The Metalink Download Description FormatPompano BeachFLUSAanthonybryan@gmail.comhttp://www.metalinker.orgtatsuhiro.t@gmail.comhttp://aria2.sourceforge.netneil@nabber.orghttp://www.nabber.orgNovell, Inc.poeml@mirrorbrain.orghttp://www.mirrorbrain.org/This document specifies Metalink, an XML-based download description
format. Metalink describes download locations
(mirrors), checksums, and other information. Clients can
transparently use this information to reliably transfer
files.Metalink is an XML-based document format that describes a file or list
of files to be downloaded from a server. Metalinks can list a number of
files, each with an extensible set of attached metadata.
Each listed file can have a description, checksum, and a list of URIs that it is
available from.Often, identical copies of a file are accessible in multiple locations
on the Internet over a variety of protocols (FTP, HTTP, and
Peer-to-Peer). In some cases, users are shown a list of these multiple
download locations (mirror servers) and must manually select one based on
geographical location, priority, or bandwidth. This is done to distribute
the load across multiple servers, and to give human users the opportunity
to choose a download location that they expect to work best for them.At times, individual servers can be
slow, outdated, or unreachable, but this can not be determined until the
download has been initiated. This can lead to the user canceling the
download and needing to restart it. During downloads, errors in
transmission can corrupt the file. There are no easy ways to repair
these files. For large downloads this can be especially troublesome. Any
of the number of problems that can occur during a download lead to
frustration on the part of users, and bandwidth wasted with retransmission.Knowledge about availability of a download on mirror servers can be
acquired and maintained by the operators of the origin server, or by a third
party. This knowledge, together with checksums,
digital signatures, and more can be stored in a machine-readable Metalink
file. The Metalink file can transfer this knowledge to the user agent,
which can peruse it in automatic ways or present the information to a human user.
User agents can fall back to alternate
mirrors if the current one has an issue. Thereby, clients
are enabled to work their way to a successful download even under adverse
circumstances. All this can be done transparently to the human user and the
download is much more reliable and efficient. In contrast, a traditional
HTTP redirect to one mirror conveys only comparatively minimal information -
a referral to a single server, and there is no provision in the HTTP protocol to
handle failures.Other features that some clients provide include multi-source
downloads, where chunks of a file are downloaded from multiple mirrors
(and optionally, Peer-to-Peer) simultaneously, which frequently results
in a faster download. Metalinks can leverage HTTP, FTP and Peer-to-Peer
protocols together, because regardless over which protocol the Metalink
was obtained, it can make a resource accessible through other protocols.
If the Metalink was obtained from a trusted source, included verification
metadata can solve trust issues when downloading files from replica
servers operated by third parties. Metalinks also provide structured
information about downloads that can be indexed by search engines.[[ Discussion of this draft should take place on
apps-discuss@ietf.org. Past discussion has gone on at the Metalink
discussion mailing list located at metalink-discussion@googlegroups.com /
http://groups.google.com/group/metalink-discussion . ]]The XML Namespaces URI for the XML data
format described in this specification is:urn:ietf:params:xml:ns:metalinkFor convenience, this data format may be referred to as
"Metalink", which this specification uses internally.This specification describes conformance of Metalink
Documents. Additionally, it places some requirements on Metalink
Processors.This specification uses the namespace prefix "metalink:" for
the Namespace URI identified in , above. Note that
the choice of namespace prefix is arbitrary and not
semantically significant.Metalink is specified using terms from the XML Infoset . However, this
specification uses a shorthand for two common terms: the
phrase "Information Item" is omitted when naming Element
Information Items and Attribute Information Items. Therefore,
when this specification uses the term "element," it is
referring to an Element Information Item in Infoset
terms. Likewise, when it uses the term "attribute," it is
referring to an Attribute Information Item.Some sections of this specification are illustrated with fragments
of a non-normative RELAX NG Compact schema . However, the text of this specification provides the definition of
conformance. A complete schema appears in .
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14, , as scoped to those conformance targets.This specification describes Metalink Documents.A Metalink Document describes a file or group of files,
how to access them, and metadata that identifies them. Its root is the metalink:metalink element.Metalink Documents are specified in terms of the
XML Information Set, serialized as XML 1.0 and identified with the
"application/metalink4+xml" media type.Metalink Documents MUST be
well-formed XML. This specification does not define a DTD for
Metalink Documents, and hence does not require them to be valid (in
the sense used by XML).Metalink allows the use of IRIs, encoded according to . Every
URI is also an IRI, so a URI may be
used wherever below an IRI is named. There is one special
consideration: when an IRI that is not also a URI is given for
dereferencing, it MUST be mapped to a URI using the steps in
Section 3.1 of .Any element defined by this specification MAY have an
xml:base attribute .
