[ZDP] A first shot at a Zope Quickstart (part 1)

[Shalabh Chaturvedi]

Hi Rik:

My $0.02:

Rik Hoekstra wrote:
> P.S. Questions:
> Should this go into the ZDP Wiki.
> Should I start a Quickstart project/task.
> (How) Do we integrate this with ZBook?

I read this and it looks really good. I think it addresses the correct audience
and presents info in the way they can easily lap up. Obviously there is some
more work required adding links and references. I do think this should go in
the ZBook. I have very few comments below.

> ----------------------------------
>
> Zope Quickstart (part 1)
>
>
> What is Zope
>
> Let's start with the official short explanation, taken from the Zope web
> site <URL: http://www.zope.org>:
>
> Zope is the leading Open Source web application server. Zope enables teams
> to collaborate in the creation and management of dynamic web-based business
> applications such as intranets and portals. Zope makes it easy to build
> features such as site search, news, personalization, and e-commerce into
> your web applications.
>
> Now this is a quite a bit especially with regards to promises, but the first
> sentence is the most important. As an application platform you can use Zope
> to build web applications, that is, interactive and dynamic web sites. This
> means it does not only present static HTML pages to your users, but also 1)
> make them interact with your site and 2) enables you to easily present data
> from databases and other data sources in an HTML form (or other forms for
> that matter). In this way a web application platform resembles cgi and other
> scripting techniques in use on the web. As a framework, however, it is much
> more structured.

This is true. Should there be more information about how Zope is different? For
example:
1. Web to Objects paradigm
2. Many facilities available (no need to implement): Object database,
    authentication & user management, DB connectors etc
3. Collaboration facilities for development of the web application.
etc

Hmm.. I see there is all this in detail below. Maybe just a mention here?


> Zope consists of several components which intimately work together to
> provide a coherent and consistent whole. It is designed for the web from
> scratch and it will cater for most common web needs, which are all present
> in the quote from the Zope site.
>
> You can use Zope from a host of different platforms, including Linux,
> Windows NT, 95, 98, 2000, and most major Unix varieties and even from BeOS.

Probably also a note about Zope working with different webservers and without
them?

>
> What Zope is good for
>
> Whether you should use Zope, depends on you needs. If you want a flexible,
> well thought out platform for your web application, you should definitely
> take a look at Zope. If you want a flashy looking, easy to start (but
> perhaps not so easy to maintain) product, if you care less about (initial)
> cost and if you do not want to spend some time learning - Zope may not be
> for you. For example: your current web site depends completely on Microsoft
> products and you have a lot of time and money invested and you do not have a
> new challenge in front of you - why change?
Er.. can the example be non-Microsoft specific?

