an HTTP DELETE request.
json()	Sends a request to a JSON REST API endpoint and parses the response.
xml()	Sends a request to an XML REST API endpoint and parses the response.
setHeader()	Overrides or adds a default header for future requests.
setTimeout()	Overrides the default socket timeout (milliseconds).
setFollow()	Overrides the default behavior for following redirects.
setAutoDecompress()	Overrides the default behavior of decompressing responses.
setDNSCache()	Enable DNS caching and set the TTL in seconds.
flushDNSCache()	Flush all IPs from the internal DNS cache.

Request Types

Here are all the request types supported by the library.

HTTP GET

PROMISE request.get( URL );
PROMISE request.get( URL, OPTIONS );

To perform a simple HTTP GET, call the get() method. All you need to provide is the URL, and the result is an object containing the response (headers and such), data (as a buffer), and performance data:

try {
	let { resp, data, perf } = await request.get('https://www.bitstamp.net/api/ticker/');
	console.log("Status: " + resp.statusCode + " " + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.get( 'https://www.bitstamp.net/api/ticker/', function(err, resp, data, perf) {
	if (err) throw(err);
	console.log("Status: " + resp.statusCode + " " + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
} );

The result of the operation is an object containing the HTTP response object from Node (IncomingMessage), a data buffer of the content (if any), and a performance tracker.

With async or promise usage, if an error occurs it is thrown. Note that an "error" in this case is something like a TCP connection failure, DNS lookup failure, socket timeout, connection aborted, or other internal client library failure. By default, HTTP response codes like 404 or 500 are not considered errors, so make sure to look at resp.statusCode if you are expecting an HTTP 200. However, if you want non-200 response codes to be considered errors, see Automatic Errors below.

To specify additional options, such as custom request headers or HTTP authentication, include an object after the URL:

try {
	let { resp, data, perf } = await request.get( 'https://www.bitstamp.net/api/ticker/', {
		"headers": {
			"X-Custom-Header": "My custom value"	
		},
		"auth": "username:password"
	});
	console.log("Status: " + resp.statusCode + " " + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.get( 'https://www.bitstamp.net/api/ticker/', {
	"headers": {
		"X-Custom-Header": "My custom value"	
	},
	"auth": "username:password"
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + " " + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
} );

Check out the Node http.request() documentation for all the properties you can pass in the options object.

By default, connections are closed at the end of each request. If you want to reuse a persistent connection across multiple requests, see the Keep-Alives section below.

HTTP HEAD

PROMISE request.head( URL )
PROMISE request.head( URL, OPTIONS )

An HTTP HEAD request will not contain any data in the response, only the response code and headers. Example:

try {
	let { resp, perf } = await request.head( 'http://myserver.com/index.html' );
	console.log("Status: " + resp.statusCode + " " + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.head( 'http://myserver.com/index.html', function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + " " + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Performance: ", perf.metrics());
} );

HTTP POST

PROMISE request.post( URL, OPTIONS )

To perform a HTTP POST, call the post() method. Provide a URL, and an options object with a data property containing your key/value pairs:

try {
	let { resp, data, perf } = await request.post( 'http://myserver.com/api/post', {
		"data": {
			"full_name": "Fred Smith", 
			"gender": "male",
			"age": 35
		}
	});
	console.log("Status: " + resp.statusCode + " " + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.post( 'http://myserver.com/api/post', {
	"data": {
		"full_name": "Fred Smith", 
		"gender": "male",
		"age": 35
	}
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
} );

Your key/value pairs will be serialized using the application/x-www-form-urlencoded format. For a multipart post, see Multipart POST below.

The result of the operation is an object containing the HTTP response object from Node (IncomingMessage), a data buffer of the content (if any), and a performance tracker.

Check out the Node http.request() documentation for all the properties you can pass in the options object.

By default, connections are closed at the end of each request. If you want to reuse a persistent connection across multiple requests, see the Keep-Alives section below.