When xml:base is used in an Metalink Document, it serves the
function described in Section 5.1.1 of ,
establishing the base URI (or IRI) for resolving any relative
references found within the effective scope of the xml:base
attribute.Any element defined by this specification MAY have an
xml:lang attribute, whose content indicates the natural language
for the element and its descendents. The language context is only
significant for elements and attributes declared to be
"Language-Sensitive" by this specification. Requirements
regarding the content and interpretation of xml:lang are
specified in XML 1.0,
Section 2.12.
All leading and trailing whitespace is part of the element content, and MUST NOT be ignored. Consequently, it is disallowed for elements where the defined type does not allow whitespace, such as dates, integers, or IRIs.
Some XML-generating implementations erroneously insert white space around values by default, and such implementations will generate invalid Metalink Documents.Metalink Documents that do not follow this specification are invalid, and partially or wholly unusable to Metalink Processors.Metalink is an extensible format. See
of this document for a full description of how Metalink Documents can
be extended.Many Metalink elements share common structures. This section
defines those structures and their requirements for convenient
reference by the appropriate element definitions.When an element is identified as being a particular kind of
construct, it inherits the corresponding requirements from that
construct's definition in this section.A Text construct contains human-readable text, usually short
in length. The content of Text constructs is
Language-Sensitive.
For example, a metalink:description with text content:
The content of the Text
construct MUST NOT contain child elements. Such text is
intended to be presented to humans in a readable fashion.
Thus, white space could be collapsed (including
line breaks) and text could be displayed using typographic
techniques such as justification and proportional
fonts.A Date construct is an element whose content MUST conform
to the "date-time" production in . In addition, an uppercase "T" character
MUST be used to separate date and time, and an uppercase "Z"
character MUST be present in the absence of a numeric time zone
offset.
Such date values happen to be compatible with the following
specifications:
,
,
and .Example Date constructs:
Date values SHOULD be as accurate as possible. For
example, it would be generally inappropriate for a publishing
system to apply the same timestamp to several Metalink Documents that
were published during the course of a single day.The "metalink:metalink" element is the document (i.e., top-level) element
of a Metalink Document, acting as a container for metadata and
data associated with the listed files. It contains one or more metalink:file child elements which consist of
metadata elements.
The following child elements are defined by this specification
(note that the presence of some of these elements is required):metalink:metalink elements MUST contain one or more metalink:file elements.metalink:metalink elements MAY contain exactly one metalink:generator element and MUST NOT contain more than one such element.metalink:metalink elements SHOULD contain exactly one metalink:origin element and MUST NOT contain more than one such element.metalink:metalink elements MAY contain exactly one metalink:published element and MUST NOT contain more than one such element.Experience teaches that downloads providing textual
content are in general more useful than those that do
not. Some applications (one example is full-text indexers)
require a minimum amount of text to function
reliably and predictably. Metalink publishers should be aware
of these issues. It is advisable that each metalink:file
element contain a non-empty metalink:description element, a
non-empty metalink:identity element, a non-empty metalink:version element, and a non-empty
metalink:publisher element when these elements are present. However, the
absence of metalink:description, metalink:identity, metalink:version, and metalink:publisher is not an error, and Metalink
Processors MUST NOT fail to function correctly as a
consequence of such an absence.The "metalink:file" element represents an individual file,
acting as a container for metadata and data associated with
the file. Each unique file described in a Metalink Document MUST have its own metalink:file element.All metalink:url elements contained in each metalink:file element SHOULD lead to identical files. That is,
each metalink:url element should be an alternative location for the same file and each
metalink:metaurl element should provide metadata to retrieve the same file in another way, such as a peer to peer network.
