[Java][okhttp-gson] Making API response headers case insensitive

docs/generators/java.md

@@ -54,4 +54,5 @@ sidebar_label: java
 |useRuntimeException|Use RuntimeException instead of Exception| |false|
 |feignVersion|Version of OpenFeign: '10.x', '9.x' (default)| |false|
 |useReflectionEqualsHashCode|Use org.apache.commons.lang3.builder for equals and hashCode in the models. WARNING: This will fail under a security manager, unless the appropriate permissions are set up correctly and also there's potential performance impact.| |false|
+|caseInsensitiveResponseHeaders|Make API response's headers case-insensitive in okhttp-gson library| |false|
 |library|library template (sub-template) to use|<dl><dt>**jersey1**</dt><dd>HTTP client: Jersey client 1.19.x. JSON processing: Jackson 2.8.x. Enable Java6 support using '-DsupportJava6=true'. Enable gzip request encoding using '-DuseGzipFeature=true'. IMPORTANT NOTE: jersey 1.x is no longer actively maintained so please upgrade to 'jersey2' or other HTTP libaries instead.</dd><dt>**jersey2**</dt><dd>HTTP client: Jersey client 2.25.1. JSON processing: Jackson 2.8.x</dd><dt>**feign**</dt><dd>HTTP client: OpenFeign 9.x or 10.x. JSON processing: Jackson 2.8.x. To enable OpenFeign 10.x, set the 'feignVersion' option to '10.x'</dd><dt>**okhttp-gson**</dt><dd>[DEFAULT] HTTP client: OkHttp 3.x. JSON processing: Gson 2.8.x. Enable Parcelable models on Android using '-DparcelableModel=true'. Enable gzip request encoding using '-DuseGzipFeature=true'.</dd><dt>**retrofit**</dt><dd>HTTP client: OkHttp 2.x. JSON processing: Gson 2.x (Retrofit 1.9.0). IMPORTANT NOTE: retrofit1.x is no longer actively maintained so please upgrade to 'retrofit2' instead.</dd><dt>**retrofit2**</dt><dd>HTTP client: OkHttp 3.x. JSON processing: Gson 2.x (Retrofit 2.3.0). Enable the RxJava adapter using '-DuseRxJava[2]=true'. (RxJava 1.x or 2.x)</dd><dt>**resttemplate**</dt><dd>HTTP client: Spring RestTemplate 4.x. JSON processing: Jackson 2.8.x</dd><dt>**webclient**</dt><dd>HTTP client: Spring WebClient 5.x. JSON processing: Jackson 2.9.x</dd><dt>**resteasy**</dt><dd>HTTP client: Resteasy client 3.x. JSON processing: Jackson 2.8.x</dd><dt>**vertx**</dt><dd>HTTP client: VertX client 3.x. JSON processing: Jackson 2.8.x</dd><dt>**google-api-client**</dt><dd>HTTP client: Google API client 1.x. JSON processing: Jackson 2.8.x</dd><dt>**rest-assured**</dt><dd>HTTP client: rest-assured : 3.x. JSON processing: Gson 2.x. Only for Java8</dd><dl>|okhttp-gson|

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java

@@ -54,6 +54,7 @@ public class JavaClientCodegen extends AbstractJavaCodegen
     public static final String PARCELABLE_MODEL = "parcelableModel";
     public static final String USE_RUNTIME_EXCEPTION = "useRuntimeException";
     public static final String USE_REFLECTION_EQUALS_HASHCODE = "useReflectionEqualsHashCode";
+    public static final String CASE_INSENSITIVE_RESPONSE_HEADERS = "caseInsensitiveResponseHeaders";
 
     public static final String PLAY_24 = "play24";
     public static final String PLAY_25 = "play25";
@@ -90,6 +91,7 @@ public class JavaClientCodegen extends AbstractJavaCodegen
     protected boolean useGzipFeature = false;
     protected boolean useRuntimeException = false;
     protected boolean useReflectionEqualsHashCode = false;
+    protected boolean caseInsensitiveResponseHeaders = false;
     protected String authFolder;
 
