Edit comment LC-2359 for Mobile Web Best Practices Working Group

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Comment LC-2359

Comment Shortname:

Commenter: Michael Cooper <cooper@w3.org>

Message-id:

Section of the document concerned:

[Free text description]Document as a wholeGuidelines for Web Content Transformation Proxies 1.0 W3C Working Draft 6 October 2009 Abstract Status of this Document Table of Contents Appendices 1 Introduction (Non-Normative) 1.1 Purpose 1.2 Audience 1.3 Scope 1.4 Principles 1.4.1 IAB Considerations 1.4.2 Priority of Intention 2 Terminology (Normative) 2.1 Types of Proxy "A transparent proxy is a proxy that does not modify the req... "A transparent proxy is a proxy that does not modify the req... 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 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 Field 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 Header Fields 4.1.6 Additional HTTP Header Fields 4.1.6.1 Proxy Treatment of Via Header Field 4.2 Proxy Forwarding of Response to User Agent 4.2.1 Applicable Responses 4.2.2 User Preferences 4.2.3 Receipt of Cache-Control: no-transform 4.2.4 Use of Cache-Control: no-transform 4.2.5 Server Rejection of HTTP Request 4.2.6 Receipt of Vary HTTP Header Field 4.2.7 Link to "handheld" Representation In this document the term current representation means a "sa... 4.2.8 WML Content 4.2.9 Proxy Decision to Transform 4.2.9.1 Alteration of Response 4.2.9.2 Link Rewriting In this document two URIs have the Same-Origin if the scheme... 4.2.9.3 HTTPS Link Rewriting 5 Testing (Normative) A References B Conformance Statement C Internet Content Types associated with Mobile Content D DOCTYPEs Associated with Mobile Content E URI Patterns Associated with Mobile Web Sites F Summary of User Preference Handling G Example Transformation Interactions (Non-Normative) G.1 Basic Content Tasting by Proxy G.2 Optimization based on Previous Server Interaction G.3 Optimization based on Previous Server Interaction, Server has Changed its Operation G.4 Server Response Indicating that this Representation is Intended for the Target Device G.5 Server Response Indicating that another Representation is Intended for the Target Device H Informative Guidance for Origin Servers (Non-Normative) H.1 Server Response to Proxy H.1.1 Use of HTTP 406 Status H.1.2 Use of HTTP 403 Status H.1.3 Server Origination of Cache-Control: no-transform Including a Cache-Control: no-transform directive can disrup... H.1.4 Varying Representations H.1.4.1 Use of Vary HTTP Header Field H.1.4.2 Indication of Intended Presentation Media Type of Representation I Applicability to Transforming Solutions which are Out of Scope (Non-Normative) J Scope for Future Work (Non-Normative) J.1 POWDER J.2 link HTTP Header Field J.3 Sources of Device Information J.4 Inter Proxy Communication J.5 Amendment to and Refinement of HTTP K Acknowledgments (Non-Normative)
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Refinement of the section concerned:

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open proposal pending resolved_yes resolved_no resolved_partial other assigned to Nobody

Type: substantive editorial typo question general comment undefined

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Response drafted Resolution implemented Reply sent to commenter

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

Comment:

4.2.3: If a website contains a "Cache-Control: no transform" directive,
proxies must NOT alter the content. Would this be a problem for a
proxy-based accessibility transcoding solution?

Related issues: (space separated ids)

WG Notes: RESOLUTION: In respect of LC-2359, resolve partial. We agree that it is heavy handed but it is the only mechanism provided by RFC 2616. We will amplify the note regarding possible damaging effects of using it - at present this notes that WAP gateways may mis-operate in its presence

Resolution: We agree that the "Cache-Control: no transform" directive is heavy handed but it is the only mechanism provided by RFC 2616. We have amplified the note in Appendix I.1.3 (the appendix provides informative guidance for Origin Servers and this section relates to the use of the "Cache-Control: no-transform" directive) to state that this directive can also disrupt the behavior of a proxy based accessibility solution.

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