Pure Data POST

To specify your own raw POST data without any key/value pre-formatting, simply pass a Buffer object as the data property value, then include your own Content-Type header in the headers object. Example:

let buf = Buffer.from("VGhpcyBpcyBhIHRlc3QhIPCfmJw=", "base64");

try {
	let { resp, data, perf } = await request.post( 'http://myserver.com/api/post', {
		"data": buf,
		"headers": {
			"Content-Type": "application/octet-stream"
		}
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

let buf = Buffer.from("VGhpcyBpcyBhIHRlc3QhIPCfmJw=", "base64");

request.post( 'http://myserver.com/api/post', {
	"data": buf,
	"headers": {
		"Content-Type": "application/octet-stream"
	}
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
} );

Multipart POST

For a multipart/form-data post, which is typically better for binary data, all you need to do is pass in a multipart property in your options object, and set it to a true value. Everything else is the same as a standard HTTP POST:

try {
	let { resp, data, perf } = await request.post( 'http://myserver.com/api/post', {
		"multipart": true, // activate multipart/form-data
		"data": {
			"foo": Buffer.from("Joe was here!"), 
			"bar": 54321
		}
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.post( 'http://myserver.com/api/post', {
	"multipart": true, // activate multipart/form-data
	"data": {
		"foo": Buffer.from("Joe was here!"), 
		"bar": 54321
	}
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
} );

Note that you can use Buffer objects instead of strings for your data values.

File Uploads

To upload files, use post() and include a files object with your options, containing key/pair pairs. Each file needs an identifier key (POST field name), and a value which should be a path to the file on disk:

try {
	let { resp, data, perf } = await request.post( 'http://myserver.com/api/upload', {
		"files": {
			"kitten1": "/images/SillyKitten1.jpg",
			"kitten2": "/images/SillyKitten2.jpg"
		}
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.post( 'http://myserver.com/api/upload', {
	"files": {
		"kitten1": "/images/SillyKitten1.jpg",
		"kitten2": "/images/SillyKitten2.jpg"
	}
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
} );

The file path can also be a readable stream, if you happen to have one of those already open:

let stream = fs.createReadStream('/images/SillyKitten1.jpg');

try {
	let { resp, data, perf } = await request.post( 'http://myserver.com/api/upload', {
		"files": {
			"file1": stream
		}
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

let stream = fs.createReadStream('/images/SillyKitten1.jpg');

request.post( 'http://myserver.com/api/upload', {
	"files": {
		"file1": stream
	}
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
} );

If you want to customize the filename of the uploaded file, set your file value to an array, with the first element containing the file path (or a stream), and the second element the desired filename:

"files": {
	"file1": ["/images/SillyKitten1.jpg", "A-New-Filename.JPG"]
}

You can combine file uploads with other POST data fields, just by including a data property in your options, similar to a standard HTTP POST. You can of course include any other options keys as well, such as custom headers:

try {
	let { resp, data, perf } = await request.post( 'http://myserver.com/api/post', {
		"files": {
			"file1": "/images/SillyKitten1.jpg"
		},
		"data": {
			"foo": Buffer.from("Joe was here!"), 
			"bar": 54321
		},
		"headers": {
			"X-Custom-Header": "My custom value"	
		}
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.post( 'http://myserver.com/api/post', {
	"files": {
		"file1": "/images/SillyKitten1.jpg"
	},
	"data": {
		"foo": Buffer.from("Joe was here!"), 
		"bar": 54321
	},
	"headers": {
		"X-Custom-Header": "My custom value"	
	}
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
} );

Including a files property automatically sets multipart/form-data mode, so you don't need to include the multipart boolean flag in this case.

