Add Sample

Issue: gh-5605

samples/boot/oauth2resourceserver-webflux/README.adoc

@@ -0,0 +1,169 @@
+= OAuth 2.0 Resource Server Sample
+
+This sample demonstrates integrations with a handful of different authorization servers.
+
+With it, you can run the integration tests or run the application as a stand-alone service to explore how you can
+secure your own service with OAuth 2.0 Bearer Tokens using Spring Security.
+
+== 1. Running the tests
+
+To run the tests, do:
+
+```bash
+../../../gradlew integrationTest
+```
+
+Or import the project into your IDE and run `OAuth2ResourceServerApplicationTests` from there.
+
+=== What is it doing?
+
+By default, the tests are pointing at a demonstration Okta instance. The test that performs a valid round trip does so
+by querying the Okta Authorization Server using the client_credentials grant type to get a valid JWT token. Then, the test
+makes a query to the Resource Server with that token. The Resource Server subsquently verifies with Okta and
+authorizes the request, returning the phrase
+
+```bash
+Hello, {subject}!
+```
+
+where subject is the value of the `sub` field in the JWT returned by the Authorization Server.
+
+== 2. Running the app
+
+To run as a stand-alone application, do:
+
+```bash
+../../../gradlew bootRun
+```
+
+Or import the project into your IDE and run `OAuth2ResourceServerApplication` from there.
+
+Once it is up, you can retreive a valid JWT token from the authorization server, and then hit the endpoint:
+
+```bash
+curl -H "Authorization: Bearer {token}" localhost:8081
+```
+
+Which will respond with the phrase:
+
+```bash
+Hello, {subject}!
+```
+
+where `subject` is the value of the `sub` field in the JWT returned by the Authorization Server.
+
+=== How do I obtain a valid JWT token?
+
+Getting a valid JWT token from an Authorization Server will vary, depending on your setup. However, it will typically
+look something like this:
+
+```bash
+curl --user {client id}:{client password} -d "grant_type=client_credentials" {auth server endpoint}/token
+```
+
+which will respond with a JSON payload containing the `access_token` among other things:
+
+```bash
+{ "access_token" : "{the access token}", "token_type" : "Bearer", "expires_in" : "{an expiry}", "scope" : "{a list of scopes}" }
+```
+
+For example, the following can be used to hit the sample Okta endpoint for a valid JWT token:
+
+```bash
+curl --user 0oaf5u5g4m6CW4x6z0h7:HR7edRoo3glhF06HTxonOKZvO4I2BWYcC_ocOHlv -d "grant_type=client_credentials" https://dev-805262.oktapreview.com/oauth2/default/v1/token
+```
+
+Which will give a response similar to this (formatting mine):
+
+```json
+{
+  "access_token": "eyJraWQiOiJFRjBFWDFFWHZGc1hGaDhuYkRGazNJN0hMUDBsZnJnc0JKMVdBWmkwRmI0IiwiYWxnIjoiUlMyNTYifQ.eyJ2ZXIiOjEsImp0aSI6IkFULmtQSUdfMEVMQmM3NVFMN3c4ZHBMVFRtNXZFVFd3d1R2dzJ3aXNISGRMbjgiLCJpc3MiOiJodHRwczovL2Rldi04MDUyNjIub2t0YXByZXZpZXcuY29tL29hdXRoMi9kZWZhdWx0IiwiYXVkIjoicmVzb3VyY2Utc2VydmVyIiwiaWF0IjoxNTI4ODYwMTkxLCJleHAiOjE1Mjg4NjM3OTEsImNpZCI6IjBvYWY1dTVnNG02Q1c0eDZ6MGg3Iiwic2NwIjpbIm9rIl0sInN1YiI6IjBvYWY1dTVnNG02Q1c0eDZ6MGg3In0.G_F9MQ3pqCy-YwfcNhryoPG5E1q4tQ7gV8OIDizR3QouUgrqT7MQsLQCTtGGLF2Fi0qq0Pr-V-wWa2MkyvcboEAhnfYi4rd3UmMrRTrNana6pVZjVWB_uj88-mZ57lFRnoYMCFbepmCxmY6D6p354H964xXWdtY7d6fw7F88DRDWMGQE0iQjMuUDg4izptVcK9db7uMonYTT1PFvOBQfwcn1zCeDVQgZFe7gjQA71CV9M6CIAXYDrpzp_hs95xco7Q3ncN3J7ZkCebLcUL6MdJS2nVuX6D6eC9PrtmCj06mb0-ydlzBSIUCPMaMQk9EhlEM_qK3d1iimCQnwo6KsIQ",
+  "token_type": "Bearer",
+  "expires_in": 3600,
+  "scope": "ok"
+}
+```
