Edit comment LC-2049 for Mobile Web Best Practices Working Group

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Comment LC-2049

Comment Shortname:

Commenter: casays <casays@yahoo.com>

Message-id:

Section of the document concerned:

[Free text description]Document as a wholeContent Transformation Guidelines 1.0 Abstract Status of this Document Table of Contents Appendices 1 Introduction (Non-Normative) 1.1 Purpose 1.2 Audience 1.3 Scope 1.4 Summary of Requirements 2 Terminology (Normative) 2.1 Types of Proxy "A transparent proxy is a proxy that does not modify the req... A non-transparent proxy is a proxy that modifies the request... 2.2 Types of Transformation Restructuring content is a process whereby the original layo... Recoding content is a process whereby the layout of the cont... Optimizing content includes removing redundant white space,... 3 Conformance (Normative) 3.1 Classes of Product 3.2 Normative and Informative Parts 3.3 Normative Language for Conformance Requirements 3.4 Content Deployment Conformance 3.5 Transformation Deployment Conformance 4 Behavior of Components (Normative) 4.1 Proxy Forwarding of Request 4.1.1 Applicable HTTP Methods 4.1.2 no-transform directive in Request 4.1.3 Treatment of Requesters that are not Web browsers 4.1.4 Serving Cached Responses 4.1.5 Alteration of HTTP Header Values In this section, the concept of "Web site" is used (rather t... 4.1.5.1 Content Tasting 4.1.5.2 Avoiding "Request Unacceptable" Responses 4.1.5.3 User Selection of Restructured Experience 4.1.5.4 Sequence of Requests 4.1.5.5 Original Headers 4.1.6 Additional HTTP Headers 4.1.6.1 Proxy Treatment of Via Header 4.2 Server Response to Proxy 4.2.1 Use of HTTP 406 Status 4.2.2 Server Origination of Cache-Control: no-transform Including a Cache-Control: no-transform directive can disrup... 4.2.3 Varying Representations 4.2.3.1 Use of Vary HTTP Header 4.2.3.2 Indication of Intended Presentation Media Type of Representation 4.3 Proxy Forwarding of Response to User Agent 4.3.1 Receipt of Cache-Control: no-transform 4.3.2 Receipt of Warning: 214 Transformation Applied 4.3.3 Server Rejection of HTTP Request 4.3.4 Receipt of Vary HTTP Header 4.3.5 Link to "handheld" Representation 4.3.6 Proxy Decision to Transform 4.3.6.1 Alteration of Response 4.3.6.2 HTTPS Link Re-writing 5 Testing (Normative) A References B Example Transformation Interactions (Non-Normative) B.1 Basic Content Tasting by Proxy B.2 Optimization based on Previous Server Interaction B.3 Optimization based on Previous Server Interaction, Server has Changed its Operation B.4 Server Response Indicating that this Representation is Intended for the Target Device B.5 Server Response Indicating that another Representation is Intended for the Target Device C Applicability to Transforming Solutions which are Out of Scope (Non-Normative) D Scope for Future Work (Non-Normative) D.1 POWDER D.2 link HTTP Header D.3 Sources of Device Information D.4 Inter Proxy Communication D.5 Amendment to and Refinement of HTTP E Administrative Arrangements (Non-Normative) F Acknowledgments (Non-Normative)
or

Refinement of the section concerned:

Status:

open proposal pending resolved_yes resolved_no resolved_partial other assigned to Nobody

Type: substantive editorial typo question general comment undefined

Resolution status:

Response drafted Resolution implemented Reply sent to commenter

Response status:

No response from Commenter yet Commenter approved disposition Commenter objected to disposition
Commenter's response (URI):

Comment:

5) Section 4.1.5.

Statement to be added:

"The request MUST NOT be altered Whenever the URI of the
request indicates that the resource being accessed is able
to provide mobile-optimized content, e.g. the domain is
*.mobi, wap.*, m.*, mobile.*, pda.*, imode.*, iphone.*,
or the leading portion of the path is /m/ or /mobile/."

Rationale: The guidelines make the assumption that all
requests may first undergo a transformation before possibly
falling back on a transformationless mode of operation.
This is unwarranted, and does not correspond to the way
many deployed proxies operate.

Obviously, it is rather pointless to go all the way to
send a request to the server and wait for its response
in order to detect whether the resources accessed are for
mobile use, when it is already possible to do this by
inspecting the request of the client. The addition to the
guidelines covers this situation, and corresponds to the
state of the art in transformation proxies. It is also
consistent with the heuristic serving to determine whether
a response is already mobile-optimized. Following this
new guideline improves the performance of the entire
content delivery chain without loss of functionality,
and is congruent with the stated objective of the
guidelines of not disturbing mobile-optimized content.

Related issues: (space separated ids)

WG Notes: RESOLUTION: ref LC-2049 resolve no, URI patterns can never be more than a heuristic, but we will move the list of examples to a non normative appendix

Resolution: The decision to transform requests does not depend on the URI pattern as discussed under 4.1.5: http://www.w3.org/TR/2009/WD-ct-guidelines-20091006/Overview.html#sec-altering-header-values

(Please make sure the resolution is adapted for public consumption)