[Hosting for a Webdesign Company]

I would suggest a VPS, they have all the power you need.  You can get a great managed VPS for $40 a month

 

http://www.webhostingtalk.com/showthread.php?t=1343484

[Is there a way to only allow access to site if user donated to you?]

The suggestion that @ginerjm has is a much better solution then what I about to suggest t a VERY simple method would be this.  If you plan to use paypal to collect the donation then...

 

Paypal has a listener that it calls after any payment (or donation) to your website is made.  Check out

 

https://developer.paypal.com/docs/classic/ipn/ht_ipn/

 

And to this php file a little code that will add the the donors email address to a dataase.  Now you have a database of all your donors and you can ask them to enter their email address to login (no password needed)

[Need an advice in web-app designing]

Can you tell me what you are confused about in particular?  

[BACK BUTTON FORM KEY ISSUE]

Like @guru said not she if what you are going is needed but I must say I like it.  I have never heard or thought of doing it but will now think it over.

 

Now for your issue.  even if you did not have your key idea the issue of the back button (reload) always has been a problem.  What I did to solve it was for any form post it is done in a window that delete itself after the post so the user can never click the back button as it is no longer there for that window.  Now you do not need to actually use a NEW window you can use a modal one.

[Need advice on a secure way to let users upload a profile picture.]

If you are going to only need the directory for just 1 image I agree with @guru but in the app I am working on for a dog rescue we store up to 10 pictures, all scanned documents for the dog such as rabies/adoption contracts so creating a directory for each dog made since.  I used the unique ID of the record not user input for the directory name (5 digits)

[Need an advice in web-app designing]

We now use ajax for any post that results in a database write. We take plan this year to take it one step further.  If there is more then 1 database write when we will do a ajax send for each write (i.e. step)

 

For example lets say you are asking for a credit card number and need to charge it.  

 

1. We would ajax send the credit card number and the server would update the database

2. Send the command to charge it

 

This way we solve an issue we have where if the reply never comes we do not know what processes completed.  This way if we get a reply from the step 1 but now reply from step 2 we now we need to only resend the command to charge again

 

What kind of app are you writing?

[curl error 7]

Sorry, I should have gave more information.  It is checking my own sites that are alive and not blocking my own IP.  Sometimes it makes it and sometime it does not.

 

It is not that it could not connect it says it did not connect due to "No buffer space available".

 

I did notice that if I run it as a cron job it fails much more often then if I call the url from by desktop computer.  When it runs as a cron job it runs as a user but when I call the url from my desktop it runs as apache

 

thanks

 

[curl error 7]

I get curl error 7 about 30% of the time.  The text for the error is

 

cURL error number: 7 - Error: Failed to connect to xxx.xxx.xxx.xxx No buffer space available

 

Any thoughts?