7.1.3 Multipart Client Uploads

The Micronaut HTTP Client supports the ability to create multipart requests. In order to build a multipart request you must set the content type to multipart/form-data and set the body to be an instance of MultipartBody:

For example:

Creating the body

  1. import io.micronaut.http.client.multipart.MultipartBody;
  3.             String toWrite = "test file";
  4.             File file = File.createTempFile("data", ".txt");
  5.             FileWriter writer = new FileWriter(file);
  6.             writer.write(toWrite);
  7.             writer.close();
  9.             MultipartBody requestBody = MultipartBody.builder()     (1)
  10.                     .addPart(                                       (2)
  11.                         "data",
  12.                         file.getName(),
  13.                         MediaType.TEXT_PLAIN_TYPE,
  14.                         file
  15.                     ).build()   ;                                    (3)

Creating the body

  1. import io.micronaut.http.multipart.CompletedFileUpload
  2. import io.micronaut.http.multipart.StreamingFileUpload
  3. import io.micronaut.http.client.multipart.MultipartBody
  4. import org.reactivestreams.Publisher
  6.         File file = new File(uploadDir, "data.txt")
  7.         file.text = "test file"
  8.         file.createNewFile()
  11.         MultipartBody requestBody = MultipartBody.builder()     (1)
  12.                 .addPart(                                       (2)
  13.                     "data",
  14.                     file.name,
  15.                     MediaType.TEXT_PLAIN_TYPE,
  16.                     file
  17.                 ).build()                                       (3)

Creating the body

  1. import io.micronaut.http.client.multipart.MultipartBody
  3.             val toWrite = "test file"
  4.             val file = File.createTempFile("data", ".txt")
  5.             val writer = FileWriter(file)
  6.             writer.write(toWrite)
  7.             writer.close()
  9.             val requestBody = MultipartBody.builder()     (1)
  10.                     .addPart(                             (2)
  11.                             "data",
  12.                             file.name,
  13.                             MediaType.TEXT_PLAIN_TYPE,
  14.                             file
  15.                     ).build()                             (3)
1You need to create a MultipartBody builder for adding parts to the body.
2Method to add a part to the body, in this case a file. There are different variations of this method which you can see in MultipartBody.Builder.
3Call the build method to assemble all parts from the builder into a MultipartBody. At least one part is required.

Creating a request

  1.                     HttpRequest.POST("/multipart/upload", requestBody)       (1)
  2.                             .contentType(MediaType.MULTIPART_FORM_DATA_TYPE) (2)

Creating a request

  1.                 HttpRequest.POST("/multipart/upload", requestBody)       (1)
  2.                         .contentType(MediaType.MULTIPART_FORM_DATA_TYPE) (2)

Creating a request

  1.                     HttpRequest.POST("/multipart/upload", requestBody)   (1)
  2.                             .contentType(MediaType.MULTIPART_FORM_DATA_TYPE) (2)
1The multipart request body with different sets of data.
2Set the content-type header of the request to multipart/form-data.