I am currently working on a GWT screen which has a requirement of browsing GWT file once but submitting it to server many times.
But in GWT upload after clicking on submit. or even submitting using singleUploader.submit() method. File browsed by FileInputType get cleared.
Can you suggest any method to upload single file many times using gwt-upload?
Not sure if it is possible. I would try to use https://developer.mozilla.org/en/docs/Web/API/XMLHttpRequest/Using_XMLHttpRequest
and would create (using native javascript) two instances of XmlHttpRequest and would try to send them both.
The anticipated problem here is that input element on the page would receive incoming events as a result of the upload process (loadstart, progress, etc). I am in doubt that it can properly handle two parallel flows of those events successfully.
Another way is to try to send the upload requests consequently, but then you will have to generate second form submit. Which is not trivial, and browsers do not support that on the high level.
Related
Have a requirement that when user is uploading a file it should work in a following manner
1)File upload dialog (in browser) is presented to the user. User picks a file.
2) Application should load only first x number of records (e.g. lets say total # of records are 100 then get first 10) and user will have a chance to do visual review of records (read only view).
3)User then decides one of two things : "Click on Submit" which will take in all the data and streams to the server, Or if s/he click on "Next" s/he can review next 10 records etc.
Is Scalaz-stream a good fit as a over all solution and in particular for doing 2) and 3) from above? To get only partial data and pause the stream then continue, consume, and repeating the process?
No, scalaz-stream is not a good idea. The Play! framework has its own framework with the Enumerator, Enumeratee, and Iteratee classes which can be used for asynchronous processing of streams, and the file upload code is already built to use it.
You have two options:
One, use HTML5 and front-end Javascript to get access to the file. This will only work in the newest browsers. This is the only option if you don't want any of the file uploaded until the user chooses "Submit".
Two, incrementally parse the upload as it comes to the server using the Enumerator framework, and respond over long-polling AJAX/Comet/Websocket to the front-end Javascript with a subset of records as they are parsed. The Iteratee that is parsing the incoming upload will have to pause and wait for further input from the front-end. This solution would be complex and would suffer from issues with the browser timing out.
Neither of these are a very good idea. It would be much simpler to have the entire file upload all at once, have the parsed records fed back to the front-end afterwards, and have the "Submit" button actually function as a "Save" button to tell the server to keep the received upload. Unless you are shoving 100 MiB+ Excel files up a mobile connection, this is likely the easiest and most compatible solution.
We have a GWT based thick client like web application. The application is considerably large and has some initial load time.
We would like to send the users of our application e-mail messages with href links that would open up a specific asset in our application. Well this of course has the effect that clicking the link opens up the application again, reloads it which we would like to avoid. Ideally we would like the href link to just signal our application/web page somehow so that we could pick up the event in our application and react to it.
Any ideas how we should approach this or is this even possible ?
Thanks!
You need to use a GWT Hyperlink which is a widget that serves as an "internal" hyperlink. That is, it is a link to another state of the running application. When clicked, it will create a new history frame using History.newItem(java.lang.String), but without reloading the page.
If you are not already using it, information is here on GWT's History mechanism
There seems not to be any elegant solution to send an event from a link to an existing browser window. Few solutions I have encountered this far:
a) Implement a cookie polling solution for the application to poll if a cookie exists or changes. The link points to our server which just sets the cookie and this way informs the running app about the event. Some tricky handling should be implemented with some kind of 2-way protocol between the returned temporary page from server to handle the situation where the application is not (yet) running.
b) The same approach as in solution a) but use html5 local storage for communication. This way the poller is not needed as the local storage fires an event when content changes. This would be a possible solution but is not for me as we have to support older browsers without local storage support.
c) A long polling ajax or a web socket for delivering events from the server to the client. A solution but seems overkill and might require a modern browser for atleast web sockets.
I have the following situation. We are using Zend Framework to create a web application that is communicating with it's database through REST services.
The problem I'm facing is that when a user tries to upload a big video file for example, the service is taking some time (sometimes a few minutes) to receive the request (which is also sending the video file encoded with base64_encode PHP function.) and returns the response for successful save or error.
My idea is to track how much of the data is sent and show the user a JS progress bar, which will be useful in these cases.
Does anyone have an idea, how I can track how much of the data is sent through the service and based on this I'll be able to show a progress bar?
Zend provides progress bar functionalities that might be paired with some javascript/jquery client.
You will easily find some example implementations like this one:
https://github.com/marcinwol/zfupload
However I don't think that REST services are the best solution for uploading videos as base64 encoding will make files bigger and slower to upload.
Check out Zend_File_Transfer that might be better suited to your needs:
http://framework.zend.com/manual/1.12/en/zend.file.transfer.introduction.html
Is there any provision in which i can limit my file upload to some limt ?
I'm using FileUploadField in my GWT screen.
Is there any way i can apply some check that only allows me to upload file max. upto 10MB only ?
TIA !
That is the job of the server. Javascript (and thus abstractions of Javascript such as GWT) are not allowed access to the file being uploaded. The server side should check the file side and throw an exception.
According to http://www.artofsolving.com/node/50 finding the error client side is tricky. You have to actually parse the html results in the iframe used for the upload in the onSubmitComplete event.
As the above answer stated It is not able to be done due to security. It is possible via ActiveX but I am in no way recommending that.
So you can not have a way to check it front end but you could make it seem like it.
Your servlet in this instance would use a push technology such as Comet to send the status of that file such as too big or completed back to the UI.
I want to create an application which will will be a webapp. I want to collect the data from the user, send it to a server where the computation will take place, and have the result displayed on the iPhone screen. The server normally takes results from a regular webpage via text fields and computes it and displays the result on the webpage. I just want the send the data via iPhone. Navigating my iPhone safari to the webpage is NOT an option, as the webpage is not optimized. So I how do I send data to the server, make it compute the results and have the results displayed on my iPhone?
Thank you.
Regards
EDIT:
I have no control over the server. Imagine my case to be as follows: The user enters a word, the word is sent by the iPhone to a Google server, the server compiles the search results and sends it back to my iPhone, and then the iPhone displays this result on the screen.Any more suggestions?
You might consider using ASIHTTPRequest/ASIFormDataRequest if you want to submit form data to your existing web page using form fields (per your description.)
In general I find ASIHTTPRequest friendlier to use than NSURLConnection / NSURLRequest.
http://allseeing-i.com/ASIHTTPRequest/
The most straightforward way is to use NSMutableURLRequest to create the GET or POST request, and then NSURLConnection to (asynchronously) send the data and receive the result. You could also use any number of third-party libraries to do the same thing.
As for the server side of things, you would have it accept a GET or POST just as you would with a web-based app, and output data in an appropriate format.
As for the output format that will be parsed by your app: With the standard classes, you can easily parse plist data and (with a little more work) XML; third-party libraries can be found to parse json and many other formats, if you so desire.