Edit comment LC-2075 for Mobile Web Best Practices Working Group

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Comment LC-2075

Comment Shortname:

Commenter: Mark Nottingham <mnot@mnot.net>

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:

* Section 4.1.5.2 Again, not specifying the heuristics is going to
lead to differences in behaviour, which will cause content authors to
have to account for this as well.

* Section 4.1.5.2 "A proxy must not re-issue a POST/PUT request..." Is
this specific to POST and PUT, or all requests with bodies, or...?

Related issues: (space separated ids)

WG Notes: See: http://www.w3.org/2008/10/20-bpwg-minutes.html#item08 Final resolutions: - LC-2075 differences in behaviour: the internal operation of the proxy is not open to our specification, we need to point out to CT proxies that in practice 406 responses are not the only way in which content proivders signal that they can't or won't handle a request, though we do say that this is the preferred way of them doing so - ref LC-2075, we have changed the text to refer only to POST and we acknowledge that this should not need restatement from RFC 2616 but we are aware of this kind of misoperation "in the wild"

Resolution: We now limit the scope to HEAD GET and POST. We observe that duplicate POSTS are seen "in the wild" and think it important to point out to operators of content transformation proxies that this is problematical. We acknowledge that not specifiying heuristics will lead to differences in behaviour. However, this is something that content transformation providers will need to do to provide the service they set out to provide. The updated text is available at: http://www.w3.org/TR/2009/WD-ct-guidelines-20091006/Overview.html#sec-avoiding-request-unacceptable

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