seaside February 2003

seaside@lists.squeakfoundation.org

14 participants
21 discussions

anchors behaving like buttons?
by Derek Brans 26 Jun '03

26 Jun '03

In Seaside, is there a way to have an anchor tag that will submit a form and perform an action (behaving just like a button)? Thank you, Derek Nerd on a Wire: Web and Information Solutions Website Design - Database Systems - Site Hosting 604.874.6463 mailto:info@nerdonawire.com For more information, visit http://nerdonawire.com

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A bit of help with Seaside
by Germán S. Arduino 25 Mar '03

25 Mar '03

Hello: I'm a newest smalltalker trying to develop my first web app with Squeak and Seaside. I've looked into Seaside examples but I haven't clear how to develop a complete app. By example: I would to have a html grid showing people records, then by means of a check box in each row I want to be able to select a record and modify or delete. Also I must to add records. But I can't figure how to build that grid (table), how to populate with my objects, and so. That is similar to all type of records (objects) that I will manage in this app (people, time, tasks, etc), then some little examples or suggests will be of great help for me. Thanks in Advance. --- Germán S. Arduino http://www.rva.com.ar

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StateHolder
by Avi Bryant 07 Mar '03

07 Mar '03

There were some recent questions about how state management works in Seaside 2.2, At some point I hope to have a tutorial on that; for now, all I have is an outline of one. I thought the outline might be useful in itself, however, so I'm forwarding it to the list (this was originally an email to Stef Ducasse). ---- Ok... so there are actually two topics I want to cover. One is the management of state while backtracking, the other is embedding components. The first topic would be a discussed in a short tutorial called "Retracing Your Steps". In broad strokes, this would be: 1. demonstrate the problem (show how the current WACounter doesn't behave properly with the back button) 2. demonstrate the implementation that fixes this (using StateHolder) 3. discuss when it's necessary or useful to use StateHolder and when it's not 4. talk about the need for and implementation of a way of limiting the ability to backtrack In more detail: 1. In the earlier tutorial, we looked at the WACounter component, which maintains a simple integer count. Clicking on the ++ or -- links increments and decrements the count. What happens when you use the back button? Try this: - start a new counter (http://localhost:9090/seaside/counter) - click on ++ until the counter shows 6 - hit the back button to where the counter shows 2 - hit the -- link You probably expect it to show 1 (2--), but it shows 5 instead. Why? We've been using the same instance of this component the whole time, and chronologically, the last value of the counter was 6. We're asking it to decrement, and it does. This may not seem like a huge problem in the case of the counter, but inconsistency is a Bad Thing. The page was showing 2, and you asked it to do something with (you thought) 2, but it applied the action to 6 instead. If, say, the page was showing a product instead of a number, and the link was "buy" instead of "--", you could have real problems. 2. Seaside solves this by introducing a class for holding state that needs to be backtrack-aware. A StateHolder is just like a ValueHolder, but it detects use of the back button, and adjusts its state accordingly. To be more specific: whenever a link is clicked on a page, all of the StateHolders for the current session take on the value that they had when that particular page was produced. We can get a StateHolder by asking the current session for one (WASession>>stateHolder). So, to modify WACounter to be consistent under backtracking, we must do two thinhgs - first, use the "abstract variable" refactoring to replace all references to 'count' with sends to accessor methods, so, for example, increment count := count + 1 becomes increment self count: self count + 1 (this is something the RB can do for us). Then, we must make the 'count' instance variable hold a StateHolder object: initialize count := session stateHolder. self count: 0. Finally, we must implement the accessors: count ^ count contents count: aNumber count contents: aNumber If we perform the experiment from before, when we click the -- when showing 2, we should now (correctly) see 1. 3. Although you can use a StateHolder anywhere you like in your code, it should only be necessary to use it in very specific cases. First of all, you should never use it in your domain model code - it would be very odd for customer data, for example, to disappear just because the user hit the back button. This is *not* meant to be a global state rewind mechanism. Instead, it is meant to be used for *UI* state. Examples of UI state are: - the current record being shown on a page - the currently selected page in a batch of search results - the currently selected pane of a tab panel - which nodes on a tree widget are expanded and so on. This is all state that is non-crucial to the domain, but that the user expects to be consistent with what they see on the page, when they click a link. There are essentially three kinds of UI state you might find in a component. These are - immutable state, that is set on initialization of a component and never changes. For example, a form that edits a customer's info will likely be instantiated with the customer it is to edit, and this value never changes. - transient state, that is reset with every request. For example, the current values of form fields (which will be modelled by inst vars in the component) are changed every time the form is submitted. - persistent but mutable state, that doesn't fall into either of the previous two categories. It is only this last kind for which StateHolders are necesary. 4. It is great to be able to provide the abilitiy to safely backtrack, but sometimes you want to prevent your users from backtracking. For example, consider a typical online store, where after filling a shopping cart, users are led through a checkout process. You may well want to be able to backtrack during that process (mistyped the shipping address), but once the credit card has been charged, you don't want the user to be able to backtrack change the contents of the shopping cart! Seaside provides the WASession>>isolate: method to control backtracking. #isolate: is passed a block, and the block is immediately evaluated. When the block ends, any pages that were created within it immediately expire. If the user backtracks to them and clicks on any link or submits any form, they will be notified that that page has expired and be redirected to a non-expired page. #isolate: calls can also be nested. ---

