Difference between revisions of "Home Library REST API"

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     }
 
     }
 
}
 
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</source>
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This program downloads the MyFolder as zip folder (MyFolder.zip) and saves it into the directory /home/valentina/Downloads/.
 +
It would produce the following output:
 +
 +
<source lang="java">
 +
Content-Type = application/zip
 +
Content-Disposition = attachment; filename="MyFolder.zip"
 +
Content-Length = 8894049
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fileName = MyFolder.zip
 +
File downloaded
 +
 
</source>
 
</source>
  

Revision as of 18:06, 3 November 2016

Overview

The Home Library REST interface provides a simple access to basic HL features.

Key features

Users can use the token to access to REST interface. They can access just their own files and the folders shared with them.

Home Library REST interface supports the following operations:

  • Create Folder: to create a folder in the given parent path;
  • List: to list the content of a folder;
  • Upload file: to upload a file in a folder;
  • Download: to download a file or a folder in ZIP format;
  • Remove files and folders: to remove a file or a folder (including subfolders).

Use cases

Users can:

  • use the browser to call API Methods, using username and his/her token as password;
  • implement a Client in different languages, setting the token on the header of the request.

Design

Architecture

API

Get started

Home Library REST is available from gCube 4.1.

Create Folder

To create a new folder: 

HL_WEBAPP/rest/CreateFolder?name=$name&description=$desc&parentPath=$path

Where:

  • name: the name of the new folder.
  • description: the description for the new folder.
  • parentPath: the position where you want to save the folder.

Example: 

HL_WEBAPP/rest/CreateFolder?name=myFolder&description=myDescription&parentPath=/Home/valentina.marioli/Workspace/MyDocs/

List

To list the content of a folder: 

HL_WEBAPP/rest/List?absPath=$path

Where:

  • absPath: the absolute path of the folder to list.

Example: 

HL_WEBAPP/rest/List?absPath=/Home/valentina.marioli/Workspace/MySpecialFolders/gcube-devNext-NextNext/

Output: A list of entries with:

  • name: the name of the file/folder;
  • flag: true if the item is a folder, false if it is a file.


<map>
  <entry>
    <string>myFolder</string>
    <boolean>true</boolean>
  </entry>
  <entry>
    <string>home-library-jcr-2.5.0-SNAPSHOT.jar</string>
    <boolean>false</boolean>
  </entry>
  <entry>
    <string>home-library-2.5.0-SNAPSHOT.jar</string>
    <boolean>false</boolean>
  </entry>
  <entry>
    <string>home-library-common-2.5.0-SNAPSHOT.jar</string>
    <boolean>false</boolean>
  </entry>
  <entry>
    <string>anotherFolder</string>
    <boolean>true</boolean>
  </entry>
</map>

Upload File

To upload a file, if it does not already exist: 

HL_WEBAPP/rest/Upload?name=$name&description=$description&parentPath=$path

Where:

  • name: the file to upload
  • description: a description for the file
  • parentPath: the position where you want to save the file.

If you want to skip mimetype and size detect steps because you already know them, you can pass them as parameter: 

HL_WEBAPP/rest/Upload?name=$name&description=$description&parentPath=$path&mimetype=$mimetype&size=$size

You have to attach the file as mutipart content of your request.

Example in Java language: 

import java.io.BufferedReader;
import java.io.File;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.nio.file.Files;
import java.util.UUID;
 
import org.gcube.common.authorization.library.provider.SecurityTokenProvider;
import com.thoughtworks.xstream.XStream;
 
public class UploadFileRest {
 
	private static final String DEFAULT_IMAGE = "default.jpg";
	private static final String ROOT_PATH = "/Home/test.user/Workspace/";
 
	public static void main(String[] args) throws Exception {
 
		SecurityTokenProvider.instance.set(HERE_YOUR_TOKEN);
		URL imageURL = UploadFileRest.class.getClassLoader().getResource(DEFAULT_IMAGE);
		File file = new File(imageURL.getFile());
 
		byte[] image = Files.readAllBytes(file.toPath());
		System.out.println(uploadFile(image, DEFAULT_IMAGE, "my description", ROOT_PATH));
 
	}
 
 
	public static String uploadFile(byte[] in, String name, String description, String parentPath) throws Exception {
		XStream xstream = new XStream();
		String uri = HL_WEBAPP + "/rest/Upload?" + "name=" + name+ "&description=" + URLEncoder.encode(description, "UTF-8") + "&parentPath=" + URLEncoder.encode(parentPath, "UTF-8");
 
		URL url = new URL(uri);
		HttpURLConnection connection = (HttpURLConnection)url.openConnection();
		connection.setDoInput(true);
		connection.setDoOutput(true);
		connection.setUseCaches(false);
		connection.setRequestProperty("Content-Type", "image/jpeg");
		connection.setRequestMethod("POST");
		TokenUtility.setHeader(connection);
 