HTTP PUT

PROMISE request.put( URL, OPTIONS )

To send an HTTP PUT, you can use the put() method. This works identically to post() in every way, except that the HTTP method is changed from POST to PUT. You can send all the various data types, upload files, etc. Example:

try {
	let { resp, data, perf } = await request.put( 'http://myserver.com/api/put', {
		"data": {
			"full_name": "Fred Smith", 
			"gender": "male",
			"age": 35
		}
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.put( 'http://myserver.com/api/put', {
	"data": {
		"full_name": "Fred Smith", 
		"gender": "male",
		"age": 35
	}
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
} );

Note that data (i.e. request body) is optional, and can be omitted.

HTTP DELETE

PROMISE request.delete( URL, OPTIONS )

To send an HTTP DELETE, you can use the delete() method. This works identically to post() in every way, except that the HTTP method is changed from POST to DELETE. You can send all the various data types, upload files, etc. Example:

try {
	let { resp, data, perf } = await request.delete( 'http://myserver.com/api/delete', {
		"data": {
			"username": "fsmith"
		}
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.delete( 'http://myserver.com/api/delete', {
	"data": {
		"username": "fsmith"
	}
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
} );

Note that data (i.e. request body) is optional, and can be omitted.

File Downloads

If you want to download the response data to a file, instead of loading it all into an in-memory Buffer object, you can specify a download property in your options object, passed to either get() or post(). Set this property to a filesystem path, and a file will be created and written to. Example:

try {
	let { resp, perf } = await request.get( 'https://upload.wikimedia.org/wikipedia/commons/9/9b/Gustav_chocolate.jpg', {
		"download": "/var/tmp/myimage.jpg"
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.get( 'https://upload.wikimedia.org/wikipedia/commons/9/9b/Gustav_chocolate.jpg', {
	"download": "/var/tmp/myimage.jpg"
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Performance: ", perf.metrics());
} );

The promise will only be resolved when the file is completely downloaded and written to the stream. If the response is encoded (compressed), this is handled transparently for you using an intermediate stream. Your file will contain the final decompressed data, and no memory will be used.

Alternatively, if you already have an open writable stream object, you can pass that to the download property. Example:

let stream = fs.createWriteStream( '/var/tmp/myimage.jpg' );

try {
	let { resp, perf } = await request.get( 'https://upload.wikimedia.org/wikipedia/commons/9/9b/Gustav_chocolate.jpg', {
		"download": stream
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

let stream = fs.createWriteStream( '/var/tmp/myimage.jpg' );

request.get( 'https://upload.wikimedia.org/wikipedia/commons/9/9b/Gustav_chocolate.jpg', {
	"download": stream
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + " " + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Performance: ", perf.metrics());
} );

Advanced Stream Control

If you need more control over the response stream, you can provide a preflight property in your options object, passed to either get() or post(). Set this property to a callback function, which will be called before the data is downloaded, but after the HTTP response headers are parsed. This allows you to essentially intercept the response and set up your own stream pipe. Example:

let stream = fs.createWriteStream( '/var/tmp/myimage.jpg' );

try {
	let { resp, perf } = await request.get( 'https://upload.wikimedia.org/wikipedia/commons/9/9b/Gustav_chocolate.jpg', {
		"download": stream,
		"preflight": function(err, resp) {
			// setup stream pipe ourselves
			resp.pipe( stream );
			return true;
		}
	});
	console.log("Status: " + resp.statusCode + " " + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

let stream = fs.createWriteStream( '/var/tmp/myimage.jpg' );

request.get( 'https://upload.wikimedia.org/wikipedia/commons/9/9b/Gustav_chocolate.jpg', {
	"download": stream,
	"preflight": function(err, resp) {
		// setup stream pipe ourselves
		resp.pipe( stream );
		return true;
	}
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + " " + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Performance: ", perf.metrics());
} );

Your preflight function can optionally return false, which will inform the library that you did not set up a stream pipe, and it should resolve the promise with a data buffer instead.

