Java tutorial
/* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */ package pkg398gmail; import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow; import com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets; import com.google.api.client.googleapis.auth.oauth2.GoogleCredential; import com.google.api.client.googleapis.auth.oauth2.GoogleOAuthConstants; import com.google.api.client.googleapis.auth.oauth2.GoogleTokenResponse; import com.google.api.client.http.HttpTransport; import com.google.api.client.http.javanet.NetHttpTransport; import com.google.api.client.json.JsonFactory; import com.google.api.client.json.jackson2.JacksonFactory; import com.google.api.client.util.Base64; import java.io.BufferedReader; import java.io.ByteArrayOutputStream; import java.io.FileReader; import java.io.IOException; import java.io.InputStreamReader; import java.nio.file.FileSystems; import java.nio.file.Files; import java.util.Arrays; import java.util.List; import java.util.Properties; import javax.activation.DataHandler; import javax.activation.DataSource; import javax.activation.FileDataSource; import javax.mail.MessagingException; import javax.mail.Multipart; import javax.mail.Session; import javax.mail.internet.InternetAddress; import javax.mail.internet.MimeBodyPart; import javax.mail.internet.MimeMessage; import javax.mail.internet.MimeMultipart; import com.google.api.services.gmail.Gmail; import com.google.api.services.gmail.model.Draft; import com.google.api.services.gmail.model.ListMessagesResponse; import com.google.api.services.gmail.model.Message; import com.google.api.services.gmail.model.ListThreadsResponse; import java.util.ArrayList; import java.util.logging.Level; import java.util.logging.Logger; /** * * @author Wellesley */ public class GmailMethods { // Check https://developers.google.com/gmail/api/auth/scopes for all available scopes private static final String SCOPE = "https://www.googleapis.com/auth/gmail.modify"; private static final String APP_NAME = "Gmail API Quickstart"; // Email address of the user, or "me" can be used to represent the currently authorized user. private static final String USER = "me"; // Path to the client_secret.json file downloaded from the Developer Console private static final String CLIENT_SECRET_PATH = "client_secret.json"; private static GoogleClientSecrets clientSecrets; private static HttpTransport httpTransport = new NetHttpTransport(); private static JsonFactory jsonFactory = new JacksonFactory(); private static GoogleAuthorizationCodeFlow flow; private static String url; private static String code; private static GoogleTokenResponse response; private static GoogleCredential credential; private static Gmail service; private static String refreshCode = "1/UGFqD3rQdkT2lSOHbCpSS7-2eCWoWP8zPOyMgHHYyh4"; public static void main(String args[]) throws IOException { normalRun(); } public static void firstRun() throws IOException { clientSecrets = GoogleClientSecrets.load(jsonFactory, new FileReader(CLIENT_SECRET_PATH)); /* This approach requires passing a one-time authorization code from your client to your server; this code is used to acquire an access token and refresh tokens for your server. */ /* When a user loads your application for the first time, they are presented with a dialog to grant permission for your application to access their Gmail account with the requested permission scopes. After this initial authorization, the user is ********only presented with the permission dialog************* if your app's client ID changes or the requested scopes have changed. */ // Allow user to authorize via url. flow = new GoogleAuthorizationCodeFlow.Builder(httpTransport, jsonFactory, clientSecrets, Arrays.asList(SCOPE)).setAccessType("offline").setApprovalPrompt("force").build(); url = flow.newAuthorizationUrl().setRedirectUri(GoogleOAuthConstants.OOB_REDIRECT_URI).build(); System.out.println( "Please open the following URL in your browser then type" + " the authorization code:\n" + url); // Read code entered by user. BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); code = br.readLine(); //code="1/UGFqD3rQdkT2lSOHbCpSS7-2eCWoWP8zPOyMgHHYyh4"; // Generate Credential using retrieved code. response = flow.newTokenRequest(code).setRedirectUri(GoogleOAuthConstants.OOB_REDIRECT_URI).execute(); /* online use credential = new GoogleCredential() .setFromTokenResponse(response); */ // offline use. //http://stackoverflow.com/questions/15064636/googlecredential-wont-build-without-googlecredential-builder //http://stackoverflow.com/questions/10533203/fetching-access-token-from-refresh-token-using-java createCredential(); // now we get the refresh token. We use this refresh the user session. String refToken = credential.getRefreshToken(); System.out.println("Refresh Token: " + refToken); // Create a new authorized Gmail API client createService(); // send message send(); } public