mime-db

What is mime-db?

The mime-db package is a comprehensive database of MIME types based on the mime-types npm package. It provides an API to access MIME type definitions, which are compiled from various sources. It is often used to look up MIME types based on file extensions or vice versa.

What are mime-db's main functionalities?

Lookup MIME type for a given file extension

This feature allows you to get the MIME type for a specific file extension. In the code sample, we are looking up the MIME type for JSON files.

const mimeDb = require('mime-db');
const mimeType = mimeDb['json'].type;

Get extensions for a given MIME type

This feature enables you to retrieve the file extensions associated with a particular MIME type. In the code sample, we are getting the extensions for 'application/json'.

const mimeDb = require('mime-db');
const extensions = mimeDb['application/json'].extensions;

Access MIME type data

This feature provides access to the data associated with a specific MIME type, including the source of the information, charset, and whether it's compressible. The code sample demonstrates how to access the data for 'application/json'.

const mimeDb = require('mime-db');
const mimeData = mimeDb['application/json'];

Other packages similar to mime-db

mime-types

The mime-types package is a lightweight version of mime-db that provides utility functions to work with MIME types, such as looking up MIME types and extensions. It is built on top of mime-db and offers a simpler API for common use cases.

mime

The mime package is another popular alternative that allows users to look up MIME types based on file extensions and vice versa. It offers a more limited dataset compared to mime-db but includes a simple API for the most common MIME type operations.

README

mime-db

This is a large database of mime types and information about them. It consists of a single, public JSON file and does not include any logic, allowing it to remain as un-opinionated as possible with an API. It aggregates data from the following sources:

• https://www.iana.org/assignments/media-types/media-types.xhtml
• https://svn.apache.org/repos/asf/httpd/httpd/trunk/docs/conf/mime.types
• https://hg.nginx.org/nginx/raw-file/default/conf/mime.types

Installation

npm install mime-db

Database Download

If you intend to use this in a web browser, you can conveniently access the JSON file via jsDelivr, a popular CDN (Content Delivery Network). To ensure stability and compatibility, it is advisable to specify a release tag instead of using the 'master' branch. This is because the JSON file's format might change in future updates, and relying on a specific release tag will prevent potential issues arising from these changes.

https://cdn.jsdelivr.net/gh/jshttp/mime-db@master/db.json

Usage

var db = require('mime-db')

// grab data on .js files
var data = db['application/javascript']

Data Structure

The JSON file is a map lookup for lowercased mime types. Each mime type has the following properties:

• .source - where the mime type is defined. If not set, it's probably a custom media type.
  • apache - Apache common media types
  • iana - IANA-defined media types
  • nginx - nginx media types
• .extensions[] - known extensions associated with this mime type.
• .compressible - whether a file of this type can be gzipped.
• .charset - the default charset associated with this type, if any.

If unknown, every property could be undefined.

Note on MIME Type Data and Semver

This package considers the programmatic api as the semver compatibility. This means the MIME type resolution is not considered in the semver bumps. This means that if you want to pin your mime-db data you will need to do it in your application. While this expectation was not set in docs until now, it is how the pacakge operated, so we do not feel this is a breaking change.

Contributing

The primary way to contribute to this database is by updating the data in one of the upstream sources. The database is updated from the upstreams periodically and will pull in any changes.

Registering Media Types

The best way to get new media types included in this library is to register them with the IANA. The community registration procedure is outlined in RFC 6838 section 5. Types registered with the IANA are automatically pulled into this library.

Direct Inclusion

If that is not possible / feasible, they can be added directly here as a "custom" type. To do this, it is required to have a primary source that definitively lists the media type. If an extension is going to be listed as associated with this media type, the source must definitively link the media type and extension as well.

To edit the database, only make PRs against src/custom-types.json or src/custom-suffix.json.

The src/custom-types.json file is a JSON object with the MIME type as the keys and the values being an object with the following keys:

• compressible - leave out if you don't know, otherwise true/false to indicate whether the data represented by the type is typically compressible.
• extensions - include an array of file extensions that are associated with the type.
• notes - human-readable notes about the type, typically what the type is.
• sources - include an array of URLs of where the MIME type and the associated extensions are sourced from. This needs to be a primary source; links to type aggregating sites and Wikipedia are not acceptable.

To update the build, run npm run build.