Uploading an avatar to my profile in grails error - grails

Question

I am new to grails and developing a web application such that a user updates profile details along with an avatar. I have a user controller that contains the logic to upload and save the avatar image. Unfortunately after choosing the avatar then upload, I get the this error which has troubled me for days:
No signature of method: eafya.User.current() is applicable for argument types: (grails.web.servlet.mvc.GrailsHttpSession) values: [Session Content: org.grails.FLASH_SCOPE = org.grails.web.servlet.GrailsFlashScope#d7b602 loggedOnUser = eafya.Patient : 1 messages = [] loginAudit = eafya.LoginAudit : 19 ] Possible solutions: count(), create(), ident(), collect(), insert(), collect(groovy.lang.Closure)
here is the controller:
package eafya
class UserController {
def current(){}
def select_avatar(){
}
def upload_avatar() {
def user = User.current(session) // or however you select the current user
// Get the avatar file from the multi-part request
def f = request.getFile('avatar')
// List of OK mime-types
def okcontents = ['image/png', 'image/jpeg', 'image/gif']
if (! okcontents.contains(f.getContentType())) {
flash.message = "Avatar must be one of: ${okcontents}"
render(view:'select_avatar', model:[user:user])
return;
}
// Save the image and mime type
user.avatar = f.getBytes()
user.avatarType = f.getContentType()
log.info("File uploaded: " + user.avatarType)
// Validation works, will check if the image is too big
if (!user.save()) {
render(view:'select_avatar', model:[user:user])
return;
}
flash.message = "Avatar (${user.avatarType}, ${user.avatar.size()} bytes) uploaded."
redirect(action:'show')
}
def avatar_image() {
def avatarUser = User.get(params.id)
if (!avatarUser || !avatarUser.avatar || !avatarUser.avatarType) {
response.sendError(404)
return;
}
response.setContentType(avatarUser.avatarType)
response.setContentLength(avatarUser.avatar.size())
OutputStream out = response.getOutputStream();
out.write(avatarUser.avatar);
out.close();
}
}