Grails 3 Loading Static Files

Question

I have a few PDF files in the assets folder of a Grails 3 application. I want to load them when the user clicks some button. i.e User clicks button "Get first book", and a grails controller looks for all files in the assets folder until it finds a match, and then returns the correct one.

Currently, I am loading the files by directly accessing the path. i.e. I am using an explicit aboslute path. According to this post, this is one of the advisable approaches. However, I want to load a file in grails by asking my application to get all assets in the asset folder, instead of using any paths.

My question then is, is it possible to get all files from the assets folder in a simple manner like we can get properties in the yml file (grailsApplication.config.someProperty)

Answer 1

this code makes something similar for me (however, my files are located outside of my project directory). Its a controller method, that receives the file name (id) and the filetype (filetype) and looks in a predefined directory. I think you just have to adapt your "serverLocation" and "contentLocation".

To get a list of the files, which you can pass to the view:

List listOfNewsletters = []

String contentLocation = grailsApplication.config.managedNewsletter.contentLocation;

File rootDirectory = new File(servletContext.getRealPath("/"));
File webappsDirectory = rootDirectory.getParentFile();
String serverLocation = webappsDirectory.getAbsolutePath();

serverLocation = serverLocation + contentLocation + "/";

File f = new File(serverLocation);

if (f.exists()) {
    f.eachFile() { File file ->
         listOfNewsletters.push([
              path: file.path,
              filename: file.name,
              filetype: "pdf"
         ])
     }
}

To deliver the file:

def openNewsletter() {
        if (params.id != null && params.filetype != null) {

            String pdf = (String) params.id + "." + (String) params.filetype;    

            String contentLocation = grailsApplication.config.managedNewsletter.contentLocation;

            File rootDirectory = new File(servletContext.getRealPath("/"));
            File webappsDirectory = rootDirectory.getParentFile();
            String serverLocation = webappsDirectory.getAbsolutePath();           

            serverLocation = serverLocation + contentLocation + "/";

            File pdfFile =new File(serverLocation + pdf);

            response.contentType  = 'application/pdf' // or whatever content type your resources are
            response.outputStream << pdfFile.getBytes()
            response.outputStream.flush()
        }
    }

Answer 2

Found the solution here: Grails : getting assets local storage path inside the controller

The following sample:

def assetResourceLocator

assetResourceLocator.findAssetForURI('file.jpg')?.getInputStream()?.bytes

worked fine for me.