Is it possible to return a json response in a Grails webflow ?
I'm wondering why you would? Webflows are designed to be "wizards" where you run from page to page, finally exiting the Flow and persisting the results, or not.
You do realize you can hit non-Flow actions from WebFlow pages? If you're writing an Ajax action for use in your Flow page, you can "render as JSON" in the action, and call the action directly using remote calls from the gsp.
There are many use cases in which integrating Ajax with Spring WebFlow would be very handy. Unfortunately, the Spring WebFlow is doing a poor job with that regards.
The work around here is to render a GSP and append it to the section of the page you are doing the Ajax call. Remember to pass "_eventId" when you build your Ajax URL.
I understand it is a valid case to expect JSON.
Work around:
Create a .gsp view with following content, and render it. (Of course, pass json string along by flow.json = (model as JSON).toString() !)
<%
response.contentType = 'application/json'
response.outputStream << json.getBytes()
%>
Related
When I add things to the Session with Session::put() in my controller action, then that data is not available in my view, with Session::get() when doing AJAX request.
The same problem goes for the Former package, which I use for nice form building. It relies on passing some info via the Session, which is used to mark fields as valid/invalid. This functionality is also not working when using AJAX.
I set a view like always, in my View:
$this->layout->content = View::make('account.login')
For AJAX requests, I do NOT render the normal way with layout, but instead get the specific "content" section of the template and return it:
$this->layout->content->renderSections()['content']
When I do a "normal" request, then Session data works fine.
When I do an AJAX request, then Session data set in the controller DURING the AJAX call is ignored. Any Session data set BEFORE the AJAX call is available.
I'm wondering if Laravel has some issue with Session under AJAX calls, or with the the "renderSection()" method above?
I have checked all the obvious problems:
AJAX request uses the same session ID as non-AJAX request.
GET/POST verbs are used correctly etc.
Replicate:
In CONTROLLER action: Session:put('foo','bar');
In VIEW file (in the content part): Session:put('foo2','bar2');
In VIEW file (in the content part): var_dump(Session::get('foo','bar')); // Returns 'bar' in non-AJAX calls, but returns nothing for AJAX calls (!!!)
In VIEW file (in the content part): var_dump(Session::get('foo2')); // Returns 'bar2' in both AJAX and non-AJAX calls as expected.
It seems like the Session values set in the controller action ARE LOST when it renders the view. Therefore my question if this is 1) an AJAX vs. SESSION issue in Laravel, or 2) an Session vs. renderElement() problem that I am not aware of?
I had the same problem and just found a potential solution:
I found a similar problem relating to laravel 3. For the session to persist in an ajax call you need to return the response correctly.
return json_encode($response);
This is causing the problem. It's not it appears a valid response to enable the session to persist. Change it to:
return Response::json($response);
This enables the session to persist!
For some reason a normal form submit or call to the method allows the first one but ajax does not.
I've seen references elsewhere about echo statements in the method affecting the session - the return I suppose must behaving similar to an echo
This is the post that triggered the solution:
http://forumsarchive.laravel.io/viewtopic.php?id=1304
I am new to Django but i am advanced programmer in other frameworks.
What i intend to do:
Press a form button, triggering Javascript that fires a Ajax request which is processed by a Django View (creates a file) that return plain simple JSON data (the name of the file) - and that is appended as a link to a DOM-Element named 'downloads'.
What i achieved so far instead:
Press the button, triggering js that fires a ajax request which is process by a Django view (creates a file) that return the whole page appended as a duplicate to the DOM-Element named 'downloads' (instead of simple JSON data).
here is the extracted code from the corresponding Django view:
context = {
'filename': filename
}
data['filename'] = render_to_string(current_app+'/json_download_link.html', context)
return HttpResponse(json.dumps(data), content_type="application/json")
I tried several variants (like https://stackoverflow.com/a/2428119/850547), with and without RequestContext object; different rendering strats.. i am out of ideas now..
