Browse Prior Art Database

The "data" URL scheme (RFC2397) Disclosure Number: IPCOM000002970D
Original Publication Date: 1998-Aug-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 4 page(s) / 9K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

L. Masinter: AUTHOR


A new URL scheme, "data", is defined. It allows inclusion of small data items as "immediate" data, as if it had been included externally.

This text was extracted from a ASCII document.
This is the abbreviated version, containing approximately 31% of the total text.

Network Working Group L. Masinter

Request for Comments: 2397 Xerox Corporation

Category: Standards Track August 1998

The "data" URL scheme

Status of this Memo

This document specifies an Internet standards track protocol for the

Internet community, and requests discussion and suggestions for

improvements. Please refer to the current edition of the "Internet

Official Protocol Standards" (STD 1) for the standardization state

and status of this protocol. Distribution of this memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (1998). All Rights Reserved.

1. Abstract

A new URL scheme, "data", is defined. It allows inclusion of small

data items as "immediate" data, as if it had been included


2. Description

Some applications that use URLs also have a need to embed (small)

media type data directly inline. This document defines a new URL

scheme that would work like 'immediate addressing'. The URLs are of

the form:


The is an Internet media type specification (with

optional parameters.) The appearance of ";base64" means that the data

is encoded as base64. Without ";base64", the data (as a sequence of

octets) is represented using ASCII encoding for octets inside the

range of safe URL characters and using the standard %xx hex encoding

of URLs for octets outside that range. If is omitted, it

defaults to text/plain;charset=US-ASCII. As a shorthand,

"text/plain" can be omitted but the charset parameter supplied.

The "data:" URL scheme is only useful for short values. Note that

some applications that use URLs may impose a length limit; for

example, URLs embedded within anchors in HTML have a length limit

determined by the SGML declaration for HTML [RFC1866]. The LITLEN

(1024) limits the number of characters which can appear in a single

attribute value literal, the ATTSPLEN (2100) limits the sum of all

lengths of all attribute value specifications which appear in a tag,

and the TAGLEN (2100) limits the overall length of a tag.

The "data" URL scheme has no relative URL forms.

3. Syntax

dataurl := "data:" [ mediatype ] [ ";base64" ] "," data

mediatype := [ type "/" subtype ] *( ";" parameter )

data := *urlchar

parameter := attribute "=" value

where "urlchar" is imported from [RFC2396], and "type", "subtype",

"attribute" and "value" are the corresponding tokens from [RFC2045],