Added 'additive' proxy strategy behavior that sets additional headers…

… to the request (#270)

docs/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 #### 7.3.2-SNAPSHOT
 
+* PR [#270](https://github.com/azagniotov/stubby4j/pull/270) - Added `additive` proxy strategy behavior that sets additional headers to the request (https://github.com/azagniotov)
+
 #### 7.3.1
 
 * PR [#264](https://github.com/azagniotov/stubby4j/pull/264) - Multiple proxy configurations support (https://github.com/azagniotov)

docs/REQUEST_PROXYING.md

@@ -122,20 +122,41 @@ This can be anything describing your proxy configuration.
 
 #### strategy (`required`)
 
-Describes how the request to-be-proxied should be proxied. Currently only `as-is` strategy is supported, which means that request will be proxied without any changes/modifications before being sent to the proxy service. In the future enhancements to the request proxying functionality, more strategies will be supported.
+Describes how the request to-be-proxied should be proxied. Currently only the following strategy values are supported:
+* `as-is`: no changes/modifications will be applied to the request before proxying it
+* `additive`: additive changes will be applied to the request before proxying it. The additive changes currently supported are setting of additional HTTP headers using the `headers` property on the `proxy-config` object.
+
+In the future enhancements to the request proxying functionality, more strategies will be supported.
 
 #### properties (`required`)
 
-Describes the properties of the proxy, e.g.: endpoint, headers, etc. Currently only `endpoint` property is supported. In the future enhancements to the request proxying functionality, more properties will be supported.
+A map of key/value pairs describing the properties of the proxy, e.g.: endpoint, etc. Currently only `endpoint` property is supported. In the future enhancements to the request proxying functionality, more properties will be supported.
+
+##### endpoint (`required`)
 
-#### endpoint (`required`)
+Must be defined under the `properties` property. Describes the target service endpoint where the request will be proxied to. This should be a protocol scheme + fully qualified domain name (i.e.: `FQDN`) without any URI paths:
 
-Describes the target service endpoint where the request will be proxied to. This should be a protocol scheme + fully qualified domain name (i.e.: `FQDN`) without any URI paths:
 * Correct: `https://jsonplaceholder.typicode.com`
 * Incorrect: `jsonplaceholder.typicode.com`
 * Incorrect: `https://jsonplaceholder.typicode.com/`
 * Incorrect: `https://jsonplaceholder.typicode.com/posts/1`
 
+#### headers (`optional`)
+
+A map of key/value pairs describing an HTTP header name and its value. The `headers` property can be used when `strategy` property is set to `additive`. The headers will be added to the request being proxied in an additive manner, i.e.: they will not replace the headers already set on the request.
+
+```yaml
+- proxy-config:
+    uuid: some-other-unique-name
+    strategy: additive
+    properties:
+      endpoint: https://jsonplaceholder.typicode.com
+    headers:
+      content-type: application/json+special
+      x-custom-header: something/unique
+      x-custom-header-2: another/thing
+```
+
 ## Application of proxy config at runtime
 
 Request proxying happens when there is at least one `proxy config` object defined in the YAML config and an incoming HTTP request did not match any of the declared `stubby4j`'s stubs.

src/functional-test/java/io/github/azagniotov/stubby4j/ProxyConfigWithStubsTest.java

@@ -140,7 +140,7 @@ public void shouldReturnProxiedResponseUsingSpecificProxyConfig_WhenStubsWereNot
         // The 'null' overrides the default value "gzip", also I had to .disableContentCompression() on WEB_CLIENT
         httpHeaders.setAcceptEncoding(null);
 
-        // The 'some-unique-name' is actually set in include-proxy-config.yaml
+        // The 'some-unique-name' is actually set in 'proxy-config' object defined in resources/yaml/include-proxy-config.yaml
         httpHeaders.set(HEADER_X_STUBBY_PROXY_CONFIG, "some-unique-name");
         request.setHeaders(httpHeaders);
 
