/**
* Flickr Web Service API Example: Authenticate Desktop Application
* User and Rotate Uploaded Image
*
* @author Daniel Jones www.danieljones.org
* Copyright 2007
*
* This example shows how to perform the steps necessary to authenticate a
* Yahoo! Flickr user and use the Flickr API to rotate an image on flickr.com.
* The Flickr Authentication API Desktop Applications How-To can be found
* here: http://www.flickr.com/services/api/auth.howto.desktop.html
*
* Before you can use the Flickr API, you must obtain an API key at the following
* URL: http://www.flickr.com/services/api/keys/apply/
*
* For the purposes of this example, be sure to choose the Desktop Application
* radio button for the Authentication Type. We do not want the user
* automatically redirected to a callback URL with the frob passed in the URL
* as a GET argument because our desktop application's token request will fail.
* You should choose Web Application for the Authentication Type if you want
* the frob argument automatically passed back to the auth handler callback URL
* for a subsequent call to flickr.auth.getToken.
*
* Now that you have an API key and at least one image uploaded to your Flickr
* account, lets get started.
*
*/
import java.math.BigInteger;
import java.security.MessageDigest;
import java.io.*;
import javax.xml.parsers.DocumentBuilderFactory;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class FlickrRotate {
public static void main(String[] args) throws Exception {
/**
* Use the key and secret provided when you registered your application
* http://www.flickr.com/services/api/keys/apply/
*/
String key = "";
String secret = "";
/**
* This example assumes that you have uploaded a photo to
* your Flickr account.
*
* The photo id can be found in the URL of the photo
* http://flickr.com/photos/xxxxxxx@N03/<use_this_photo_id>/
*/
String photoId = "";
/**
* Request a frob to identify the login session. This call requires
* a signature. The signature starts with your shared secret and
* is followed by your API key and the method name. The API key and
* method name are prepended by the words "api_key" and "method" as
* shown in the following line.
**/
String methodGetFrob = "flickr.auth.getFrob";
String sig = secret + "api_key" + key + "method" + methodGetFrob;
/**
* The API signature must be MD5 encoded and appended to the request
*/
String signature = MD5(sig);
String request = "http://api.flickr.com/services/rest/?method=" + methodGetFrob + "&api_key=" + key + "&api_sig=" + signature;
System.out.println("GET frob request: " + request);
HttpClient client = new HttpClient();
GetMethod method = new GetMethod(request);
// Send GET request
int statusCode = client.executeMethod(method);
if (statusCode != HttpStatus.SC_OK) {
System.err.println("Method failed: " + method.getStatusLine());
}
InputStream rstream = null;
// Get the response body
rstream = method.getResponseBodyAsStream();
// Retrieve the XML response to the frob request and get the frob value.
Document response = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(rstream);
String frob = null;
// Check if frob is in the response
NodeList frobResponse = response.getElementsByTagName("frob");
Node frobNode = frobResponse.item(0);
if (frobNode != null) {
frob = frobNode.getTextContent();
System.out.println("Successfully retrieved frob: " + frob);
} else {
printFlickrError(response);
return;
}
System.out.println("Get frob XML response:");
/**
* Create a Flickr login link
* http://www.flickr.com/services/auth/?api_key=[api_key]&perms=[perms]&frob=[frob]&api_sig=[api_sig]
* We are using "write" for the perms value because we will be rotating an image.
*/
sig = secret + "api_key" + key + "frob" + frob + "permswrite";
signature = MD5(sig);
request = "http://www.flickr.com/services/auth/?api_key=" + key + "&perms=write&frob=" + frob + "&api_sig=" + signature;
/**
* Copy/paste the generated link into your favorite web browser and follow the instructions
*/
System.out.println("Browse to the following flickr url to authenticate yourself and then press enter.");
System.out.println(request);
BufferedReader infile = new BufferedReader ( new InputStreamReader (System.in) );
String line = infile.readLine();
/**
* Get auth token using frob. Once again, a signature is required
* for authenticated calls to the Flickr API.