This specification assigns no significance to the order of
metalink:file elements or to the order of
metalink:url or metalink:metaurl elements. Significance is determined by the value of the "priority" attribute of the metalink:url or metalink:metaurl elements.The following child elements are defined by this specification
(note that it requires the presence of some of these elements):metalink:file elements MAY contain exactly one metalink:copyright
element and MUST NOT contain more than one such element.metalink:file elements MAY contain exactly one metalink:description
element and MUST NOT contain more than one such element.metalink:file elements MAY contain exactly one metalink:identity
element and MUST NOT contain more than one such element.metalink:file elements MAY contain one or more metalink:hash elements.metalink:file elements MAY contain one or more metalink:language
element.metalink:file elements MAY contain exactly one metalink:logo
element and MUST NOT contain more than one such element.metalink:file elements MAY contain one or more metalink:os
element.metalink:file elements MUST contain at least one metalink:url element or at least one metalink:metaurl element. Typically, metalink:file elements contain more than one metalink:url element to provide multiple download sources.metalink:file elements MAY contain one or more metalink:pieces elements.metalink:file elements MAY contain exactly one metalink:publisher
element and MUST NOT contain more than one such element.metalink:file elements MAY contain one or more metalink:signature elements.metalink:file elements SHOULD contain exactly one metalink:size
element and MUST NOT contain more than one such element.metalink:file elements MAY contain exactly one metalink:version
element and MUST NOT contain more than one such element.metalink:file elements MUST have a "name" attribute, which contains the local filename that the downloaded file will be written to. Hence, if a Metalink Document contains multiple metalink:file elements, the value of the "name" attribute MUST be unique for each.
In this example, a subdirectory "debian-amd64/sarge/" will be created
and a file named "Contents-amd64.gz" will be created inside it. The path MUST NOT contain any directory traversal directives or
information. The path MUST be relative. The path MUST NOT begin with a "/", "./" or
"../", contain "/../", or end with "/..".The "metalink:pieces" element acts as a container for a list of checksums of
non-overlapping pieces of the file. The checksums MUST be listed in the same order as the corresponding pieces appear in the file, starting at
the beginning of the file.
metalink:pieces elements MUST have a "type" attribute.
The IANA registry named "Hash Function Textual Names" defines values for hash types. See for security implications.metalink:pieces elements MUST have a "length" attribute, which is a positive integer
that describes the length of the pieces of the file in octets. The whole file is divided into non-overlapping pieces of this length,
starting from the beginning of the file. That is, every piece should be the same size, apart from
the last piece which is the remainder. The last piece extends to the end of the file, and can therefore be shorter than the other pieces.
The "metalink:copyright" element is a Text construct that conveys a
human-readable copyright for a file.
The "metalink:description" element is a Text construct that conveys a
human-readable file description.
The "metalink:generator" element's content identifies the generating agent name and versionused to generate a Metalink Document, for debugging and other purposes.
metalink:generator element's content is defined below in ABNF notation .
Examples:
token is of type text. Although any character allowed in text MAY appear in an agent-version, this token SHOULD only be used for a version identifier (i.e., successive versions of the same agent
SHOULD only differ in the agent-version portion of the agent value).The "metalink:hash" element is a Text construct that conveys a
hash, also known as a checksum, for a file. All hashes are encoded in lowercase hexadecimal format. Hashes are used to verify the integrity of a complete file or portion of a file to determine if the file has been transferred without any errors.
Metalink Documents MAY contain one or multiples hashes of a complete file. metalink:hash elements
with a "type" attribute MUST contain a hash of the complete file. In this example, both SHA-1 and SHA-256 hashes of the complete file are included.
Metalink Documents MAY also contain hashes for individual pieces of a file. metalink:hash elements that are inside a metalink:pieces container element have a hash for that specific piece or chunk of the file, and are of the same hash type as the metalink:pieces element they are contained in.metalink:hash elements without a "type" attribute MUST contain a hash for that specific piece or chunk of the file and MUST be listed in the
same order as the corresponding pieces appear in the file, starting at the beginning of the file. The size of the piece is equal to the value of the "length" attribute of the metalink:pieces element. See for more information on the size of pieces.In this example, SHA-1 and SHA-256 hashes of the complete file are included, along with four SHA-1 piece hashes.
metalink:hash elements MUST have a "type" attribute, if and only if
it contains a hash of the complete file. The IANA registry named "Hash Function Textual Names" defines values for hash types. See for security implications.The "metalink:identity" element is a Text construct that conveys a
human-readable identity for a file. For example, the identity of Firefox 3.5 would be "Firefox".
The "metalink:language" element is a Text construct that conveys a
code for the language of a file, per .