@@ -175,7 +175,9 @@ public void should_UpdateStubbedProxyConfig_WithJsonRequest_ByValidUuid() throws
         assertThat(getResponseContent).isEqualTo(
                 "- proxy-config:\n" +
                         "    uuid: some-unique-name\n" +
-                        "    strategy: custom\n" +
+                        "    strategy: additive\n" +
+                        "    headers:\n" +
+                        "      x-original-stubby4j-custom-header: custom/value\n" +
                         "    properties:\n" +
                         "      endpoint: https://jsonplaceholder.typicode.com");
 
@@ -208,7 +210,9 @@ public void should_UpdateStubbedProxyConfig_WithJsonRequest_ByValidUuid() throws
         assertThat(getResponseContent).isEqualTo(
                 "- proxy-config:\n" +
                         "    uuid: some-unique-name\n" +
-                        "    strategy: custom\n" +
+                        "    strategy: additive\n" +
+                        "    headers:\n" +
+                        "      x-custom-header: custom/value\n" +
                         "    properties:\n" +
                         "      endpoint: https://UPDATED.com");
     }

src/functional-test/resources/json/request/json_payload_11.json

@@ -2,7 +2,10 @@
   {
     "proxy-config": {
       "uuid": "some-unique-name",
-      "strategy": "custom",
+      "strategy": "additive",
+      "headers": {
+        "x-custom-header": "custom/value"
+      },
       "properties": {
         "endpoint": "https://UPDATED.com"
       }

src/functional-test/resources/yaml/include-proxy-config.yaml

@@ -6,20 +6,22 @@
 
 - proxy-config:
     uuid: some-unique-name
-    strategy: custom
+    strategy: additive
+    headers:
+      x-original-stubby4j-custom-header: custom/value
     properties:
       endpoint: https://jsonplaceholder.typicode.com
 
 - proxy-config:
     description: description-2
     uuid: some-unique-name-two
-    strategy: custom
+    strategy: additive
     properties:
       endpoint: https://google.com
 
 - proxy-config:
     description: description-3
     uuid: some-unique-name-three
-    strategy: custom
+    strategy: additive
     properties:
       endpoint: https://google.com

src/integration-test/java/io/github/azagniotov/stubby4j/yaml/YamlParserTest.java

@@ -967,7 +967,7 @@ public void shouldUnmarshall_toProxyConfigs() throws Exception {
 
         final StubProxyConfig customStubProxyConfig = proxyConfigs.get("some-unique-name");
         assertThat(customStubProxyConfig.getUUID()).isEqualTo("some-unique-name");
-        assertThat(customStubProxyConfig.getStrategy()).isEqualTo(StubProxyStrategy.CUSTOM);
+        assertThat(customStubProxyConfig.getStrategy()).isEqualTo(StubProxyStrategy.ADDITIVE);
         assertThat(customStubProxyConfig.getProperties().size()).isEqualTo(1);
         assertThat(customStubProxyConfig.getProperties().get("endpoint")).isEqualTo("https://jsonplaceholder.typicode.com");
 
@@ -985,7 +985,7 @@ public void shouldUnmarshall_toProxyConfigs() throws Exception {
                 "- proxy-config:\n" +
                         "    description: woah! this is a unique proxy-config\n" +
                         "    uuid: some-unique-name\n" +
-                        "    strategy: custom\n" +
+                        "    strategy: additive\n" +
                         "    properties:\n" +
                         "      endpoint: https://jsonplaceholder.typicode.com\n");
     }
@@ -1014,7 +1014,7 @@ public void shouldUnmarshall_toProxyConfigsWithStubs() throws Exception {
 
         final StubProxyConfig customStubProxyConfig = proxyConfigs.get("some-unique-name");
         assertThat(customStubProxyConfig.getUUID()).isEqualTo("some-unique-name");
-        assertThat(customStubProxyConfig.getStrategy()).isEqualTo(StubProxyStrategy.CUSTOM);
+        assertThat(customStubProxyConfig.getStrategy()).isEqualTo(StubProxyStrategy.ADDITIVE);
         assertThat(customStubProxyConfig.getProperties().size()).isEqualTo(1);
         assertThat(customStubProxyConfig.getProperties().get("endpoint")).isEqualTo("https://jsonplaceholder.typicode.com");
 
