express-form-post

Express Form Post

A simple solution to handling file and form submissions

express-form-post was designed to become a central module primarily to abstract away setting up file uploads for aws-s3 and dropbox storage apis. This api streams buffer data to endpoints and can even validate the request's body before deciding to save the file. Works great for any application that needs signups or works with file uploads!

Note: This module works in any node.js setting. Express is not required for usage.

Installation

$ npm install express-form-post --save

Usage

The information for the uploaded file will be available in the files object in the request object. Fields that were sent along the request will be available on thebody object in the request object. express-form-post can be dropped in as middleware or used as a function to handle file upload. Check out the samples on the github repository for more specific usage!

Quick Start with express

var express = require("express");
var app = express();
var efp = require("express-form-post");
var formPost = efp();

app.use(formPost.middleware());

Usage as an asynchronous function (Highly Recommended)

You can also use express-form-post's method 'upload' instead of the middleware method. It is a more intuitive way of handling the upload. I would recommend using this if you want to handle errors in any sophisticated way (if you're doing something more than just logging the error).

This allows you to use express-form-post without express routing

var express = require("express");
var app = express();
var efp = require("express-form-post");
var formPost = efp();

app.post("/upload", function(req, res, next) { 
	formPost.upload(req, res, function(err) {
		if(err) {
			console.log(err);
		}
		console.log("My files are located here:", req.files);
		res.redirect("/");
	});
}

Usage with Disk Storage

var express = require("express");
var app = express();
var efp = require("express-form-post");
const formPost = efp({
	store: "disk",
	directory: path.join(__dirname, "tmp"),
	maxfileSize: 10000,
	filename: function(originalname, fieldname, mimetype) {
		return Date.now() + "-" + originalname;
	},
	validateFile: function(cb, fieldname, mimetype) {
		console.log(mimetype);
		if(mimetype != "application/pdf") {
			return cb(false);
		}
		return cb();
	},
	validateBody: function(cb, body) {
		// validates password length before uploading file
		if(body.password.length > 7) {
			return cb(false);
		}
		cb();
	}
});

app.post("/upload", formPost.middleware(), function(req, res, next) {
	console.log("I just received files", req.files);
	res.send("Upload successful!");
});

Usage with aws-s3

$ npm install aws-sdk --save

var express = require("express");
var app = express();
var efp = require("express-form-post");
const formPost = efp({
	store: "aws-s3",
	maxfileSize: 100000,
	filename: function(originalname, fieldname, mimetype) {
		return originalname;
	},
	api: {
		accessKeyId: process.env.AWS_ACCESS_KEY_ID,
		secretAccessKey: process.env.secretAccessKey,
		bucketName: process.env.S3_BUCKET_NAME,
		ACL: "public-read"
	}
})

app.post("/upload", formPost.middleware(), function(req, res, next) {
	console.log("I just received files", req.files);
	res.send("Upload successful!");
});

Usage with dropbox

$ npm install dropbox-stream --save

var express = require("express");
var app = express();
var efp = require("express-form-post");
const formPost = efp({
	store: "dropbox",
	filename: function(originalname, fieldname, mimetype) {
		return originalname;
	},
	api: {
		accessToken: process.env.dropboxAccessToken
	}
});

app.use(formPost.middleware(function(err) {
	if(err) console.log(err);
	console.log("Here are my files", req.files);
}));

API

When initializing an instance of efp (express-form-post) you can provide it different options that will change the way efp handles your file uploads.

express-form-post([opts])

express-form-post accepts an "optional" options parameter list. Keep in mind all fields are OPTIONAL. If you don't provide any, the express-form-post api will take care of that using the default options.

Key	Description	Note
store	The type of store	check below for available store methods
directory	The folder to which the file will be saved	defaults to current directory
filename	function to determine file save name	defaults to the a unique 64 bit hash generated by hasha
maxfileSize	Maximum Size of the uploaded file in bytes	defaults to infiniti
minfileSize	Minimum Size of the uploaded file in bytes	defaults to 0
validateFile	function to validate uploaded file	takes two optional parameters: fieldname and mimetype
validateBody	function to validate the body of the request before storing the validated file	request body is the parameter
api	api configuration information (api keys)	read further documentation for specifications

Validation

One of the advantages of using express-form-post to handle file uploads is the validation api. There are two (optional) validation methods available during setup: validateFile and validateBody.

If specifying a validation method property, you must call the callback argument or your file will go unhandled.

Both validate functions were designed to be an intuitive way to create conditional file handling. In order to invalidate a request/file upload, you just need to return the callback with the argument false. Examples are listed below.

validateBody(callback, body)

The validateBody method validates the request's body before sending off your file to the specified store. This is especially helpful for handling signups that require uploading some type of file (e.g a resume). For example, if the user signs up without filling in the proper fields, you can cancel the file upload (saves api requests and creates faster responses for errors). Here is an example with validating that a field called 'username' was sent.

const formPost = efp({
	validateBody: function(cb, body) {
		if(body.username == undefined) {
			return cb(false);
		}
		cb();
	}
});

validateFile(fieldname, mimetype)

The validateFile method validates the file data itself. An example use case would be checking if the file is a pdf. This particular example is listed below.

const formPost = efp({
	validateFile: function(fieldname, mimetype) {
		if(mimetype != "application/pdf") {
			return cb(false);
		} else {
			cb();
		}
	}
});

Available storage methods

• disk
• aws s3
• dropbox

Storage handlers

There are three different ways to handle form data with express-form-post. The three ways are available as methods in the instance of a express-form-post object.

upload(request, response[, callback])

This method is used inside routes as a function rather than middleware. This allows better readability and customizability. This function takes in three parameters : request, response, and an optional callback. The request and response object should be the ones provided by express.

middleware([callback])

This method is used as middleware and provides a good layer of abstraction for file handling.

fields

This method is used to only parse the fields and ignore the files. I would recommend against using this and to use body-parser instead, but fields is available for those who are not looking to download multiple modules that do the same.

Configuring cloud storage

Here are the different information you can input for each api storage. These options would go inside the api property of the options listed above.

aws-s3

Key	Description	Note
accessKeyId	AWS access key id	This is required. You can find it here : aws console
secretAccessKey	secret key for aws	Optional based on your s3 settings
bucketName	The name of your bucket.	This is required.
ACL	Access control list	Privacy control. Defaults to "private"

dropbox

Key	Description	Note
accessToken	used by Dropbox to identify your app	This is required. Check out the docs
clientId	Dropbox client Id	Optional
selectUser	Specific user in a team box	Optional

Samples

Samples are also available on the github page. Please take a look and reach out if you have any questions: github