I understand that Scalatra is a lightweight framework. However, I'm wondering if there are any tricks for managing small amounts of state. I have a form with a textarea and a few checkboxes. For example, suppose the textarea contains a math equation and the checkboxes some additional options. When I submit (method=POST), I would like to display a result beneath the form, but maintain the same options (same text in the textarea, same checkboxes checked).
Is there a good way to accomplish this? Or do I need to manually set the values when generating the HTML? I'm presently generating HTML using Jade.
Do it server side with a resource returning JSON, and call it dynamically using JavaScript XHR.
No need of state! Go away Evil State!
EDIT
~A bit more explanation~
You create a webservice that take computation parameter as input (using ?= in url with GET, or better using JSON payload with POST), then the service do the computation and return a JSON representation of the result
You call that scalatra webservice using AJAX from your web application and you update the content of the webpage using the JSON result returned by the web server
If you don't already know much about AJAX, read tutorials and I think you will understand better what I mean. You can too search for example of Scalatra resource that return JSON representation (using lift-json i.e.)
As a side note, you can take a look at Bowler: http://www.bowlerframework.org
which make REST development on scalatra easier.
Related
I was browsing the typo3 core Forms framework documentation but with no relevant answer to my requirements which are:
The form has to be displayed in a frontend overlay.
The filling process involves multiple steps where the user would be able to go back and forth.
The form fields must still be editable by a redactor.
I'm not sure about how the form framework behaves, so far I remember I think that multiple steps are configurable from the backend module but I don't know if it sends request to the controller after each step or if it sends everything only on submit.
I have an idea about how to implement it though, it's based on this question how to get a typo3 form framework html via ajax. Which would just let me provide the whole html content to the frontender and let him split the whole form into steps. The separation would be based on the addition of some special tags via the editor that would surround the fields you want in each step.
What do you think about that approach?
The form framework proceeds each form step seperately. So without developing your own form runtime, you have to keep proceeding every step seperate.
I see two possibilities:
1. Send each form step from frontend to the form controller and replace the response (html form) in the frontend.
That is the fast and easy way, as you use the existing form runtime.
Prepare a page which returns the rendered form as html
Fetch this page by JavaScript
Send the form data back to the given form action
The form controller proceeds the form with all its validators, rules and finishers and returns the next step, previous step, the current step with existing errors or the finishers response on success
Replace your form in the frontend with the already rendered html response of the form framework
The advantage of this way: Less effort and you can rely on the already existing validators, as you get an already validated response.
The disadvantage of this way --> it is more difficult to implement frontend validation, as you have a mix between frontend and server side validation.
2. Make the form framework kind of headless and work json based
In my opinion the better approach, but with a lot more effort to take.
You have to extend / overwrite the controller and the form runtime. This allows you more flexibility in handling the form by JavaScript and e.g. return the errors in a json object. It makes life easier when you want the form render and handle with a JS framework like react or vue.
To your question:
What do you think about that approach?
If I got it right, you want to keep ONE form step in the backend, but let the editor divide this form step into multiple steps by adding tags? You can try, but I don't see any real advantage in keeping the original form steps and proceed every step by sending the step to the controller and handle the response (like mentioned in 1.)
Summary:
In the past, I was thinking a lot about handling forms by JavaScript and came to the conclusion:
Keep the form framework's behaviour completely untouched with server side processing or make it frontend driven, with an own runtime. All mixtures between client and server side rendering will sooner or later run into bigger problems or at least a high effort. The form framework is pretty complex with a lot of possibilities, hook driven behaviour, etc. From my experience, you have to know it pretty good to develop without loosing control. In smaller projects with just one or two basic forms, I would try to avoid special cases with lots of JS. In bigger projects (with more budget), I would definitely go with my second mentioned approach (currently, I'm developing vue.js based rendering and handling of the form frontend). But these are just my five cents...
Im a relative newcomer to GWT.
Im working on a GWT application, where I have a lot of table data that is to be displayed on a page and a redirect to a different service which happens when I click on each cell's data. Currently what is happening is that the entire HTML(with all of the cells' hyperlinks) is being created on the server side and returned as a big string which is rendered on the client side. As you can imagine, it doesnt scale well. I need to make this redirect more dynamic. Can anyone suggest how I could link the DOM elements with GWT code to make this happen?
