Traps and pitfalls when writing web apps?

[Vincent Delporte]

Hello

I'm about to write a prototype for a business application, but since
this my first real web application, I'm looking for a good book or
article that sums up the different issues web developers will
encounter when coming from the world of dedicated applications (VB,
Delphi, etc.)

I'm thinking of issues specific to web apps like the statelessness of
HTTP, dealing with the back button, etc.

Any good resource? It'd be even better if they have examples in PHP,
but a language-agnostic resource is good enough.

Thank you!

[flamer die.spam@hotmail.com]

Re: Traps and pitfalls when writing web apps?


Vincent Delporte wrote:

Hello
>
I'm about to write a prototype for a business application, but since
this my first real web application, I'm looking for a good book or
article that sums up the different issues web developers will
encounter when coming from the world of dedicated applications (VB,
Delphi, etc.)
>
I'm thinking of issues specific to web apps like the statelessness of
HTTP, dealing with the back button, etc.
>
Any good resource? It'd be even better if they have examples in PHP,
but a language-agnostic resource is good enough.
>
Thank you!

php.net has the majority of what you will need, i find the user
commenst to be the most useful part.

Flamer.

[Iván Sánchez Ortega]

Re: Traps and pitfalls when writing web apps?

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Hash: SHA1

Vincent Delporte wrote:

I'm about to write a prototype for a business application, but since
this my first real web application, I'm looking for a good book or
article that sums up the different issues web developers will
encounter when coming from the world of dedicated applications (VB,
Delphi, etc.)

First and foremost: Don't trust user input. Ever.

In other words: whenever you receive data from the user (usually by a posted
form, or by some GET variables), clean, check and double-check the data for
validity. Don't ever assume that the user has put a valid value in a form
input field.

Another point to take into account: Every page is a *different* run of your
program. HTTP is a stateless protocol, ya' know. That means:
- - Be careful when passing data from one page to another
- - Be careful about race conditions

- --
- ----------------------------------
Iván Sánchez Ortega -i-punto-sanchez--arroba-mirame-punto-net

¿Quieres aprender a leer?, Escríbeme!
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[Vincent Delporte]

Re: Traps and pitfalls when writing web apps?

On Fri, 28 Jul 2006 02:28:56 +0200, Iván Sánchez Ortega
<i.punto.sanche z--@rroba--mirame.punto.ne twrote:

>First and foremost: Don't trust user input. Ever.

Thx guys. So, no article or book on the subjet?

[Tony Marston]

Re: Traps and pitfalls when writing web apps?


"Vincent Delporte" <justask@acme.c omwrote in message
news:sohic2l2aj mi9kseovj0iimqh ggqabaads@4ax.c om...

Hello
>
I'm about to write a prototype for a business application, but since
this my first real web application, I'm looking for a good book or
article that sums up the different issues web developers will
encounter when coming from the world of dedicated applications (VB,
Delphi, etc.)
>
I'm thinking of issues specific to web apps like the statelessness of
HTTP, dealing with the back button, etc.

Try http://www.tonymarston.net/php-mysql...ttonblues.html
And http://www.tonymarston.net/php-mysql/client-clones.html
And http://www.tonymarston.net/php-mysql...-protocol.html

--
Tony Marston

http://www.tonymarston.net

http://www.radicore.org

[ronverdonk]

The info you are looking for is usually scatterd among different sites and books. The OReilly online book store is usually a good place to start (www.oreilly.co m).

But if you need an overview, have a look at the book:
"Deliver First Class Web Sites: 101 Essential Checklists"

Ronald :cool:

[Vincent Delporte]

Re: Traps and pitfalls when writing web apps?

On Fri, 28 Jul 2006 09:31:45 +0100, "Tony Marston"
<tony@NOSPAM.de mon.co.ukwrote:

>Try http://www.tonymarston.net/php-mysql...ttonblues.html
>And http://www.tonymarston.net/php-mysql/client-clones.html
>And http://www.tonymarston.net/php-mysql...-protocol.html

Thanks a lot. That's exactly the kind of articles I was looking for.
Are there more, on other traps I don't even exist and in which I will
fall unless warned before? :-)

[Tony Marston]

Re: Traps and pitfalls when writing web apps?


"Vincent Delporte" <justask@acme.c omwrote in message
news:uv5kc2h4d0 vtt2c5ioggccih6 nef1e2b3q@4ax.c om...

On Fri, 28 Jul 2006 09:31:45 +0100, "Tony Marston"
<tony@NOSPAM.de mon.co.ukwrote:

>>Try http://www.tonymarston.net/php-mysql...ttonblues.html
>>And http://www.tonymarston.net/php-mysql/client-clones.html
>>And http://www.tonymarston.net/php-mysql...-protocol.html

>
Thanks a lot. That's exactly the kind of articles I was looking for.
Are there more, on other traps I don't even exist and in which I will
fall unless warned before? :-)

Do a google search using "php security" and you will see some useful
articles.

--
Tony Marston

http://www.tonymarston.net

http://www.radicore.org

[Vincent Delporte]

Re: Traps and pitfalls when writing web apps?