*/
String methodGetToken = "flickr.auth.getToken";
sig = secret + "api_key" + key + "frob" + frob + "method" + methodGetToken;
signature = MD5(sig);
request = "http://api.flickr.com/services/rest/?method=" + methodGetToken + "&api_key=" + key + "&frob=" + frob + "&api_sig=" + signature;
System.out.println("Token request: " + request);
method = new GetMethod(request);
// Send GET request
statusCode = client.executeMethod(method);
if (statusCode != HttpStatus.SC_OK) {
System.err.println("Method failed: " + method.getStatusLine());
}
rstream = null;
// Get the response body
rstream = method.getResponseBodyAsStream();
/**
* Retrieve the XML response to the token request and get the token value
*/
response = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(rstream);
String token = null;
// Check if token is in the response
NodeList tokenResponse = response.getElementsByTagName("token");
Node tokenNode = tokenResponse.item(0);
if (tokenNode != null) {
token = tokenNode.getTextContent();
System.out.println("Successfully retrieved token: " + token);
} else {
printFlickrError(response);
return;
}
/**
* Now that we have authenticated with Flickr and obtained an auth
* token with write privileges, it's time to rotate the image.
*
* http://api.flickr.com/services/rest/?method=flickr.photos.transform.rotate&
* api_key=[api_key]&photo_id=[photo_id]°rees=180&auth_token=[auth_token]&api_sig=[api_sig]
*/
String methodRotate = "flickr.photos.transform.rotate";
sig = secret + "api_key" + key + "auth_token" + token + "degrees180" + "method" + methodRotate + "photo_id" + photoId;
signature = MD5(sig);
/**
* Create POST data for rotate request. The Flickr API documentation
* specifies that calls to flickr.photos.transform.rotate be made
* via HTTP POST.
*/
request = "http://api.flickr.com/services/rest/";
PostMethod pmethod = new PostMethod(request);
pmethod.addParameter("method", methodRotate);
pmethod.addParameter("photo_id", photoId);
pmethod.addParameter("degrees", "180");
pmethod.addParameter("api_key", key);
pmethod.addParameter("auth_token", token);
pmethod.addParameter("api_sig", signature);
// Send POST request
statusCode = client.executeMethod(pmethod);
if (statusCode != HttpStatus.SC_OK) {
System.err.println("Method failed: " + pmethod.getStatusLine());
}
rstream = null;
// Get the response body
rstream = pmethod.getResponseBodyAsStream();
/**
* Retrieve the XML response to the rotate request and get the XML response
*/
response = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(rstream);
String photoid = null;
// Check if photoid is in the response
NodeList rotateResponse = response.getElementsByTagName("photoid");
Node rotateNode = rotateResponse.item(0);
if (rotateNode != null) {
photoid = rotateNode.getTextContent();
System.out.println("Successfully flipped photo " + photoid);
System.out.println("Refresh the photo in your web browser and you will see it has been flipped.");
} else {
printFlickrError(response);
return;
}
}
/**
* Get the MD5 hash of a text string
*/
public static String MD5(String text)
{
String md5Text = "";
try {
MessageDigest digest = MessageDigest.getInstance("MD5");
md5Text = new BigInteger(1, digest.digest((text).getBytes())).toString(16);
} catch (Exception e) {
System.out.println("Error in call to MD5");
}
if (md5Text.length() == 31) {
md5Text = "0" + md5Text;
}
return md5Text;
}
/**
* Print the Flickr response error code and message
* @param response The XML error response Document
*/
public static void printFlickrError(Document response)
{
NodeList error = response.getElementsByTagName("err");
String code = error.item(0).getAttributes().item(0).getTextContent();
String msg = error.item(0).getAttributes().item(1).getTextContent();
System.out.println("Flickr request failed with error code " + code + ", " + msg);
}
}