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Browser Code Panel in Konqueror 3.1
by Markus Fritsche 26 Feb '03

26 Feb '03

The does not appear in konqueror 3.1, and in IE 5.5 it is only two lines long. Are these browser bugs? Regards, Markus

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[repeated] Hopelessly stupid newbie question
by Randy Siler 26 Feb '03

26 Feb '03

My mail system melted down and I lost any response that may have been made to my question yesterday. If you were by chance good enough to write me an answer, and if it is still in your sent mail folder, would you please resend it, I'd really love to read it. I feel just sick that I might have missed out. Thanks very much, Randy Begin forwarded message: > From: Randy Siler <rsiler(a)u.washington.edu> > Date: Mon Feb 24, 2003 3:34:27 PM US/Pacific > To: "The Squeak Enterprise Aubergines Server - general discussion." > <seaside(a)lists.squeakfoundation.org> > Subject: Hopelessly stupid newbie question > > I need to write a simple web application that at the very least > collects data from a web form. > Of course I'd love to use Squeak and I see many technologies in Squeak > that appear more than adequate for my needs. > > I've worked through tutorial and chapters in books and tried adapting > what I find to what I need, > but when I try to do what I want to do, I find I get lost before I get > it done, probably because I want to do something simpler or different > from the tutorials. > > I had thought that Seaside was the way to go and worked through it > before starting out to build my simple little form processor. I build > my form in a WYSIWYG editor and got to the point of specifying the > form action. When I tried to divine from seaside examples I started to > get the sense that maybe I had misconceptualized seaside as being > suited to functioning as a simple form cgi that would allow me to > easily get the form data from a web form. Specifically, the form > actions specified in the seaside examples always contain those numbers > (I forget what you call them) that I couldn't imagine supplying (which > makes me think that in seaside you don't do it like I was > thinking--make a form in an editor). (Do you always dynamically > generate the forms from seaside?) > > Am I right about this? Should I be using something else if I just want > a simple form cgi in Squeak? > > Or can I use seaside in a much simpler albeit less powerful way until > I get my feet wet? > > > Very much appreciate any insight > > Randy >

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newbie question
by j s 23 Feb '03

