Adding ManyFormDataWriter, a test and making encoding ctor more customizable

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

@@ -70,15 +70,23 @@ public FormEncoder () {
    * @param delegate  delegate encoder, if this encoder couldn't encode object.
    */
   public FormEncoder (Encoder delegate) {
-    this.delegate = delegate;
+    this(delegate, asList(
+      new MultipartFormContentProcessor(delegate),
+      new UrlencodedFormContentProcessor()
+    ));
+  }
 
-    val list = asList(
-        new MultipartFormContentProcessor(delegate),
-        new UrlencodedFormContentProcessor()
-    );
+  /**
+   * Constructor with specified delegate encoder and custom processors.
+   *
+   * @param delegate  delegate encoder, if this encoder couldn't encode object.
+   * @param customProcessors processors for mutlipart and url-encoded content types.
+   */
+  public FormEncoder (Encoder delegate, Iterable<ContentProcessor> customProcessors) {
+    this.delegate = delegate;
 
-    processors = new HashMap<ContentType, ContentProcessor>(list.size(), 1.F);
-    for (ContentProcessor processor : list) {
+    processors = new HashMap<ContentType, ContentProcessor>(2, 1.F);
+    for (ContentProcessor processor : customProcessors) {
       processors.put(processor.getSupportedContentType(), processor);
     }
   }

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

@@ -27,6 +27,7 @@
 import java.util.LinkedList;
 import java.util.Map;
 
+import feign.form.multipart.ManyFormDataWriter;
 import lombok.experimental.FieldDefaults;
 import lombok.val;
 
@@ -65,6 +66,7 @@ public MultipartFormContentProcessor (Encoder delegate) {
     writers = new LinkedList<>();
     addWriter(new ByteArrayWriter());
     addWriter(new FormDataWriter());
+    addWriter(new ManyFormDataWriter());
     addWriter(new SingleFileWriter());
     addWriter(new ManyFilesWriter());
     addWriter(new SingleParameterWriter());

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

@@ -0,0 +1,37 @@
+package feign.form.multipart;
+
+import feign.codec.EncodeException;
+import feign.form.FormData;
+import lombok.val;
+
+public class ManyFormDataWriter implements Writer {
+    private final FormDataWriter formDataWriter = new FormDataWriter();
+    @Override
+    public void write(Output output, String boundary, String key, Object value) throws EncodeException {
+        if (value instanceof FormData[]) {
+            for (FormData formData : (FormData[]) value) {
+                formDataWriter.write(output, boundary, key, formData);
+            }
+        } else if (value instanceof Iterable) {
+            val fields = (Iterable)value;
+            for (Object formData : fields) {
+                formDataWriter.write(output, boundary, key, formData);
+            }
+        } else {
+            throw new IllegalStateException();
+        }
+    }
+
+    @Override
+    public boolean isApplicable(Object value) {
+        if (value instanceof FormData[]) {
+            return true;
+        }
+        if (value instanceof Iterable) {
+            val iterable = (Iterable) value;
+            val iterator = iterable.iterator();
+            return iterator.hasNext() && iterator.next() instanceof FormData;
+        }
+        return false;
+    }
+}

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

@@ -169,6 +169,17 @@ void testFormData () throws Exception {
       .isEqualTo("popa.txt:application/custom-type");
   }
 
+  @Test
+  void testMultipleFormDataList () throws Exception {
+    val formData = asList(
+            new FormData("application/custom-type", "file1.txt", "Allo".getBytes("UTF-8")),
+            new FormData("image/jpeg", "file2.jpg", "Allo".getBytes("UTF-8"))
+    );
+
+    assertThat(API.uploadFormData(formData))
+            .isEqualTo("file1.txt:application/custom-type,file2.jpg:image/jpeg");
+  }
+
   @Test
   void testSubmitRepeatableQueryParam () throws Exception {
     val names = new String[] { "Milada", "Thais" };

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

@@ -29,6 +29,7 @@
 import java.io.IOException;
 import java.util.Collection;
 import java.util.List;
+import java.util.stream.Collectors;
 
 import lombok.val;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
@@ -197,6 +198,19 @@ public ResponseEntity<String> uploadFormData (
     return ResponseEntity.status(status).body(file.getOriginalFilename() + ':' + file.getContentType());
   }
 
+  @PostMapping(path = "/upload/many_form_data", consumes = MULTIPART_FORM_DATA_VALUE)
+  public ResponseEntity<String> uploadFormData (
+          @RequestPart("file[]") List<MultipartFile> files
+  ) {
+    val status = files != null
+            ? OK
+            : I_AM_A_TEAPOT;
+    val response = files.stream()
+            .map(file -> file.getOriginalFilename() + ':' + file.getContentType())
+            .collect(Collectors.joining(","));
+    return ResponseEntity.status(status).body(response);
+  }
+
   @PostMapping(path = "/submit/url", consumes = APPLICATION_FORM_URLENCODED_VALUE)
   public ResponseEntity<String> submitRepeatableQueryParam (
     @RequestParam("names") String[] names

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

@@ -72,6 +72,10 @@ public interface TestClient {
   @Headers("Content-Type: multipart/form-data")
   String uploadFormData (@Param("file") FormData formData);
 
+  @RequestLine("POST /upload/many_form_data")
+  @Headers("Content-Type: multipart/form-data")
+  String uploadFormData (@Param("file[]") List<FormData> formData);
+
   @RequestLine("POST /submit/url")
   @Headers("Content-Type: application/x-www-form-urlencoded")
   String submitRepeatableQueryParam (@Param("names") String[] names);