How to upload image on page using ajax in codeigniter? On form image needs to be uploaded then
user should fill further information. I try ajax but unable to figure out simplest way
http://net.tutsplus.com/tutorials/javascript-ajax/how-to-upload-files-with-codeigniter-and-ajax/
This is how I did it for the first time, easier than it might look and should work without too much problems.
Related
Im trying to upload multiple files by dropzone.js in my MVC Project. The files upload successfully but the problem: after upload files, the page reset and i cant see the results. I have almost searched all the related subjects in this site and the other examples. I see people want to learn how they can refresh page :) but i want to stop page after upload. The results preview disappear quickly. Thanks for any help.
After hours, i see its not about dropzone, its about mvc. Because of post data in mvc, if you save a file, modelstate change, then automatically redirect the previous action/view and the results disappear. So it seems like a page refresh. Anyway, its suggested to use PRG instead of POST. Or redirect another GET action after successfully upload.
I'm using a custom written auto uploader to import images from users to Amazon S3. I'm building up a parallel image library in my database, so I know what images I can access on S3 to not waste any http-requests.
However, my uploader sometimes throws errors (e.g. source image missing) and although I'm validating, I'm sometimes ending up with entries in my media table and no matching image on S3.
To correct these, I'm thinking of creating a cfthread/cfschedule which clears my image database from faulty entries. What I'm not sure is how to capture 404 responses. Right now I'm having this on a page:
<img src="#variables.imageSrc#" alt="#some alt#" title="#some title#" class="ui-li-thumb ui-corner-all" />
which tries to load the image and returns a 404 if not successful.
Question
How would I capture this 404? I don't want to put anything in the markup, so I assume this should go to onrequestend or another Coldfusion event being monitored in my application.cfc. If so, is there an easy way to identify image request, because I would not want to run a big routine on every applicationr request.
Thanks for insights!
EDIT:
I don't think running isDefined on every image before displaying it is feasable, because it will be a double request to S3 and there is a lot of images. I want to take the 404 and then clean up my database, so next time the image will not be accessed anymore.
If you don't want to use cfhttp and test each image like Matt suggested, why not trigger an ajax call from the browser using the onError handler of the img tag. Something like this but instead of showing a custom graphic, trigger your ajax to set your flag, or maybe even delete the image since it's happening invisible to the user. jQuery/JavaScript to replace broken images
More info on Image onerror Event
I'm curious to see how you would use isdefined on an image. From your code posted isdefined("variables.imageSrc") wouldn't help you much.
If you're running a scheduled task to do this, why not use cfhttp to perform a GET request on the image asset? You can then check the status code in the response to validate the file existence on the server, and then update the database accordingly.
I have a problem with images in my web app. let say I have a form where there are some text fields, dropdowns, upload ajax control for multiple image upload and button Save.
I know how to upload images and posting a form and saving everything to database but the problem is that I want to achieve the following user experience:
User can upload multiple images and browser after successful upload shows thumbnail (this I know how to do it)...the problem here is that I do not want to save images to db before button save is pressed. Is there any convinient how to save temporary images...I have tried temp table which after button is pressed, copies all images to image table but here is browser refresh problem that looses all the data and images stay in a temp table. Can you use a session for storing temporary images or any other way (I think session is not particulary good idea for such things.)
One easy way to achieve that is to use the HTML5 File API and display a thumbnail once the user selects a file to upload. You don't even need to waste bandwidth as everything happens on the client. Once the user submits the form, then the image will be uploaded to the server.
Another possibility is to use one of the gazillions of available AJAX upload controls such as Uploadify, Valums Ajax Upload, Uploadify, the jQuery form plugin, ... which will allow you to upload the file to the server using an AJAX request so that you can resize it there and return the resized image to the client that you could display the thumbnail on the client.
I've been trying to use the webimage helper in webmatrix to upload an image using ajax but its not clear to me how i can pass data to the webimage.getImageRequest("Image") method from the ajax post.This helper seems to retrieve its file upload data from the browser when the page form is posted.For me, i dont want to refresh the form...I just want ajax to handle process
The issue here isn't the WebHelper - uploaded files are not posted with ajax requests:
How can I upload files asynchronously?
So you're probably getting a file name, but no content. That thread above shows a few work arounds that should work fine with the WebHelper. I've also had pretty good luck with uploadify:
http://www.uploadify.com/
Happy Coding!
I am wanting to allow my user to upload an image, using a form. In the same form I want to display the image that has been uploaded. Is this is possible to do without actually submitting all the form?
Thanks
You could use any number of flash or AJAX image uploaders to accomplish this.