A Simple Grails Controller for File Management
Using Grails as a CMS, often times you want your users to add and remove files to a page similar to the way assets are attached to a page in the Confluence Wiki. I recently had to write a controller to handle files upload and download, and thought it might be interesting to share this since it is done so often in the Grails world.
Download the controller : FileResourceController.groovy
Download the view : list.gsp
Download complete sample app : uploader.zip
( to run: install grails. Invoke grails run-app. Navigate to http://localhost:8080 )
Usage- copy the list.gsp into your grails-app/views/fileResource/ directory, and your controller into grails-app/controllers
Config- Define a variable called images.location in conf/config.groovy
There are three methods in the controller:
- list -> gets a list of files = File.list()
- upload -> uploads a file chosen by the user
- delete -> removes chosen file = File.delete()
There are some choices made in the views
- The path to the file was written into a textarea to facilitate copy and paste.
- The views preview in a new window using HTML links to maximize cross browser compatibility.
- File upload goes first, since we don’t know how many items are in this list.
What’s could be improved?
- A more robust solution would integrate both a hierarchical directory structure or allow you to navigate up and down directories or specify an initial directory.
- Version control for files would be nice, similar to the grails.org wiki.
- Ideally, updates to this list would be AJAX based so you can include this page into a modalbox
- Pagination and sorting of files based on file properties.
Reference -
Neat. I might integrate this into a future version of grails.org to provide better support for files uploads
Graeme Rocher
November 26, 2008 at 4:44 am
Hi,
I get the following error just when I try to upload a file! Not sure if it’s because I’m running on a Mac?
Message: No signature of method: org.mortbay.jetty.Request.getFile() is applicable for argument types: (java.lang.String) values: {“fileUpload”}
Caused by: groovy.lang.MissingMethodException: No signature of method: org.mortbay.jetty.Request.getFile() is applicable for argument types: (java.lang.String) values: {“fileUpload”}
Class: FileResourceController
At Line: [29]
Code Snippet:
29: def f = request.getFile(‘fileUpload’)
30: if(!f.empty) {
Also, I don’t see a the styled version of the upload page!
Regards,
Carl
Carl
November 26, 2008 at 6:05 am
Hi Carl, I fixed the style issue but am able to upload perfectly. This is on Grails 1.0.4
Tomas Lin
November 26, 2008 at 11:22 am
Thanks Thomas – That did the trick!
Thanks
Carl
November 26, 2008 at 12:18 pm
[...] ตัวอย่างนี้ใช้ controller ตัวเดียวกับ view เป็น .gsp อีกไฟล์สร้างตัวจัดการไฟล์อย่างง่ายที่ upload, ดูและลบไฟล์ได้ มีคำอธิบายและตัวอย่าง application ที่พร้อมรันไว้บนหน้าเวบแล้วครับ [...]
เกรลส์ หกสิบหก » สร้างตัวจัดการไฟล์ง่าย ๆ ด้วยเกรลส์
November 29, 2008 at 9:24 pm
Hi,
I just playing around with file upload, grails and photos in facebook through flex.
First time i upload a file (or many files at once) it works perfectly, but when i try to upload another file(s), almost always, i get an exception
“[105132] errors.GrailsExceptionResolver
java.lang.NullPointerException
at java.net.URLDecoder.decode(URLDecoder.java:119)”, that fires an error on the client (Flex). And i have another problem with this, sometimes i choose a file (after i’ve uploaded some) new files (or requests) come with old data, i mean, old file.
I’ve read about new flash security policy and they say it’s just about writting a crossdomain.xml file at server. But i’ve tried everything and nothing seems to work.
I am sure it is not a grails problem. Tell me if you want to see some code, grails or flex one.
Thank you very much. Greetings from Cali, Colombia
Jonathan
December 30, 2008 at 2:43 pm
I got the same error as Carl (No signature of method: org.mortbay.jetty.Request.getFile() is applicable for argument types: (java.lang.String) values: {”fileUpload”}) until I added action=”upload” to the File Upload form in list.gsp, like so:
Anon Omas
February 19, 2009 at 11:31 am