Progress Updates

If you would like to receive progress updates during a file download or large data transfer, add a progress property to your options object, and set it to a callback function. Your function will be called repeatedly during the data transfer, and be passed the current data chunk as a buffer, and the HTTP response object from Node (IncomingMessage). Example use:

try {
	let { resp, perf } = await request.get( 'https://upload.wikimedia.org/wikipedia/commons/9/9b/Gustav_chocolate.jpg', {
		"download": "/var/tmp/myimage.jpg"
		"progress": function(chunk, resp) {
			// called repeatedly during download
			console.log( "Got chunk, " + chunk.length + " bytes" );
		}
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.get( 'https://upload.wikimedia.org/wikipedia/commons/9/9b/Gustav_chocolate.jpg', {
	"download": "/var/tmp/myimage.jpg",
	"progress": function(chunk, resp) {
			// called continuously during download
			console.log( "Got chunk, " + chunk.length + " bytes of " + resp.headers['content-length'] );
		}
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Performance: ", perf.metrics());
} );

Note that progress events only fire on data received (i.e. downloaded).

Keep-Alives

To reuse the same socket connection across multiple requests, you have two options. First, you can use the built-in Keep-Alive handler by calling the setKeepAlive() method and passing true. Example:

request.setKeepAlive( true );

This will attempt to use HTTP Keep-Alives for all HTTP and HTTPS requests, by using two global http.Agent objects (one per protocol). Note that you can configure the options passed to the agents by specifying them as a secondary object to the setKeepAlive() method:

request.setKeepAlive( true, {
	keepAlive: true,
	keepAliveMsecs: 1000,
	maxSockets: 256,
	maxFreeSockets: 256,
	timeout: 5000
} );

Alternatively, you can use your own http.Agent object (provided by Node). Simply construct an instance, set the keepAlive property to true, and pass it into the options object for your requests, using the agent property:

let http = require('http');
let agent = new http.Agent({ keepAlive: true });

try {
	let { resp, data, perf } = await request.get( 'http://myserver.com/api/get', {
		"agent": agent, // custom agent for connection pooling
		"headers": {
			"X-Custom-Header": "My custom value"	
		}
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

let http = require('http');
let agent = new http.Agent({ keepAlive: true });

request.get( 'http://myserver.com/api/get', {
	"agent": agent, // custom agent for connection pooling
	"headers": {
		"X-Custom-Header": "My custom value"	
	}
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
} );

You can then use the same agent object for subsequent requests on the same host (provided the server you are connecting to also supports Keep-Alives).

JSON REST API

PROMISE request.json( URL, JSON )
PROMISE request.json( URL, JSON, OPTIONS )

The json() method is designed for sending requests to JSON REST APIs. If you want to send a JSON REST style HTTP POST to an API endpoint, and expect to receive a JSON formatted response, this wraps up all the serialization and parsing for you. Example:

try {
	let { resp, data, perf } = await request.json( 'http://myserver.com/api', { 
		"foo": "test", 
		"bar": 123 
	} );
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.json( 'http://myserver.com/api', { "foo": "test", "bar": 123 }, function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
} );

This will serialize the object into a JSON string, and send it as the HTTP POST data to the provided URL, with a Content-Type of application/json. It also expects the response back from the server to be JSON, and will parse it for you. The result will contain the HTTP response object (IncomingMessage), the parsed JSON object, and a performance tracker.

You can also specify options such as custom request headers using this API. Simply include an options object as the final argument (similar to the get() and post() methods). Example:

let json = {
	"foo": "test", 
	"bar": 123
};

try {
	let { resp, data, perf } = await request.json( 'http://myserver.com/api', json, {
		"headers": {
			"X-Custom-Header": "My custom value"	
		}
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

let json = {
	"foo": "test", 
	"bar": 123
};

request.json( 'http://myserver.com/api', json, {
	"headers": {
		"X-Custom-Header": "My custom value"	
	}
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
} );

