MIME Encapsulation of Aggregate Documents, such as HTML (MHTML)
RFC 2557
Document | Type |
RFC - Proposed Standard
(March 1999; Errata)
Obsoletes RFC 2110
Was draft-ietf-mhtml-rev (mhtml WG)
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Authors | Alex Hopmann , Jacob Palme , Nick Shelness | ||
Last updated | 2020-01-21 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized with errata bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 2557 (Proposed Standard) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
Network Working Group J. Palme Request for Comments: 2557 Stockholm University/KTH Obsoletes: 2110 A. Hopmann Category: Standards Track Microsoft Corporation N. Shelness Lotus Development Corporation March 1999 MIME Encapsulation of Aggregate Documents, such as HTML (MHTML) 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 (1999). All Rights Reserved. Abstract HTML [RFC 1866] defines a powerful means of specifying multimedia documents. These multimedia documents consist of a text/html root resource (object) and other subsidiary resources (image, video clip, applet, etc. objects) referenced by Uniform Resource Identifiers (URIs) within the text/html root resource. When an HTML multimedia document is retrieved by a browser, each of these component resources is individually retrieved in real time from a location, and using a protocol, specified by each URI. In order to transfer a complete HTML multimedia document in a single e-mail message, it is necessary to: a) aggregate a text/html root resource and all of the subsidiary resources it references into a single composite message structure, and b) define a means by which URIs in the text/html root can reference subsidiary resources within that composite message structure. This document a) defines the use of a MIME multipart/related structure to aggregate a text/html root resource and the subsidiary resources it references, and b) specifies a MIME content-header (Content-Location) that allow URIs in a multipart/related text/html root body part to reference subsidiary resources in other body parts of the same multipart/related structure. Palme, et al. Standards Track [Page 1] RFC 2557 MIME Encapsulation of Aggregate Documents March 1999 While initially designed to support e-mail transfer of complete multi-resource HTML multimedia documents, these conventions can also be employed to resources retrieved by other transfer protocols such as HTTP and FTP to retrieve a complete multi-resource HTML multimedia document in a single transfer or for storage and archiving of complete HTML-documents. Differences between this and a previous version of this standard, which was published as RFC 2110, are summarized in chapter 12. Table of Contents 1. Introduction ................................................. 3 2. Terminology ................................................. 4 2.1 Conformance requirement terminology ...................... 4 2.2 Other terminology ........................................ 4 3. Overview ..................................................... 6 4. The Content-Location MIME Content Header ..................... 6 4.1 MIME content headers ..................................... 6 4.2 The Content-Location Header .............................. 7 4.3 URIs of MHTML aggregates ................................. 8 4.4 Encoding and decoding of URIs in MIME header fields ...... 8 5. Base URIs for resolution of relative URIs .................... 9 6. Sending documents without linked objects ..................... 10 7. Use of the Content-Type "multipart/related" .................. 11 8. Usage of Links to Other Body Parts ........................... 13 8.1 General principle ........................................ 13 8.2 Resolution of URIs in text/html body parts ............... 13 8.3 Use of the Content-ID header and CID URLs ................ 14 9. Examples ..................................................... 14 9.1 Example of a HTML body without included linked objects ... 15 9.2 Example with an absolute URI to an embedded GIF picture .. 15 9.3 Example with relative URIs to embedded GIF pictures ...... 16 9.4 Example with a relative URI and no BASE available ........ 17 9.5 Example using CID URL and Content-ID header to an embedded GIF picture .............................................. 18 9.6 Example showing permitted and forbidden references between nested body parts ........................................ 19 10. Character encoding issues and end-of-line issues ............ 21Show full document text