In Rails I have a form with text fields inside it. When I click on one of them I want to set session[:something]. Is this possible?
Yes, by making an Ajax call back to the server.
What's the purpose of setting the session here?
Are you trying to pass some information back to the server?
If yes, then you can add hidden field(s) within the form, that you can set programmatically when you respond to the click. The data within these fields will then be POSTed back to the server when the form is submitted.
If not, then you can just use cookies. In which case you can use something like http://plugins.jquery.com/project/Cookie or http://pastie.org/1986824 to work with cookies. Note that cookies are also available on the server side (but are not meant to be for storing large amounts of data).
If you need to pass back information to the server immediately, then use an AJAX call. Some examples are available here (using jQuery): http://net.tutsplus.com/tutorials/javascript-ajax/5-ways-to-make-ajax-calls-with-jquery/.
Related
I have a regular text input field, whose value is submitted via AJAX. After I migrate away from this page, and hit Back button, I can still see the value of the field there.
My questions are:
Does most of modern browsers support this user-entered values?
How can I remove the persisted value using Rails?
Thank you.
Your browser is remembering the form input values and displaying them when you go back. This likely doesn't have anything to do with Rails*.
You can't really do anything via Ruby/Rails code to change this behavior, but you can do it with JavaScript. Here's a random SO question that covers it: Reset form on Back button.
I'm not sure if there's a perfect way to handle this in every browser. Also note that many users would prefer that the browser keep the form values they've entered.
Note: I only qualify with "likely" because it is possible to write an app that explicitly remembers form values and restores them when the page is visited again, but by default, Rails isn't going to do that. It'd involve a fair bit of Rails and JavaScript code.
Does most of modern browsers support this user-entered values?
Yes, I believe they all support it to various degrees
How can I remove the persisted value using Rails?
This is a client side issue, not a Rails issue. You could use javascript to clear the input fields
A similar question and answer: Clear all fields in a form upon going back with browser back button
BFCache? https://developer.mozilla.org/en-US/docs/Working_with_BFCache
I'd like to make a button on a view page that changes an attribute in my database. I know how to do it via a form (but we don't want to do that) and I have used a convoluted ajax method to do it (which is just overly complicated), but it seems like there has got to be a better way.
Nope (to a better way).
Q: How do you change a value in the database?
A: You have to send a[n] HTTP request to your server.
What are your options for sending HTTP requests to a server?
Submitting a form and having the server respond with a new view.
An asynchronous Javascript call with either XML or JSON (AJAX or AJAS)
You could write your own Javascript to do the "AJAX", or your would just use what's already out there.
I have a pretty extensive form on one of my rails sites and I was wondering if its possible to dynamically save the form for every onchange input. What I'm trying to prevent is users taking the time to fill the form out and then lose all their changes because of a connectivity issue or something stupid like that...
Any suggestions? Basically, I don't want the form to have to be submitted at all. I just want the form to save like a preference would in an Mac OS X (no apply or save button it just saves).
using rails 3...thanks!
The strain that would put on your server and DB would be several orders of magnitude higher than a more traditional approach. I also agree with Kyle that I would be very confused about the lack of submit button. At the very least, you'll need to notify users each time data is sent to the server and saved successfully, otherwise they'll have no idea why you aren't asking them to save.
Also, think about all the overhead. With every keystroke the user will have to initiate a connection, send their HTTP headers, cookies, the contents of the form, etc.
Have you considered an autosave feature instead? Maybe save the form every 2 minutes if changes have been made, and then put a submit button on the form as well? I think it would save you a great deal of pain, but get you almost the same benefit.
You could attach an ajax event to each input losing focus that would call the Controllers update method.
Most users would be surprised by this behavior though because it isn't the expected behavior of a web site.
If you use AJAX to call update, then here are a few things that might help: jQuery's serialize() function can help gather the form data into a post request without having to call the forms submit action. Using save(:validate => false) will bypass validation if you are saving drafts and want to skip validation until the final save.
I can set javascript variables.. but can I retrieve them? if so. how?
I think what you really asking how you can retrieve client-side state, right? The process of "setting" a variable is actually downloading code into the browser which runs and has that side-effect. To get state back from the browser, be that Javascript variables or DOM element values, requires the opposite, i.e. to upload something.
What you most likely want is do XHR requests within your Javascript back to the server to transmit the required state. Make sense?
My application (Asp.Net MVC) has great interaction with the user interface (jQuery/js). For example, setting various searches charts, moving the gadgets on the screen and more .. I of course want to keep all data for each user. So that data will be available from any page in the Dumaine and the user will accepts his preferences.
Now I keep all data in a cookie because it did not seem logical asynchronous access to the server each time the user changes something and thet happens a lot.When the user logout from the application I save the cookie to the database.
The Q is how to save the settings back to the db - from the client to the server.
because the are a lot of interactin that I want to record.
example scanrios: closing widget,moving widget,resizing menues, ordering columens..
I want to record that actions. if I will fire ajax saving rutine for each action
ןt will be too cumbersome. Maybe I have no choice..
Maybe I should run an asynchronous saving all of a certain interval seconds.
The problem is the cookie becomes very large. The thought that this huge cookie is attached to each server request makes me feel that my attitude is wrong.
Another problem cookies have size limit. It varies from your browser but I definitely have been close to the border - my cookie easily become 4kb
Is there another solution?
Without knowing your code, have you considered storing the users preferences in a/your database. A UserPreference table with columns for various settings is a possibility.
You could update it via AJAX/JSON if you had a 'Save Preferences' option, or just update it on postback.
EDIT 1: After thinking about it, I think having an explicit 'save preferences' button would be beneficial and practical.
Somewhere on your page, where the use edits the things that generate the cookie, put an button called save, then hook up a jQuery click handler. On click, build a CSV string or another method of storing the preferences for posting back to the server, then use $.post to send it back to an action method in a controller.
Once there, store it in the database somehow (up to you exactly how), then return a JSON array with a success attribute, to denote whether the preference storing was successful.
When the page is loading, get the preferences out of the database and perform you manipulation.
Another solution would be to store the user preferences into the session and write some server side logic (like action filter) that would write those preferences as JSON encoded string on each page (in a script tag towards the end of the markup) making them available to client scripts.