> If you check out Zope, be prepared to spend some time learning. Not that it
> is hard to start a simple web site in Zope. If you have a set of HTML pages
> that you want to put into Zope, it will take you a half hour in a simple
> Zope setup to get it up and running. This may be a good starting point, but
> it cant't be more than a starting point, as Zope is for dynamic sites. If
> you only have static pages to serve, you may be better off with a
> specialized web server (like Apache). If you have dynamic content (and who
> wants to be static rather than dynamic?) read on.
>
> There is more to Zope than just this. Zope is an advanced platform, and it
> is **well structured**. Therefore, it works best with a well-structured web
> application. So you should be prepared to do some thinking about the
> structure of your site. This *will* pay off in term of maintainability and
> ease of extending.
>
>
> Using Zope alongside another Web techniques
>
> You may already be considering using Zope, but you already have considerable
> effort put into another tool for your site, for instance straight cgi, php
> or asp. Zope integrates well with any webserver able to run cgi. This means
> you can continue to use your old scripts side by side with Zope. (However it
> is not unlikely that once you get the knack of Zope you'll want to migrate
> all your major Web scripting applications - you have been warned). How to
> make them work together, will depend mostly on what you actually *are* using
> right now, so please read the specific sections for that information.
> [links]
>
>
> Zope Requirements
>
> If you consider using Zope, there may be a number of questions related to
> cost, requirements in hard and software.
> Zope is freely available from the Zope site http://www.zope.org. Zope is an
> open source product.
> The latest version is indicated on the downloading page. It depends on the
> platform you're running on what version you will have to download [links].
> There are binary versions for Win32 and for Linux [other?]. You can always
> download a source release if you want to build the package yourself. The
> development version of Zope is available from CVS [link].
> Zope is platform independent. This means that you can develop in Zope on one
> platform (say Windows 95) and have a production machine on a very different
> one (say
>
> For Zope, you will need relatively modest hardware. Digital Creations (who
> created Zope) set out to have Zope run on a hardware configuration of less
> than $ 1000. Zope.org *is* running on such a configuration.
>
> You may use Zope for free, but you are asked to put the Zope attribution
> buttion on your homepage or somewhere most appropriate on your site.
>
>
> Setting up Zope
>
> After you've downloaded the package, the setup procedure you'll have to
> follow depends on the platform you're working on and of questions whether
> you want Zope to integrate with existing webservers and so on.[links]
>
> In a very generalized setup walkthrough you'll have to:
> 1) ensure you are running with the proper permissions on your system
> 2) unpack or execute (Windows) the distribution
> 3) Perhaps/probably change some parameters for running Zope
> 4) Set a superuser name/password combination
> 5) Startup Zope.
>
> In a typical Win32 setup session you could be up and running in 20 minutes -
> if you have a reasonable connection to the web (but the Zope download is
> modest). In Linux ... [XXX complete]
>
> Zope will run on its own, but it has very good possibilities for integration
> with existing webservers. To test your first setup with Zope and to check it
> is running well, you probably are best off by setting up Zope on its own. In
> this way you will know if something has gone wrong with Zope at setup time.
> Afterwards you can then start integrating Zope with existing components,
> like external webservers.
>
> If installation has gone well, you can test it by firing up your web browser
> and point it to http://localhost:<zopeport>, in which <zopeport> should be
> replaced by the port you installed Zope under (see the specific installing
> information). You should get a welcome page for you Zope installation. You
> can test whether you can authenticate with Zope by clicking the link
> pointing to the  management screens.
>
> Getting Started
>
> So now you have Zope running, now what. There are several options for
> getting started with Zope. If you just want experience the look and feel of
> Zope, the Tutorial [link] is your best bet [short explanation]. To be sure,
> the tutorial is probably your best bet anyway, but if you downloaded Zope to
> get some things done, here are some pointers.
>
> [links]
>
> Some Zope principles
>
> To get started, you'll need to know something about Zope's architecture if
> you do not want to get hopelessly confused.
>
> First: Zope is about object publishing. While this may sound technical
> (because it is), this should not deter you from using the system, as you
> will never need to use the objects directly. If you have never programmed
> much, or never programmed in an object oriented language, this is not the
> place to introduce you to it [link]
> Suffice it here to state that objects are "self-contained" pieces of
> software with their own properties and behaviour. In Zope, they replace
> files. They live in the Zope database (well, they might live somewhere else,
> but that is not important now.) Superficially seen, they mimic the behaviour
> of a filesystem: there are objects that mimic folders and there are objects
> that mimic all types of documents (images, files, html files etcetera).
> Folder-like (called "folderish" objects in "Zopish") may contain other
> objects. They are object managers. As you can also add other folders to
> folder objects, in this way you can build object hierarchies.
>
> This implies that if you made a website in Zope (using the tutorial for
> example), and want to inspect what you've made "by hand", you will not be
> able to find it. The Zope database (*ZODB* or *Zope Object Database*) is
> called data.fs. It is in the <zopehome>/var directory. The behaviour of the
> Zope objects are defined in so-called *methods* in standard OO (=Object
> Oriented [programming]) terminology. These methods can either be called
> directly through the Web, using Zope of course, or they are called inside
> the Zope framework. The properties of the Zope objects are also called
> properties.
> How all this fits together will not concern us here - if you are interested
> [links]
>
> Second: Zope is managed through the web. In effect this means: 1) your
> objects are tanslated to urls if you call zope. In this way, if you have an
> object hierarchy consisting of a few folders and some other objects like so:
>
> /root
>   /folder1
>     file1
>     image
>     file2
>     /folder2
>       file3
>       file4
>
> If your site is called www.zopesite.org, the url of file1 will be
> http://zopesite/folder1/file1. The url of folder2 will be
> http://zopesite/folder1/folder2 and the url of file4 will be
> http://zopesite/folder1/folder2/file3. Zope has a number of tricks to change
> these representations, but that is much too advanced stuff to treat here
> [links]
> 2)You can create and modify objects using the management interface that is
> built into Zope. We already had a glance at it above.

