Gmail API を使用してメールを送信するには、次の 2 つの方法があります。
- 「
messages.send
メソッドを使用します。 -
drafts.send
メソッドを使用します。
メールは、raw
プロパティ内の base64url でエンコードされた文字列として送信されます。
メッセージ リソース。概要
ワークフローは次のとおりです。
- メール コンテンツを都合の良い方法で作成し、 base64url 文字列。
- 新しいメッセージ リソースを作成し、その
raw
プロパティを base64url に設定する 文字列を入力します。 messages.send
を呼び出します。下書きを送信する場合はdrafts.send
を呼び出します。 メッセージを送信します。
このワークフローの詳細は、選択したクライアントによって異なる場合があります。 プログラミング言語です。
メッセージの作成
Gmail API では、次に準拠する MIME メール メッセージが RFC 2822 と base64url 文字列としてエンコードされます。多くのプログラミング言語には、 MIME の作成とエンコードのプロセスを簡素化するライブラリやユーティリティ ブロックすることもできます。次のコードサンプルは、MIME メッセージの作成方法を示しています。 Google API クライアント ライブラリを使用します。
Java
MimeMessage
を使用すると、メール メッセージの作成を大幅に簡素化できます。
javax.mail.internet
パッケージのクラス。次の例は
ヘッダーを含むメール メッセージを作成します。
import java.util.Properties; import javax.mail.MessagingException; import javax.mail.Session; import javax.mail.internet.InternetAddress; import javax.mail.internet.MimeMessage; /* Class to demonstrate the use of Gmail Create Email API */ public class CreateEmail { /** * Create a MimeMessage using the parameters provided. * * @param toEmailAddress email address of the receiver * @param fromEmailAddress email address of the sender, the mailbox account * @param subject subject of the email * @param bodyText body text of the email * @return the MimeMessage to be used to send email * @throws MessagingException - if a wrongly formatted address is encountered. */ public static MimeMessage createEmail(String toEmailAddress, String fromEmailAddress, 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(fromEmailAddress)); email.addRecipient(javax.mail.Message.RecipientType.TO, new InternetAddress(toEmailAddress)); email.setSubject(subject); email.setText(bodyText); return email; } }
次のステップでは、MimeMessage
をエンコードし、Message
をインスタンス化します。
にし、base64url でエンコードされたメッセージ文字列を
raw
プロパティ。
import com.google.api.services.gmail.model.Message; import java.io.ByteArrayOutputStream; import java.io.IOException; import javax.mail.MessagingException; import javax.mail.internet.MimeMessage; import org.apache.commons.codec.binary.Base64; /* Class to demonstrate the use of Gmail Create Message API */ public class CreateMessage { /** * Create a message from an email. * * @param emailContent Email to be set to raw of message * @return a message containing a base64url encoded email * @throws IOException - if service account credentials file not found. * @throws MessagingException - if a wrongly formatted address is encountered. */ public static Message createMessageWithEmail(MimeMessage emailContent) throws MessagingException, IOException { ByteArrayOutputStream buffer = new ByteArrayOutputStream(); emailContent.writeTo(buffer); byte[] bytes = buffer.toByteArray(); String encodedEmail = Base64.encodeBase64URLSafeString(bytes); Message message = new Message(); message.setRaw(encodedEmail); return message; } }
Python
次のコードサンプルは、MIME メッセージを作成し、
base64url 文字列を作成し、Message
の raw
フィールドに代入します。
resource:
import base64 from email.message import EmailMessage import google.auth from googleapiclient.discovery import build from googleapiclient.errors import HttpError def gmail_create_draft(): """Create and insert a draft email. Print the returned draft's message and id. Returns: Draft object, including draft id and message meta data. Load pre-authorized user credentials from the environment. TODO(developer) - See https://developers.google.com/identity for guides on implementing OAuth2 for the application. """ creds, _ = google.auth.default() try: # create gmail api client service = build("gmail", "v1", credentials=creds) message = EmailMessage() message.set_content("This is automated draft mail") message["To"] = "gduser1@workspacesamples.dev" message["From"] = "gduser2@workspacesamples.dev" message["Subject"] = "Automated draft" # encoded message encoded_message = base64.urlsafe_b64encode(message.as_bytes()).decode() create_message = {"message": {"raw": encoded_message}} # pylint: disable=E1101 draft = ( service.users() .drafts() .create(userId="me", body=create_message) .execute() ) print(f'Draft id: {draft["id"]}\nDraft message: {draft["message"]}') except HttpError as error: print(f"An error occurred: {error}") draft = None return draft if __name__ == "__main__": gmail_create_draft()
添付ファイル付きのメッセージの作成
添付ファイル付きのメールの作成は、 ファイルをマルチパート MIME としてアップロードする メッセージはプログラミング言語によって異なります。次のコードでは、 次のサンプルは、マルチパート MIME メッセージを 表示されます。
Java
次の例は、マルチパート MIME メッセージを作成する方法、 エンコードと割り当てのステップは上記と同じです。
