Home Library REST API

From Gcube Wiki
Revision as of 12:30, 17 February 2017 by Valentina.marioli (Talk | contribs) (→‎Download)

Jump to: navigation, search

Overview

The Home Library REST interface provides a simple access to basic HL features. It is available from gCube 4.1 (home-library: 2.5; home-library-jcr: 2.5; home-library-model: 1.4).

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: to remove a file or a folder (including subfolders).

Use cases

Users can:

  • use the browser to call API Methods, using username and the own 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.


For production environment, please look for the webapp's endpoint in the information system by using the Resource Management portlet. The resource you need to look for/inspect is :

  • type : GCoreEndpoint
  • ServiceClass : DataAccess
  • ServiceName : HomeLibraryWebapp

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.

Using cURL: 

curl --header "gcube-token: ***********************" /
--request POST 'HL_WEBAPP/rest/CreateFolder?name=testFolder&description=test&parentPath=/Home/test.user/Workspace/myFolder'

Delete

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.

Using cURL: 

curl --header "gcube-token: ***********************" /
HL_WEBAPP/rest/Delete?absPath=/Home/test.user/Workspace/myfile.pdf

Download

This feature will be available from gCube 4.2 (home-library: 2.6; home-library-jcr: 2.6; home-library-model: 1.5).

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.

Using cURL: 

curl --header "gcube-token: ***********************" /
--request GET 'HL_WEBAPP/rest/Delete?absPath=/Home/test.user/Workspace/myfile.pdf' /
--output /home/user/mydocs/myfile.pdf

Using Java: 

package org.apache.jackrabbit.j2ee.rest;
 
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;
    private static final String GCUBE_TOKEN = "gcube-token";
 
    /**
     * 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 {
 
    public static void main(String[] args) {
        SecurityTokenProvider.instance.set(HERE_YOUR_TOKEN);
        String absPath = "/Home/test.user/Workspace/MyFolder/";
        String fileURL = HL_WEBAPP + "/rest/Download?absPath=" + absPath;
        String saveDir = "/home/user/Downloads/";
        try {
            HttpDownloadUtility.downloadFile(fileURL, saveDir);
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
}

This program downloads the folder "MyFolder" as zip folder (MyFolder.zip) and saves it into the directory "/home/user/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

Get Public Link

To get a public link of a file: 

HL_WEBAPP/rest/GetPublicLink?absPath=$path&shortUrl=$flag

Where:

  • absPath: the absolute path of the folder to list;
  • shortUrl: true to get a short url, false otherwise. It will be false by default.

Returns a link to the file.

Using cURL: 

curl --header "gcube-token: ***********************" /
--request POST 'HL_WEBAPP/rest/GetPublicLink?absPath=/Home/test.user/Workspace/myfile.pdf&shortUrl=true'

List

To list the content of a folder: 

HL_WEBAPP/rest/List?absPath=$path

Where:

  • absPath: the absolute path of the folder to list;
  • showHidden: true to show hidden files, false otherwise. It will be false by default.

Output:

  • a list of entries with:
    • a String: the name of the file/folder;
    • a Boolean : a flag set to true if the item is a folder, false if it is a file.

Output example: 

<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>


Using cURL: 

curl --header "gcube-token: ***********************" /
--request POST 'HL_WEBAPP/rest/List?absPath=/Home/test.user/Workspace/&showHidden=false'

Unzip

To upload a zip file in a specific folder. 

HL_WEBAPP/rest/Unzip?name=$name&parentPath=$path&replace=$flag&hardReplace=$flag

Where:

  • name: the name of the file to unzip;
  • parentPath: the path to save the decompressed folder;
  • replace: true to overwrite the files with the same names; false otherwise.
  • hardReplace: true to delete the destination folder, if it already exists; false otherwise.

The zip file has to be attached to the http request.

Output:

  • the path of the decompressed folder.

How it works:

  • if replace is true but a file with the same name does not exist in such folder, the file will be created;
  • if replace is false and a file with the same name does not exist in such folder, the file will be created;
  • if replace is true and a file with the same name already exists in such folder, the file will be overwritten;
  • if replace is false and a file with the same name already exists in such folder, the file will be created adding a progressive number to the destination folder name.


Using CURL: 

curl --header "gcube-token: ************************" /
--request POST --data-binary @/home/valentina/test.zip /
--header "Content-Type: application/zip" /
'HL_WEBAPP/rest/Unzip?name=test.zip&parentPath=/Home/valentina.marioli/Workspace/testaa&replace=true&hardReplace=true'

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.

Output:

  • the path where the file has been saved.

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

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

Using CURL: 

curl --header "gcube-token: ************************" /
--request POST --data-binary @/home/valentina/test.jpg /
--header "Content-Type: image/jpeg" /
'HL_WEBAPP/rest/Upload?name=test.jpg&description=test&parentPath=/Home/test.user/Workspace/myfolder'

Using Java: 

package org.apache.jackrabbit.j2ee.rest;
 
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 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/";
        private static final String GCUBE_TOKEN = "gcube-token";
 
	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.setRequestProperty(GCUBE_TOKEN, SecurityTokenProvider.instance.get());
		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);
	}
 
}
Retrieved from "https://wiki.gcube-system.org/index.php?title=Home_Library_REST_API&oldid=28361"