The "metalink:logo" element's content is an IRI reference that identifies an image that provides visual
identification for a file.
The image SHOULD have an aspect ratio of one (horizontal)
to one (vertical) and SHOULD be suitable for presentation
at a small size.The "metalink:metaurl" element contains the IRI of a metadata file, also known as a metainfo file, about a resource to download. For example, this could be the IRI of a BitTorrent .torrent file, a Metalink Document, or other type of metadata file. Note that
the information in the metalink:hash element does not apply to these metadata files, but to the files that are described by them.
metalink:metaurl
elements MAY have a priority attribute. Values MUST be positive integers between 1 and 999999. Lower values indicate a higher priority. metalink:metaurl
elements without a priority attribute are considered to have the lowest priority, i.e. 999999. The priority values of metalink:metaurl and metalink:url elements are compared and those with the lowest values, starting with 1, are used first. Multiple metalink:metaurl and metalink:url elements MAY have the same
priority, i.e. one BitTorrent .torrent file and three FTP URIs could have priority="1". See also the "priority" attribute of the metalink:url element.metalink:metaurl elements MUST have a "type" attribute that indicates
the MIME media type of the metadata available at the IRI. In the case of BitTorrent as specified in , the value "torrent" is required. Types without "/" are reserved. Currently, "torrent" is the only reserved value.metalink:metaurl elements MAY have a "name" attribute that indicates
a specific file in a BitTorrent .torrent file or a Metalink Document that describes multiple files.In this example, a file named "Contents-amd64.gz" is indicated, in a "debian-amd64/sarge/" subdirectory.
The path MUST NOT contain any directory traversal directives or
information. The path MUST be relative. The path MUST NOT begin with a "/", "./" or
"../", contain "/../", or end with "/..".The "metalink:origin" element is an IRI where the Metalink Document was originally published. If the dynamic attribute of metalink:origin is "true", then updated
versions of the Metalink can be found at this IRI.
The metalink:origin element MAY have a "dynamic" attribute, set to "true" or "false", which tells if a Metalink at the origin IRI will contain dynamic updated information or if it is static and not likely to be updated.The "metalink:os" element is a Text construct that conveys an
Operating System for a file. The IANA registry named "Operating System Names" defines values for OS types.
The "metalink:published" element is a Date construct indicating an
instant in time associated with an event early in the life cycle of
the entry.
Typically, metalink:published will be associated with the
initial creation or first availability of the resource. The metalink:updated element is used when a Metalink Document has been updated after initial publication.The "metalink:publisher" element contains a human-readable group or other entity which has published the file described in the Metalink Document and a URI for more information.
The metalink:publisher element MUST have a "name" attribute that
indicates the human-readable name of the publisher.The metalink:publisher element MAY have a "url" attribute
whose value MUST be an IRI reference . When dereferenced, the resulting URI (mapped from an
IRI, if necessary) SHOULD produce a representation that is
relevant to that agent.The "metalink:signature" element is a Text construct that conveys a
digital signature for a file described in a Metalink Document. Digital signatures verify that a file is from the entity that has signed it.
Example:
metalink:signature elements MUST have a "type" attribute that indicates
the MIME media type of the included digital signature.
The "metalink:size" element indicates the length of
the linked content in octets; it is a hint about the
content length of the representation returned when the IRI
is mapped to a URI and
dereferenced. This value MUST be a non-negative integer.
The "metalink:updated" element is a Date construct indicating the
most recent instant in time when a Metalink was modified in a
way the publisher considers significant. Therefore, not all
modifications necessarily result in a changed metalink:updated
value.
Publishers MAY change the value of this element over time.The "metalink:url" element contains a file IRI.
Most metalink:file container elements will contain multiple metalink:url elements,
and each one SHOULD be a valid alternative to download the same file.
metalink:url
elements MAY have a priority attribute. Values MUST be positive integers between 1 and 999999. Lower values indicate a higher priority. metalink:url
elements without a priority attribute are considered to have the lowest priority, i.e. 999999. Multiple metalink:url elements can have the same
priority, i.e. ten mirrors could have priority="1".metalink:url elements MAY have a "location" attribute, which
is a alpha-2 two letter country code for the geographical location of the physical server an IRI is used
to access.
The "metalink:version" element is a Text construct that conveys a
human-readable version for a file. The version of Firefox 3.5 would be "3.5".