If you pass null or false as the JSON data argument, the request will be sent as a GET instead of a POST. You can also customize the HTTP method by passing a method property into the options object. For example, the following would send as a HTTP PUT with the JSON serialized in the request body:

let json = {
	"foo": "test", 
	"bar": 123
};

try {
	let { resp, data, perf } = await request.json( 'http://myserver.com/api', json, {
		"method": "PUT", // override the default method here
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

let json = {
	"foo": "test", 
	"bar": 123
};

request.json( 'http://myserver.com/api', json, {
	"method": "PUT", // override the default method here
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
} );

You can also send a custom request method with no body:

try {
	let { resp, data, perf } = await request.json( 'http://myserver.com/delete/user/345', false, {
		"method": "DELETE", // override the default method here
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.json( 'http://myserver.com/delete/user/345', false, {
	"method": "DELETE", // override the default method here
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
} );

Note: If the server doesn't send back JSON, or it cannot be parsed, an error will be thrown.

XML REST API

PROMISE request.xml( URL, XML )
PROMISE request.xml( URL, XML, OPTIONS )

The xml() method is designed for sending requests to XML REST APIs. If you want to send a XML REST style HTTP POST to an API endpoint, and expect to receive a XML formatted response, this wraps up all the serialization and parsing for you. Example:

try {
	let { resp, data, perf } = await request.xml( 'http://myserver.com/api', { 
		"foo": "test", 
		"bar": 123 
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.xml( 'http://myserver.com/api', { "foo": "test", "bar": 123 }, function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
} );

This will serialize the object into an XML document (using the pixl-xml package), and send it as the HTTP POST data to the provided URL, with a Content-Type of text/xml. It also expects the response back from the server to be XML, and will parse it for you. The result will contain the HTTP response object (IncomingMessage), the parsed XML document, and a performance tracker.

You can also specify options such as custom request headers using this API. Simply include an options object as the final argument (similar to the get() and post() methods). Example:

let xml = {
	"foo": "test", 
	"bar": 123
};

try {
	let { resp, data, perf } = await request.xml( 'http://myserver.com/api', xml, {
		"headers": {
			"X-Custom-Header": "My custom value"	
		}
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

let xml = {
	"foo": "test", 
	"bar": 123
};

request.xml( 'http://myserver.com/api', xml, {
	"headers": {
		"X-Custom-Header": "My custom value"	
	}
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
} );

Please note that pixl-xml discards the XML root node element when parsing XML, and similarly the request library doesn't expect one when serializing. Meaning, you should omit the XML root node element (just include the contents), and expect the server XML result to be parsed in a similar fashion.

For example, if you wanted to send this XML:

<?xml version="1.0"?>
<Document>
	<foo>test</foo>
	<bar>123</bar>
</Document>

Then just include an object with foo and bar properties:

{
	"foo": "test", 
	"bar": 123
}

See the pixl-xml documentation for details, including how to include attributes, etc.

By default, the XML will be serialized to a document with <Request> as the root node name. However if you are posting to an API that requires a specific XML root node name, you can set it with the xmlRootNode property in the options object. Example of this:

let xml = {
	"foo": "test", 
	"bar": 123
};

try {
	let { resp, data, perf } = await request.xml( 'http://myserver.com/api', xml, {
		"xmlRootNode": "Document"
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

let xml = {
	"foo": "test", 
	"bar": 123
};

request.xml( 'http://myserver.com/api', xml, {
	"xmlRootNode": "Document"
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
} );

If you pass null or false as the XML data argument, the request will be sent as a GET instead of a POST. You can also customize the HTTP method by passing a method property into the options object. For example, the following would send as a HTTP PUT with the XML serialized in the request body:

let xml = {
	"foo": "test", 
	"bar": 123
};

try {
	let { resp, data, perf } = await request.xml( 'http://myserver.com/api', xml, {
		"method": "PUT", // override the default method here
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

let xml = {
	"foo": "test", 
	"bar": 123
};

request.xml( 'http://myserver.com/api', xml, {
	"method": "PUT", // override the default method here
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
} );

You can also send a custom request method with no body:

try {
	let { resp, data, perf } = await request.xml( 'http://myserver.com/delete/user/234', false, {
		"method": "DELETE", // override the default method here
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.xml( 'http://myserver.com/delete/user/234', false, {
	"method": "DELETE", // override the default method here
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
} );

Note: If the server doesn't send back XML, or it cannot be parsed, an error will be thrown.