@@ -1027,7 +1027,7 @@ public void shouldUnmarshall_toProxyConfigsWithStubs() throws Exception {
         assertThat(customStubProxyConfig.getProxyConfigAsYAML()).isEqualTo(
                 "- proxy-config:\n" +
                         "    uuid: some-unique-name\n" +
-                        "    strategy: custom\n" +
+                        "    strategy: additive\n" +
                         "    properties:\n" +
                         "      endpoint: https://jsonplaceholder.typicode.com\n");
     }

src/integration-test/resources/yaml/proxy-config-duplicate-uuid.yaml

@@ -6,6 +6,6 @@
 
 - proxy-config:
     uuid: some-unique-name
-    strategy: custom
+    strategy: additive
     properties:
       endpoint: https://jsonplaceholder.typicode.com

src/integration-test/resources/yaml/proxy-config-valid-config-with-stubs.yaml

@@ -5,7 +5,7 @@
 
 - proxy-config:
     uuid: some-unique-name
-    strategy: custom
+    strategy: additive
     properties:
       endpoint: https://jsonplaceholder.typicode.com
 

src/integration-test/resources/yaml/proxy-config-valid-config.yaml

@@ -10,6 +10,6 @@
 - proxy-config:
     description: woah! this is a unique proxy-config
     uuid: some-unique-name
-    strategy: custom
+    strategy: additive
     properties:
       endpoint: https://jsonplaceholder.typicode.com

src/integration-test/resources/yaml/proxy-config-without-default-config.yaml

@@ -6,6 +6,6 @@
 
 - proxy-config:
     uuid: another-unique-name
-    strategy: custom
+    strategy: additive
     properties:
       endpoint: https://jsonplaceholder.typicode.com

src/main/java/io/github/azagniotov/stubby4j/stubs/StubProxyConfig.java

@@ -50,6 +50,10 @@ public StubProxyStrategy getStrategy() {
         return strategy;
     }
 
+    public boolean isAdditiveStrategy() {
+        return strategy == StubProxyStrategy.ADDITIVE;
+    }
+
     public final Map<String, String> getHeaders() {
         return new HashMap<>(headers);
     }
@@ -102,12 +106,7 @@ public static final class Builder extends AbstractBuilder<StubProxyConfig> {
 
         public Builder() {
             super();
-            this.description = null;
-            this.uuid = DEFAULT_UUID;
-            this.strategy = null;
-            this.headers = new LinkedHashMap<>();
-            this.properties = new LinkedHashMap<>();
-            this.proxyConfigAsYAML = null;
+            reset();
         }
 
         public Builder withDescription(final String description) {
@@ -170,15 +169,20 @@ public StubProxyConfig build() {
                     properties,
                     proxyConfigAsYAML);
 
+            reset();
+
+            this.fieldNameAndValues.clear();
+
+            return stubProxyConfig;
+        }
+
+        private void reset() {
             this.description = null;
             this.uuid = DEFAULT_UUID;
-            this.strategy = null;
+            this.strategy = StubProxyStrategy.AS_IS;
             this.headers = new LinkedHashMap<>();
             this.properties = new LinkedHashMap<>();
             this.proxyConfigAsYAML = null;
-            this.fieldNameAndValues.clear();
-
-            return stubProxyConfig;
         }
     }
 }

src/main/java/io/github/azagniotov/stubby4j/stubs/StubProxyStrategy.java

@@ -8,8 +8,21 @@
 import static io.github.azagniotov.stubby4j.utils.StringUtils.toLower;
 
