Folium Resource Server

Simple server to host folium Javascript and CSS resources for custom-hosted Folium maps.

Also contains a bash script to scrape the folium repository and download all the external resources required for hosting.

Motivation

Ever wished that you were able to server Folium maps within self-hosted / non-Internet environment? This repository fulfils the other half of the resources that is required for Folium rendered HTML to run.

Folium requires two sets of external resources:

1. Tileserver resources. This is official supported by the latest official folium library.

   Check these resources:

   • https://github.com/maptiler/tileserver-gl for the custom hosting of map tiles.
   • https://python-visualization.github.io/folium/modules.html for how to specify the custom tileserver URL.

2. Javascript and CSS files required by many third-party libraries of folium, such as leaflet. These are currently not officially supported for overriding, which is understandable because of the sheer amount of external JS and CSS resources.

   This repository provides the extracted JS and CSS files (and the corresponding extra resources for the CSS files), and is able to custom host these static files for access.

   To overcome the issue of overriding the URLs to these resources, this repository works in tandem with https://github.com/dsaidgovsg/folium-override-server. The generated external/folium-css.json and external/folium-js.json files are meant for the above repository to use, to know how to string replace all found external URLs to point to this repository hosted resources in static directory.

   The tag release system here follows this format vX.Y.Z_folium-v0.10.1. The vX.Y.Z part is the semver for this repository, while the folium-v0.10.1 part is to match the resources that was extracted from folium v0.10.1.

   In general, the users should be more mindful of the folium version since it needs to match with the folium version that was used to generate the folium map. There is probably a high chance that a slight mismatch version of folium and this repository would work, but it is not a 100% guarantee.

Set-Up

The set-up is Docker centric and uses NGINX to host the static files.

Pull and run

The built image is already available. This pulls and just runs the webserver.

docker pull dsaidgovsg/folium-resource-server:v0.1.3_folium-v0.10.1
docker run --rm -it -p 8080:8080 dsaidgovsg/folium-resource-server:v0.1.3_folium-v0.10.1

To test that this is working, enter the following link into your web browser:

http://localhost:8080/code.jquery.com/jquery-1.12.4.min.js

You should see the contents of the JS being displayed.

Manual build

You will need both docker and docker-compose. Simply run the following:

docker-compose up --build

to get a running static HTTP file server.

To test that this is working, enter the following link into your web browser:

http://localhost:8080/code.jquery.com/jquery-1.12.4.min.js

You should see the contents of the JS being displayed.

Alternative set-up

For the Folium resource static file server, you could also just take all the files in static and host them in any static file webserver that you prefer.

How to refresh the resources and external configuration

Simply run static-fetch.sh. Note that this requires a higher version of bash, and has been tested to work on Ubuntu 18.04 LTS's default bash.

Both the static directory which contains the downloaded JS and CSS resources to host, as well as the external directory which contains the configuration for https://github.com/dsaidgovsg/folium-override-server to use will be updated.

There are flags that can be added to tweak the behaviour of the script, run

./static-fetch.sh -h

to find out more.