Regards
In GWT there is Ui Binder
Declare your all ui on client side and hit the server only for the valuable data.
Browsers are better at building DOM structures by cramming big strings of HTML into innerHTML attributes than by a bunch of API calls. UiBinder naturally takes advantage of this, and the result is that the most pleasant way to build your app is also the best way to build it.
So avoid passing html through the wire.
I am trying out the Lift web framework, but I am having a hard time understanding a basic aspect.
I have lift 2.5 M4 running on my localhost:8080. How can I make a CURL request with some parameters, for instance localhost:8080?category=apples&name=flowers, get those paremeters inside Scala, perform a Mongo query based on those paremeters and display JSON output for an Ajax client?
A very basic example of creating a page and getting the request header and paremeters would be awesome.
The page must be a REST service type. Which means it's not using Lift's templating system to generate the buttons etc, as the Lift Cookbook examples illustrate.
There is an example at Simply Lift, it should work and give you a JSON / XNK output without involving template system.
If you need get the parameter in your callback, just use net.liftweb.http.S.param(name), it will give you a Box[String], where holds the parameter if it exists.
Alright, so a better title here may have been "Progressive Enhancement with REST in CakePHP", but at least now I'll know you didn't read the question if your answer just refers to the difference between the two ;)
I'm pretty familiar with REST and how to integrate it with CakePHP, but I'm not 100% on board with how to still maintain a conventionally functioning website. Using Router::mapResources sounds like a great idea, but this creates a problem with maintaining the "gracefully degradation" version of the site, because both POST requests to /resource/ AND GET requests for /resource/add will route to the same action (add). Clearly I'll want this action to return a JSON object if they're using the REST api, but if they're using the degraded version of the site (no JS perhaps), it should be a add form, right?
What's the best way to deal with this. Do you route your REST requests to other action names using Router::resourceMap()? Do you do that crazy hack I saw to have the /api/ prefix part of the resourceMap so you can use api_action functions? Do you have the actions handle both REST and conventional requests via checking isAjax()? If so, how do you ensure that you can rely on the browser to properly support the other two request types?
I've searched around quite a bit but haven't found anything about how to keep conventional requests available in Cake along side REST, so if anyone has any advice or experience, I'd love to hear it!
CakePHP uses extension routing as well, via Router::parseExtension() so;
/test/action will render views/test/action.ctp
/test/action.html also
/test/action.json will render views/test/json/action.ctp
/test/action.xml will render views/test/xml/action.ctp
If all views are designed to handle the same data as set by your controller, you'll be able to show a regular HTML form and handle the posted data the same way as you'd handle the AJAX request.
You'll probably might have to add checks if any data is posted/submitted inside the /add, /edit, /delete actions to prevent items being deleted without a form being posted (haven't tested that though, it might be that cake blocks these urls if mapresources is set for the controller)
REST in CakePHP:
http://book.cakephp.org/2.0/en/development/rest.html
(Extension) Routing
http://book.cakephp.org/2.0/en/development/routing.html#file-extensions
I am working on a restaurant web portal which will send periodic emails to the registered users such as changes in menu, discounts and offers, birthday wishes etc.
Here is how I am doing it-
I create a JSP page with the HTML formatting. This page accepts certain parameters that will customize the page.
The MailDaemon scans the db and upon a certain trigger will make a GET request to the JSP.
The returned JSP represents the final mail content which is then sent using the JavaMail API.
My questions are these -
Do I really need to make a GET request? Or can I obtain the JSP result directly in my Daemon class?
Does my approach have any drawbacks? Any better solutions (architecturally speaking)
Any other templating solutions for the job?
It's possible to buffer a response from your JSP using javax.servlet.RequestDispatcher#include by wrapping original response in javax.servlet.ServletResponseWrapper (in case your MailDaemon is a servlet)
Your approach is OK. Though it'll be easier to leverage another templating engine.
Apache Velocity or FreeMarker. These two are not tied to web, so you can easily use them without servlet container.
If I understand correctly, you're using the JSP as a templating engine to generate the body of an HTML email. If you want to keep using JSPs for that, I don't think there's a better solution than making a GET request to get the generated HTML.
But you could also use an embeddable templating engine like Velocity or FreeMarker to generate the HTML to a String, directly from the mail daemon.