This specification describes Metalink's XML markup
vocabulary. Markup from other vocabularies ("foreign markup")
can be used in an Metalink Document.The Metalink namespace is reserved for future
forward-compatible revisions of Metalink. Future versions
of this specification could add new elements and
attributes to the Metalink markup vocabulary. Software
written to conform to this version of the specification
will not be able to process such markup correctly and,
in fact, will not be able to distinguish it from markup
error. For the purposes of this discussion, unrecognized
markup from the Metalink vocabulary will be considered
"foreign markup".Metalink Processors that encounter foreign markup in a
location that is legal according to this specification
MUST NOT stop processing or signal an error. It might be
the case that the Metalink Processor is able to process the
foreign markup correctly and does so. Otherwise, such
markup is termed "unknown foreign markup".When unknown foreign markup is encountered as a child of
metalink:file, metalink:metalink, Metalink Processors MAY
bypass the markup and any textual content and MUST NOT change
their behavior as a result of the markup's presence.When unknown foreign markup is encountered in a Text
Construct, software SHOULD ignore
the markup and process any text content of foreign
elements as though the surrounding markup were not
present.Metalink allows foreign markup anywhere in an Metalink
document, except where it is explicitly forbidden.
Child elements of metalink:file and metalink:metalink
are considered Metadata elements and
are described below. The role of
other foreign markup is undefined by this
specification.A Simple Extension element MUST NOT have any
attributes or child elements. The element MAY contain
character data or be empty. Simple Extension elements
are not Language-Sensitive.
The element can be interpreted as a simple property (or
name/value pair) of the parent element that encloses it. The
pair consisting of the namespace-URI of the element and the
local name of the element can be interpreted as the name of
the property. The character data content of the element can
be interpreted as the value of the property. If the element
is empty, then the property value can be interpreted as an
empty string.The root element of a Structured Extension element
MUST have at least one attribute or child element. It
MAY have attributes, it MAY contain well-formed XML
content (including character data), or it MAY be
empty. Structured Extension elements are
Language-Sensitive.
The structure of a Structured Extension element, including
the order of its child elements, could be significant.This specification does not provide an interpretation of a
Structured Extension element. The syntax of the XML contained
in the element (and an interpretation of how the element
relates to its containing element) is defined by the
specification of the Metalink extension.This document makes use of the XML registry specified in . Accordingly, IANA has made the following registration:Registration request for the Metalink namespace:URI: urn:ietf:params:xml:ns:metalinkRegistrant Contact: See the "Author's Address" section of this
document.XML: None. Namespace URIs do not represent an XML specification.A Metalink Document, when serialized as XML 1.0, can be identified
with the following media type: application metalink4+xml None. This parameter has semantics identical
to the charset parameter of the
"application/xml" media type as specified in . Identical to those of
"application/xml" as described in , Section 3.2. As defined in this
specification.In addition, as this media type uses the "+xml" convention,
it shares the same security considerations as described in
, Section 10. There are no
known interoperability issues. This
specification. No known
applications currently use this media type.Additional information: As specified for
"application/xml" in , Section 3.2. .meta4 As specified for
"application/xml" in , Section 5. As specified in , Section 6. TEXT Anthony Bryan <anthonybryan@gmail.com>
COMMONIESGBecause Metalink is an XML-based format, existing XML security
mechanisms can be used to secure its content.Producers of Metalink Documents may have sound reasons for signing
otherwise-unprotected content. For example, a merchant
might digitally sign a Metalink that lists a file download to verify its origin. Other merchants may wish to sign and encrypt Metalink Documents that list digital songs that have been purchased. Of course,
many other examples are conceivable as well.Publishers are encouraged to offer Metalink documents via authenticated HTTP under TLS as specified in . The choice of a secure content layer is entirely possible for content providers.Publishers are also encouraged to include digital signatures of the files within the Metalink Documents, if they are available, as described in .Metalink Processors handle URIs and IRIs. See Section 7 of and Section 8 of for security
considerations related to their handling and use.There is potential for spoofing attacks where the attacker publishes
Metalink Documents with false information. Malicious publishers might create Metalink Documents containing inaccurate information anywhere in the document.
