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Wiki source code of ERPrototaculous

Version 171.1 by Ravi Mendis on 2009/07/20 08:13
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1 == Introduction ==
2
3 ERPrototaculous was developed to provide the ajax functionality in ERDivaLook.
4
5 === What is ERPrototaculous? ===
6
7 Features include:
8
9 * 'Organic' support for Prototype and Scriptaculous in WebObjects.
10 ** Light-weight dynamic elements to support Prototype
11 ** No custom patches to Prototype
12 ** Sans the need to extend Prototype
13 * Use of [[Unobtrusive Javascript>>http://en.wikipedia.org/wiki/Unobtrusive_JavaScript]].
14 * Pseudo-stateless ajax responses
15 * A set of widgets in the Prototype + Scriptaculous family.
16
17 ==== Unobtrusive Javascript in ERPrototaculous ====
18
19 Unobtrusive javascript is used in contrast to on-demand style of ajax programming.
20 By including Javascript as well as CSS globally in the page wrapper, CSS and Javascript don't have to load inside each and every ajax requests.
21 This keeps the ajax responses compact and granular.
22
23 The result is **faster** and more **reliable** ajax in WebObjects.
24
25 ==== Prototype WebObjects Elements ====
26
27 ##Ajax.Updater## and ##Ajax.Request## have been implemented as WebObjects elements.
28
29 ===== Ajax.Updater =====
30
31 Support for Prototype's [[Ajax.Updater>>http://www.prototypejs.org/api/ajax/updater]] is in the form of three elements:
32
33 * AjaxUpdaterLink
34 * AjaxUpdaterButton
35 * AjaxUpdaterForm (with ##onsubmit## for ajax form submission)
36
37 These components will update a **container** on the page:
38
39 {{code value="javascript"}}
40
41 new Ajax.Updater('container', url, {options});
42
43 {{/code}}
44
45 ===== Ajax.Request =====
46
47 Prototype's [[Ajax.Request>>http://www.prototypejs.org/api/ajax/request]] is in the form of:
48
49 * AjaxRequestLink
50 * AjaxRequestButton
51
52 These are used for strictly **background** ajax communication:
53
54 {{code value="javascript"}}
55
56 new Ajax.Request(url, {options});
57
58 {{/code}}
59
60 ==== Prototype + Scriptaculous Widgets ====
61
62 * Accordion
63 * LightWindow
64 * ModalBox
65 * CalendarDateSelect
66 * FileUpload
67
68 Support for these widgets have been similarly implemented as **button** and **link** variants, depending whether it is used inside a form or not.
69
70 == Ajax Forms in ERPrototaculous ==
71
72 Differences from using forms in WebObjects. i.e ##WOForm##:
73
74 1. All ajax form controls must be named. This includes text fields, selects and buttons.
75 (WebObjects dynamically assigned names are not compatible with ERPrototaculous).
76 1. All ajax forms in an ERPrototaculous app need to be instances of ##AjaxUpdaterForm##.
77 1. Ajax form submit buttons can be a:
78
79 *
80 ** Static ##<button>##.
81 ** WOSubmitButton (if the result is to update whole page/app).
82 ** AjaxUpdaterButton (to update a **container**). Or
83 ** AjaxRequestButton (for a **background** ajax request).
84
85 So forms are different in Ajax.framework and ERPrototaculous.
86
87 In ERPrototaculous you may still have typical WebObjects forms (i.e WOForm) as well as use ajax forms (i.e **AjaxUpdaterForm**).
88 They behave differently in that an AjaxUpdaterForm will update the contents of a container as opposed to the entire page.
89
90 {{warning title="Name your form controls!"}}
91
92 You must name your form controls, otherwise under certain circumstances ajax form submission will break.
93
94 {{/warning}}
95
96 == Ajax Response Handling in ERPrototaculous ==
97
98 One notable difference between the ERPrototaculous and Ajax frameworks is in the way they handle ajax responses.
99 In ERPrototaculous, updates and actions break with //The WebObjects Way// by being pseudo-stateless.
100
101 WebObjects typically vends a fresh response for each and every action. With ajax, this is not necessary.
102
103 In a typical WebObjects application, when a user clicks on the back button and clicks on a link in on that page in the browser history, WebObjects needs to remember how to handle that action and to return the correct page. This is no longer true for ajax.
104 The reason is a user never travels backwards or forwards through the ajax application history.
105 (i.e there is no forward/back buttons in a 100% ajax app - as there aren't in desktop apps).
106
107 So for ajax, the current state of the page fragment component is all that is necessary.
108
109 {{info title="No More"}}
110
111 A 100% ajax WO-app (like an [ERDivaLook|ERDivaLook] app) will no longer be plagued by the well known _limitation_ of WebObjects - the browser *backtrack problem*.
112
113 {{/info}}
114
115 == Ajax Actions in ERPrototaculous ==
116
117 Typically, in a WebObjects application, an action would return the contents of the entire page.
118
119 Ajax responses are mostly page fragments or just part of a page.
120 So you should make sure the actions in ERPrototaculous (or AjaxUpdaterButton and AjaxRequestButton) return the proper page fragment as opposed to the entire page.
121 This breaks with WO-tradition, so this is where you need to be careful.
122
123 {{note title="Actions"}}
124
125 ERPrototaculous actions *differ* from Ajax.framework actions - _They must return only the page fragment_.
126
127 {{/note}}
128
129 To assist with page fragments inside **forms**, you can make your ajax action responses a subclass of **WXPageFragment** (a utility to handle the forms processing between Prototype and WebObjects).
130
131 == Update Containers in ERPrototaculous ==
132
133 Perhaps the only real similarity to Ajax.framework is the ajax update container.
134 **WXGenericContainer** is the ERPrototaculous update container.
135 It is similar to an AjaxUpdateContainer when it has the binding ##ajax = true##, otherwise it's pretty much like **WOGenericContainer**.
136
137 It has been implemented as a utility or //convenience// for Prototype's ##Ajax.Updater##.