Edit comment LC-2065 for Mobile Web Best Practices Working Group

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Comment LC-2065

Comment Shortname:

Commenter: Dennis Bournique <db@wapreview.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:

My name is Dennis Bournique. I write about mobile browsing, primarily from a user perspective, at http://wapreview.com. I've done a little web development, mostly mobile specific sites, but I'm by no means an expert on the technical side of this issue.

Putting on my user hat, I'd like to make a request that the Content Transformation Guidelines include a requirement that content transformation proxies "must" provide end users (consumers of web content) with a way to turn off transformation both globally and on a site by site basis.

As an end user, I’ve experienced both the joys and the frustrations of using content transformation proxies.

In general, I believe in content transformation as a valuable tool to make web content, which would otherwise be difficult or impossible to use, available through the limited browsers of many mobile phones.

I have also been frustrated when a carrier or content provider unilaterally imposes content transformation with no way for me to disable it. I've been unable to access content through content transformation proxies that was previously available on the same device using a direct connection. This has happened both with installable content such as midlets and ringtones and also with pure html and xhtml pages, including mobile optimized pages and those that are not. I have also seen my secure end to end HTTPS traffic being forced through content transformation proxies, exposing it to the potential for a "man in the middle" attack.

I understand that the Guidelines are intended to prevent these sorts of problems by specifying when content transformation proxies must allow content to flow directly between server and user agent without modification. This is good, but no technical solution can ever be perfect. There will always be edge cases where content transformation does more harm than good. For this reason it is important that end users have the option to opt-out of content transformation.

I propose that the Guidelines be amended to include the following or similar language.

"...1. Content transformation proxies, if they are modifying traffic between a server and a user agent in any way, MUST provide a mechanism allowing the end user to resubmit the request and disable content transformation for the duration of the current session."

"...2. Content transformation proxies, must provide a means for end users of that proxy to disable all content transformation until they take explicit action to re-enable it."

Related issues: (space separated ids)

WG Notes: Was: ACTION-830 See: http://www.w3.org/2008/09/02-bpwg-minutes.html#item04 Then: http://www.w3.org/2008/09/30-bpwg-minutes.html#item06 Final resolution: Move content from Appendix E to 4.3.6 somewhere and reword appropriately (and yes, partial to LC-2065)

Resolution: We agree and have modified the wording, and have added an appendix that spells out where the various user preference clauses are to be found in the document. The appendix is available at: http://www.w3.org/TR/2009/WD-ct-guidelines-20091006/Overview.html#sec-Summary-User-Preference-Handling

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