web_architecture.theory.txt

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STANDARDS ==>                     #W3C TAG findings:
                                  #  - "Architecture of the World Wide Web, Volume One"
                                  #  - "Authoritative metadata"

SUMMARY ==>                       #Web: separate identification (URI), interaction (URI scheme) and format (MIME).
                                  #Metadata: 
                                  #  - can be inside any of them, and describe any of them
                                  #  - encapsulating > embedded > external


                                             /=+===============================+=\ 
                                            /  :                               :  \  
                                            )==:            GENERAL            :==(   
                                            \  :_______________________________:  /    
                                             \=+===============================+=/


INTERNET ==>                      #Network of all networks
                                  #Includes the web, but also other technologies: email, FTP and any other possible protocol

WEB ==>                           #Global set of resources:
                                  #  - identified and linking to each other using URIs 
                                  #  - represented using MIME types
                                  #Architecture provides orthogonality by separating resource into:
                                  #  - identification (presentation|view):
                                  #     - i.e. URIs
                                  #     - good identifier should enforce:
                                  #        - sameness (global)
                                  #        - no ambiguity 
                                  #        - uniqueness (no aliases)
                                  #     - orthogonality: should not be bound to specific URI scheme nor MIME type
                                  #  - interaction (controller):
                                  #     - i.e. URI schemes
                                  #        - sometimes connected to protocols, but not necessary
                                  #     - good interaction should:
                                  #        - avoid dead links
                                  #        - link resources to each other using URIs or #HASH
                                  #     - orthogonality: should not retrict URI syntax, and allow using any MIME type
                                  #  - formats (representation|content|model):
                                  #     - i.e. MIME types
                                  #     - good format should allow:
                                  #        - extensions
                                  #        - versioning
                                  #     - orthogonality: should allow embedding any URI with any URI scheme
                                  #Order: URI -> interaction -> format
                                  #Often used technologies include HTTP, HTML


                                             /=+===============================+=\ 
                                            /  :                               :  \  
                                            )==:           METADATA            :==(   
                                            \  :_______________________________:  /    
                                             \=+===============================+=/


METADATA ==>                      #Can be inside:
                                  #  - URI, e.g. DATE in tag: URI
                                  #  - interaction, e.g. HTTP header
                                  #  - representation, e.g. HTML tag
                                  #Can describe:
                                  #  - URI, e.g. Link [S] rel
                                  #  - interaction, e.g. Date [S]
                                  #  - representation, e.g. Content-Type [S]
                                  #Can be:
                                  #  - encapsulating: 
                                  #     - what it contains, following order: URI -> interaction -> representation
                                  #     - e.g. Content-Type [S]
                                  #     - has priority over embedded:
                                  #        - sender carries intention, so can provide different metadata for same message
                                  #           - e.g. same file can be sent as Content-Type: plain/text [S] or as Content-Type: application/json [S] depending on
                                  #             sender intention
                                  #        - easier to provide metadata for sender than for receiver
                                  #           - e.g. server knows Content-Type [S] or Date [S], but it's hard for client to guess it
                                  #  - embedded: 
                                  #     - itself, i.e. URI|interaction|representation describing itself
                                  #     - e.g. Date [S], <meta>
                                  #     - has priority over external:
                                  #        - since external, is not authoritative
                                  #        - allow changing content without updating links
                                  #  - external: 
                                  #     - another resource, i.e. URI|interaction|representation describing URI
                                  #     - e.g. Link [S], <link>
                                  #Conflicts:
                                  #  - priority: encapsulating > embedded > external
                                  #  - should be detected
                                  #  - must give option for user to be prompted for consent
                                  #If not provided:
                                  #  - can guess 
                                  #  - but should not use a default