It seems to me that there is NO possibility to make ajax requests without using a template in the response.. :-/ (but i hope i am wrong)
But even then: Why is Django return the main template (with full DOM) that i have NOT passed to the context...
I just want JSON data - not more!
I hope my problem is understandable... if you need more informations let me know and i will add them.
EDIT:
for the upcoming questions - json_download_link.html looks like this:
Download
But i don't even want to use that!
corresponding jquery:
$.post(url, form_data)
.done(function(result){
$('#downloads').append(' Download CSV')
})
I don't understand your question. Of course you can make an Ajax request without using a template. If you don't want to use a template, don't use a template. If you just want to return JSON, then do that.
Without having any details of what's going wrong, I would imagine that your Ajax request is not hitting the view you think it is, but is going to the original full-page view. Try adding some logging in the view to see what's going on.
There is no need to return the full template. You can return parts of template and render/append them at the frontend.
A template can be as small as you want. For example this is a template:
name.html
<p>My name is {{name}}</p>
You can return only this template with json.dumps() and append it on the front end.
What is your json_download_link.html?
assuming example.csv is string
data ={}
data['filename'] = u'example.csv'
return HttpResponse(simplejson.dumps(data), content_type="application/json")
Is this what you are looking for?
I am very new to AJAX and I am stuck with a problem. I have a <div> in my JSP. I have another JSP that is included in the above JSP using <jsp:include>. The problem is that the included JSP does DB operations and it takes a lot of time to render. I want the former JSP to be loaded first and then latter JSP to be rendered in the DIV. I searched but couldn't understand how to resolve it. Basically, I want the former JSP to be displayed and then the latter to be displayed once it completes operations. Currently, the former JSP takes lots of time to load as the latter is included in the former JSP and will render only when the latter JSP has completed loading.
Appreciate your help. :)
I believe this is not the correct approach . The DB interaction part should be done by the DAO classes triggered by some Servlet . Using JSP for DB interactions is bad . Having said that your current problem can be solved by the below approach :
Remove all the DB operations from the JSP.
Keep a div inside your main JSP.
On load , trigger an AJAX call to a Servlet.
Servlet/DAO class performs the DB operations and returns back the result. Store the result in session if needed.
Inside the success handler of the AJAX request function , write a call back function which loads the other JSP file.
Check this answer Load a jsp page using AJAX load method.
The popular approach is to use javascript library such as jQuery and invoke the long-running operation using ajax
$.ajax('/longrunningop', {
type: 'POST',
data: 'a=1&b=2'}).done(function(data) {
// code to display data to div here..
});
Good practice is you code the long running operation to return JSON instead of JSP
I need to get response data (incuding html markup) on server and then replace them to anothe one and send to the client.
Is where the best way to do this?
Response.OutputStream is closed for reading.
So what can I use for reading data?
I need to get response data (incuding html markup) in controller
For obvious reasons that's not possible. The response HTML is generated when the view executes, at a much later stage after the controller action has finished executing.
If you want to modify the response HTML you could write a response filter.
I have a JSP page which has a form with an input text. When I submit, it goes to a servlet. The servlet processes and creates some objects and sets in request using request.setAttribute(). It then forwards to a page which has some custom JSP tags which use the objects set in servlet.
I want to replace this by Ajax. I have implemented it as follows:
First, the form is submitted through Ajax using POST, the objects which were set earlier using request.setAttribute() are converted to JSON string and sent as response. On success, there is another Ajax GET call to a JSP page which has my custom tags and the JSON string is passed as parameter. The response of this Ajax call is set inside a div.
But it are two Ajax requests. How can I make it a single Ajax request instead?
As per the comments, you just need to let the first request forward to the desired JSP instead of returning the JSON string which you in turn pass back to the JSP.
request.getRequestDispatcher("/WEB-INF/next.jsp?jsonstring=" + jsonstring).forward(request, response);