static void normalRun() throws IOException { clientSecrets = GoogleClientSecrets.load(jsonFactory, new FileReader(CLIENT_SECRET_PATH)); createCredentialWithRefresh(); // now we get the refresh token. We use this refresh the user session. String refToken = credential.getRefreshToken(); System.out.println("Refresh Token: " + refToken); // Create a new authorized Gmail API client createService(); // send message send(); } public static void createCredential() { credential = new GoogleCredential.Builder().setTransport(httpTransport).setJsonFactory(jsonFactory) .setClientSecrets(clientSecrets).build().setFromTokenResponse(response); } public static void createCredentialWithRefresh() { credential = new GoogleCredential.Builder().setTransport(httpTransport).setJsonFactory(jsonFactory) .setClientSecrets(clientSecrets).build().setRefreshToken(refreshCode); } public static void createService() { service = new Gmail.Builder(httpTransport, jsonFactory, credential).setApplicationName(APP_NAME).build(); } public static void send() throws IOException { try { sendMessage(service, "me", createEmail("wra216@lehigh.edu", "me", "test", "test")); } catch (MessagingException ex) { Logger.getLogger(GmailApiQuickstart.class.getName()).log(Level.SEVERE, null, ex); } } // get all the messages with the labels. public static List<Message> listMessagesWithLabels(Gmail service, String userId, List<String> labelIds) throws IOException { ListMessagesResponse response = service.users().messages().list(userId).setLabelIds(labelIds).execute(); List<Message> messages = new ArrayList<Message>(); while (response.getMessages() != null) { messages.addAll(response.getMessages()); if (response.getNextPageToken() != null) { String pageToken = response.getNextPageToken(); response = service.users().messages().list(userId).setLabelIds(labelIds).setPageToken(pageToken) .execute(); } else { break; } } for (Message message : messages) { System.out.println(message.toPrettyString()); } return messages; } public static MimeMessage createEmail(String to, String from, String subject, String bodyText) throws MessagingException { Properties props = new Properties(); Session session = Session.getDefaultInstance(props, null); MimeMessage email = new MimeMessage(session); email.setFrom(new InternetAddress(from)); email.addRecipient(javax.mail.Message.RecipientType.TO, new InternetAddress(to)); email.setSubject(subject); email.setText(bodyText); return email; } public static Draft createDraft(Gmail service, String userId, MimeMessage email) throws MessagingException, IOException { Message message = createMessageWithEmail(email); Draft draft = new Draft(); draft.setMessage(message); draft = service.users().drafts().create(userId, draft).execute(); System.out.println("draft id: " + draft.getId()); System.out.println(draft.toPrettyString()); return draft; } // include attachments. public static MimeMessage createEmailWithAttachment(String to, String from, String subject, String bodyText, String fileDir, String filename) throws MessagingException, IOException { Properties props = new Properties(); Session session = Session.getDefaultInstance(props, null); MimeMessage email = new MimeMessage(session); InternetAddress tAddress = new InternetAddress(to); InternetAddress fAddress = new InternetAddress(from); email.setFrom(fAddress); email.addRecipient(javax.mail.Message.RecipientType.TO, tAddress); email.setSubject(subject); MimeBodyPart mimeBodyPart = new MimeBodyPart(); mimeBodyPart.setContent(bodyText, "text/plain"); mimeBodyPart.setHeader("Content-Type", "text/plain; charset=\"UTF-8\""); Multipart multipart = new MimeMultipart(); multipart.addBodyPart(mimeBodyPart); mimeBodyPart = new MimeBodyPart(); DataSource source = new FileDataSource(fileDir + filename); mimeBodyPart.setDataHandler(new DataHandler(source)); mimeBodyPart.setFileName(filename); String contentType = Files.probeContentType(FileSystems.getDefault().getPath(fileDir, filename)); mimeBodyPart.setHeader("Content-Type", contentType + "; name=\"" + filename + "\""); mimeBodyPart.setHeader("Content-Transfer-Encoding", "base64"); multipart.addBodyPart(mimeBodyPart); email.setContent(multipart); return email; } // method to send message. public static void sendMessage(Gmail service, String userId, MimeMessage email) throws MessagingException, IOException { Message message = createMessageWithEmail(email); message = service.users().messages().send(userId, message).execute(); System.out.println("Message id: " + message.getId()); System.out.println(message.toPrettyString()); } public static Message createMessageWithEmail(MimeMessage email) throws MessagingException, IOException { ByteArrayOutputStream bytes = new ByteArrayOutputStream(); email.writeTo(bytes); String encodedEmail = Base64.encodeBase64URLSafeString(bytes.toByteArray()); Message message = new Message(); message.setRaw(encodedEmail); return message; } }