On Fri, 28 Jul 2006 16:11:30 +0100, "Tony Marston"
<tony@NOSPAM.de mon.co.ukwrote:

>Do a google search using "php security" and you will see some useful
>articles.

OK, but my question isn't specifically about security. It's a more
general question about the web-specific issues that desktop
applications don't have to deal with.

[Ivan Marsh]

Re: Traps and pitfalls when writing web apps?

On Fri, 28 Jul 2006 21:15:29 +0200, Vincent Delporte wrote:

On Fri, 28 Jul 2006 16:11:30 +0100, "Tony Marston"
<tony@NOSPAM.de mon.co.ukwrote:

>>Do a google search using "php security" and you will see some useful
>>articles.

>
OK, but my question isn't specifically about security. It's a more
general question about the web-specific issues that desktop applications
don't have to deal with.

The number one thing is understanding the difference between client-side
and server-side.

--
The USA Patriot Act is the most unpatriotic act in American history.
Feingold-Obama '08 - Because the Constitution isn't history,
It's the law.

[Vincent Delporte]

Re: Traps and pitfalls when writing web apps?

On Fri, 28 Jul 2006 14:51:36 -0500, Ivan Marsh <annoyed@you.no w>
wrote:

>The number one thing is understanding the difference between client-side
>and server-side.

With AJAX, there's no such thing ;-)

[Rik]

Re: Traps and pitfalls when writing web apps?

Vincent Delporte wrote:

On Fri, 28 Jul 2006 14:51:36 -0500, Ivan Marsh <annoyed@you.no w>
wrote:

>The number one thing is understanding the difference between
>client-side and server-side.

>
With AJAX, there's no such thing ;-)

Oh yes there is, and no little difference at that. There's a lot different
in posting/getting information over HTTP (or any other protocol) and a local
application.

It seems it's more userfriendly/doesn't take that much trips to the server
and back (*) using the capabilities from AJAX, that's true. AJAX is usefull
in some cases, but hardly the holy grail here.

(*) From the users standpoint. Normally there's even more traffic going on
when people are using ajax, only not on specific request from the user.

Grtz,
--
Rik Wasmus

[Kenneth Downs]

Re: Traps and pitfalls when writing web apps?

Vincent Delporte wrote:

Hello
>
I'm about to write a prototype for a business application, but since
this my first real web application, I'm looking for a good book or
article that sums up the different issues web developers will
encounter when coming from the world of dedicated applications (VB,
Delphi, etc.)
>
I'm thinking of issues specific to web apps like the statelessness of
HTTP, dealing with the back button, etc.
>
Any good resource? It'd be even better if they have examples in PHP,
but a language-agnostic resource is good enough.
>
Thank you!

Can I assume you come from the world of LAN apps, or Client/Server? If so,
I can share some experience, which I hope may be of use.

Probably the most important thing is to identify the architectural
differences between web and your past experiences and to embrace them
thoroughly in your new designs.

For instance, consider statelessness. My background in desktop and C/S apps
made this incomprehensibl e to me at first glance. How could anything
possibly work with no memory of the last request? At first I began
investigating sessions and schemes for maintaining state with the idea in
mind of keeping my stateful mindset. Though I learned a lot, this did not
give me a working system. At some point it dawned that statelessness must
be embraced and worked into my entire mindset, at which point the code
flowed and the systems worked.

The same goes for the back button. You can't stop them from hitting it. A
desktop guy will attempt to prevent it by popping up a browser window with
no toolbars. But all such schemes can be defeated because the reality of
the web is that the user is in control of the client, so you have to
embrace that fact in your design and enforce your needs in other ways.

Same goes for input. You can't control what the user sends, they can send
any kind of malicious code imaginable, so you have to code that assumption
in.

Anyway, that's my experince, hope it helps in some small way.

And good luck! Come on in, the water's fine!


--
Kenneth Downs
Secure Data Software, Inc.
(Ken)nneth@(Sec )ure(Dat)a(.com )

[Vincent Delporte]

Re: Traps and pitfalls when writing web apps?

On Sat, 29 Jul 2006 09:57:37 -0400, Kenneth Downs
<knode.wants.th is@see.sigblock wrote:

>Probably the most important thing is to identify the architectural
>differences between web and your past experiences and to embrace them
>thoroughly in your new designs.

Thanks for the input. Considering how different the two environments
are, I'm suprised not to have found a book, or at least one with a
good chapter that would spell out the differences, and list the issues
peculiar to web apps that desktop developers don't have to deal with.

Unless someone can recommend an application server for PHP, I'll go
next door and read up on TurboGears :-)

[Ivan Marsh]

Re: Traps and pitfalls when writing web apps?

On Sat, 29 Jul 2006 00:16:15 +0200, Vincent Delporte wrote:

On Fri, 28 Jul 2006 14:51:36 -0500, Ivan Marsh <annoyed@you.no wwrote:

>>The number one thing is understanding the difference between client-side
>>and server-side.

>
With AJAX, there's no such thing ;-)

Uh... that's so incorrect I doesn't even deserve an answer.

--
The USA Patriot Act is the most unpatriotic act in American history.
Feingold-Obama '08 - Because the Constitution isn't history,
It's the law.