+
+Then, using that access token:
+
+```bash
+curl -H  "Authorization: Bearer eyJraWQiOiJFRjBFWDFFWHZGc1hGaDhuYkRGazNJN0hMUDBsZnJnc0JKMVdBWmkwRmI0IiwiYWxnIjoiUlMyNTYifQ.eyJ2ZXIiOjEsImp0aSI6IkFULmtQSUdfMEVMQmM3NVFMN3c4ZHBMVFRtNXZFVFd3d1R2dzJ3aXNISGRMbjgiLCJpc3MiOiJodHRwczovL2Rldi04MDUyNjIub2t0YXByZXZpZXcuY29tL29hdXRoMi9kZWZhdWx0IiwiYXVkIjoicmVzb3VyY2Utc2VydmVyIiwiaWF0IjoxNTI4ODYwMTkxLCJleHAiOjE1Mjg4NjM3OTEsImNpZCI6IjBvYWY1dTVnNG02Q1c0eDZ6MGg3Iiwic2NwIjpbIm9rIl0sInN1YiI6IjBvYWY1dTVnNG02Q1c0eDZ6MGg3In0.G_F9MQ3pqCy-YwfcNhryoPG5E1q4tQ7gV8OIDizR3QouUgrqT7MQsLQCTtGGLF2Fi0qq0Pr-V-wWa2MkyvcboEAhnfYi4rd3UmMrRTrNana6pVZjVWB_uj88-mZ57lFRnoYMCFbepmCxmY6D6p354H964xXWdtY7d6fw7F88DRDWMGQE0iQjMuUDg4izptVcK9db7uMonYTT1PFvOBQfwcn1zCeDVQgZFe7gjQA71CV9M6CIAXYDrpzp_hs95xco7Q3ncN3J7ZkCebLcUL6MdJS2nVuX6D6eC9PrtmCj06mb0-ydlzBSIUCPMaMQk9EhlEM_qK3d1iimCQnwo6KsIQ" \
+  localhost:8081
+```
+
+I get:
+
+```bash
+Hello, 0oaf5u5g4m6CW4x6z0h7!
+```
+
+== 3. Testing against other Authorization Servers
+
+The sample is already prepared to demonstrate integrations with a handful of other Authorization Servers. Do exercise
+one, simply uncomment two commented out sections, both in the application.yml file:
+
+```yaml
+spring:
+  security:
+    oauth2:
+      resourceserver:
+        issuer:
+```
+
+First, find the above section in the application.yml. Beneath it, you will see sections for each Authorization Server
+already prepared with the one for Okta commented out:
+
+```yaml
+#          master: #keycloak
+#            issuer: http://localhost:8080/auth/realms/master
+#            jwk-set-uri: http://localhost:8080/auth/realms/master/protocol/openid-connect/certs
+          okta:
+            issuer: https://dev-805262.oktapreview.com/oauth2/default
+            jwk-set-uri: https://dev-805262.oktapreview.com/oauth2/default/v1/keys
+```
+
+Comment out the `okta` section and uncomment the desired section.
+
+Second, find the following section, which the sample needs in order to retreive a valid token from the Authorization
+Server:
+
+```yaml
+#  ### keycloak
+#  token-uri: http://localhost:8080/auth/realms/master/protocol/openid-connect/token
+#  token-body:
+#    grant_type: client_credentials
+#  client-id: service
+#  client-password: 9114712b-be55-4dab-b270-04734abda1c4
+#  container:
+#    config-file-name: keycloak.config
+#    docker-file-name: keycloak.docker
+  ### okta
+  token-uri: https://dev-805262.oktapreview.com/oauth2/default/v1/token
+  token-body:
+    grant_type: client_credentials
+  client-id: 0oaf5u5g4m6CW4x6z0h7
+  client-password: HR7edRoo3glhF06HTxonOKZvO4I2BWYcC_ocOHlv
+```
+
+Comment out the `okta` section and uncomment the desired section.
+
+=== How can I test with my own Authorization Server instance?
+
+To test with your own Okta or other Authorization Server instance, simply provide the following information:
+
+```yaml
+spring.security.oauth2.resourceserver.issuer.name.uri: the issuer uri
+spring.security.oauth2.resourceserver.issuer.name.jwk-set-uri: the jwk key uri
+```
+
+And indicate, using the sample.provider properties, how the sample should generate a valid JWT token:
+
+```yaml
+sample.provider.token-uri: the token endpoint
+sample.provider.token-body.grant_type: the grant to use
+sample.provider.token-body.another_property: another_value
+sample.provider.client-id: the client id
+sample.provider.client-password: the client password, only required for confidential clients
+```
+
+You can provide values for any OAuth 2.0-compliant Authorization Server.