danielshiplett / jhipster_uploader

An example of how to get JHipster and ng-flow to play together.

README for uploader_example

Introduction

This application is to demonstrate how to connect ng-flow (the file uploader) to a JHipster-based application.

This example will implement a very simple file uploader resource/service to handle the required functions of the ng-flow client library. It will save all uploaded chunks/files into the src/main/webapp/assets directory.

Usage

Run the application with 'mvn spring-boot:run'

Go to the site.

Log in as user/user.

See the new Navbar item for 'Uploader' and click it.

Upload a file.

Description (or what you need to know)

The basic idea is that the ng-flow client will get a new flow identifier at the start of a flow. We have a function to handle this that returns a random UUID.

Next the client will test if a chunk is already uploaded. We return 502 if it hasn't. This is some of the weirdness with the HTTP codes that I haven't quite figured out yet. I think this could be handled better.

Assuming the test returns the 502 then the client will do a MultiPart POST with the data for the next chunk. We take this and save off the chunk.

We track which chunks we have received and which ones we haven't.

When the last chunk arrives we will merge them back into the original file and delete the chunks.

Client Setup

Beyond the bower installation, you will also need to include the 'flow' service in the Angular app.js file and add the addition flowFileProvider configuration section.

We are configured to only allow one file upload at a time.

We also specify the location of the unqiue identifier function.

Client Usage

See the app/uploader client code for how to use the ng-flow library. Basically just add the flow directives at the top.

You can also do fancy things like track the upload progress with a progress bar and display info about the upload after it is done.

Upload Domain Object

A simple object that tracks the original file name from the client along with expected chunks and file size.

Several things to note:

• LocalDate should really be LocalDateTime but there is no JHipster support
• Manually added List because there is no JHipster support
• ID is a String but we always put a UUID.toString there

UploadServiceImpl

The most basic I could think of was to save locally. A better implementation would put the file somewhere that they could be retrieved again. And probably not store them in the project path.

UploadResource

Basically just obeys the requirements for the flowJS library that underpins the ng-flow library.