Sending pdf data through rest api inside json

Question

I have made a webservice that send multiple pdfs as response to client using mutlipart/formdata but as it happens one of the client is salesforce which does not support mutlipart/ formdata.

They want a json in response like - { "filename": xyzname, "fileContent": fileContent }

I tried encoding data in Base64 using apache codec library but pdf on client side seems to get corrupted and I am unable to open it using acrobat.

Please find code below -

import org.apache.commons.io.FileUtils;
//------Server side ----------------
@POST
@Consumes(MULTIPART_FORM_DATA)  
@Produces(MediaType.APPLICATION_JSON)
@Path("somepath")
public Response someMethod(someparam)   throws Exception
{
....
JSONArray filesJson = new JSONArray();
String base64EncodedData =      Base64.encodeBase64URLSafeString(loadFileAsBytesArray(tempfile));
JSONObject fileJSON = new JSONObject();
fileJSON.put("fileName",somename);
fileJSON.put("fileContent", base64EncodedData);
filesJson.put(fileJSON);
.. so on ppopulate jsonArray...
//sending reponse
responseBuilder =    Response.ok().entity(filesJson.toString()).type(MediaType.APPLICATION_JSON_TYPE)    ;
response = responseBuilder.build();   
}

//------------Client side--------------

Response clientResponse = webTarget.request()
            .post(Entity.entity(entity,MediaType.MULTIPART_FORM_DATA));
String response = clientResponse.readEntity((String.class));
JSONArray fileList = new JSONArray(response);
for(int count= 0 ;count< fileList.length();count++)
{
JSONObject fileJson = fileList.getJSONObject(count);        
byte[] decodedBytes = Base64.decodeBase64(fileJson.get("fileContent").toString());
outputFile = new File("somelocation/" + fileJson.get("fileName").toString()   + ".pdf");                    
FileUtils.writeByteArraysToFile(outputFile,        fileJson.get("fileContent").toString().getBytes());
}

-------------------------------

Kindly advise.

Answer 1

We are doing the same, basically sending PDF as JSON to Android/iOS and Web-Client (so Java and Swift).

The JSON Object:

public class Attachment implements Serializable {
    private String name;
    private String content;
    private Type contentType; // enum: PDF, RTF, CSV, ...

    // Getters and Setters
}

And then from byte[] content it is set the following way:

public Attachment createAttachment(byte[] content, String name, Type contentType) {
    Attachment attachment = new Attachment();
    attachment.setContentType(contentType);
    attachment.setName(name);
    attachment.setContent(new String(Base64.getMimeEncoder().encode(content), StandardCharsets.UTF_8));
}

Client Side Java we create our own file type object first before mapping to java.io.File:

public OurFile getAsFile(String content, String name, Type contentType) {
    OurFile file = new OurFile();
    file.setContentType(contentType);
    file.setName(name);
    file.setContent(Base64.getMimeDecoder().decode(content.getBytes(StandardCharsets.UTF_8)));
    return file;
  }

And finally:

public class OurFile {
    //...
    public File getFile() {
        if (content == null) {
          return null;
        }
        try {
          File tempDir = Files.createTempDir();
          File tmpFile = new File(tempDir, name + contentType.getFileEnding());
          tempDir.deleteOnExit();
          FileUtils.copyInputStreamToFile(new ByteArrayInputStream(content), tmpFile);
          return tmpFile;
        } catch (IOException e) {
          throw new RuntimeException(e);
        }
     }