从 Android/Java 上传 Base64 到 RoR Carrierwave

Question

我添加了来自use base64 image with Carrierwave 的解决方案，以便从Java 类上传图像。这就是我的 FileUploader 类现在的样子——我相信问题出在：

# encoding: utf-8

class FileUploader < CarrierWave::Uploader::Base

  # Include RMagick or MiniMagick support:
    include CarrierWave::RMagick
  # include CarrierWave::MiniMagick

  # Choose what kind of storage to use for this uploader:
  storage :file
  # storage :fog

  #START FROM BASE64 POST LINKED ABOVE
  class FilelessIO < StringIO
    attr_accessor :original_filename
    attr_accessor :content_type
  end

  before :cache, :convert_base64

  def convert_base64(file)
    if file.respond_to?(:original_filename) &&
        file.original_filename.match(/^base64:/)
      fname = file.original_filename.gsub(/^base64:/, '')
      ctype = file.content_type
      decoded = Base64.decode64(file.read)
      file.file.tempfile.close!
      decoded = FilelessIO.new(decoded)
      decoded.original_filename = fname
      decoded.content_type = ctype
      file.__send__ :file=, decoded
    end
    file
  end
#END FROM POST LINKED ABOVE


  # Override the directory where uploaded files will be stored.
  # This is a sensible default for uploaders that are meant to be mounted:
  def store_dir
    "uploads/#{model.class.to_s.underscore}/#{model.user_id}"
  end

  # Provide a default URL as a default if there hasn't been a file uploaded:
  # def default_url
  #   "/images/fallback/" + [version_name, "default.png"].compact.join('_')
  # end

  # Process files as they are uploaded:
  # process :scale => [200, 300]
  #
  # def scale(width, height)
  #   # do something
  # end

  # Create different versions of your uploaded files:
    version :thumb do
      process :resize_to_fit  => [200, 300]
    end

    version :web do
      process :resize_to_fit  => [1000, 1000]
    end

  # Add a white list of extensions which are allowed to be uploaded.
  # For images you might use something like this:
   def extension_white_list
     %w(jpg jpeg gif png)
   end

  # Override the filename of the uploaded files:
  # Avoid using model.id or version_name here, see uploader/store.rb for details.
   def filename
     if original_filename
     Time.new.to_i.to_s+"_"+original_filename
     end
   end

end

图片模型：

class Picture < ActiveRecord::Base

  belongs_to :user
  belongs_to :folders

  attr_accessible :user_id, :picture_name, :picture_description,
    :folder_id, :picture_path, :file_save

  mount_uploader :picture_path, FileUploader

   before_save :update_pictures_attributes

  def update_pictures_attributes
      self.file_size = picture_path.file.size
  end

end

现在进行 Post 调用时，保存在 db 中的文件路径为 nil - 但其他所有内容都已保存。这是java/android类：

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.client.*;
import org.apache.http.client.entity.*;
import org.apache.http.client.methods.*;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.*;
import org.apache.http.message.*;
import org.apache.commons.io.FileUtils;
import org.json.*;
import android.util.Base64;
import android.util.Log;

public class Uploader {

    private String url;
    private String fileName;

    public Uploader(String url, String fileName){
        this.url = url;
        this.fileName = fileName;
    }

    public Boolean upload() throws JSONException, ClientProtocolException, IOException {
        Boolean success = true;
        JSONObject jsonObject = constructPictureJson();
            DefaultHttpClient httpClient = new DefaultHttpClient();

            ResponseHandler <String> responseHandler = new BasicResponseHandler();
            HttpPost postMethod = new HttpPost(url);
            postMethod.setEntity(new StringEntity(jsonObject.toString()));
            postMethod.setHeader("Accept", "application/json");
            postMethod.setHeader("Content-type", "application/json");
            postMethod.setHeader("Data-type", "json");
            try{
            httpClient.execute(postMethod, responseHandler);
            } catch (org.apache.http.client.HttpResponseException error){
                Log.d("Uploader Class Error", "Error code: "+error.getStatusCode());
                Log.d("Uploader Class Error", "Error message: "+error.getMessage());
                success = false;
            }
            //Log.d("server resposne", response);
            return success;
    }

    public JSONObject constructPictureJson() throws JSONException, IOException{
        String userId = "1"; 
        String folderId = "1";
        String[] file = fileName.split("/");
        JSONObject pictureData = new JSONObject();
        pictureData.put("user_id", userId);
        pictureData.put("folder_id", folderId); 
        pictureData.put("picture_name", "picture name");
        pictureData.put("picture_description", "1"); 
        pictureData.put("content_type", "jpg");
        pictureData.put("original_filename", "base64:"+file[file.length-1]);
        pictureData.put("filename", file[file.length-1]);
        pictureData.put("picture_path", encodePicture(fileName));

        return pictureData;
    }

    public String encodePicture(String fileName) throws IOException{
        File picture = new File(fileName);
        return Base64.encodeToString(FileUtils.readFileToByteArray(picture), Base64.DEFAULT);
    }

}

有人有什么想法吗？我整天都被困在这上面。我认为因为我对 Ruby 了解不多，所以我要么（1）错误地请求；或者 (2) 我用 Carrierwave 错误地实现了 base64 图像。

Answer 1

终于解决了问题！我希望这个答案可以帮助其他试图解决这个问题的人，因为没有好的资源。这令人惊讶，因为我认为其他人也会想做同样的事情。我对 Carrierwave 初始化文件的原始更改似乎是一条死胡同。

最终的结果是在控制器中创建上传的图像对象，然后将其注入回参数中。

对于这个特定的例子，我们正在获取一个 base64 文件（我假设你有，因为 JSON 不支持嵌入文件）并将其保存为系统中的临时文件，然后我们正在创建 UploadedFile 对象并最终重新注入它进入参数。

我的 json/params 是什么样的：

picture {:user_id => "1", :folder_id => 1, etc., :picture_path {:file => "base64 awesomeness", :original_filename => "my file name", :filename => "my file name"}}

这是我的控制器现在的样子：

40        # POST /pictures
41    # POST /pictures.json
42    def create
43  
44      #check if file is within picture_path
45      if params[:picture][:picture_path]["file"]
46           picture_path_params = params[:picture][:picture_path]
47           #create a new tempfile named fileupload
48           tempfile = Tempfile.new("fileupload")
49           tempfile.binmode
50           #get the file and decode it with base64 then write it to the tempfile
51           tempfile.write(Base64.decode64(picture_path_params["file"]))
52     
53           #create a new uploaded file
54           uploaded_file = ActionDispatch::Http::UploadedFile.new(:tempfile => tempfile, :filename => picture_path_params["filename"], :original_filename => picture_path_params["original_filename"]) 
55     
56           #replace picture_path with the new uploaded file
57           params[:picture][:picture_path] =  uploaded_file
58     
59      end
60  
61      @picture = Picture.new(params[:picture])
62  
63      respond_to do |format|
64        if @picture.save
65          format.html { redirect_to @picture, notice: 'Picture was successfully created.' }
66          format.json { render json: @picture, status: :created, location: @picture }
67        else
68          format.html { render action: "new" }
69          format.json { render json: @picture.errors, status: :unprocessable_entity }
70        end
71      end
72    end

此时剩下要做的就是删除临时文件，我相信这可以通过tempfile.delete来完成

我希望这对您的问题有所帮助！我昨天花了一整天的时间寻找解决方案，而我所看到的一切都是死路一条。但是，这适用于我的测试用例。