Unaware downloaders could be deceived into downloading a malicious or worthless file. Malicious publishers could attempt a distributed denial of service attack by inserting unrelated IRIs into Metalink Documents.Metalink Documents SHOULD be signed using XML-Signature and
Syntax Processing and are
subject to the security considerations implied by its
use. This addresses the issue of spoofing.Digital signatures provide authentication, message
integrity, and non-repudiation with proof of
origin.Currently, some of the hash types defined in the IANA registry named "Hash Function Textual Names" are considered insecure. These include the whole Message Digest family of algorithms which are not suitable for cryptographically strong verification. Malicious people could provide files that appear to be identical to another file because of a collision, i.e. the weak cryptographic hashes of the intended file and a substituted malicious file could match.If a Metalink Document contains hashes, it SHOULD include "sha-256" which is SHA-256, as specified in , or stronger. It MAY also include other hashes from the IANA registry named "Hash Function Textual Names".The BitTorrent Protocol SpecificationKey words for use in RFCs to Indicate Requirement LevelsHarvard University1350 Mass. Ave.CambridgeMA 02138- +1 617 495 3864sob@harvard.edu
General
keyword
In many standards track documents several words are used to signify
the requirements in the specification. These words are often
capitalized. This document defines these words as they should be
interpreted in IETF documents. Authors who follow these guidelines
should incorporate this phrase near the beginning of their document:
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
RFC 2119.
Note that the force of these words is modified by the requirement
level of the document in which they are used.
HTTP Over TLSXML Media TypesThis document standardizes five new media types -- text/xml, application/xml, text/xml-external-parsed-entity, application/xml-external-parsed-entity, and application/xml-dtd -- for use in exchanging network entities that are related to the Extensible Markup Language (XML). This document also standardizes a convention (using the suffix '+xml') for naming media types outside of these five types when those media types represent XML MIME (Multipurpose Internet Mail Extensions) entities.Date and Time on the Internet: TimestampsThis document defines a date and time format for use in Internet protocols that is a profile of the ISO 8601 standard for representation of dates and times using the Gregorian calendar.Uniform Resource Identifier (URI): Generic SyntaxInternationalized Resource Identifiers (IRIs)Media Type Specifications and Registration ProceduresAugmented BNF for Syntax Specifications: ABNFTags for Identifying LanguagesXML Information Set (Second Edition)XML Base (Second Edition)Namespaces in XML 1.0 (Third Edition)Extensible Markup Language (XML) 1.0 (Fifth Edition)XML-Signature Syntax and Processing (Second Edition)ISO 3166-1:2006. Codes for the representation of names of countries and their subdivisions -- Part 1: Country codesInternational Organization for StandardizationSecure Hash Standard (SHS)National Institute of Standards and Technology (NIST)Data elements and interchange formats - Information interchange - Representation of dates and timesInternational Organization for StandardizationXML Schema Part 2: Datatypes Second EditionDate and Time FormatsRELAX NG Compact SyntaxOASIS Technical Committee: RELAX NGThe IETF XML RegistryThe Atom Syndication FormatThe layout and shape of this document relies heavily on work pioneered in the Atom Syndication Format as specified in .The content and concepts within are a product of the Metalink community. Key contributors provided early implementations: A. Bram Neijt, Hampus Wessman, Darius Liktorius, Manuel Subredu, Michael Burford,
Giorgio Maone, Nils Maier, Max Velasques, Manolo Valdes, Hayden Legendre, Frederick Cheung, Rene Leonhardt, Per Oyvind Karlsen, Matt Domsch, Yazsoft,
KGet developers, Free Download Manager developers, Orbit developers, Arne Babenhauserheide, Mathias Berchtold, Xienzhenyu and TheWorld Browser developers, Xi Software, Agostino Russo, and James Antill.The Metalink community has dozens of contributors who proposed ideas and wording for this
document, or contributed to the evolution of Metalink, including:Paul Burkhead, Kristian Weston, Nicolas Alvarez, Urs Wolfer, Bridget and Ethan Fletcher, Patrick Ruckstuhl, Sebastien Willemijns, Micah Cowan, Ruben Kerkhof,
Danny Ayers, Nick Dominguez, Gary Zellerbach, James Clark, Daniel Stenberg, John and Sandra Sowder, Salvatore Musumeci, Steve Eshelman,
Lucas Hewett, Ryan Cronin, Dave Winquist, Bob Denison,
Wes Shelton, Kees Cook, Josh Colbert, Steve Kleisath, Chad Neptune, Nick Carrabba, Chris
Carrabba, Erin Solari, Derick Cordoba, Ryan Alexander,
Tom Mainville, Janie Wargo, Jason Hansen, Tim Bray, Dan Brickley, Markus Hofmann,
Dan Connolly, Tim Berners-Lee, Louis Suarez-Potts, Ross Smith, Jeff Covey,
Ed Lee, Shawn Wilsher, Mike Connor, Johan Svedberg, Dedric Carter, and Debi
Goulding. We also thank the Anthony Family, the Bryan Family, Juanita Anthony and Zimmy Bryan.We also thank the following contributors for assistance and review: Eran Hammer-Lahav, Lisa Dusseault, Mark Nottingham, Peter Saint-Andre, Julian Reschke, Chris Newman,
Ian Macfarlane, Dave Cridland, Barry Leiba, Uri Blumenthal, Paul Hoffman, Felix Sasaki, Matthias Fuchs, Mark Baker, Scott Cantor, and Brian Carpenter.This appendix is informative.The Relax NG schema explicitly excludes elements in
the Metalink namespace that are not defined in this
revision of the specification. Requirements for Metalink
Processors encountering such markup are given in Sections
and .
