Scoold Q&A

by Erudika

GitHub Readme.md

Scoold Q&A

Scoold - Stack Overflow in a JAR

Join the chat at https://gitter.im/Erudika/scoold

Scoold is a Q&A/knowledge base platform written in Java. The project was created back in 2008, released in 2012 as social network for schools inspired by Stack Overflow. In 2017 it was refactored, repackaged and open-sourced.

Scoold can run anywhere - Heroku, DigitalOcean, AWS, Azure or any VPS hosting provider. It's lightweight (~4000 LOC), the backend is handled by a separate service called Para. Scoold does not require a database, and the controller logic is really simple because all the heavy lifting is delegated to Para. This makes the code easy to read and can be learned quickly by junior developers.

Scoold Pro, the paid version of Scoold, has premium features which make it the perfect knowledge sharing platform for your company or team.

This project is fully funded and supported by Erudika - an independent, bootstrapped company.

Features

  • Full featured Q&A platform
  • Database-agnostic, optimized for cloud deployment
  • Full-text search
  • Distributed object cache
  • Location-based search and "near me" filtering of posts
  • I18n with RTL language support
  • Reputation and voting system with badges
  • Spaces (Teams) - groups of isolated questions and users
  • Webhooks with signature signing
  • Minimal frontend JS code based on jQuery
  • Modern, responsive layout powered by Materialize CSS
  • Suggestions for similar questions and hints for duplicate posts
  • Email notifications for post replies and comments
  • Spring Boot project (single JAR)
  • LDAP authentication support
  • Social login (Facebook, Google, GitHub, LinkedIn, Microsoft, Slack, Twitter) with Gravatar support
  • Syntax highlighting for code in posts, GFM markdown support with tables, task lists and strikethrough
  • Emoji support - cheat sheet
  • SEO friendly

Pro Features

  • Slack / Mattermost integration
  • SAML support
  • Anonymous posts
  • Unlimited spaces
  • Multiple admins
  • Multiple identity domains
  • Sticky / Favorite posts
  • Advanced syntax highlighting
  • Image uploads
  • Security notifications
  • Email digest of recent questions
  • Account suspensions/permabans
  • Wiki-style answers
  • Mentions with notifications
  • Custom authentication support

...and more!

Buy Scoold Pro 299 EUR

Live Demo

The demo is deployed on a free dyno and it might take a minute to wake up.

Live demo on Heroku

Quick Start with a managed Para backend (easier)

JDK 1.8 or higher is required to build and run the project. All major operating systems are supported.

  1. First, you need to create a developer app with Facebook, Google or any other identity provider that you wish to use. This isn't necessary if you're planning to login with LDAP, SAML or with a email and password. Save the obtained API keys in application.conf, as shown below.

Important: Authorized redirect URLs for Google and Facebook should look like this: https://{your_scoold_host}, https://{your_scoold_host}/signin. For all the other identity providers you must whitelist the Para host with the appropriate authentication endpoint. For example, for GitHub, the redirect URL could be: https://paraio.com/github_auth.

  1. Create a new app on ParaIO.com and copy your access keys to a file
  2. Click one of the quick deploy buttons or skip to step 3 for local deployment:
btn deploy to aws button btn
  1. Create a dedicated application.conf for Scoold and configure it to connect to the hosted Para service at https://paraio.com
  2. Start Scoold with java -jar -Dserver.port=8000 -Dconfig.file=./application.conf scoold.jar OR mvn spring-boot:run
  3. Open http://localhost:8000 in your browser

Quick Start with a self-hosted Para backend (harder)

Note: The Para backend server is deployed separately and is required for Scoold to run.

  1. run Para locally on port 8080 and initialize it with GET localhost:8080/v1/_setup
  2. Save the access keys for the root Para app somewhere safe, you'll need them to configure Para CLI tool below
  3. Create a new directory for Scoold containing its own dedicated application.conf and configure it to connect to Para on port 8080
  4. Start Scoold with java -jar -Dserver.port=8000 -Dconfig.file=./application.conf scoold.jar OR mvn spring-boot:run
  5. Open http://localhost:8000 in your browser

Use the Para CLI tool to create a separate app for Scoold:

$ npm install -g para-cli
# run setup and enter the keys for the root app and endpoint 'http://localhost:8080'
$ para-cli setup
$ para-cli ping
$ para-cli new-app "scoold" --name "Scoold"

Important: Do not use the same application.conf file for both Para and Scoold! Keep the two applications in separate directories, each with its own configuration file. All settings shown below are meant to be kept in the Scoold config file. If you want to sign up with an email and password, SMTP settings must be configured before deploying Scoold to production.

Read the Para docs for details on how to run and configure your Scoold backend.

Hardware requirements

Scoold and Para can both be hosted on the same machine, provided it has at least 3 GB of RAM. Scoold requires:

  • at least 500 MB RAM
  • 1 vCPU or more
  • 10 GB disk space or more (primarily for logs and storing images)

Para requires:

  • at least 1 GB RAM
  • 1 vCPU (2 are recommended)
  • 10 GB disk space or more (unless the database is stored on the same machine)

JVM parameters: e.g. java -jar -Xms600m -Xmx600m scoold.jar

Configuration

Important: Create a separate app for Scoold, instead of using app:para, when hosting your own instance of Para.

The most important settings are para.endpoint - the URL of the Para server, as well as, para.access_key and para.secret_key. Connection to a Para server is required for Scoold to run.