		// Write file to response.
	        OutputStream output = connection.getOutputStream();
	        output.write(in);
	        output.close();
 
		BufferedReader r = new BufferedReader(new  InputStreamReader(connection.getInputStream()));
 
		StringBuffer response = new StringBuffer();
		String inputLine;
		while ((inputLine = r.readLine()) != null) {
			response.append(inputLine);
		}
 
		String xmlOut = response.toString();
		return (String) xstream.fromXML(xmlOut);
	}
 
}

Download

To download a file or a folder in ZIP format: 

HL_WEBAPP/rest/Download?absPath=$path

Where:

  • absPath: the absolute path of the file/folder to download.

Output:

  • a file: if the item to download is a file;
  • a compressed zipped folder: if the item to download is a folder.

Example in Java language: 

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
 
/**
 * A utility that downloads a file from a URL.
 *
 */
public class HttpDownloadUtility {
    private static final int BUFFER_SIZE = 4096;
 
    /**
     * Downloads a file from a URL
     * @param fileURL HTTP URL of the file to be downloaded
     * @param saveDir path of the directory to save the file
     * @throws IOException
     */
    public static void downloadFile(String fileURL, String saveDir)
            throws IOException {
        URL url = new URL(fileURL);
        HttpURLConnection httpConn = (HttpURLConnection) url.openConnection();
        httpConn.setRequestProperty(GCUBE_TOKEN, SecurityTokenProvider.instance.get());
        int responseCode = httpConn.getResponseCode();
 
        // check HTTP response code first
        if (responseCode == HttpURLConnection.HTTP_OK) {
            String fileName = "";
            String disposition = httpConn.getHeaderField("Content-Disposition");
            String contentType = httpConn.getContentType();
            int contentLength = httpConn.getContentLength();
 
            if (disposition != null) {
                // extracts file name from header field
                int index = disposition.indexOf("filename=");
                if (index > 0) {
                    fileName = disposition.substring(index + 10,
                            disposition.length() - 1);
                }
            } else {
                // extracts file name from URL
                fileName = fileURL.substring(fileURL.lastIndexOf("/") + 1,
                        fileURL.length());
            }
 
            System.out.println("Content-Type = " + contentType);
            System.out.println("Content-Disposition = " + disposition);
            System.out.println("Content-Length = " + contentLength);
            System.out.println("fileName = " + fileName);
 
            // opens input stream from the HTTP connection
            InputStream inputStream = httpConn.getInputStream();
            String saveFilePath = saveDir + File.separator + fileName;
 
            // opens an output stream to save into file
            FileOutputStream outputStream = new FileOutputStream(saveFilePath);
 
            int bytesRead = -1;
            byte[] buffer = new byte[BUFFER_SIZE];
            while ((bytesRead = inputStream.read(buffer)) != -1) {
                outputStream.write(buffer, 0, bytesRead);
            }
 
            outputStream.close();
            inputStream.close();
 
            System.out.println("File downloaded");
        } else {
            System.out.println("No file to download. Server replied HTTP code: " + responseCode);
        }
        httpConn.disconnect();
    }
}

Note that in the static method downloadFile(), we have to check HTTP response code from the server to make sure the URL is available (HTTP status 200). Then we extract the file name either from the HTTP header Content-Disposition (in case the URL is an indirect link), or from the URL itself (in case the URL is the direct link). We also print out some debugging information like Content-Type, Content-Disposition, Content-Length and file name.

And here is a test program which employs the utility class above: 

import java.io.IOException;
 
public class HttpDownloader {
 
    private static final String HTTP_URL_REPOSITORY = "http://node11.d.d4science.research-infrastructures.eu:8080/home-library-webapp";
 
    public static void main(String[] args) {
        SecurityTokenProvider.instance.set(HERE-MY-TOKEN);
        String absPath = "/Home/valentina.marioli/Workspace/MyFolder/";
        String fileURL = HTTP_URL_REPOSITORY + "/rest/Download?" + "absPath=" + absPath;
        String saveDir = "/home/valentina/Downloads/";
        try {
            HttpDownloadUtility.downloadFile(fileURL, saveDir);
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
}

This program downloads the MyFolder as zip folder (MyFolder.zip) and saves it into the directory /home/valentina/Downloads/. It would produce the following output: 

Content-Type = application/zip
Content-Disposition = attachment; filename="MyFolder.zip"
Content-Length = 8894049
fileName = MyFolder.zip
File downloaded

Delete File or folder

To remove a file or a folder: 

HL_WEBAPP/rest/Delete?absPath=$path

Where:

  • absPath: the absolute path of the file/folder to remove.

Output:

  • true: if the file/folder has been correctly removed;
  • false: otherwise.
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