14.9: Chapter Summary

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The easiest way to get started is to download the Seaside One-Click Experience from http://seaside.st
Turn the server on and off by evaluating ZnZincServerAdaptor startOn: 8080 and ZnZincServerAdaptor stop.
Toggle Halos to directly view application source code, run-time objects, CSS and HTML.
Remove the root decoration class WAToolDecoration in the application configuration, to disable the toolbar
Send WAAdmin applicationDefaults removeParent: WADevelopmentConfiguration instance, to disable toolbar for new Components
Seaside web applications are composed of components, each of which is an instance of a subclass of WAComponent.
Only a root component may be registered as an application. It should implement canBeRoot on the class side. Alternatively it may register itself as an application in its class-side initialize method by sending WAAdmin register: self asApplicationAt: application path. If you override description it is possible to return a descriptive application name that will be displayed in the configuration editor.
To backtrack state, a component must implement the states method to answer an array of objects whose state will be restored if the user clicks the browser’s Back button.
A component renders itself by implementing renderContentOn:. The argument to this method is an HTML rendering canvas (usually called html).
A component can render a subcomponent by sending self render: subcomponent.
HTML is generated programmatically by sending messages to brushes. A brush is obtained by sending a message, such as paragraph or div, to the HTML canvas.
If you send a cascade of messages to a brush that includes the message with:, then with: should be the last message sent. The with: message sets the contents and renders the result.
Actions should appear only in callbacks. You should not change the state of the application while you are rendering it.
You can bind various form widgets and anchors to instance variables with accessors by sending the message on: instance variable of: object to the brush.
You can define the CSS for a component hierarchy by defining the method style, which should return a string containing the style sheet. (For deployed applications, it is more usual to refer to a style sheet located at a static URL.)
Control flows can be programmed by sending x call: y, in which case component x will be replaced by y until y answers by sending answer: with a result in a callback. The receiver of call: is usually self, but may in general be any visible component.
A control flow can also be specified as a task — a instance of a subclass of WATask. It should implement the method go, which should call: a series of components in a workflow.
Use WAComponents’s convenience methods request:, inform:, confirm: and chooseFrom:caption: for basic interactions.
To prevent the user from using the browser’s Back button to access a previous execution state of the web application, you can declare portions of the workflow to be a transaction by enclosing them in an isolate: block.