Copy the Scoold example configuration below to your application.conf and edit it if necessary:

### Minimal configuration ###
# the name of the application
para.app_name = "Scoold"
# the port for Scoold
para.port = 8000
# change this to "production" later
para.env = "development"
# the URL where Scoold is hosted, or http://localhost:8000
para.host_url = "https://your-scoold-domain.com"
# the URL of Para - could also be "http://localhost:8080"
para.endpoint = "https://paraio.com"
# access key for your Para app
para.access_key = "app:scoold"
# secret key for your Para app
para.secret_key = ""
# the identifier of admin user - check Para user object
para.admins = "admin@domain.com"
##############################

####### Authentication #######
# enable or disable email and password authentication
para.password_auth_enabled = true
# Session cookie name
para.auth_cookie = "scoold-auth"
# Facebook - create your own Facebook app first!
para.fb_app_id = "123456789"
# Google - create your own Google app first!
para.google_client_id = "123-abcd.apps.googleusercontent.com"
###############################

### Misc. ###
# if false, commenting is allowed after 100+ reputation
para.new_users_can_comment = true
# if true, posts by new users require approval from moderator
para.posts_need_approval = false
# reputation needed for posts to be auto-approved
para.posts_rep_threshold = 100
# needed for geolocation filtering of posts
para.gmaps_api_key = ""
# Enable/disable near me feature (geolocation)
para.nearme_feature_enabled = false
# GA code
para.google_analytics_id = "UA-123456-7"
# enables syntax highlighting in posts
para.code_highlighting_enabled = true
# If true, the default space will be accessible by everyone
para.is_default_space_public = true
# If true, users can change their profile pictures
para.avatar_edits_enabled = true
# If true, users can change their names
para.name_edits_enabled = true
# Enable/disable webhooks support
para.webhooks_enabled = true
# Enable/disable wiki style answers
para.wiki_answers_enabled = true
# Comment limits
para.max_comments_per_id = 1000
para.max_comment_length = 255
# Post body limit (characters)
para.max_post_length = 20000
# Sets the default tag for new questions
para.default_question_tag = "question"
# Enable/disable numeric pagination (< 1 2 3...N >)
para.numeric_pagination_enabled = false

On startup, Scoold will try to connect to Para 10 times, with a 10 second interval between retries. After that it will fail and the settings will not be persisted. If you set the maximum number of retries to -1 there will be an infinite number of attempts to connect to Para. These parameters are controlled by:

para.connection_retries_max = 10
para.connection_retry_interval_sec = 10

Docker

Tagged Docker images for Scoold are located at erudikaltd/scoold on Docker Hub. First, have your Scoold application.conf configuration file ready in the current directory and run this command:

$ docker run -ti -p 8000:8000 --rm -v $(pwd)/application.conf:/scoold/application.conf \
  -e JAVA_OPTS="-Dconfig.file=/scoold/application.conf" erudikaltd/scoold

Environment variables

JAVA_OPTS - Java system properties, e.g. -Dpara.port=8000 BOOT_SLEEP - Startup delay, in seconds

Docker Compose

You can start the whole stack, Para + Scoold, with a single command using docker-compose. First, create a new directory and copy docker-compose.yml to it from this repository. Create these 4 files:

  1. para.env - containing environment variables for Para, like JAVA_OPTS
  2. scoold.env - containing environment variables for Scoold, like JAVA_OPTS
  3. para-application.conf - containing the Para configuration (see example below)
  4. scoold-application.conf - containing the Scoold configuration (see example above)

An example para.env file:

JAVA_OPTS="-Dconfig.file=/para/application.conf -Dloader.path=lib"

Example for scoold.env:

JAVA_OPTS=-Dconfig.file=/scoold/application.conf
BOOT_SLEEP=6

Example for para-application.conf:

para.env = "production"
para.dao = "H2DAO"

Then you can start both Scoold and Para with Docker Compose like so:

$ docker-compose up

Follow the quick start guide above to initialize Para and create a new app for Scoold. Once you have the access keys for that app, update scoold-application.conf with those and restart the Para + Scoold Docker stack.

Kubernetes

There's a Helm chart inside the helm/ folder. First edit helm/scoold/values.yaml and then you can deploy Scoold to Kubernetes with a single command:

cd helm; helm install ./scoold

For more info, read the README at helm/README.md.

Docker registry for Scoold Pro images

If you purchase Scoold Pro you can get access to the private Docker registry hosted on the AWS Elastic Container Registry. Access to the private registry is not given automatically upon purchase - you have to request it. You will then be issued a special access key and secret for AWS ECR which you save as a new profile in your ~/.aws/credentials. Then execute the following BASH commands:

# authenticate docker with ECR using the temporary access token
$(aws --profile ScooldEcrProfile ecr get-login --no-include-email --region eu-west-1)
# list all tags
aws --profile ScooldEcrProfile ecr list-images --repository-name scoold-pro
# pull image with a specific tag
docker pull 374874639893.dkr.ecr.eu-west-1.amazonaws.com/scoold-pro:{tag}

The :latest tag is not supported. The command aws get-login gives you an access token to the private Docker registry which is valid for 12 hours.

For connecting Kubernetes to AWS ECR, please refer to this article.

In case you don't want to use AWS CLI for logging into the Scoold Pro registry, install the AWS ECR Docker Credentials Helper.

Deploying Scoold to Heroku

One-click deployment

Deploy

Manual deployment

  1. First, clone this repository and create a new Heroku app
  2. Add Heroku as a Git remote target and push your changes with git push heroku master
  3. Go to the Heroku admin panel, under "Settings", "Reveal Config Vars" and set all the configuration variables shown above.
  4. Open the app in your browser at https://{appname}.herokuapp.com.

Note: On Heroku, all configuration variables (config vars) must be set without dots ".", for example para.endpoint becomes para_endpoint.

It's also helpful to install the Heroku CLI tool.

Deploying Scoold to DigitalOcean

  1. Create a droplet running Ubuntu and SSH into it
  2. Create a user ubuntu with adduser ubuntu
  3. Execute (as root) wget https://raw.githubusercontent.com/Erudika/scoold/master/installer.sh && bash installer.sh
  4. Copy the configuration file to your droplet: scp application.conf root@123.234.12.34:/home/ubuntu
  5. Restart Scoold with ssh root@123.234.12.34 "systemctl restart scoold.service"
  6. Go to http://123.234.12.34:8000 and verify that Scoold is running (use the correct IP address of your droplet)
  7. Configure SSL on DigitalOcean or install nginx + letsencrypt on your droplet (see instructions below)

Deploying Scoold to AWS

deploy to aws button

Lightsail

  1. Click the button above
  2. Choose "Linux", "OS only", "Ubuntu 18.04 LTS"
  3. Click "+ Add launch script" and copy/paste the contents of installer.sh
  4. Download the default SSH key pair or upload your own
  5. Choose the 512MB instance or larger (1GB recommended)
  6. Wait for the instance to start and open the IP address in your browser at port 8000

