how to use MS Office with proprietary java back-end document system

Question

Currently I have a document system that launches documents in Star Office or LibreOffice in an iframe.

Moving to the future I ideally want to retain the document system

Answer 1

Well I had the same problem, so I actually wrote a quick PPT editor with Apache POI and SVG edit.. But then I switched to the Office Web Apps.. Here is quick implementation of the WOPI server, I am a Java guy so my .NET skills are quite horrible. Writing a servlet should be trivial.

Logic is simple:

Pass WOPISrc to the office web apps - this is basically the URL of your WOPI server with the file location in it. You can ignore access_token/access_token_ttl for now.

The Office Web Apps with hit the WOPISrc url with at least 2 requests:

1. It will be a meta data request, which is basically is a GET call to the WOPIsrc. You will create a WOPI (CheckFileInfo) object and send it back JSON encoded to the office web apps.
2. Now the Office Web Apps will request the file itself, it will append ( /contents ) to the end of the WOPIsrc. So just send it back in binary format.
3. (Optional) Office Web Apps will do a POST to the ( WOPISrc + "/contents") on save. You can grab the data from the POST and save to the disk.

Note: Word doesn't work :/ You can view only, for the edit you need to implement Cobalt protocol (FSSHTTP). I am somewhat researching this topic, but it will be easier to write in C# since you can grab a Cobalt assembly. Otherwise this protocols implements SOAP (FSSHTTP) with BASE64 encoded binary messages (FSSHTTPB)

Open the Office Web Apps with something like this:

http://OFFICEWEBAPPS.HOST/p/PowerPointFrame.aspx?PowerPointView=EditView&access_token=12345&WOPISrc=URLENCODED_URL_OF_THE_WOPI_SERVER

Like: http://WOPISERVER.HOST:2000/wopi/files/1.pptx

This will open 1.pptx in your c:\temp

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections;
using System.Runtime.Serialization;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using System.Web;
using System.IO;
using System.Runtime.Serialization.Json;

namespace WopiServerTutorial
{
    public class WopiServer
    {
        private HttpListener Listener;

        static void Main(string[] args)
        {
            WopiServer s = new WopiServer();
            s.Start();

            Console.WriteLine("A simple wopi webserver. Press a key to quit.");
            Console.ReadKey();

            s.Stop();
        }

        public void Start()
        {
            Listener = new HttpListener();
            Listener.Prefixes.Add(@"http://+:8080/");
            Listener.Start();
            Listener.BeginGetContext(ProcessRequest, Listener);
            Console.WriteLine(@"WopiServer Started");
        }

        public void Stop()
        {
            Listener.Stop();
        }

        private void ProcessRequest(IAsyncResult result)
        {
            HttpListener listener = (HttpListener)result.AsyncState;
            HttpListenerContext context = listener.EndGetContext(result);

            Console.WriteLine(@"Got a " + context.Request.HttpMethod  + " request for URL: " + context.Request.Url.PathAndQuery);
            var stringarr = context.Request.Url.AbsolutePath.Split('/');
            var rootDir = @"C:\\temp\\";

            if (stringarr.Length == 5 && context.Request.HttpMethod.Equals(@"GET"))
            {
                Console.WriteLine(@"Getting content for the file: " + rootDir + stringarr[3]);

                // get file's content
                var file = rootDir + stringarr[3];
                var stream = new FileStream(file, FileMode.Open);
                var fi = new FileInfo(file);

                context.Response.ContentType = @"application/octet-stream";
                context.Response.ContentLength64 = fi.Length;
                stream.CopyTo(context.Response.OutputStream);
                context.Response.Close();
            }
            //else if (stringarr.Length == 5 && context.Request.HttpMethod.Equals(@"POST"))
            //{
            //    // write
            //}
            else if (stringarr.Length == 4 && context.Request.HttpMethod.Equals(@"GET"))
            {
                Console.WriteLine(@"Getting metdata for the file: " + rootDir + stringarr[3]);
                var fi = new FileInfo(rootDir + stringarr[3]);

