I’ve set up a multi-app/page Dash application which runs perfectly well through the development Flask server and Waitress (without setting up a Reverse Proxy yet) but I’m struggling to get the last piece of the puzzle working via FastCGI (v3.0.0 downloaded from the latest repository) on IIS8.5 (on Windows Server 2012 R2).
There are two issues:
- In IE11 and Chrome (both updated to the latest versions from July 2018), the first page that the user hits requires a refresh; sometimes the app gets stuck in the 'Loading… state and sometimes it delivers a failed to load dependencies error. After a refresh almost everything (20 plots plus 2 data tables split over 5 pages) loads correctly.
- The second issue (probably the most important as this gives the customer the key capability they are looking for), only in IE11, is that the background images I want to embed into a scatter plot are not rendered. Examining the IE11 console output/coding shows that the image HTML tags are missing from the Cartesian Layer of the plot:
js-plotly-plot > plot-container plotly > svg-container > main-svg > cartesianlayer > subplot xy > layer-subplot > imagelayer > image
In Chrome (and IE11 using Flask/Waitress) the image tag contains a base64 encoded string that represents the image; however in IE11 with my production configuration the tags are empty.
A few notes:
- We have not been able to use the Plotly/Dash production deployment server options due to company restrictions, hence going it alone with this.
- Apache or Linux based approach cannot be used due to company restrictions.
- Chrome cannot be used in Production environment due to company restrictions and IE11 is the only option.
- HTTPS with a valid SSL certificate is being used.
- CSRF Protect has been set to False.
- All interactive charts load correctly.
- Logging/Print statements have confirmed that the correct paths to images are correct.
- Attempts to access the images via direct links in the browser are successful.
- Deletion of cache on the client side and compatibility view settings have been investigated but have not proven to be successful.
- I have attempted to base64 encode images and instruct them to be decoded, as well as sending a direct link, but this has not been successful.
- The structure of the multi-page app follows the instructions in the Dash documentation (big thanks to @chriddyp and the person that has written all of the documentation).
- Update Dash and dependencies to latest versions (I have everything as of early February, version 0.18.1).
- Investigate the Reverse Proxy option with Waitress (this is not what we want to do in Production but we may be forced to do it).