Elatic Beanstalk

  1. Clone this repo and change directory to it
  2. Generate a WAR package with mvn -Pwar package
  3. Create a new Beanstalk web app
  4. Upload the WAR package target/scoold-x.y.z.war to Beanstalk, modify any additional options and hit "Create"

Authentication with Amazon Cognito

Scoold is fully compatible with Amazon Cognito because Cognito is just another OAuth 2.0 service provider. Here's how to configure Scoold to work with Amazon Cognito:

  1. Create a Cognito user pool (if you don't have one already)
  2. Create a Cognito App client with the OAuth 2.0 authorization code grant enabled:
  3. Create a Cognito login subdomain for your app client like this: https://scoold.auth.eu-west-1.amazoncognito.com
  4. Edit the Scoold configuration file application.conf and add a new OAuth 2.0 authentication provider:
para.oa2_app_id = "cognito_app_client_id"
para.oa2_secret = "cognito_app_client_secret"
para.security.oauth.authz_url = "https://scoold.auth.eu-west-1.amazoncognito.com/login"
para.security.oauth.token_url = "https://scoold.auth.eu-west-1.amazoncognito.com/oauth2/token"
para.security.oauth.profile_url = "https://scoold.auth.eu-west-1.amazoncognito.com/oauth2/userInfo"
para.security.oauth.provider = "Continue with Cognito"
  1. Restart Scoold and login with a user from your Cognito user pool

Deploying Scoold to Azure

Deploy to Azure

  1. Click the button above
  2. Fill in the required parameters
  3. Launch the container
  4. Go to your container and press "Connect" using /bin/sh
  5. In the terminal type in vi application.conf, hit i and paste in your configuration
  6. Hit Esc and type in :wq then restart your container Another option is to attach a secret volume to your container, containing the configuration. It should be mounted as /scoold/application.conf.

Deploying Scoold to Google App Engine

  1. Clone this repo and change directory to it
  2. Create a project in the Google Cloud Platform Console
  3. Install the Google Cloud SDK
  4. Delete Dockerfile and app.yml
  5. Edit app.gae.yaml to suit your needs
  6. Deploy it with gcloud preview app deploy app.gae.yaml

Deploying Scoold to a servlet container

The instructions for Tomcat in particular are:

  1. Generate a WAR package with mvn -Pwar package
  2. Rename the WAR package to ROOT.war if you want it deployed to the root context or leave it as is
  3. Put the WAR package in Tomcat/webapps/ & start Tomcat
  4. Put application.conf in Tomcat/webapps/scoold-folder/WEB-INF/classes/ & restart Tomcat

Scoold is compatible with Tomcat 9+.

Deploying Scoold under a specific context path

To deploy Scoold at a different path instead of the root path, set para.context_path = "/newpath. The default value for this setting is blank, meaning Scoold will be deployed at the root directory.

Content-Security-Policy header

This header is enabled by default for enhanced security. It can be disabled with para.csp_header_enabled = false. The default value is modified through para.csp_header = "new_value". The default CSP header is:

default-src 'self';
base-uri 'self';
connect-src 'self' scoold.com www.google-analytics.com www.googletagmanager.com;
frame-src 'self' accounts.google.com staticxx.facebook.com;
font-src cdnjs.cloudflare.com fonts.gstatic.com fonts.googleapis.com;
style-src 'self' 'unsafe-inline' fonts.googleapis.com cdnjs.cloudflare.com static.scoold.com;
img-src 'self' https: data:;
object-src 'none;
report-uri /reports/cspv;
script-src 'unsafe-inline' https: 'nonce-{{nonce}}' 'strict-dynamic';

The placeholder {{nonce}} will get replaced by the CSP nonce value used for whitelisting scripts.

Note: If you get CSP violation errors, check your para.host_url and para.cdn_url configuration, or edit the value of para.csp_header.

Additionally, there are 4 options to extend the values of connect-src, frame-src, font-src and style-src respectively:

para.csp_connect_sources = "connect-domain1.com connect-domain2.com"
para.csp_frame_sources = "frame-domain1.com frame-domain2.com"
para.csp_font_sources = "font-domain1.com font-domain2.com"
para.csp_style_sources = "style-domain1.com style-domain2.com"

You can also enable or disable CSP violation reports (visible only to admins) by setting para.csp_reports_enabled = true. Keep in mind that if your website has a lot of traffic, this will result in hundreds of new reports being created each hour.

External scripts and JS snippets

You can append external scripts and JS snippets to the end of the page by setting the para.external_scripts property.

# URL
para.external_scripts.myscript1 = "https://mydomain.com/script.js"
# Base64 encoded JavaScript snippet
para.external_scripts.myscript2 = "J2Y2M3VlcH .... enZ2OScpOw=="

Important: Watch out for console errors in the browser after you add external scripts. In such cases you might have to modify the frame-src or connect-src portions of the CSP header (see the 4 options above).

Serving static files from a CDN

Scoold will serve static files (JS, CSS, fonts) from the same domain where it is deployed. You can configure the para.cdn_url to enable serving those files from a CDN. The value of the CDN URL must not end in "/".

SMTP configuration

Scoold uses the JavaMail API to send emails. If you want Scoold to send notification emails you should add the following SMTP settings to your config file:

# system email address
para.support_email = "support@scoold.com"

para.mail.host = "smtp.example.com"
para.mail.port = 587
para.mail.username = "user@example.com"
para.mail.password = "password"
para.mail.tls = true
para.mail.ssl = false

# enable SMTP debug logging
para.mail.debug = true

The email template is located in src/main/resources/emails/notify.html.

For Gmail you have to turn on "Less secure app access" in your Google account settings. There's no need to configure mail.tls or mail.ssl, just set the mail.host to smtp.gmail.com and your Gmail email and password.

Email verification

You can enable or disable the email verification step by setting para.security.allow_unverified_emails = true (in Scoold's application.conf). By default, email verification is turned off when Scoold is running in development mode. This will allow new users to register with fake emails and Scoold will not send them a confirmation email. It's useful for testing purposes or in certain situations where you want to programmatically sign up users who don't have an email.