Default Headers

By default the request library will add the following outgoing headers to every request:

User-Agent: PixlRequest 1.0.0
Accept-Encoding: gzip, deflate, br

You can override these by passing in custom headers with your request:

try {
	let { resp, data, perf } = await request.post( 'http://myserver.com/api/post', {
		"headers": {
			"User-Agent": "My Request Library!",
			"Accept-Encoding": "none"
		},
		"data": {
			"full_name": "Fred Smith", 
			"gender": "male",
			"age": 35
		}
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.post( 'http://myserver.com/api/post', {
	"headers": {
		"User-Agent": "My Request Library!",
		"Accept-Encoding": "none"
	},
	"data": {
		"full_name": "Fred Smith", 
		"gender": "male",
		"age": 35
	}
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
} );

Or by overriding your class instance defaults before making a request:

request.setHeader( "Accept-Encoding", "none" );

You can also replace the entire header set by rewriting the defaultHeaders property:

request.defaultHeaders = {
	"User-Agent": "My Request Library!",
	"Accept-Encoding": "none"
};

Handling Timeouts

PixlRequest handles timeouts in two different ways. First, by measuring the "time to first byte" (TTFB), from the start of the request. This is not an idle timeout, and not a connect timeout -- it is the maximum amount of time allowed from the start of the request, to the first byte received. Separately, it also can track an idle timeout after the first byte has been received. You can set each timeout separately.

The default TTFB timeout and idle timeout for all requests is 30 seconds. You can customize this per request by including timeout and/or idleTimeout properties with your options object, and setting them to a number of milliseconds:

try {
	let { resp, data, perf } = await request.post( 'http://myserver.com/api/post', {
		"data": {
			"full_name": "Fred Smith", 
			"gender": "male",
			"age": 35
		},
		"timeout": 10 * 1000, // 10 second TTFB timeout
		"idleTimeout": 5 * 1000 // 5 second idle timeout
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.post( 'http://myserver.com/api/post', {
	"data": {
		"full_name": "Fred Smith", 
		"gender": "male",
		"age": 35
	},
	"timeout": 10 * 1000, // 10 second TTFB timeout
	"idleTimeout": 5 * 1000 // 5 second idle timeout
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
} );

Or you can set default timeouts for all requests on your class instance, using the setTimeout() and setIdleTimeout() methods:

request.setTimeout( 10 * 1000 ); // 10 seconds
request.setIdleTimeout( 5 * 1000 ); // 5 seconds

When a timeout occurs, an error event is emitted. The error message will follow one of these formats, depending on which timeout was fired:

Request Timeout (### ms)
Idle Timeout (### ms)

Note that any timeout results in the socket being destroyed (i.e. request.destroy() is called on the request object, which in turn destroys the socket).

Automatic Redirects

The default behavior for handling redirect responses (i.e. HTTP 302 and friends) is to not follow them automatically, and instead return the original 3xx response. You can change this by including a follow property with your options object, and setting it to the maximum number of redirects you want to allow:

try {
	let { resp, data, perf } = await request.post( 'http://myserver.com/api/post', {
		"data": {
			"full_name": "Fred Smith", 
			"gender": "male",
			"age": 35
		},
		"follow": 2, // auto-follow up to 2 redirects
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.post( 'http://myserver.com/api/post', {
	"data": {
		"full_name": "Fred Smith", 
		"gender": "male",
		"age": 35
	},
	"follow": 2, // auto-follow up to 2 redirects
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: ", data);
	console.log("Performance: ", perf.metrics());
} );

Alternatively, you can set a class instance default by calling the setFollow() method:

request.setFollow( 2 ); // auto-follow up to 2 redirects

If you want to follow an unlimited number of redirects, set this to boolean true (not advised). To disable the auto-follow behavior, set it to 0 or false.

