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LinkedDataHub (LDH) is open source software you can use to manage data, create visualizations and build apps on RDF Knowledge Graphs.

LDH features a completely data-driven application architecture: generic server and client components process declarative RDF/OWL, SPARQL, and XSLT instructions.The default application structure and user interface are provided, making LDH a standalone product, yet they can be completely overridden and customized, thus also making LDH alow-code application platform. Unless a custom processing is required, no imperative code such as Java or JavaScript needs to be involved at all.

1. Install Docker
   • Install Docker Compose, if it is not already included in the Docker installation
2. Fork this repository and clone the fork into a folder
3. In the folder, create an.env file and fill out the missing values (you can use.env_sample as a template). For example:

COMPOSE_CONVERT_WINDOWS_PATHS=1COMPOSE_PROJECT_NAME=linkeddatahubPROTOCOL=httpsPROXY_HTTP_PORT=81PROXY_HTTPS_PORT=4443HOST=localhostABS_PATH=/OWNER_MBOX=john@doe.comOWNER_GIVEN_NAME=JohnOWNER_FAMILY_NAME=DoeOWNER_ORG_UNIT=My unitOWNER_ORGANIZATION=My orgOWNER_LOCALITY=CopenhagenOWNER_STATE_OR_PROVINCE=DenmarkOWNER_COUNTRY_NAME=DKOWNER_KEY_PASSWORD=changeit

4. Run this from command line:

docker-compose up

5. LinkedDataHub will start and create the following sub-folders:
   • certs where your WebID certificates are stored
   • data where the triplestore(s) will persist RDF data
   • uploads where LDH stores content-hashed file uploads
6. Installcerts/owner.p12 into a web browser of your choice (password is theOWNER_KEY_PASSWORD value)
   • Google Chrome:Settings > Advanced > Manage Certificates > Import...
   • Mozilla Firefox:Options > Privacy > Security > View Certificates... > Import...
   • Apple Safari: The file is installed directly into the operating system. Open the file and import it using theKeychain Access tool.
   • Microsoft Edge: Does not support certificate management, you need to install the file into Windows.Read more here.
7. Openhttps://localhost:4443/ in that web browser

After a successful startup, the last line of the Docker log should read:

linkeddatahub_1    | 02-Feb-2020 02:02:20.200 INFO [main] org.apache.catalina.startup.Catalina.start Server startup in 3420 ms

• You will likely get a browser warning such asYour connection is not private in Chrome orWarning: Potential Security Risk Ahead in Firefox due to the self-signed server certificate. Ignore it: clickAdvanced andProceed orAccept the risk to proceed.
  • If this option does not appear in Chrome (as observed on some MacOS), you can openchrome://flags/#allow-insecure-localhost, switchAllow invalid certificates for resources loaded from localhost toEnabled and restart Chrome
• .env_sample and.env files might be invisible in MacOS Finder which hides filenames starting with a dot. You should be able tocreate it using Terminal however.
• On Linux your user may need to be a member of thedocker group. Add it using

sudo usermod -aG docker ${USER}

and re-login with your user. An alternative, but not recommended, is to run

sudo docker-compose up

Besides owner WebID configuration, the most common case is changing the base URI from the defaulthttps://localhost:4443/ to your own.

Lets usehttps://ec2-54-235-229-141.compute-1.amazonaws.com/linkeddatahub/ as an example. We need to split the URI into components and set them in the.env file using the following parameters:

PROTOCOL=httpsHTTP_PORT=80HTTPS_PORT=443HOST=ec2-54-235-229-141.compute-1.amazonaws.comABS_PATH=/linkeddatahub/

ABS_PATH is required, even if it's just/.

Dataspaces are configured inconfig/system.trig. Their base URIs need to be relative to the base URI configured in the.env file.

Reusing thehttps://ec2-54-235-229-141.compute-1.amazonaws.com/linkeddatahub/ as the new base URI, the easiest way is to simple replace the defaulthttps://localhost:4443/ value with it. It can be done using the following shell command:

sed -i 's/https:\/\/localhost:4443\//https:\/\/ec2-54-235-229-141.compute-1.amazonaws.com\/linkeddatahub\//g' config/system.trig

Note thatsed requires to escape forward slashes/ with backslashes\.

If you need to start fresh and wipe the existing setup (e.g. after configuring a new base URI), you can do that using

sudo rm -rf certs data && docker-compose down -v

This will remove the persisted data, server and owner certificates as well as their Docker volumes.

• Get started
• Reference
• User guide

Source code:

LinkedDataHub includes a basic HTTPtest suite.

• Jersey
• XOM
• JavaMail
• Guava
• CSV2RDF
• Processor
• Web-Client

Pleasereport issues if you've encountered a bug or have a feature request.

Commercial consulting, development, and support are available fromAtomGraph.

• @atomgraphhq
• W3CDeclarative Linked Data Apps Community Group