Welcome email customization

To customize the message sent when a new user signs up with Scoold, modify these properties in your Scoold configuration file:

para.emails.welcome_text1 = "You are now part of {0} - a friendly Q&A community..."
para.emails.welcome_text2 = "To get started, simply navigate to the "Ask question" page and ask a question..."
para.emails.welcome_text3 = "Best, <br>The {0} team<br><br>"

Social login

For authenticating with Facebook or Google, you only need your Google client id (e.g. 123-abcd.apps.googleusercontent.com), or Facebook app id (only digits). For all the other providers, GitHub, LinkedIn, Twitter, Slack and Microsoft, you need to set both the app id and secret key. Note: if the credentials are blank, the sign in button is hidden for that provider.

# Facebook
para.fb_app_id = "123456789"
# Google
para.google_client_id = "123-abcd.apps.googleusercontent.com"
# GitHub
para.gh_app_id = ""
para.gh_secret = ""
# LinkedIn
para.in_app_id = ""
para.in_secret = ""
# Twitter
para.tw_app_id = ""
para.tw_secret = ""
# Microsoft
para.ms_app_id = ""
para.ms_secret = ""
# Slack
para.sl_app_id = ""
para.sl_secret = ""

You also need to set your host URL when running Scoold in production:

para.host_url = "https://your.scoold.url"

This is required for authentication requests to be redirected back to the origin.

Important: You must to whitelist the Para endpoints in the admin consoles of each authentication provider. For example, for GitHub you need to whitelist https://parahost.com/github_auth as a callback URL (redirect URL). Same thing applies for the other providers, except Facebook and Google. For these two providers you need to whitelist these two URLs, containing the public address of Scoold:

https://myscoold.com
https://myscoold.com/signin

For locally hosted authentication providers (SAML, LDAP, Mattermost, etc.) the authentication endpoints will also be pointing to the URL of your Scoold server.

If you skip this step, authentication will most likely not work.

OAuth 2.0 login

You can authenticate users against any OAuth 2.0/OpenID Connect server through the generic OAuth 2 filter in Para. Here are all the options which you can set in the Scoold configuration file:

# minimal setup
para.oa2_app_id = ""
para.oa2_secret = ""
para.security.oauth.authz_url = "https://your-idp.com/login"
para.security.oauth.token_url = "https://your-idp.com/token"
para.security.oauth.profile_url = "https://your-idp.com/userinfo"
para.security.oauth.scope = "openid email profile"

# extra options
para.security.oauth.accept_header = ""
para.security.oauth.domain = "paraio.com"
para.security.oauth.parameters.id = "sub"
para.security.oauth.parameters.picture = "picture"
para.security.oauth.parameters.email = "email"
para.security.oauth.parameters.name = "name"

# Sets the string on the login button
para.security.oauth.provider = "Continue with OpenID Connect"

# Enable/disable access token delegation
para.security.oauth.token_delegation_enabled = false

Access token delegation is an additional security feature, where the access token from the identity provider (IDP) is stored in the user's idpAccessToken field and validated on each authentication request with the IDP. If the IDP revokes a delegated access token, then that user would automatically be logged out from Scoold and denied access immediately.

You can add two additional custom OAuth 2.0/OpenID connect providers called "second" and "third". Here's what the settings look like for the "second" provider:

# minimal setup (second provider)
para.oa2second_app_id = ""
para.oa2second_secret = ""
para.security.oauthsecond.authz_url = "https://your-idp.com/login"
para.security.oauthsecond.token_url = "https://your-idp.com/token"
para.security.oauthsecond.profile_url = "https://your-idp.com/userinfo"
para.security.oauthsecond.scope = "openid email profile"

# extra options (second provider)
para.security.oauthsecond.accept_header = ""
para.security.oauthsecond.domain = "paraio.com"
para.security.oauthsecond.parameters.id = "sub"
para.security.oauthsecond.parameters.picture = "picture"
para.security.oauthsecond.parameters.email = "email"
para.security.oauthsecond.parameters.name = "name"

# Sets the string on the login button (second provider)
para.security.oauthsecond.provider = "Continue with Second OAuth 2.0 provider"

# Enable/disable access token delegation (second provider)
para.security.oauthsecond.token_delegation_enabled = false

For the "third" OAuth 2.0 provider it's the same configuration but replace "second" with "third".

LDAP configuration

LDAP authentication is initiated with a request like this POST /signin?provider=ldap&access_token=username:password. There are several configuration options which Para needs in order to connect to your LDAP server. These are the defaults:

# minimal setup
para.security.ldap.server_url = "ldap://localhost:8389/"
para.security.ldap.base_dn = "dc=springframework,dc=org"
para.security.ldap.user_dn_pattern = "uid={0}"
# add this ONLY if you are connecting to Active Directory
para.security.ldap.active_directory_domain = ""

# extra options
para.security.ldap.user_search_base = ""
para.security.ldap.user_search_filter = "(cn={0})"
para.security.ldap.password_attribute = "userPassword"
para.security.ldap.username_as_name = false

# Sets the string on the login button (PRO)
para.security.ldap.provider = "Continue with LDAP"

For Active Directory LDAP, the search filter defaults to (&(objectClass=user)(userPrincipalName={0})). The syntax for this allows either {0} (replaced with username@domain) or {1} (replaced with username only). For regular LDAP, only {0} is a valid placeholder and it gets replaced with the person's username.

Here's an example Active Directory configuration (note that any other settings than the ones below will be ignored):

para.security.ldap.server_url = "ldap://server:389"
para.security.ldap.active_directory_domain = "domain.com"
para.security.ldap.user_search_filter = "userPrincipalName={0}"
para.security.ldap.base_dn = "ou=dev,dc=domain,dc=com"

PRO Scoold Pro can authenticate users with an internal (local) LDAP server, even if your Para backend is hosted outside of your network (like ParaIO.com). This adds an extra layer of security and flexibility and doesn't require a publicly accessible LDAP server. To enable this feature, add this to your configuration:

para.security.ldap.is_local = true
# required for passwordless authentication with Para
para.app_secret_key = "change_to_long_random_string"

Note that the secret key above is not the same as your Para secret key! You have to generate a random string for that (min. 32 chars).

Please, read the LDAP docs for Para to learn more about the settings above.

SAML configuration

PRO First, you have to setup Para as a SAML service provider using the config below. Then you can exchange SAML metadata with your SAML identity provider (IDP). The SP metadata endpoint is /saml_metadata/{appid}. For example, if your Para endpoint is paraio.com and your appid is scoold, then the metadata is available at https://paraio.com/saml_metadata/scoold.