The library recognizes HTTP codes 301, 302, 307 and 308 as "redirect" responses, as long as a Location header accompanies them.

Automatic Errors

When using get() or post(), HTTP response codes like 404 or 500 are not considered errors, so you have to look at resp.statusCode if you are expecting an HTTP 200. However, this is configurable. If you would like all non-200 response codes to be considered errors, call the setAutoError() method and pass true. Example:

request.setAutoError( true );

Note that if you allow redirects, they will not generate an error.

To customize which response codes are considered "successful" and should not generate an error, call the setSuccessMatch() method, and pass in a new one. The default match is shown here, which considered any HTTP response code in the 200 - 299 range to be successful:

request.setSuccessMatch( /^2\d\d$/ );

Note that this regular expression also affects the json() and xml() wrapper methods.

Automatic Retries

By default errors are not retried, and the promise is resolved immediately on the first error. However, you can enable automatic retries by either including a retries property in your options object (set to the maximum number of retries you want to allow), or by calling the setRetries() method, and specifying the maximum amount for all requests:

request.setRetries( 5 );

This example would make up to 6 total attempts (the initial attempt plus up to 5 retries), before ultimately failing the operation and resolving the promise with the last error encountered.

For the purpose of automatic retries an "error" is considered to be any core error emitted on the request object, such as a DNS lookup failure, TCP connect failure, socket timeout, or any HTTP response code in the 5xx range (500 - 599), such as an Internal Server Error. Any other errors, for example anything in the 4xx range, are not retried, as they are typically considered to be more permanent.

Compressed Responses

The request library automatically handles Brotli, Gzip and Deflate encoded responses that come back from the remote server. These are transparently decoded for you. However, you should know that by default all outgoing requests include an Accept-Encoding: gzip, deflate, br header, which broadcasts our support for it. If you do not want responses to be compressed, you can unset this header. See the Default Headers section above.

Alternately, if you would prefer that the library not do anything regarding compression, and pass the compressed response directly through without touching it, call the setAutoDecompress() method, and pass in false:

request.setAutoDecompress( false );

Abort Signals

If you have a long-running request that you may want to abort in the middle, you can use a Node.js AbortController. Just pass in the signal property from your controller into the request options object, and then you can call abort() on the controller whenever you want. Example:

const controller = new AbortController();

// abort after 500ms
setTimeout( function() {
	controller.abort();
}, 500 );

// send long request
try {
	let { resp, data, perf } = await request.get( 'http://myserver.com/some/large/file.mp4', {
		"signal": controller.signal // our abort signal here
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

const controller = new AbortController();

// abort after 500ms
setTimeout( function() {
	controller.abort();
}, 500 );

// send long request
request.get( 'http://myserver.com/some/large/file.mp4', {
	"signal": controller.signal // our abort signal here
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Performance: ", perf.metrics());
} );

Note that abort signals are designed to abort requests that have already received the "first byte". Meaning, we already received the response headers, and are streaming down the data. That's the phase of the request that is "abortable".

Performance Metrics

The request library keeps high resolution performance metrics on every HTTP request, including the DNS lookup time, socket connect time, request send time, wait time, receive time, decompress time, and total elapsed time. These are all tracked using the pixl-perf module, and included in the result object for all operations. Example use:

try {
	let { resp, data, perf } = await request.get( 'https://www.bitstamp.net/api/ticker/' );
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.get( 'https://www.bitstamp.net/api/ticker/', function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
} );

This would output something like the following:

Status: 200 OK
Performance: { 
  scale: 1000,
  perf: { 
     total: 548.556,
     dns: 25.451,
     connect: 120.155,
     send: 270.92,
     wait: 122.2,
     receive: 3.462,
     decompress: 4.321 
  },
  counters: { 
    bytes_sent: 134, 
    bytes_received: 749 
  } 
}