 public enum StubProxyStrategy {
+    /**
+     * No changes/modifications will be applied to the request before proxying it.
+     * <p>
+     * See: https://github.com/azagniotov/stubby4j/blob/master/docs/REQUEST_PROXYING.md#supported-yaml-properties
+     */
     AS_IS("as-is"),
-    CUSTOM("custom");
+
+    /**
+     * Additive changes will be applied to the request before proxying it. The additive changes
+     * currently supported are setting of additional HTTP headers using the `headers` property on the
+     * `proxy-config` object.
+     * <p>
+     * See: https://github.com/azagniotov/stubby4j/blob/master/docs/REQUEST_PROXYING.md#supported-yaml-properties
+     */
+    ADDITIVE("additive");
 
     private static final Map<String, StubProxyStrategy> PROPERTY_NAME_TO_ENUM_MEMBER;
 

src/main/java/io/github/azagniotov/stubby4j/stubs/StubRepository.java

@@ -225,6 +225,9 @@ private StubResponse proxyRequest(final StubHttpLifecycle incomingHttpLifecycle)
 
         try {
             incomingRequest.getHeaders().put(HEADER_X_STUBBY_PROXY_REQUEST, proxyRoundTripUuid);
+
+            handleIfAdditiveProxyStrategy(incomingRequest, proxyConfig);
+
             final StubbyResponse stubbyResponse = stubbyHttpTransport.httpRequestFromStub(incomingRequest, proxyEndpoint);
             for (Map.Entry<String, List<String>> entry : stubbyResponse.headers().entrySet()) {
                 final String headerName = ObjectUtils.isNull(entry.getKey()) ? "null" : entry.getKey();
@@ -253,6 +256,16 @@ private StubResponse proxyRequest(final StubHttpLifecycle incomingHttpLifecycle)
         }
     }
 
+    private void handleIfAdditiveProxyStrategy(final StubRequest incomingRequest, final StubProxyConfig proxyConfig) {
+        if (proxyConfig.isAdditiveStrategy()) {
+            if (proxyConfig.hasHeaders()) {
+                for (final Map.Entry<String, String> headerEntry : proxyConfig.getHeaders().entrySet()) {
+                    incomingRequest.getHeaders().put(headerEntry.getKey(), headerEntry.getValue());
+                }
+            }
+        }
+    }
+
     private void recordResponse(StubHttpLifecycle incomingRequest, StubHttpLifecycle matchedStub, StubResponse matchedStubResponse) {
         final String recordingSource = String.format("%s%s", matchedStubResponse.getBody(), incomingRequest.getUrl());
         try {

src/test/java/io/github/azagniotov/stubby4j/stubs/StubProxyConfigBuilderTest.java

@@ -28,6 +28,22 @@ public void cleanup() throws Exception {
         RegexParser.REGEX_PATTERN_CACHE.clear();
     }
 
+    @Test
+    public void stubbedProxyConfigDefaultStrategyNotAdditive() throws Exception {
+
+        final StubProxyConfig stubProxyConfig = builder.build();
+        assertThat(stubProxyConfig.isAdditiveStrategy()).isFalse();
+        assertThat(stubProxyConfig.getStrategy()).isEqualTo(StubProxyStrategy.AS_IS);
+    }
+
+    @Test
+    public void stubbedProxyConfigStrategyAdditive() throws Exception {
+
+        final StubProxyConfig stubProxyConfig = builder.withStrategy(StubProxyStrategy.ADDITIVE.toString()).build();
+        assertThat(stubProxyConfig.isAdditiveStrategy()).isTrue();
+        assertThat(stubProxyConfig.getStrategy()).isEqualTo(StubProxyStrategy.ADDITIVE);
+    }
+
     @Test
     public void stubbedProxyConfigHasNoHeaders() throws Exception {
 
@@ -173,7 +189,7 @@ public void stubbedProxyConfigNotEqualsAssertingConfig() throws Exception {
 
         final StubProxyConfig assertingStubProxyConfig = builder
                 .withUuid("unique")
-                .withStrategy("custom")
+                .withStrategy("additive")
                 .withPropertyEndpoint("http://google.com")
                 .build();