SAML authentication is initiated by sending users to the Para SAML authentication endpoint /saml_auth/{appid}. For example, if your Para endpoint is paraio.com and your appid is scoold, then the user should be sent to https://paraio.com/saml_auth/scoold. Para (the service provider) will handle the request and redirect to the SAML IDP. Finally, upon successful authentication, the user is redirected back to https://paraio.com/saml_auth/scoold which is also the assertion consumer service (ACS).

Note: The X509 certificate and private key must be encoded as Base64 in the configuration file. Additionally, the private key must be in the PKCS#8 format (---BEGIN PRIVATE KEY---). To convert from PKCS#1 to PKCS#8, use this:

openssl pkcs8 -topk8 -inform pem -nocrypt -in sp.rsa_key -outform pem -out sp.pem

There are lots of configuration options but Para needs only a few of those in order to successfully authenticate with your SAML IDP (listed in the first rows below).

# minimal setup
# IDP metadata URL, e.g. https://idphost/idp/shibboleth
para.security.saml.idp.metadata_url = ""

# SP endpoint, e.g. https://paraio.com/saml_auth/scoold
para.security.saml.sp.entityid = ""

# SP public key as Base64(x509 certificate)
para.security.saml.sp.x509cert = ""

# SP private key as Base64(PKCS#8 key)
para.security.saml.sp.privatekey = ""

# attribute mappings (usually required)
# e.g. urn:oid:0.9.2342.19200300.100.1.1
para.security.saml.attributes.id = ""
# e.g. urn:oid:0.9.2342.19200300.100.1.3
para.security.saml.attributes.email = ""
# e.g. urn:oid:2.5.4.3
para.security.saml.attributes.name = ""


# extra options (optional)
# this is usually the same as the "EntityId"
para.security.saml.sp.assertion_consumer_service.url = ""
para.security.saml.sp.nameidformat = ""

# IDP metadata is usually automatically fetched
para.security.saml.idp.entityid = ""
para.security.saml.idp.single_sign_on_service.url = ""
para.security.saml.idp.x509cert = ""

para.security.saml.security.authnrequest_signed = false
para.security.saml.security.want_messages_signed = false
para.security.saml.security.want_assertions_signed = false
para.security.saml.security.want_assertions_encrypted = false
para.security.saml.security.want_nameid_encrypted = false
para.security.saml.security.sign_metadata = false
para.security.saml.security.want_xml_validation = true
para.security.saml.security.signature_algorithm = ""

para.security.saml.attributes.firstname = ""
para.security.saml.attributes.picture = ""
para.security.saml.attributes.lastname = ""
para.security.saml.domain = "paraio.com"

# Sets the string on the login button
para.security.saml.provider = "Continue with SAML"

Scoold Pro can authenticate users with an internal (local) SAML provider, even if your Para backend is hosted outside of your network (like ParaIO.com). This adds an extra layer of security and flexibility and doesn't require your SAML endpoints to be publicly accessible. To enable this feature, add this to your configuration:

para.security.saml.is_local = true
# required for passwordless authentication with Para
para.app_secret_key = "change_to_long_random_string"

Note that the secret key above is not the same as your Para secret key! You have to generate a random string for that (min. 32 chars).

Custom authentication (Single Sign-on)

PRO Para supports custom authentication providers through its "passwordless" filter. This means that you can send any user info to Para and it will authenticate that user automatically without passwords. The only verification done here is on this secret key value which you provide in your Scoold Pro configuration file:

para.app_secret_key = "change_to_long_random_string"

This key is used to protect requests to the passwordless filter and it's different from the Para secret key for your app. Here's the basic authentication flow:

  1. A user wants to sign in to Scoold Pro and clicks a button
  2. The button redirects the user to a remote login page you or your company set up.
  3. The user enters their credentials and logs in.
  4. If the credentials are valid, you send back a special JSON Web Token (JWT) to Scoold with the user's basic information.
  5. Scoold verifies the token and the user is signed in to Scoold

The JWT must contain the following claims:

  • email - user's email address
  • name - user's display name
  • identifier - a unique user id in the format custom:123
  • appid - the app id (optional)

The JWT is signed with the value of para.app_secret_key and should have a short validity period (e.g. 10 min). The JWT should also contain the claims iat and exp and, optionally, nbf. Supported signature algorithms for the JWT are HS256, HS384 or HS512. Once you generate the JWT on your backend (step 4 above), redirect the successful login request back to Scoold:

GET https://scoold-host/signin/success?jwt=eyJhbGciOiJIUzI1NiI..&passwordless=true

The UI button initiating the authentication flow above can be customized like this:

para.security.custom.provider = "Continue with Acme Co."
# location of your company's login page
para.security.custom.login_url = ""

There's an example login page implementing this sort of authentication.

Spaces (a.k.a. Teams)

Spaces are a way to organize users and questions into isolated groups. There's a default space, which is publicly accessible by default. Each user can belong to one or more spaces, but a question can only belong to a single space. Permission to access a space is given by an administrator. You can bulk edit users' spaces and also move a question to a different space.

By default there's a public "default" space where all questions go. When you create a new space and assign users to it they will still see all the other questions when they switch to the "default" space. To make the default space private set para.is_default_space_public = false.

PRO In Scoold PRO you can create as many space as you need. The open source version is limited to 10 spaces. Also in PRO you can automatically assign multiple spaces to new users, whereas in the OSS version you can only assign one.

If you want to assign space(s) to new users automatically, add this to your configuration:

# put space ids here, the "scooldspace:" prefix is optional
para.auto_assign_spaces = "my-space-one,my-other-space"

Alternatively, Scoold Pro can have spaces delegated to users from an OpenID Connect/OAuth 2.0 identity provider. You have to enable access token delegation with para.security.oauth.token_delegation_enabled = true and Scoold will try to obtain spaces from a custom attribute like spaces. Such custom attributes can be configured in the IDP and pushed to clients (Scoold) embedded in access tokens. If you want to change the name of the custom attribute supplied by your IDP, set para.security.oauth.spaces_attribute_name, which by default is equal to spaces. The value of that attribute should contain comma-separated list of spaces. If the spaces pushed from the IDP do not exist, Scoold will create them for you.