Zope also makes the ZOBD available through ftp and webdav, so those interfaces
can be used too.

> You'll need an appropriate id and password to access it. If everything went
> well, you set these when you installed Zope (see above). The ZContent
> management Guide [link] covers the use of the management interface in much
> more detail than we could here. Nonetheless here follows a high-level
> overview for the impatient.
>
> Overview of the Zope Management Interface
>
> [screenshot, there should be other screenshots above as well]
> The web management interface consists of a few different sections. At a
> first glance, you will see the different frames that together make up a
> Mac/Windows Explorer-like interface. The left frame is used for navigation,
> the right frame for editing etcetera. The right frame has tabs displayed at
> the top. Behind the tabs are different views of aspects of the current
> object, or they indicate that different actions useful in the context of the
> selected object may be performed there. All this is pretty standard user
> interface stuff.
>
> Left Frame
>
> The left frame of the management interface has basically 2 different
> sections: the Control Panel and the tree of folders and other items. Once
> again, please remember that these *look* like folders, files and documents,
> but in reality they are object representations - not real folders or files.
> The Control Panel object contains the interface to a few basic operations in
> Zope:
> o database management (of the ZODB database)
> o other basic management actions
> o product managment
>
> Products are Zope components. They may be added to and removed from the
> system. After they have been installed they usually become objects that are
> addable through the management interface.

Nitpick: products don't 'become' objects but make new types of objects
available for use.

> Right Frame
>
> Adding, modifying and deleting objects is done in the right frame in the
> management interface. To get technical: in effect this is done by calling
> *manage* methods in Zope, but that won't concern us here [links]
> The available objects that are useful in a certain context are shown in the
> drop down list under the contents tab. Basic object types are:
> o Folder
> o Images and Files
> o DTML Document and DTML Method
> o User Folder
>
> Deleting and modifying objects is rather straightforward. They will not be
> covered here.
>
> Adding Objects
>
> There are many more objects and the list may be extended by adding Products.
> Adding an object normally includes the following sequence of actions:
>
> 1. In the management interface you click the object to be added in the drop
> down list
> 2. you get a form with some fields to fill in
> 3. after the form is submitted the object is created
> 4. you are returned to the management interface (sometimes through a dialog
> that tells you the action has succeeded)
>
> While the basic object types more or less speak for themselves, I shall
> outline their function here:
>
> o A folder contains other objects. It has its own properties, that may be
> added under the properties tab
> o A User Folder contains Users. Users are necessary for security. Security
> in Zope is a sophisticated issue; it will *not* be treated in this cursory
> introduction
> o Images and Files are what they seem. Zope is able to sniff their type by
> their extension. They have their own properties
> o DTML Methods and DTML Documents are very much alike. They are the basic
> objects that contain content. Content may be XML or plain text, but it
> usually is a mixture of HTML and DTML. DTML stands for Document Template
> Markup Language, which sounds more like XML than it is at the moment. We'll
> return to DTML below, suffice it here to state that it is used for putting
> logic into Zope.
> The differences between DTML Documents and DTML Methods are slight, but
> important. The differences boil down to DTML Documents being separate
> objects and DTML Methods only methods of the containing object, that is
> snippets that may contain bits of static content and logic (so I lied when I
> wrote that they were objects).
> This has implications for their use: DTML Methods should only be used for
> logic and modular pieces of information: for DTML and for some HTML
> snippets. DTML Documents (should) contain content with some (as little as
> possible) DTML. As a rule of thumb, the DTML in DTML Documents should only
> be used for including DTML Methods, that modify the content of the DTML
> Document.
>
> For instance, if you have a header to be used in all pages at your site, it
> should be a DTML method. It may be included into a DTML Document with DTML,
> like this:
>
> ExmplHeader (this is a DTML Method):
>
> <html>
> <head><title><dtml-var title></title></head>
> <body>
> <h1><dtml-var title></h1>
>
> ExmplDocument:
>
> <dtml-var ExmplHeader>
> <p>all sorts of interesting content</p>
> <dtml-var ExmplFooter>
>
> (the footer is not included here)
>
One last thing. DTMLDocs and Methods have been given a special place in the
introduction. I feel all the basic objects can be explained in detail in
another section (or chapter) and here only an outline and link could be
provided.

That's it for now. I'll mail again if I come up with more!

Cheers,
Shalabh.