[[ to be removed by the RFC editor before publication as an RFC. ]]Updated versions can be found at http://tools.ietf.org/html/draft-bryan-metalink with frequent updates in Subversion at http://metalinks.svn.sourceforge.net/viewvc/metalinks/internetdraft/ Known issues concerning this draft:
None.-25 : December xx, 2009.
Julian Reschke XML issues.Generator ABNF and reference. Remove license element.Update IPR to "trust200902".dynamic element changed to dynamic attribute of origin element.-24 : December 08, 2009.
Document Shepherd review changes.Example XML indentation.Baseline file hash: SHA-256.-23 : November 26, 2009.
Apps Area AD review changes, Change RFC3688 from Normative to Informative Reference.Schema: integer changed to positiveInteger or nonNegativeInteger where fitting.-22 : November 09, 2009.
Clarifications.-21 : October 13, 2009.
Update author details.-20 : October 12, 2009.
RFC 5646 updates RFC 4646.-19 : October 5, 2009.
Remove organization for independent authors.-18 : October 4, 2009.
File extension: .meta4Hashes clarification, modified to allow multiple metalink:os elements, add size element to example.-17 : September 28, 2009.
Typo correction.-16 : August 31, 2009.
Clarifications.-15 : August 26, 2009.
Rename "preference" attribute of metaurl and url elements to "priority", where lower values indicate higher priority.-14 : August 24, 2009.
Update abstract and introduction.-13 : August 21, 2009.
Remove files, resources, verification container elements.MIME type: application/metalink4+xml-12 : August 18, 2009.
Remove "piece" attribute from hash elements in pieces container elements.Rename "uri" attribute of license and publisher elements to "url".-11 : August 08, 2009.
Renamed type element (static or dynamic values) to dynamic element (true or false values).Removed metadata inheritance and most other elements from files element.-10 : July 28, 2009.
Schema fixes.Rename metadata element to metaurl, add name attribute to it similar to file element's name attribute.Update REC-xmldsig-core reference to second edition.-09 : July 11, 2009.
Replace ISO639-2 references with RFC 4646.Add ISO3166-1.-08 : July 04, 2009.
Clarifications.Remove "uri" and "version" attributes from generator element.-07 : June 18, 2009.
This ID describes the Metalink document format/schema.Remove "Client Implementation Considerations" section.Expand "Known issues" section of Document History.-06 : March 3, 2009.
Add authors and this Document History section.-05 : January 13, 2009.
Clarifications.-04 : December 31, 2008.
New IPR notice as required by IETF.Correct "metalink:pieces" Element text.Add hash examples.Slim down "Securing Metalink Documents" section.Recommend at least SHA-1.-03 : September 19, 2008.
New namespace - urn:ietf:params:xml:ns:metalinkUse the IANA registry named "Operating System Names" to define values for OS types.Add "Client Implementation Considerations" section, which includes Content Negotiation.-02 : September 4, 2008.
Use the IANA registry named "Hash Function Textual Names" for hash types.metadata Element for listing .torrent, .metalink, etc.Remove type attribute for url Element.-01 : August 28, 2008.
Clarify directory info in name attribute, hash types, add text for preference attribute.-00 : August 23, 2008.
Initial draft; Text largely based on RFC 4287, ideas from Metalink 3.0 specification.