running draw.io from local file system fails in Chrome and Electron

Story: As a user I want to run draw.io locally, ideally also without an internet connection.

Using Chrome/Chromium

What I tried:

1. I cloned the git repo and went to the war folder.
2. I opened index.html or app.html using chrome.

What I expected: I expected to see the where-do-you-want-to-save screen and, afterwards, the draw.io application

What happened:

• Chrome displayed the content of the index.html- page (Flowchart Maker and Online Diagram Software […] Loading… Please ensure JavaScript is enabled )
• on the devtools console, I got

app.min.js:325 XMLHttpRequest cannot load file:///home/[somefolders]/draw.io/war/stencils.xml. Cross origin requests are only supported for protocol schemes: http, data, chrome, chrome-extension, https, chrome-extension-resource.mxXmlRequest.send @ app.min.js:325
app.min.js:325

Uncaught NetworkError: Failed to execute 'send' on 'XMLHttpRequest': Failed to load 'file:///home/[somefolders]/draw.io/war/stencils.xml'.

I tried using Firefox instead, there it works without errors – I can use draw.io there without problems

(On Firefox 49.0, and Chromium 53.0.2785.143; running on Ubuntu 16.04 (64-bit))

Via HTTP-Server

What I tried: I tried to run draw.io on a local server (via python -m SimpleHTTPServer):

What happened

It worked in non of the browsers:

• In Firefox: SSL_ERROR_RX_RECORD_TOO_LONG
• In Chrome: ERR_SSL_PROTOCOL_ERROR
  while the server says: code 400, message Bad request version after some (base64?) encoded lines which start right after “/images/logo-confluence.png” is loaded.

(same browser versions and OS as above)

Via Electron

What I tried

1. in the war folder, I ran npm install
2. npm start

What happened: As on Chrome, it never got beyond the initial page as it seemed to be unable to access needed javascript files, e.g. file:///home/[somefolders]/mxgraph2/javascript/src/js/mxClient.js.

Note that the repo was cloned into file:///home/[somefolders]/draw.io/ initially, so the file looked for is not even searched for in the repo.

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Sorry for the long issue, I hope the descriptions are clear enough. Also, if you need any more extensive log files, I can provide those too.

[jdittrich]

If you want to run draw.io locally you can:

• Run it in Firefox by opening the index.html. You can add the index.html?offline=1 parameter to suppress the cloud based saving options.
• Run it in Firefox or Chrome by
  1. Running a local http server (e.g. pythons python -m SimpleHTTPServer 8000) in the /war directory.
  2. Then open the draw.io’sindex.htmlwith the parameters offline=1 and https=0, (e.g. http://localhost:8000/index.html?offline=1&https=0)

[CholoTook]

Thanks for any help