Added FormData object (#38)

* Added FormData object

* Fixed PMD checks

* Updated README with FormData example

* Added FormData creation example

README.md

@@ -80,18 +80,37 @@ interface SomeApi {
 
     ...
 
+    // File parameter
     @RequestLine("POST /send_photo")
     @Headers("Content-Type: multipart/form-data")
     void sendPhoto (@Param("is_public") Boolean isPublic, @Param("photo") File photo);
 
+    // byte[] parameter
+    @RequestLine("POST /send_photo")
+    @Headers("Content-Type: multipart/form-data")
+    void sendPhoto (@Param("is_public") Boolean isPublic, @Param("photo") byte[] photo);
+
+    // FormData parameter
+    @RequestLine("POST /send_photo")
+    @Headers("Content-Type: multipart/form-data")
+    void sendPhoto (@Param("is_public") Boolean isPublic, @Param("photo") FormData photo);
     ...
 
 }
 ```
 
-In example above, we send file in parameter named **photo** with additional field in form **is_public**.
+In the example above, the `sendPhoto` method uses the `photo` parameter using three different supported types.
 
-> **IMPORTANT:** You can specify your files in API method by declaring type **File** or **byte[]**.
+* `File` will use the File's extension to detect the `Content-Type`.
+* `byte[]` will use `application/octet-stream` as `Content-Type`.
+* `FormData` will use the `FormData`'s `Content-Type`.
+
+`FormData` is custom object that wraps a `byte[]` and defines a `Content-Type` like this:
+
+```java
+    FormData formData = new FormData("image/png", myDataAsByteArray);
+    someApi.sendPhoto(true, formData);
+```
 
 ### Spring MultipartFile and Spring Cloud Netflix @FeignClient support
 

feign-form/pom.xml

@@ -37,6 +37,14 @@ limitations under the License.
     <maven.compiler.target>1.6</maven.compiler.target>
   </properties>
 
+  <dependencies>
+    <dependency>
+      <groupId>com.google.code.findbugs</groupId>
+      <artifactId>annotations</artifactId>
+      <version>3.0.1</version>
+    </dependency>
+  </dependencies>
+
   <build>
     <plugins>
       <plugin>

feign-form/src/main/java/feign/form/FormData.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2018 Artem Labazin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package feign.form;
+
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
+
+/**
+ * This object encapsulates a byte array and its associated content type.
+ * Use if if you want to specify the content type of your provided byte array.
+ */
+
+@SuppressFBWarnings({"EI_EXPOSE_REP", "EI_EXPOSE_REP2"})
+public final class FormData {
+  private final String contentType;
+  private final byte[] data;
+
+  public FormData (String contentType, byte[] data) {
+    this.contentType = contentType;
+    this.data = data;
+  }
+
+  public String getContentType () {
+    return contentType;
+  }
+
+  public byte[] getData () {
+    return data;
+  }
+}

feign-form/src/main/java/feign/form/MultipartFormContentProcessor.java

@@ -29,6 +29,7 @@
 import feign.codec.Encoder;
 import feign.form.multipart.ByteArrayWriter;
 import feign.form.multipart.DelegateWriter;
+import feign.form.multipart.FormDataWriter;
 import feign.form.multipart.ManyFilesWriter;
 import feign.form.multipart.Output;
 import feign.form.multipart.ParameterWriter;
@@ -57,6 +58,7 @@ public class MultipartFormContentProcessor implements ContentProcessor {
   public MultipartFormContentProcessor (Encoder delegate) {
     writers = new ArrayList<Writer>(6);
     addWriter(new ByteArrayWriter());
+    addWriter(new FormDataWriter());
     addWriter(new SingleFileWriter());
     addWriter(new ManyFilesWriter());
     addWriter(new ParameterWriter());

feign-form/src/main/java/feign/form/multipart/FormDataWriter.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2018 Artem Labazin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package feign.form.multipart;
+
+import feign.form.FormData;
+
+import lombok.val;
+
+public class FormDataWriter extends AbstractWriter {
+  @Override
+  public boolean isApplicable (Object value) {
+    return value instanceof FormData;
+  }
+
+  @Override
+  protected void write (Output output, String key, Object value) throws Exception {
+    val formData = (FormData) value;
+    writeFileMetadata(output, key, null, formData.getContentType());
+    output.write(formData.getData());
+  }
+}

feign-form/src/test/java/feign/form/BasicClientTest.java

@@ -28,6 +28,7 @@
 import java.nio.file.Paths;
 import java.util.Map;
 import lombok.val;
+import org.apache.tomcat.util.http.fileupload.IOUtils;
 import org.junit.Assert;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -158,4 +159,11 @@ public void testUnknownTypeFile() throws Exception {
       val stringResponse = api.uploadUnknownType(path.toFile());
       Assert.assertEquals("application/octet-stream", stringResponse);
   }
+
+  @Test
+  public void testFormData() throws Exception {
+      val formData = new FormData("application/custom-type", "Allo".getBytes("UTF-8"));
+      val stringResponse = api.uploadFormData(formData);
+      Assert.assertEquals("application/custom-type", stringResponse);
+  }
 }

feign-form/src/test/java/feign/form/Server.java

@@ -178,4 +178,15 @@ public ResponseEntity<String> uploadUnknownType (@RequestPart("file") MultipartF
                  : I_AM_A_TEAPOT;
     return ResponseEntity.status(status).body(file.getContentType());
   }
+
+  @PostMapping(
+    path = "/upload/form_data",
+    consumes = MULTIPART_FORM_DATA_VALUE
+  )
+  public ResponseEntity<String> uploadFormData (@RequestPart("file") MultipartFile file) {
+    val status = file != null
+                 ? OK
+                 : I_AM_A_TEAPOT;
+    return ResponseEntity.status(status).body(file.getContentType());
+  }
 }

feign-form/src/test/java/feign/form/TestClient.java

@@ -16,14 +16,15 @@
 
 package feign.form;
 
+import java.io.File;
+import java.util.List;
+import java.util.Map;
+
 import feign.Headers;
 import feign.Param;
 import feign.QueryMap;
 import feign.RequestLine;
 import feign.Response;
-import java.io.File;
-import java.util.List;
-import java.util.Map;
 
 /**
  *
@@ -69,4 +70,8 @@ public interface TestClient {
   @RequestLine("POST /upload/unknown_type")
   @Headers("Content-Type: multipart/form-data")
   String uploadUnknownType (@Param("file") File file);
+
+  @RequestLine("POST /upload/form_data")
+  @Headers("Content-Type: multipart/form-data")
+  String uploadFormData (@Param("file") FormData formData);
 }