All the perf values are in milliseconds (represented by the scale). Here are descriptions of all the metrics:

Metric	Description
`dns`	Time to resolve the hostname to an IP address via DNS. Omitted if cached, or you specify an IP on the URL.
`connect`	Time to connect to the remote socket (omitted if using Keep-Alives and reusing a host).
`send`	Time to send the request data (typically for POST / PUT). Also includes SSL handshake time (if HTTPS).
`wait`	Time spent waiting for the server response (after request is sent).
`receive`	Time spent downloading data from the server (after headers received).
`decompress`	Time taken to decompress the response (if encoded with Brotli, Gzip or Deflate).
`total`	Total time of the entire HTTP transaction.

As indicated above, some of the properties may be omitted depending on the situation. For example, if you are using a shared http.Agent with Keep-Alives, then subsequent requests to the same host won't perform a DNS lookup or socket connect, so those two metrics will be omitted. Similarly, if the response from the server isn't compressed, then the decompress metric will be omitted.

Note that the send metric includes the SSL / TLS handshake time, if using HTTPS. Also, this metric may be 0 if using plain HTTP GET or HEAD, as it is mainly used to measure the POST or PUT data send time (i.e. uploading file data).

The bytes_sent and bytes_received values in the counters object represent the total amount of raw bytes sent and received over the socket. This includes the raw request line and request/response headers.

See the pixl-perf module for more details.

DNS Caching

You can optionally have the library cache DNS lookups in RAM, for faster subsequent requests on the same hostnames. You can also specify the TTL (time to live) to control how long hostnames will be cached. This means it will only request a DNS lookup for a given hostname once every N seconds. To enable this feature, call setDNSCache() and specify the number of seconds for the TTL:

request.setDNSCache( 300 ); // 5 minute TTL

This will cache hostnames and their IP addresses in RAM for 5 minutes. Meaning, during that time subsequent requests to the same hostname will not require a DNS lookup. After 5 minutes, the cache objects will expire, and the next request will perform another DNS lookup.

Note that while the feature can be enabled or disabled per request object, the DNS cache itself is global. Meaning, it is shared by all pixl-request objects in the same process.

Flushing the Cache

To flush the DNS cache (i.e. eject all the IPs from it), call the flushDNSCache() method. Example:

request.flushDNSCache();

SSL Certificate Validation

If you are trying to connect to a host via HTTPS and getting certificate errors, you may have to bypass Node's SSL certification validation. To do this, set the rejectUnauthorized options property to false. Example:

try {
	let { resp, data, perf } = await request.get( 'https://www.bitstamp.net/api/ticker/', {
		"rejectUnauthorized": false
	});
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
}
catch (err) {
	throw err;
}

Example using callback

request.get( 'https://www.bitstamp.net/api/ticker/', {
	"rejectUnauthorized": false
}, 
function(err, resp, data, perf) {
	if (err) throw err;
	console.log("Status: " + resp.statusCode + ' ' + resp.statusMessage);
	console.log("Headers: ", resp.headers);
	console.log("Content: " + data);
	console.log("Performance: ", perf.metrics());
} );

Please only do this if you understand the security ramifications, and completely trust the host you are connecting to, and the network you are on. Skipping the certificate validation step should really only be done in special circumstances, such as testing your own internal server with a self-signed cert.

License

The MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

pixl-request

Overview

Table of Contents

Usage

Method List

Request Types

HTTP GET

HTTP HEAD

HTTP POST

Pure Data POST

Multipart POST

File Uploads

HTTP PUT

HTTP DELETE

File Downloads

Advanced Stream Control

Progress Updates

Keep-Alives

JSON REST API

XML REST API

Default Headers

Handling Timeouts

Automatic Redirects

Automatic Errors

Automatic Retries

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