Webhooks

Webhooks are enabled by default in Scoold. To disable this functionality set para.webhooks_enabled = false. If you are self-hosting Para, you need to also enable webhooks there using the same configuration option. You can add/remove webhooks in the "Administration" page.

For more details about webhooks, please read the Para docs on webhooks.

Domain-restricted user registrations

You can restrict signups only to users from a particular identity domain, say acme-corp.com. To do so, set the following configuration property:

para.approved_domains_for_signups = "acme-corp.com"

Then a user with email john@acme-corp.com will be allowed to login (the identity provider is irrelevant), but user bob@gmail.com will be denied access.

PRO In Scoold PRO this setting can also contain a comma-separated list of identity domains:

para.approved_domains_for_signups = "acme-corp.com,gmail.com"

Admins

You can specify the user with administrative privileges in your application.conf file:

para.admins = "joe@example.com"

PRO In Scoold PRO you can have multiple admin users by specifying a comma-separated list of user identifiers. This works both for new and existing users.

para.admins = "joe@example.com,fb:1023405345366,gh:1234124"

If you remove users who are already admins from the list of admins para.admins, they will be demoted to regular users. Similarly, existing regular users will be promoted to admins if they appear in the list above.

Anonymous posts

PRO This feature is enabled with para.anonymous_posts_enabled = true. It allows everyone to ask questions and write replies, without having a Scoold account. Posting to the "Feedback" section will also be open without requiring users to sign in. This feature is disabled by default.

Additionally, people may wish to make their profile details anonymous from the Settings page. To allow this option set:

para.profile_anonimity_enabled = true

Disabling the "Feedback" section

PRO In Scoold PRO you can disable the "Feedback" functionality of the site by setting para.feedback_enabled = false. This will remove the link to /feedback and disable the feature entirely.

LaTeX/MathML support and advanced highlighting

PRO You can enable this feature by setting para.mathjax_enabled = true. Then you can use MathML expressions by surrounding them with $$ signs, e.g. $$ \frac {1}{2} $$ By default, MathJax is disabled.

The Prism syntax highlighter is included and it supports many different languages. You need to specify the language for each code block if you want the highlighting to be more accurate (see all supported languages). For example:

```csharp
var dict = new Dictionary<string>();
```

Image uploads

PRO Images can be uploaded to the local file system or Imgur. If you set the Imgur client id, Imgur is automatically selected as the storage service. To use Imgur for file storage, specify your Imgur API client id:

para.imgur_client_id = "x23e8t0askdj"

Local file storage is used by default. To configure the directory on the server where files will be stored, set:

para.file_uploads_dir = "uploads"

To upload an image just drag & drop the file you want to upload onto the post editor. A link will automatically appear when the upload is finished.

Profile pictures (avatars) can also be changed by dragging a new image on top of the existing profile picture on a user's /profile page. For best results, use a square image here.

In the future, more upload services could be supported such as S3.

Slack integration

Scoold PRO integrates with Slack on a number of levels. First, Scoold users can sign in with Slack. They can also use slash commands to search and post questions. Also Scoold can notify Slack users when they are mentioned on Scoold. Finally, Scoold allows you to map spaces to Slack workspaces or channels. By default, each Slack workspace (team) is mapped to a single Scoold space when people sign in with Slack.

Important: Most of the Slack operations require a valid Slack ID stored in Scoold which enables the mapping of Slack users to Scoold accounts and vice versa. Slack IDs are set automatically when a Scoold user signs in with Slack.

The integration endpoint for Slack is /slack - this is where Scoold will accept and process requests from Slack. To enable the Slack integration you need to register for a Slack app first and set para.sl_app_id and para.sl_secret. Follow the detailed instructions here.

Here are the configuration properties for Slack:

para.slack.app_id = "SHORT_APPID"
para.slack.map_workspaces_to_spaces = true
para.slack.map_channels_to_spaces = false
para.slack.post_to_space = "workspace|scooldspace:myspace|default"

para.slack.notify_on_new_question = true
para.slack.notify_on_new_answer = true
para.slack.default_question_tags = "via-mattermost"

Setting para.slack.map_channels_to_spaces will ask for additional permissions, namely channels:read and groups:read. On sign in, Scoold will read all your channels and create spaces from them. The workspace space is always created if para.slack.map_workspaces_to_spaces = true, which is the default setting.

When creating quesitons from Slack they are posted to the channel workspace by default, if para.slack.map_channels_to_spaces is enabled. For example, in this case, for a team "My Team" and channel "chan", your space will become "My Team #chan". This is controlled by para.slack.post_to_space which is blank by default. If you set it to workspace, then questions will be posted to the "My Team" space. Or you could set a specific Scoold space to post to with para.slack.post_to_space = "scooldspace:myspace". If the value is default then all questions posted from Slack will go to the default space.

You can also create answers to questions from Slack, either from the message action button or by typing in the /scoold ask command. This requires the URL of a specific question you wish to answer.

Slack notifications

Scoold will notify the channels where you have it installed, whenever a new question or answer is created. To install the application on multiple channels go to the Administration page and click the "Add to Slack" button for each channel. You can receive notification on up to 10 channels simultaneously. Notification for new posts will go to the channel associated with the space in which the post was created. For example if para.slack.map_workspaces_to_spaces is true, and a question is created in space "Team1 #general", Scoold will search for webhook registrations matching that team/channel combination and send a notification there. Direct message webhooks will be used only if there's no space-matching channel found.

Approving new posts from Slack

This works if you have enabled para.posts_need_approval. When a new question or answer is created by a user with less reputation than the threshold, a notification message will be sent to Slack, giving you the option to either approve or delete that post. The action can only be performed by moderators.

Slash commands

Typing in /scoold help gives you a list of commands available:

  • /scoold - Interact with your Scoold server
  • /scoold ask [text] Ask a question directly, first sentence becomes the title. Example: /scoold ask How does this work? @john I'm having troubles with...
  • /scoold answer [question URL] [answer] Answer a question directly. Example: /scoold answer https://host/question/123 This is my answer to your question, @john.
  • /scoold search [query] Search for questions. Example: /scoold search solution AND quick*
  • /scoold search-people [query] Search for people. Example: /scoold search-people John*
  • /scoold search-tags [query] Search for tags. Example: /scoold search-tags solution*
  • /scoold version Get version information for Scoold and Para.
  • /scoold whoami Get information for your Scoold account.
  • /scoold stats Get general statistics.

