[ZDP] BackTalk to Document Zope Developer's Guide (2.4 edition)/Object Publishing

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Tue Dec 2 05:44:45 EST 2003

A comment to the paragraph below was recently added via http://zope.org/Documentation/Books/ZDG/current/ObjectPublishing.stx#2-2


    When you contact Zope with a web browser, your browser sends an
    HTTP request to Zope's web server. After the request is completely
    received, it is processed by 'ZPublisher', which is Zope's object
    publisher. 'ZPublisher' is a kind of light-weight ORB (Object
    Request Broker). It takes the request and locates an object to
    handle the request. The publisher uses the request URL as a map to
    locate the published object. Finding an object to handle the
    request is called *traversal*, since the publisher moves from
    object to object as it looks for the right one. Once the published
    object is found, the publisher calls a method on the published
    object, passing it parameters as necessary.  The publisher uses
    information in the request to determine which method to call, and
    what parameters to pass. The process of extracting parameters from
    the request is called *argument marshalling*. The published object
    then returns a response, which is passed back to Zope's web
    server. The web server, then passes the response back to your web

      % Anonymous User - Dec. 21, 2001 8:39 am - I don't understand.Sorry.

      % Anonymous User - Jan. 11, 2002 9:53 am - Maybe clarify, that "Web Server" is just the
        front end, passing requests to and receiving responses from  ZPublisher, ZPublisher mapping requests to  

      % tibi - Feb. 22, 2002 6:00 am - Prehaps give an example at this point: say the URL http://zope/animals/monkey/feed?fruit=banana&num=17 is translated in Python to the call animals.monkey.feed(fruit = banana, num = 17)

      % Jace - July 8, 2002 5:41 am:
       In the above example, the actual call will be animals.monkey.feed(fruit = "banana", num = "17"). Note that
       they are passed as strings. If the second parameter was meant to be passed as an integer, the URL should have
       been "http://zope/animals/monkey/feed?fruit=banana&num:int=17.

      % Anonymous User - Aug. 9, 2002 12:29 am:
       Last 2 comments are illustrative and helpful and might be expanded upon.

      % Anonymous User - Sep. 4, 2002 11:24 pm:
       num:int is not a standard convention

      % Anonymous User - Oct. 4, 2002 10:55 pm:
       num:int nevertheless is part of Zope and above examples are on the right track:
       exemplify URL traversal as July 8 above;
       point out "feed" need not be contained in ~/monkey (acquisition) 
       and pattern Form/Action/Response is eased by num:int (conversion) 
       (with [apologies for lack of]![refs to] detail) 
       then reader may see the promised land. How ease it is to publish objects...:)blf

      % Anonymous User - Dec. 31, 2002 2:54 pm:
       What is the significance of the phrase "After the request is completely received". What is the difference
       between receiving the request and "completely" receiving the the request?

      % Anonymous User - Dec. 2, 2003 5:44 am:
       Some web servers start to process the HTTP request when it partially arrives at the server. Imagine for
       example a huge file upload. When the header is already at the server some action may be taken to check if the
       client is allowed to upload any file at all. This may help to prevent DOS attacks that upload huge files
       which are discarded but only after they were processed and put a huge load on the server.

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