Auto-configure headers with static values in REST starter.

release-notes.md

@@ -5,6 +5,20 @@ For Spring Boot 3.4.x.
 
 `spring-addons-starter-rest` provides auto-configuration for `RestClient`, `WebClient` and tooling for `@HttpExchange` proxy generation.
 
+### `8.0.1`
+- Auto-configure static headers with `spring-addons-starter-rest`. Sample:
+```yaml
+com:
+  c4-soft:
+    springaddons:
+      rest:
+        client:
+          greet-client:
+            base-url: ${client-uri}/api
+            headers:
+              X-API-KEY: change-me
+```
+
 ### `8.0.0`
 - [`spring-addons-starter-rest`](https://github.com/ch4mpy/spring-addons/tree/master/spring-addons-starter-rest) now expose as `@Bean` some `RestClient` and `WebClient` instances (or builders) with the following configured using application properties:
   - Base URI

spring-addons-starter-rest/README.md

@@ -4,6 +4,7 @@ This starter aims at auto-configuring `RestClient` and `WebClient` using applica
 - `Basic` or OAuth2 `Bearer` authorization; for the latter, using either a client registration or forwarding the access token in the security context of a resource server.
 - proxy settings with consideration of `HTTP_PROXY` and `NO_PROXY` environment variables. Finer-grained configuration or overrides can be achieved with custom properties.
 - connection and read timeouts
+- headers with static values (for instance an API key)
 
 Instantiated REST clients are `WebClient` in WebFlux apps and `RestClient` in servlets, but any client can be switched to `WebClient` in servlets.
 
@@ -93,6 +94,15 @@ com:
             http:
               proxy:
                 enabled: false
+          chouette-client:
+            base-url: https://something.pf/api
+            # add headers with static values
+            headers:
+              X-API-KEY: change-me
+              X-MULTI-VALUED-HEADER: 
+              - foo
+              - bar
+              - bam
 ```
 The `biduleClientBuilder` bean can be used to define a `biduleClient` bean as follows:
 ```java

spring-addons-starter-rest/src/main/java/com/c4_soft/springaddons/rest/AbstractWebClientBuilderFactoryBean.java

@@ -45,6 +45,11 @@ public WebClient.Builder getObject() throws Exception {
 
     setAuthorizationHeader(builder, clientProps.getAuthorization(), clientId);
 
+    for (var header : clientProps.getHeaders().entrySet()) {
+      builder.defaultHeader(header.getKey(),
+          header.getValue().toArray(new String[header.getValue().size()]));
+    }
+
     return builder;
   }
 

spring-addons-starter-rest/src/main/java/com/c4_soft/springaddons/rest/SpringAddonsRestClientBeans.java

@@ -175,6 +175,11 @@ public RestClient.Builder getObject() throws Exception {
 
       setAuthorizationHeader(builder, clientProps.getAuthorization(), clientId);
 
+      for (var header : clientProps.getHeaders().entrySet()) {
+        builder.defaultHeader(header.getKey(),
+            header.getValue().toArray(new String[header.getValue().size()]));
+      }
+
       return builder;
     }
 

spring-addons-starter-rest/src/main/java/com/c4_soft/springaddons/rest/SpringAddonsRestProperties.java

@@ -4,6 +4,7 @@
 import java.net.URL;
 import java.nio.charset.Charset;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import org.springframework.boot.autoconfigure.AutoConfiguration;
@@ -119,6 +120,13 @@ public static class RestClientProperties {
      */
     private Optional<String> beanName = Optional.empty();
 
+    /**
+     * Some static headers to add to all requests sent by this client (for instance an API key). The
+     * key is the header name. If the value contains several entries, the header is set several
+     * times.
+     */
+    private Map<String, List<String>> headers = new HashMap<>();
+
     public Optional<URL> getBaseUrl() {
       return baseUrl.map(t -> {
         try {