Message actions

Here are the interactive message actions which are currently implemented:

  • create_question - "Ask on Scoold", Creates a new question on Scoold directly from a chat message.
  • create_question_dialog - "Edit & ask on Scoold", Opens up a dialog to edit question before posting.
  • create_answer_dialog - "Answer on Scoold", Opens up a dialog to edit your answer before posting.

These allow you to perform actions from any channel and best of all, these can turn any chat message into a question or answer.

If you get an error "User not authorised to open dialogs" it means that your Scoold user is not logged in via Slack and Scoold doesn't have a Slack access token on record. Simply log into Scoold with Slack and the error should go away.

Mattermost integration

Scoold PRO also integrates with Mattermost. Scoold users can sign in with Mattermost, use slash commands to interact with Scoold and also get in-chat notification for mentions and new posts on Scoold. Scoold allows you to map spaces to Mattermost teams or channels. By default, each Mattermost team is mapped to a single Scoold space when people sign in with Mattermost.

Important: Most of the Mattermost operations require a valid Mattermost ID stored in Scoold which enables the mapping of Mattermost users to Scoold accounts and vice versa. Mattermost IDs are set automatically when a Scoold user signs in with Mattermost.

The integration endpoint for Mattermost is /mattermost - this is where Scoold will accept and process requests from Mattermost. To enable the Mattermost integration you need to enable OAuth 2.0 apps and create one in Mattermost's System Console. Then set para.mm_app_id and para.mm_secret. Follow the detailed instructions here.

Here are the configuration properties for Mattermost:

para.mattermost.server_url = "http://localhost:8065"
para.mattermost.bot_username = "scoold"
para.mattermost.bot_icon_url = "http://localhost:8000/images/logowhite.png"
para.mattermost.map_workspaces_to_spaces = true
para.mattermost.map_channels_to_spaces = false
para.mattermost.post_to_space = "workspace|scooldspace:myspace|default"

para.mattermost.notify_on_new_question = true
para.mattermost.notify_on_new_answer = true
para.mattermost.default_question_tags = "via-mattermost"

Note: Mattermost does not support message actions like in Slack. This means that you can't create a question from a any chat message. The reply dialog box can be opened from a "Reply" button under each question notification message or via the /scoold answer-form command. The dialog box for new questions is opened via the new slash command /scoold ask-form.

All the other slash commands and notifications work just like with Slack and are described above. The Mattermost integration will automatically create a slash command for each channel linked to Scoold on the admin page.

Self-hosting Para and Scoold through SSL

The recommended way for enabling HTTPS with your own SSL certificate in a self-hosted environment is to run a reverse-proxy server like NGINX in front of Scoold. As an alternative you can use Apache or Lighttpd.

  1. Start Para on port :8080
  2. Start Scoold on port :8000
  3. Start NGINX with the configuration below
Example configuration for NGINX
server_tokens off;
add_header X-XSS-Protection "1; mode=block";
add_header X-Content-Type-Options nosniff;

server {
  listen 80 default_server;
  listen [::]:80 default_server;
  server_name www.domain.com domain.com;

  # Redirect all HTTP requests to HTTPS with a 301 Moved Permanently response.
  return 301 https://$host$request_uri;
}

server {
  listen 443 ssl http2;
  listen [::]:443 ssl http2;
  server_name www.domain.com domain.com;

  # certs sent to the client in SERVER HELLO are concatenated in ssl_certificate
  ssl_certificate /path/to/signed_cert_plus_intermediates;
  ssl_certificate_key /path/to/private_key;
  ssl_session_timeout 1d;
  ssl_session_cache shared:SSL:50m;
  ssl_session_tickets off;

  # modern configuration. tweak to your needs.
  ssl_protocols TLSv1.2;
  ssl_ciphers 'ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256';
  ssl_prefer_server_ciphers on;

  # HSTS (ngx_http_headers_module is required) (15768000 seconds = 6 months)
  add_header Strict-Transport-Security max-age=15768000;

  # OCSP Stapling - fetch OCSP records from URL in ssl_certificate and cache them
  ssl_stapling on;
  ssl_stapling_verify on;

  # Verify chain of trust of OCSP response using Root CA and Intermediate certs
  ssl_trusted_certificate /path/to/root_CA_cert_plus_intermediates;

  # Cloudflare DNS
  resolver 1.1.1.1;

  # Required for LE certificate enrollment using certbot
  location '/.well-known/acme-challenge' {
    default_type "text/plain";
    root /var/www/html;
  }

  location / {
    proxy_pass http://localhost:8000;
    proxy_redirect http:// $scheme://;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto https;
    proxy_set_header Host $http_host;
  }
}

Securing Scoold with SSL using Nginx and Certbot (Let's Encrypt)

First of all, configure the DNS records for your domain to point to the IP address where Scoold is hosted.

  1. SSH into your Ubuntu server and install Nginx and Certbot
sudo apt-get install nginx certbot python-certbot-nginx
  1. Get a certificate and autoconfigure nginx to use it
sudo certbot --nginx
  1. Turn on the Ubuntu firewall to block port 8000 and only allow ports 80 and 443.
ufw allow 'Nginx Full' && sudo ufw enable
  1. Configure nginx to forward requests from the web on ports 80 and 443 to localhost:8000
location / {
	proxy_pass http://localhost:8000;
	proxy_redirect http:// $scheme://;
	proxy_set_header X-Real-IP $remote_addr;
	proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
	proxy_set_header X-Forwarded-Proto https;
	proxy_set_header Host $http_host;
}

That's it! If the Certbot validation above fails, your DNS is not configured properly or you have conflicting firewall rules. Refer to this article for more details.

Periodic summary emails (email digest)

PRO You can choose to enable periodic summary emails for all users in Scoold or allow them to opt-in for these messages. By default summary emails are disabled and users can unsubscribe if they are enabled by admins. A summary email contains all new questions for a past period of time (daily, weekly). Admins can enable summary emails for everyone from the Settings page if para.summary_email_controlled_by_admins = true. If that parameter is false each person (by default) controls whether they want to receive summary emails or not.