23 Feb '03

Hi, Thank you for responding. The link that you provided has some very valuable information. I am only trying to understand the given example. If that is the simplest program possible, why does it not work? Is there some setup code that needs to be executed? Maybe I do not have Squeak configured properly. regards js:) Hi: First, I must say that I'm a newbie also. Anyway I will try to help. You are looking the paper related to the Seaside Design, Kernel section. I think that could be more useful try with the Tutorial: "A Walk on the Seaside". You can see several working examples and figure out easily how to develop a "Hello World" example. Also, Avi Bryant has wroted a mail explaining me more things that was VERY useful for me. I've put that mail at the Seaside swiki in: http://swiki.squeakfoundation.org/sea/62 HTH Regards. ------------------------------- Germ�n S. Arduino http://gsa.swiki.net ------------------------------- ----- Original Message ----- From: j s To: seaside at lists.squeakfoundation.org Sent: Saturday, February 22, 2003 4:17 AM Subject: [Seaside] newbie question Hi, I am trying to understand more about the Seaside application. In the Seaside Borges webpage, there is an paragraph as follows ------------------------------------------------------------------------ As a quick example, here is the simplest possible Seaside application: WAApplication named: 'hello' do: [:session | session respond: [:response | response nextPutAll: 'Hello world!']] Making a call to WAApplication class>>named:do: associates an application name with a one-parameter block. When a request is first made for that application name to the Seaside server, a new WASession object will be created and passed into the block. In this case, the application simply generates a single response and then exits. ---------------------------------------------------------------------------- --------------------- If I evaluate the example the I get an error " named:do: not understood " I traced through the WACounter example but it appears to do its job in a slightly different way. Thank you for any help. __________________________________________________ Do you Yahoo!? Yahoo! Tax Center - forms, calculators, tips, more http://taxes.yahoo.com/

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newbie question
by j s 22 Feb '03

22 Feb '03

Hi, I am trying to understand more about the Seaside application. In the Seaside Borges webpage, there is an paragraph as follows ------------------------------------------------------------------------ As a quick example, here is the simplest possible Seaside application: WAApplication named: 'hello' do: [:session | session respond: [:response | response nextPutAll: 'Hello world!']] Making a call to WAApplication class>>named:do: associates an application name with a one-parameter block. When a request is first made for that application name to the Seaside server, a new WASession object will be created and passed into the block. In this case, the application simply generates a single response and then exits. ------------------------------------------------------------------------------------------------- If I evaluate the example the I get an error " named:do: not understood " I traced through the WACounter example but it appears to do its job in a slightly different way. Thank you for any help. --------------------------------- Do you Yahoo!? Yahoo! Tax Center - forms, calculators, tips, and more

2 1

File Upload
by Glenn Swanlund 19 Feb '03

19 Feb '03

Is there a way in Seaside to upload a file? Regards, Glenn

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Not getting head and body tags... and disappearing outer component.
by Derek Brans 09 Feb '03

09 Feb '03

Hi Avi and Julian, This problem has two parts, but I thought they might be related. Part 1: Not getting head and body tags When I look at the generated code for my page this is how it starts: <link rel="stylesheet" type="text/css" href="/seaside/best.bc.ca/advocacy/k=26025b80-3bc4-11d7-808e-000393814416" > <table cellpadding="2" cellspacing="1" width="100%"> <tr> <td align="center"> <table cellpadding="2" cellspacing="1"> <tr> <td> <table cellpadding="3" cellspacing="0"> <tr> <th align="center" class="tab-current"> I'm wondering what I could possibly be doing that's making the head and body tags not appear. Part 2: Disappearing outer component. Something else that's strange: sometimes when I call a page in a certain way, I just end up with the inner component (seen above,near the end). <table cellpadding="3" cellspacing="0"> <tr> <th align="center" class="tab-current"> The actual container is nested a few tags deeper. By calling the page I lose the outer component responsible for the outer html: <link rel="stylesheet" type="text/css" href="/seaside/best.bc.ca/advocacy/k=26025b80-3bc4-11d7-808e-000393814416" > <table cellpadding="2" cellspacing="1" width="100%"> <tr> <td align="center"> <table cellpadding="2" cellspacing="1"> <tr> <td> In other words, I start with: <outer component> <inner component> <container catching the call> When I call a page inside the container I end up with: <inner component> <container with new component> ...no outer component Any ideas? Thanks, Derek Nerd on a Wire: Web and Information Solutions Website Design - Database Systems - Site Hosting 604.874.6463 mailto:info@nerdonawire.com For more information, visit http://nerdonawire.com

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StateHolders and complex objects -djb
by Derek Brans 08 Feb '03

08 Feb '03

Avi, Julian, Are stateholders able to manage collections? Do attributes on objects in the collection get rolled back? In general, if a stateholder maintains some complex object, what aspects of that object get rolled back? Nerd on a Wire: Web and Information Solutions Website Design - Database Systems - Site Hosting 604.874.6463 mailto:info@nerdonawire.com For more information, visit http://nerdonawire.com

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seaside February 2003