Retrofit 2 Download Adapter

A file download specialized call for Retrofit 2.

Usage

Basics

Use Download.Builder as return type of the retrofit method, @Streamingannotation is required.

interface Service {
  @Streaming
  @GET
  Download.Builder download(@Url String url);
}

Add DownloadCallAdapterFactory when setting up retrofit, and then create the service as usual.

Retrofit retrofit = new Retrofit.Builder()
  ...
  .addCallAdapterFactory(DownloadCallAdapterFactory.create())
  ...
  .build();
  
Service service = retrofit.create(Service.class);

Specify the destination file with .to, a regular retrofit Call<ReponseBody> will be returned. To start the download use .execute or .enqueue.

File myFile = ...
service.download(someUrl)
  .to(myFile)
  .enqueue(new Callback<ResponseBody>() {
    @Override
    public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
      ...
    }

    @Override
    public void onFailure(Call<ResponseBody> call, Throwable t) {
      ...
    }
  });

Progress

Set a ProgressListenerto be notified of the download advancement.

service.download(someUrl)
  .progress(new ProgressListener() {
    @Override
    public void onProgress(Download download, long bytesRead, long totalBytesRead, long contentLength) {
      dialog.setProgress((int) (totalBytesRead * 100f / contentLength));
    }
  })
  .to(...)
  .enqueue(...)

Tag

Extra data can be stored with .tag, it can be handy in some situations.

MyFilePojo myFilePojo = ...
service.download(someUrl)
  .tag(myFilePojo)
  .to(...)
  .enqueue(new Callback<ResponseBody>() {
    @Override
    public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
      Download download = (Download) call;
      MyFilePojo myFilePojo = (MyFilePojo) download.tag();
      openFile(download.file(), myFilePojo.mimeType());
    }

    @Override
    public void onFailure(Call<ResponseBody> call, Throwable t) {
      ...
    }
  });

Validation

Validate the download when finished.

final String expectedChecksum = ...
service.download(someUrl)
  .validate(Checksum.MD5, new ValidationCallback() {
    @Override
    public void validate(Download download, String checksum) throw IOException {
      if (!expectedChecksum.equals(checksum)) {
        throw new IOException("Invalid checksum");
      }
    }
  })
  .to(...)
  .enqueue(...);

Filters

Stream can be modified before being written to the file with Filters.

service.download(someUrl)
  .addFilter(new OutputStreamFilter() {
    @Override
    public OutputStream create(Download download, OutputStream downstream) throws IOException {
      return new CipherOutputStream(downstream, new MyFancyCipher());
    }
  })
  .to(...)
  .enqueue(...);

Download

The latest JAR

or maven

<dependency>
  <groupId>com.github.samizerouta.retrofit</groupId>
  <artifactId>retrofit2-download-adapter</artifactId>
  <version>1.0.0</version>
</dependency>

or gradle

compile 'com.github.samizerouta.retrofit:retrofit2-download-adapter:1.0.0'

Snapshots of the development version are available in Sonatype's snapshots repository.

License

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.

p4535992 / retrofit2-download-adapter Goto Github PK