Uploading file throws No signature of method exception (in getFile() method) - grails

Question

Im trying to upload a file, and store it in a file. This is the code in the GSP:
<g:form method="post" enctype="multipart/form-data" action="update">
<input type="file" name="cv" id="cv"/>
<g:actionSubmit action="upload" name="upload" value="Upload" />
</g:form>
In the Controller:
def upload(){
def f = request.getFile('cv')
InputStream file = f.inputStream
byte[] bytes = file.bytes
println('bytes: '+bytes)
}
As I say in the title, i got an exception here. Any help? Thanks.
EDIT (Full Stacktrace, by request):
Error 500: Internal Server Error
URI
/com.publidirecta.azafatas/azafataCertificada/index
Class
groovy.lang.MissingMethodException
Message
No signature of method:org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestWrapper.getFile() is applicable for argument types: (java.lang.String) values: [cv] Possible solutions: getXML(), getPart(java.lang.String), getAt(java.lang.String), getAt(java.lang.String), getLocale(), getJSON()
Around line 1158 of grails-app/controllers/com/publidirecta/AzafataCertificadaController.groovy
1155: def upload(){
1156: println("Acción upload. Params: "+params)
1157: Azafata aza=Azafata.findByUsername(params.user)
1158: def f = request.getFile('cv')
1159: InputStream file = f.inputStream
1160: byte[] bytes = file.bytes
1161: }
Trace
Line | Method
->> 1158 | upload in AzafataCertificadaController.groovy
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
| 886 | runTask in java.util.concurrent.ThreadPoolExecutor$Worker
| 908 | run . . in ''
^ 680 | run in java.lang.Thread

Answer 1

The problem is that your request is not treated as a MultiPartRequest. Do something like this:
MultipartRequest multipartRequest = request as MultipartRequest
if(multipartRequest){
MultipartFile attachmentFile = multipartRequest.getFile("attachment_file".toString())
if (attachmentFile) {
-- copy it ---
}
}