                CheckFileInfo cfi = new CheckFileInfo();
                cfi.AllowExternalMarketplace = false;
                cfi.BaseFileName = fi.Name;
                cfi.BreadcrumbBrandName = "";
                cfi.BreadcrumbBrandUrl = "";
                cfi.BreadcrumbDocName = "";
                cfi.BreadcrumbDocUrl = "";
                cfi.BreadcrumbFolderName = "";
                cfi.BreadcrumbFolderUrl = "";
                cfi.ClientUrl = "";
                cfi.CloseButtonClosesWindow = false;
                cfi.CloseUrl = "";
                cfi.DisableBrowserCachingOfUserContent = true;
                cfi.DisablePrint = true;
                cfi.DisableTranslation = true;
                cfi.DownloadUrl = "";
                cfi.FileUrl = "";
                cfi.FileSharingUrl = "";
                cfi.HostAuthenticationId = "s-1-5-21-3430578067-4192788304-1690859819-21774";
                cfi.HostEditUrl = "";
                cfi.HostEmbeddedEditUrl = "";
                cfi.HostEmbeddedViewUrl = "";
                cfi.HostName = @"SharePoint";
                cfi.HostNotes = @"HostBIEnabled";
                cfi.HostRestUrl = "";
                cfi.HostViewUrl = "";
                cfi.IrmPolicyDescription = "";
                cfi.IrmPolicyTitle = "";
                cfi.OwnerId = @"4257508bfe174aa28b461536d8b6b648";
                cfi.PresenceProvider = "AD";
                cfi.PresenceUserId = @"S-1-5-21-3430578067-4192788304-1690859819-21774";
                cfi.PrivacyUrl = "";
                cfi.ProtectInClient = false;
                cfi.ReadOnly = false;
                cfi.RestrictedWebViewOnly = false;
                cfi.SHA256 = "";
                cfi.SignoutUrl = "";
                cfi.Size = fi.Length;
                cfi.SupportsCoauth = false;
                cfi.SupportsCobalt = false;
                cfi.SupportsFolders = false;
                cfi.SupportsLocks = true;
                cfi.SupportsScenarioLinks = false;
                cfi.SupportsSecureStore = false;
                cfi.SupportsUpdate = true;
                cfi.TenantId = @"33b62539-8c5e-423c-aa3e-cc2a9fd796f2";
                cfi.TermsOfUseUrl = "";
                cfi.TimeZone = @"+0300#0000-11-00-01T02:00:00:0000#+0000#0000-03-00-02T02:00:00:0000#-0060";
                cfi.UserCanAttend = false;
                cfi.UserCanNotWriteRelative = false;
                cfi.UserCanPresent = false;
                cfi.UserCanWrite = true;
                cfi.UserFriendlyName = "";
                cfi.UserId = "";
                cfi.Version = @"%22%7B59CCD75F%2D0687%2D4F86%2DBBCF%2D059126640640%7D%2C1%22";
                cfi.WebEditingDisabled = false;

                // encode json
                var memoryStream = new MemoryStream();
                var json = new DataContractJsonSerializer(typeof(CheckFileInfo));
                json.WriteObject(memoryStream, cfi);
                memoryStream.Flush();
                memoryStream.Position = 0;
                StreamReader streamReader = new StreamReader(memoryStream);
                var jsonResponse = Encoding.UTF8.GetBytes(streamReader.ReadToEnd());

                context.Response.ContentType = @"application/json";
                context.Response.ContentLength64 = jsonResponse.Length;
                context.Response.OutputStream.Write(jsonResponse, 0, jsonResponse.Length);
                context.Response.Close();
            }
            else
            {
                byte[] buffer = Encoding.UTF8.GetBytes("");
                context.Response.ContentLength64 = buffer.Length;
                context.Response.ContentType = @"application/json";
                context.Response.OutputStream.Write(buffer, 0, buffer.Length);
                context.Response.OutputStream.Close();
            }