     public JavaClientCodegen() {
@@ -122,6 +124,8 @@ public JavaClientCodegen() {
         cliOptions.add(CliOption.newBoolean(USE_RUNTIME_EXCEPTION, "Use RuntimeException instead of Exception"));
         cliOptions.add(CliOption.newBoolean(FEIGN_VERSION, "Version of OpenFeign: '10.x', '9.x' (default)"));
         cliOptions.add(CliOption.newBoolean(USE_REFLECTION_EQUALS_HASHCODE, "Use org.apache.commons.lang3.builder for equals and hashCode in the models. WARNING: This will fail under a security manager, unless the appropriate permissions are set up correctly and also there's potential performance impact."));
+        cliOptions.add(CliOption.newBoolean(CASE_INSENSITIVE_RESPONSE_HEADERS, "Make API response's headers case-insensitive in " + OKHTTP_GSON + " library"));
+
 
         supportedLibraries.put(JERSEY1, "HTTP client: Jersey client 1.19.x. JSON processing: Jackson 2.8.x. Enable Java6 support using '-DsupportJava6=true'. Enable gzip request encoding using '-DuseGzipFeature=true'. IMPORTANT NOTE: jersey 1.x is no longer actively maintained so please upgrade to 'jersey2' or other HTTP libaries instead.");
         supportedLibraries.put(JERSEY2, "HTTP client: Jersey client 2.25.1. JSON processing: Jackson 2.8.x");
@@ -232,6 +236,10 @@ public void processOpts() {
             this.setUseReflectionEqualsHashCode(convertPropertyToBooleanAndWriteBack(USE_REFLECTION_EQUALS_HASHCODE));
         }
 
+        if (additionalProperties.containsKey(CASE_INSENSITIVE_RESPONSE_HEADERS)) {
+            this.setUseReflectionEqualsHashCode(convertPropertyToBooleanAndWriteBack(CASE_INSENSITIVE_RESPONSE_HEADERS));
+        }
+
         final String invokerFolder = (sourceFolder + '/' + invokerPackage).replace(".", "/");
         final String apiFolder = (sourceFolder + '/' + apiPackage).replace(".", "/");
         authFolder = (sourceFolder + '/' + invokerPackage + ".auth").replace(".", "/");
@@ -659,6 +667,10 @@ public void setUseReflectionEqualsHashCode(boolean useReflectionEqualsHashCode)
         this.useReflectionEqualsHashCode = useReflectionEqualsHashCode;
     }
 
+    public void setCaseInsensitiveResponseHeaders(final Boolean caseInsensitiveResponseHeaders) {
+        this.caseInsensitiveResponseHeaders = caseInsensitiveResponseHeaders;
+    }
+
     final private static Pattern JSON_MIME_PATTERN = Pattern.compile("(?i)application\\/json(;.*)?");
     final private static Pattern JSON_VENDOR_MIME_PATTERN = Pattern.compile("(?i)application\\/vnd.(.*)+json(;.*)?");
 

modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/ApiResponse.mustache

@@ -4,6 +4,10 @@ package {{invokerPackage}};
 
 import java.util.List;
 import java.util.Map;
+{{#caseInsensitiveResponseHeaders}}
+import java.util.Map.Entry;		
+import java.util.TreeMap;
+{{/caseInsensitiveResponseHeaders}}
 
 /**
  * API response returned by API call.
@@ -30,7 +34,13 @@ public class ApiResponse<T> {
      */
     public ApiResponse(int statusCode, Map<String, List<String>> headers, T data) {
         this.statusCode = statusCode;
-        this.headers = headers;
+        {{#caseInsensitiveResponseHeaders}}
+        Map<String, List<String>> responseHeaders = new TreeMap<String, List<String>>(String.CASE_INSENSITIVE_ORDER);
+        for(Entry<String, List<String>> entry : headers.entrySet()){
+           responseHeaders.put(entry.getKey().toLowerCase(), entry.getValue());
+        }
+        {{/caseInsensitiveResponseHeaders}}
+        this.headers = {{#caseInsensitiveResponseHeaders}}responseHeaders{{/caseInsensitiveResponseHeaders}}{{^caseInsensitiveResponseHeaders}}headers{{/caseInsensitiveResponseHeaders}};
         this.data = data;
     }
 

modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/apiException.mustache

@@ -0,0 +1,96 @@
+{{>licenseInfo}}
+
+package {{invokerPackage}};
+
+import java.util.Map;
+import java.util.List;
+{{#caseInsensitiveResponseHeaders}}
+import java.util.Map.Entry;		
+import java.util.TreeMap;
+{{/caseInsensitiveResponseHeaders}}
+
+{{>generatedAnnotation}}
+public class ApiException extends{{#useRuntimeException}} RuntimeException {{/useRuntimeException}}{{^useRuntimeException}} Exception {{/useRuntimeException}}{
+    private int code = 0;
+    private Map<String, List<String>> responseHeaders = null;
+    private String responseBody = null;
+
+    public ApiException() {}
+
+    public ApiException(Throwable throwable) {
+        super(throwable);
+    }
+
+    public ApiException(String message) {
+        super(message);
+    }
+
+    public ApiException(String message, Throwable throwable, int code, Map<String, List<String>> responseHeaders, String responseBody) {
+        super(message, throwable);
+        this.code = code;
+        {{#caseInsensitiveResponseHeaders}}
+        Map<String, List<String>> headers = new TreeMap<String, List<String>>(String.CASE_INSENSITIVE_ORDER);
+        for(Entry<String, List<String>> entry : responseHeaders.entrySet()){
+        	headers.put(entry.getKey().toLowerCase(), entry.getValue());
+        }
+        {{/caseInsensitiveResponseHeaders}}
+        this.responseHeaders = {{#caseInsensitiveResponseHeaders}}headers{{/caseInsensitiveResponseHeaders}}{{^caseInsensitiveResponseHeaders}}responseHeaders{{/caseInsensitiveResponseHeaders}};
+        this.responseBody = responseBody;
+    }
+
+    public ApiException(String message, int code, Map<String, List<String>> responseHeaders, String responseBody) {
+        this(message, (Throwable) null, code, responseHeaders, responseBody);
+    }
+
+    public ApiException(String message, Throwable throwable, int code, Map<String, List<String>> responseHeaders) {
+        this(message, throwable, code, responseHeaders, null);
+    }
+
+    public ApiException(int code, Map<String, List<String>> responseHeaders, String responseBody) {
+        this((String) null, (Throwable) null, code, responseHeaders, responseBody);
+    }
+
+    public ApiException(int code, String message) {
+        super(message);
+        this.code = code;
+    }
+
+    public ApiException(int code, String message, Map<String, List<String>> responseHeaders, String responseBody) {
+        this(code, message);
+        {{#caseInsensitiveResponseHeaders}}
+        Map<String, List<String>> headers = new TreeMap<String, List<String>>(String.CASE_INSENSITIVE_ORDER);
+        for(Entry<String, List<String>> entry : responseHeaders.entrySet()){
+        	headers.put(entry.getKey().toLowerCase(), entry.getValue());
+        }
+        {{/caseInsensitiveResponseHeaders}}
+        this.responseHeaders = {{#caseInsensitiveResponseHeaders}}headers{{/caseInsensitiveResponseHeaders}}{{^caseInsensitiveResponseHeaders}}responseHeaders{{/caseInsensitiveResponseHeaders}};
+        this.responseBody = responseBody;
+    }
+
+    /**
+     * Get the HTTP status code.
+     *
+     * @return HTTP status code
+     */
+    public int getCode() {
+        return code;
+    }
+
+    /**
+     * Get the HTTP response headers.
+     *
+     * @return A map of list of string
+     */
+    public Map<String, List<String>> getResponseHeaders() {
+        return responseHeaders;
+    }
+
+    /**
+     * Get the HTTP response body.
+     *
+     * @return Response body in the form of string
+     */
+    public String getResponseBody() {
+        return responseBody;
+    }
+}