The period for which a summary report is generated is controlled by:

para.summary_email_period_days = 2

The values of this setting can range from 1 to 30 days, where 2 means "every other day", 7 means "every week". The summary email contains a list of the top 25 recent questions. For more questions set para.summary_email_items = 30.

Mentions

PRO In Scoold Pro you can mention anyone in a question, answer or comment with @Name. A popup menu will appear once you start typing after @ giving you a list of names to choose from. The selected user will be mentioned with a special mention tag in the form of @<userID|John Doe>. You can edit the name part of that tag (after |) but nothing else, if you want the mention to work. You can mention up to 10 people in a post.

Users can opt-in to receive email notifications when they are mentioned or that can be switched on/off by admins. For the latter option set:

para.mention_emails_controlled_by_admins = true

Security headers

Scoold attaches several security headers to each response. These can be enabled or disabled with the following configuration properties:

# Strict-Transport-Security
para.hsts_header_enabled = true

# X-Frame-Options
para.framing_header_enabled = true

# X-XSS-Protection
para.xss_header_enabled = true

# X-Content-Type-Options
para.contenttype_header_enabled = true

# Referrer-Policy
para.referrer_header_enabled = true

Voting

By default, votes expire after a certain period, meaning the same user can vote again on the same post (after 30 days by default). Votes can also be amended within a certain number of seconds (30s by default). There are two configurable parameters which allow you to modify the length of those periods:

para.vote_locked_after_sec = 30
para.vote_expires_after_sec = 2592000

Customizing the UI

There are a number of settings that let you customize the appearance of the website without changing the code.

para.fixed_nav = false
para.show_branding = true
para.logo_url = "/logo.svg"
para.logo_width = 90
para.stylesheet_url = "/style.css"
para.inline_css = ""
para.favicon_url = "/favicon.ico"

If you wish to add just a few simple CSS rules to the <head> element, instead of replacing the whole stylesheet, simply add them as inline CSS:

para.inline_css = ".scoold-logo: { width: 100px; }"

You can set a short welcome message for unauthenticated users which will be displayed on the top of the page:

para.welcome_message = "Hello and welcome to Scoold!"

Alternatively, clone this repository and edit the following:

  • HTML templates are in src/main/resources/templates/
  • CSS stylesheets can be found in src/main/resources/static/styles/
  • JavaScript files can be found in src/main/resources/static/scripts
  • Images are in located in src/main/resources/static/images/

Also, please refer to the documentation for Spring Boot and Spring MVC.

Translating Scoold

You can translate Scoold to your language by copying the English language file and translating it. When you're done, change the file name from "lang_en.properties" to "lang_xx.properties" where "xx" is the language code for your locale. Finally, open a pull request here.

Language File Progress Albanian lang_sq.properties 0% Arabic lang_ar.properties ✔️ (Google Translate) Belarusian lang_be.properties 0% Bulgarian lang_bg.properties ✔️ Catalan lang_ca.properties 0% Chinese (Traditional) lang_zh_tw.properties ✔️ Thanks Kyon Cheng! Chinese (Simplified) lang_zh_cn.properties ✔️ Thanks Kyon Cheng! Croatian lang_hr.properties 0% Czech lang_cs.properties 0% Danish lang_da.properties ✔️ Thanks @viking1972! Dutch lang_nl.properties ✔️ Thanks Jan Halsema! English lang_en.properties ✔️ Estonian lang_et.properties 0% Finnish lang_fi.properties 0% French lang_fr.properties ✔️ Thanks Charles Maheu! German lang_de.properties ✔️ Thanks Patrick Gäckle! Greek lang_el.properties 0% Hebrew lang_iw.properties ✔️ Thanks David A. Hindi lang_hi.properties ✔️ Thanks Rakesh Gopathi! Hungarian lang_hu.properties 0% Icelandic lang_is.properties 0% Indonesian lang_in.properties 0% Irish lang_ga.properties 0% Italian lang_it.properties 0% Japanese lang_ja.properties ✔️ Thanks Mozy Okubo! Korean lang_ko.properties ✔️ Thanks HyunWoo Jo! Lithuanian lang_lt.properties 0% Latvian lang_lv.properties 0% Macedonian lang_mk.properties 0% Malay lang_ms.properties 0% Maltese lang_mt.properties 0% Norwegian lang_no.properties 0% Polish lang_pl.properties 0% Portuguese lang_pt.properties 0% Romanian lang_ro.properties 0% Russian lang_ru.properties 0% Serbian lang_sr.properties 0% Slovak lang_sk.properties 0% Slovenian lang_sl.properties 0% Spanish lang_es.properties ✔️ Thanks Trisha Jariwala! Swedish lang_sv.properties 0% Thai lang_th.properties 0% Turkish lang_tr.properties ✔️ Thanks Aysad Kozanoglu! Ukrainian lang_uk.properties 0% Vietnamese lang_vi.properties 0%

Scoold API

The REST API is a work in progress. The API can be accessed from /api and the Swagger documentation and console are located at /api.html.

You can use the public endpoint /api to check the health of the server. A GET /api will return 200 if the server is healthy and connected to Para, otherwise status code 500 is returned. The response body is similar to this:

{
  "healthy": true,
  "message": "Scoold API, see docs at http://localhost:8000/api.html"
}

Building Scoold

To compile it you'll need JDK 8+ and Maven. Once you have it, just clone and build:

$ git clone https://github.com/erudika/scoold.git && cd scoold
$ mvn install

To run a local instance of Scoold for development, use:

$ mvn -Dconfig.file=./application.conf spring-boot:run

To generate a WAR package, run:

$ mvn -Pwar package

Support

You can get support here by submitting an issue. Also you can head over to the Gitter chat room for help. Issues related to Scoold Pro must be reported to Erudika/scoold-pro. Paid/priority support is also available.

Getting help

Blog

Read more about Scoold on our blog

Contributing

  1. Fork this repository and clone the fork to your machine
  2. Create a branch (git checkout -b my-new-feature)
  3. Implement a new feature or fix a bug and add some tests
  4. Commit your changes (git commit -am 'Added a new feature')
  5. Push the branch to your fork on GitHub (git push origin my-new-feature)
  6. Create new Pull Request from your fork

Please try to respect the code style of this project. To check your code, run it through the style checker:

mvn validate

For more information see CONTRIBUTING.md

Square Face

License

Apache 2.0