            Listener.BeginGetContext(ProcessRequest, Listener);
        }
    }

    [DataContract]
    public class CheckFileInfo
    {
        [DataMember]
        public bool AllowExternalMarketplace { get; set; }
        [DataMember]
        public string BaseFileName { get; set; }
        [DataMember]
        public string BreadcrumbBrandName { get; set; }
        [DataMember]
        public string BreadcrumbBrandUrl { get; set; }
        [DataMember]
        public string BreadcrumbDocName { get; set; }
        [DataMember]
        public string BreadcrumbDocUrl { get; set; }
        [DataMember]
        public string BreadcrumbFolderName { get; set; }
        [DataMember]
        public string BreadcrumbFolderUrl { get; set; }
        [DataMember]
        public string ClientUrl { get; set; }
        [DataMember]
        public bool CloseButtonClosesWindow { get; set; }
        [DataMember]
        public string CloseUrl { get; set; }
        [DataMember]
        public bool DisableBrowserCachingOfUserContent { get; set; }
        [DataMember]
        public bool DisablePrint { get; set; }
        [DataMember]
        public bool DisableTranslation { get; set; }
        [DataMember]
        public string DownloadUrl { get; set; }
        [DataMember]
        public string FileSharingUrl { get; set; }
        [DataMember]
        public string FileUrl { get; set; }
        [DataMember]
        public string HostAuthenticationId { get; set; }
        [DataMember]
        public string HostEditUrl { get; set; }
        [DataMember]
        public string HostEmbeddedEditUrl { get; set; }
        [DataMember]
        public string HostEmbeddedViewUrl { get; set; }
        [DataMember]
        public string HostName { get; set; }
        [DataMember]
        public string HostNotes { get; set; }
        [DataMember]
        public string HostRestUrl { get; set; }
        [DataMember]
        public string HostViewUrl { get; set; }
        [DataMember]
        public string IrmPolicyDescription { get; set; }
        [DataMember]
        public string IrmPolicyTitle { get; set; }
        [DataMember]
        public string OwnerId { get; set; }
        [DataMember]
        public string PresenceProvider { get; set; }
        [DataMember]
        public string PresenceUserId { get; set; }
        [DataMember]
        public string PrivacyUrl { get; set; }
        [DataMember]
        public bool ProtectInClient { get; set; }
        [DataMember]
        public bool ReadOnly { get; set; }
        [DataMember]
        public bool RestrictedWebViewOnly { get; set; }
        [DataMember]
        public string SHA256 { get; set; }
        [DataMember]
        public string SignoutUrl { get; set; }
        [DataMember]
        public long Size { get; set; }
        [DataMember]
        public bool SupportsCoauth { get; set; }
        [DataMember]
        public bool SupportsCobalt { get; set; }
        [DataMember]
        public bool SupportsFolders { get; set; }
        [DataMember]
        public bool SupportsLocks { get; set; }
        [DataMember]
        public bool SupportsScenarioLinks { get; set; }
        [DataMember]
        public bool SupportsSecureStore { get; set; }
        [DataMember]
        public bool SupportsUpdate { get; set; }
        [DataMember]
        public string TenantId { get; set; }
        [DataMember]
        public string TermsOfUseUrl { get; set; }
        [DataMember]
        public string TimeZone { get; set; }
        [DataMember]
        public bool UserCanAttend { get; set; }
        [DataMember]
        public bool UserCanNotWriteRelative { get; set; }
        [DataMember]
        public bool UserCanPresent { get; set; }
        [DataMember]
        public bool UserCanWrite { get; set; }
        [DataMember]
        public string UserFriendlyName { get; set; }
        [DataMember]
        public string UserId { get; set; }
        [DataMember]
        public string Version { get; set; }
        [DataMember]
        public bool WebEditingDisabled { get; set; }
    }
}

Answer 2

Office supports editing files using WebDAV protocol. There are libraries which help implement it.