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I should have been more clear, sorry. Yes, validation always needs to be done on the server side. What I'm wondering is if tools exist for automatically gener

by akamaka 17y ago

I should have been more clear, sorry. Yes, validation always needs to be done on the server side. What I'm wondering is if tools exist for automatically generating the client-side validation from the same rules that have been specified on the server side. If one were to use the JQuery-based tool that the article submitter created, you'd have double the work, and making changes would risk introducing inconsistancies.

apsurd 17y ago
I think most of us just accept "double the work" because it's better for the user. Instant error/success messages skyrocket the usability of an app, and as mentioned here before, yslow tells us that app speed is frequently relative to front-end perception rather than actual server-side bottlenecks. I.E. a website that instantly responds to your input is "faster" than one than doesn't, even if its doing twice the work. Most validation is just a bunch of regex, so you can minimize inconsistencies by making sure the expressions are equivalent.
roryokane 17y ago
Yes, there is at least one tool that does this. There is a Ruby on Rails plugin called Client-Side Validation. It generates client-side Javascript validation based on the existing validation in the model, which the server already checks against. You can find it here: http://agilewebdevelopment.com/plugins/client_side_validation http://agilewebdevelopment.com/plugins/client_side_validatio.... I haven't tried it myself, so I can't vouch for how well it works. There also may be other, newer libraries for doing this out there. I certainly agree that elimination of this repetition would be very helpful when developing websites. If the code can be generated automatically for you, there are very few situations where you wouldn't want client-side as well as server-side validation. (Some of those few situations might include expecting the user to have a computer too slow for Javascript or being unable to expose the validation method to the user for security reasons.)
- akamaka 17y ago
  Thanks for pointing me to this plugin.
trezor 17y ago
Regular ASP.Net gives you this trough server-side validation controls, which is up to you to embed in your forms. This generates client-side Javascript with visual feedback for the user, where you are to some extent in control how the results will look. If you tune up your ASP.Net to go include Enterprise Library you can use simple "proxy validation controls" which infers validation rules from attributes/annotations added to your base entity-classes. This again bleeds to the client-side allowing you to set validation rules once and only once. Even programmatic violation of these rules will result in errors. While rather enterprisey to work with, it is rather neat on a technical level. I'd be surprised if you can't do the same with Java. If you are however stuck with some ghetto PHP framework chances are yes, you will have to double or tripple your validation-logic because the language is simply too lacking to allow for complex runtime reflection based auto-generated sub-classes based on class metadata.
- akamaka 17y ago
  Thanks for the helpful response, I haven't worked with ASP.net, and wasn't aware of this!

by akamaka 17y ago

apsurd 17y ago

I think most of us just accept "double the work" because it's better for the user. Instant error/success messages skyrocket the usability of an app, and as mentioned here before, yslow tells us that app speed is frequently relative to front-end perception rather than actual server-side bottlenecks. I.E. a website that instantly responds to your input is "faster" than one than doesn't, even if its doing twice the work. Most validation is just a bunch of regex, so you can minimize inconsistencies by making sure the expressions are equivalent.

roryokane 17y ago

Yes, there is at least one tool that does this. There is a Ruby on Rails plugin called Client-Side Validation. It generates client-side Javascript validation based on the existing validation in the model, which the server already checks against. You can find it here: http://agilewebdevelopment.com/plugins/client_side_validation http://agilewebdevelopment.com/plugins/client_side_validatio.... I haven't tried it myself, so I can't vouch for how well it works. There also may be other, newer libraries for doing this out there. I certainly agree that elimination of this repetition would be very helpful when developing websites. If the code can be generated automatically for you, there are very few situations where you wouldn't want client-side as well as server-side validation. (Some of those few situations might include expecting the user to have a computer too slow for Javascript or being unable to expose the validation method to the user for security reasons.)

akamaka 17y ago
Thanks for pointing me to this plugin.

trezor 17y ago

Regular ASP.Net gives you this trough server-side validation controls, which is up to you to embed in your forms. This generates client-side Javascript with visual feedback for the user, where you are to some extent in control how the results will look. If you tune up your ASP.Net to go include Enterprise Library you can use simple "proxy validation controls" which infers validation rules from attributes/annotations added to your base entity-classes. This again bleeds to the client-side allowing you to set validation rules once and only once. Even programmatic violation of these rules will result in errors. While rather enterprisey to work with, it is rather neat on a technical level. I'd be surprised if you can't do the same with Java. If you are however stuck with some ghetto PHP framework chances are yes, you will have to double or tripple your validation-logic because the language is simply too lacking to allow for complex runtime reflection based auto-generated sub-classes based on class metadata.

akamaka 17y ago
Thanks for the helpful response, I haven't worked with ASP.net, and wasn't aware of this!