using grails and google app engine to store image as blob and the view dynamically

Question

I am trying to dynamically display an image that I am storing in the google datastore as a Blob. I am not getting any errors but I am getting a broken image on the page that I view.

Any help would be awesome!

I have the following code in my grails app

domain class has the following

@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
Long id

@Persistent
String siteName

@Persistent
String url

@Persistent
Blob img

@Persistent
String yourName

@Persistent
String yourURL

@Persistent
Date date

static constraints = {
    id( visible:false)
}

My save method in the controller has this

def save = {
    params.img = new Blob(params.imgfile.getBytes())
    def siteInfoInstance = new SiteInfo(params)
    if(!siteInfoInstance.hasErrors() ) {
        try{

            persistenceManager.makePersistent(siteInfoInstance)
        } finally{
            flash.message = "SiteInfo ${siteInfoInstance.id} created"
            redirect(action:show,id:siteInfoInstance.id)    
        }
    }

    render(view:'create',model:[siteInfoInstance:siteInfoInstance])

}

My view has the following

<img src="${createLink(controller:'siteInfoController', action:'showImage', id:fieldValue(bean:siteInfoInstance, field:'id'))}"></img>

and the method in my controller that it is calling to display a link to the image looks like this

def showImage = {

    def site =  SiteInfo.get(params.id)// get the record
    response.outputStream << site.img // write the image to the outputstream
    response.outputStream.flush()
}

Answer 1

are you getting back a correct byte[] from your binding? IIRC, grails has some problems with byte arrays and files on the app engine because it uses a file-based multipart resolver that is not kosher with the JRE blacklist.

Also try returning a content type on your response:

response.contentType = "image/png";