Agile Web Development with Rails 5.1

Uploading Files to Rails Applications

Your application may allow users to upload files. For example, a bug-reporting system might let users attach log files and code samples to a problem ticket, or a blogging application could let its users upload a small image to appear next to their articles.

In HTTP, files are uploaded as a multipart/form-data POST message. As the name suggests, forms are used to generate this type of message. Within that form, you’ll use <input> tags with type="file". When rendered by a browser, this allows the user to select a file by name. When the form is subsequently submitted, the file or files will be sent back along with the rest of the form data.

To illustrate the file upload process, we’ll show some code that ...