Fix #523 by having the default filename of multipart/form-data in files.upload requests (#524)

* Add test cases verifying the behaviors reported at #523

* Set a placeholder for filename if absent

* Re-package new tests

Author: seratch

bolt-kotlin-examples/src/test/kotlin/test_with_remote_apis/issues/Issue523Test.kt

@@ -0,0 +1,52 @@
+package test_with_remote_apis.issues
+
+import com.slack.api.Slack
+import junit.framework.TestCase.assertNull
+import org.junit.Test
+import java.io.File
+
+class Issue523Test {
+
+    private val slack = Slack.getInstance()
+    private val token = System.getenv("SLACK_SDK_TEST_USER_TOKEN")
+    private val slackMethods = slack.methods(token)
+
+    @Test
+    fun text_no_filename() {
+        val file = File("src/test/resources/sample.txt")
+        val response = slackMethods.filesUpload {
+            it.fileData(file.readBytes()).filetype("text")
+        }
+        // assertEquals("no_file_data", response.error)
+        assertNull(response.error)
+    }
+
+    @Test
+    fun text_filename() {
+        val file = File("src/test/resources/sample.txt")
+        val response = slackMethods.filesUpload {
+            it.fileData(file.readBytes()).filetype("text").filename("test.txt")
+        }
+        assertNull(response.error)
+    }
+
+    @Test
+    fun image_no_filename() {
+        val file = File("src/test/resources/sample.jpg")
+        val response = slackMethods.filesUpload {
+            it.fileData(file.readBytes()).filetype("jpg")
+        }
+        // assertEquals("no_file_data", response.error)
+        assertNull(response.error)
+    }
+
+    @Test
+    fun image() {
+        val file = File("src/test/resources/sample.jpg")
+        val response = slackMethods.filesUpload {
+            it.fileData(file.readBytes()).filetype("jpg").filename("test.jpg")
+        }
+        assertNull(response.error)
+    }
+
+}

bolt-kotlin-examples/src/test/resources/sample.jpg

@@ -0,0 +1,5 @@
+Hello, World!!!!!
+
+This is a sample text file.
+
+日本語

bolt-kotlin-examples/src/test/resources/sample.txt

@@ -1129,6 +1129,9 @@ public static MultipartBody.Builder toMultipartBody(FilesUploadRequest req) {
         MultipartBody.Builder form = new MultipartBody.Builder();
 
         if (req.getFileData() != null) {
+            if (req.getFilename() == null) {
+                req.setFilename("uploaded_file"); // filename is required for multipart/form-data
+            }
             RequestBody file = RequestBody.create(req.getFileData(), MultipartBody.FORM);
             form.addFormDataPart("file", req.getFilename(), file);
         } else if (req.getFile() != null) {

slack-api-client/src/main/java/com/slack/api/methods/RequestFormBuilder.java

@@ -25,6 +25,9 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.Arrays;
 
 import static org.hamcrest.CoreMatchers.*;
@@ -393,6 +396,44 @@ public void createFileForAThread() throws IOException, SlackApiException {
         }
     }
 
+    @Test
+    public void issue523_text() throws IOException, SlackApiException {
+        MethodsClient slackMethods = slack.methods(userToken);
+        File file = new File("src/test/resources/sample.txt");
+        byte[] fileData = Files.readAllBytes(Paths.get(file.toURI()));
+        FilesUploadResponse response = slackMethods.filesUpload(r -> r.fileData(fileData).filename("sample.txt"));
+        assertThat(response.getError(), is(nullValue()));
+    }
+
+    @Test
+    public void issue523_image() throws IOException, SlackApiException {
+        MethodsClient slackMethods = slack.methods(userToken);
+        File file = new File("src/test/resources/user_photo.jpg");
+        byte[] fileData = Files.readAllBytes(Paths.get(file.toURI()));
+        FilesUploadResponse response = slackMethods.filesUpload(r -> r.fileData(fileData).filename("sample.jpg"));
+        assertThat(response.getError(), is(nullValue()));
+    }
+
+    @Test
+    public void issue523_text_no_filename() throws IOException, SlackApiException {
+        MethodsClient slackMethods = slack.methods(userToken);
+        File file = new File("src/test/resources/sample.txt");
+        byte[] fileData = Files.readAllBytes(Paths.get(file.toURI()));
+        FilesUploadResponse response = slackMethods.filesUpload(r -> r.fileData(fileData));
+        // assertThat(response.getError(), is("no_file_data"));
+        assertThat(response.getError(), is(nullValue()));
+    }
+
+    @Test
+    public void issue523_image_no_filename() throws IOException, SlackApiException {
+        MethodsClient slackMethods = slack.methods(userToken);
+        File file = new File("src/test/resources/user_photo.jpg");
+        byte[] fileData = Files.readAllBytes(Paths.get(file.toURI()));
+        FilesUploadResponse response = slackMethods.filesUpload(r -> r.fileData(fileData));
+        // assertThat(response.getError(), is("no_file_data"));
+        assertThat(response.getError(), is(nullValue()));
+    }
+
     @Test
     public void uploadAndPostMessage() throws IOException, SlackApiException {
         MethodsClient slackMethods = slack.methods(userToken);