import com.google.api.client.googleapis.json.GoogleJsonError; import com.google.api.client.googleapis.json.GoogleJsonResponseException; import com.google.api.client.http.HttpRequestInitializer; import com.google.api.client.http.javanet.NetHttpTransport; import com.google.api.client.json.gson.GsonFactory; import com.google.api.services.gmail.Gmail; import com.google.api.services.gmail.GmailScopes; import com.google.api.services.gmail.model.Draft; import com.google.api.services.gmail.model.Message; import com.google.auth.http.HttpCredentialsAdapter; import com.google.auth.oauth2.GoogleCredentials; import java.io.ByteArrayOutputStream; import java.io.File; import java.io.IOException; 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 org.apache.commons.codec.binary.Base64; /* Class to demonstrate the use of Gmail Create Draft with attachment API */ public class CreateDraftWithAttachment { /** * Create a draft email with attachment. * * @param fromEmailAddress - Email address to appear in the from: header. * @param toEmailAddress - Email address of the recipient. * @param file - Path to the file to be attached. * @return the created draft, {@code null} otherwise. * @throws MessagingException - if a wrongly formatted address is encountered. * @throws IOException - if service account credentials file not found. */ public static Draft createDraftMessageWithAttachment(String fromEmailAddress, String toEmailAddress, File file) throws MessagingException, IOException { /* Load pre-authorized user credentials from the environment. TODO(developer) - See https://developers.google.com/identity for guides on implementing OAuth2 for your application.*/ GoogleCredentials credentials = GoogleCredentials.getApplicationDefault() .createScoped(GmailScopes.GMAIL_COMPOSE); HttpRequestInitializer requestInitializer = new HttpCredentialsAdapter(credentials); // Create the gmail API client Gmail service = new Gmail.Builder(new NetHttpTransport(), GsonFactory.getDefaultInstance(), requestInitializer) .setApplicationName("Gmail samples") .build(); // Create the email content String messageSubject = "Test message"; String bodyText = "lorem ipsum."; // Encode as MIME message Properties props = new Properties(); Session session = Session.getDefaultInstance(props, null); MimeMessage email = new MimeMessage(session); email.setFrom(new InternetAddress(fromEmailAddress)); email.addRecipient(javax.mail.Message.RecipientType.TO, new InternetAddress(toEmailAddress)); email.setSubject(messageSubject); MimeBodyPart mimeBodyPart = new MimeBodyPart(); mimeBodyPart.setContent(bodyText, "text/plain"); Multipart multipart = new MimeMultipart(); multipart.addBodyPart(mimeBodyPart); mimeBodyPart = new MimeBodyPart(); DataSource source = new FileDataSource(file); mimeBodyPart.setDataHandler(new DataHandler(source)); mimeBodyPart.setFileName(file.getName()); multipart.addBodyPart(mimeBodyPart); email.setContent(multipart); // Encode and wrap the MIME message into a gmail message ByteArrayOutputStream buffer = new ByteArrayOutputStream(); email.writeTo(buffer); byte[] rawMessageBytes = buffer.toByteArray(); String encodedEmail = Base64.encodeBase64URLSafeString(rawMessageBytes); Message message = new Message(); message.setRaw(encodedEmail); try { // Create the draft message Draft draft = new Draft(); draft.setMessage(message); draft = service.users().drafts().create("me", draft).execute(); System.out.println("Draft id: " + draft.getId()); System.out.println(draft.toPrettyString()); return draft; } catch (GoogleJsonResponseException e) { // TODO(developer) - handle error appropriately GoogleJsonError error = e.getDetails(); if (error.getCode() == 403) { System.err.println("Unable to create draft: " + e.getDetails()); } else { throw e; } } return null; } }
Python
前の例と同様に、この例では
メッセージを base64url に送信し、Message
の raw
フィールドに割り当てています。
リソースです。
import base64 import mimetypes import os from email.message import EmailMessage from email.mime.audio import MIMEAudio from email.mime.base import MIMEBase from email.mime.image import MIMEImage from email.mime.text import MIMEText import google.auth from googleapiclient.discovery import build from googleapiclient.errors import HttpError def gmail_create_draft_with_attachment(): """Create and insert a draft email with attachment. Print the returned draft's message and id. Returns: Draft object, including draft id and message meta data. Load pre-authorized user credentials from the environment. TODO(developer) - See https://developers.google.com/identity for guides on implementing OAuth2 for the application. """ creds, _ = google.auth.default() try: # create gmail api client service = build("gmail", "v1", credentials=creds) mime_message = EmailMessage() # headers mime_message["To"] = "gduser1@workspacesamples.dev" mime_message["From"] = "gduser2@workspacesamples.dev" mime_message["Subject"] = "sample with attachment" # text mime_message.set_content( "Hi, this is automated mail with attachment.Please do not reply." ) # attachment attachment_filename = "photo.jpg" # guessing the MIME type type_subtype, _ = mimetypes.guess_type(attachment_filename) maintype, subtype = type_subtype.split("/") with open(attachment_filename, "rb") as fp: attachment_data = fp.read() mime_message.add_attachment(attachment_data, maintype, subtype) encoded_message = base64.urlsafe_b64encode(mime_message.as_bytes()).decode() create_draft_request_body = {"message": {"raw": encoded_message}} # pylint: disable=E1101 draft = ( service.users() .drafts() .create(userId="me", body=create_draft_request_body) .execute() ) print(f'Draft id: {draft["id"]}\nDraft message: {draft["message"]}') except HttpError as error: print(f"An error occurred: {error}") draft = None return draft def build_file_part(file): """Creates a MIME part for a file. Args: file: The path to the file to be attached. Returns: A MIME part that can be attached to a message. """ content_type, encoding = mimetypes.guess_type(file) if content_type is None or encoding is not None: content_type = "application/octet-stream" main_type, sub_type = content_type.split("/", 1) if main_type == "text": with open(file, "rb"): msg = MIMEText("r", _subtype=sub_type) elif main_type == "image": with open(file, "rb"): msg = MIMEImage("r", _subtype=sub_type) elif main_type == "audio": with open(file, "rb"): msg = MIMEAudio("r", _subtype=sub_type) else: with open(file, "rb"): msg = MIMEBase(main_type, sub_type) msg.set_payload(file.read()) filename = os.path.basename(file) msg.add_header("Content-Disposition", "attachment", filename=filename) return msg if __name__ == "__main__": gmail_create_draft_with_attachment()
メッセージを送信する
メッセージを作成したら、
呼び出しのリクエスト本文の
messages.send
(デモンストレーション)
見てみましょう。
Java
import com.google.api.client.googleapis.json.GoogleJsonError; import com.google.api.client.googleapis.json.GoogleJsonResponseException; import com.google.api.client.http.HttpRequestInitializer; import com.google.api.client.http.javanet.NetHttpTransport; import com.google.api.client.json.gson.GsonFactory; import com.google.api.services.gmail.Gmail; import com.google.api.services.gmail.GmailScopes; import com.google.api.services.gmail.model.Message; import com.google.auth.http.HttpCredentialsAdapter; import com.google.auth.oauth2.GoogleCredentials; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.util.Properties; import javax.mail.MessagingException; import javax.mail.Session; import javax.mail.internet.InternetAddress; import javax.mail.internet.MimeMessage; import org.apache.commons.codec.binary.Base64; /* Class to demonstrate the use of Gmail Send Message API */ public class SendMessage { /** * Send an email from the user's mailbox to its recipient. * * @param fromEmailAddress - Email address to appear in the from: header * @param toEmailAddress - Email address of the recipient * @return the sent message, {@code null} otherwise. * @throws MessagingException - if a wrongly formatted address is encountered. * @throws IOException - if service account credentials file not found. */ public static Message sendEmail(String fromEmailAddress, String toEmailAddress) throws MessagingException, IOException { /* Load pre-authorized user credentials from the environment. TODO(developer) - See https://developers.google.com/identity for guides on implementing OAuth2 for your application.*/ GoogleCredentials credentials = GoogleCredentials.getApplicationDefault() .createScoped(GmailScopes.GMAIL_SEND); HttpRequestInitializer requestInitializer = new HttpCredentialsAdapter(credentials); // Create the gmail API client Gmail service = new Gmail.Builder(new NetHttpTransport(), GsonFactory.getDefaultInstance(), requestInitializer) .setApplicationName("Gmail samples") .build(); // Create the email content String messageSubject = "Test message"; String bodyText = "lorem ipsum."; // Encode as MIME message Properties props = new Properties(); Session session = Session.getDefaultInstance(props, null); MimeMessage email = new MimeMessage(session); email.setFrom(new InternetAddress(fromEmailAddress)); email.addRecipient(javax.mail.Message.RecipientType.TO, new InternetAddress(toEmailAddress)); email.setSubject(messageSubject); email.setText(bodyText); // Encode and wrap the MIME message into a gmail message ByteArrayOutputStream buffer = new ByteArrayOutputStream(); email.writeTo(buffer); byte[] rawMessageBytes = buffer.toByteArray(); String encodedEmail = Base64.encodeBase64URLSafeString(rawMessageBytes); Message message = new Message(); message.setRaw(encodedEmail); try { // Create send message message = service.users().messages().send("me", message).execute(); System.out.println("Message id: " + message.getId()); System.out.println(message.toPrettyString()); return message; } catch (GoogleJsonResponseException e) { // TODO(developer) - handle error appropriately GoogleJsonError error = e.getDetails(); if (error.getCode() == 403) { System.err.println("Unable to send message: " + e.getDetails()); } else { throw e; } } return null; } }
Python
import base64 from email.message import EmailMessage import google.auth from googleapiclient.discovery import build from googleapiclient.errors import HttpError def gmail_send_message(): """Create and send an email message Print the returned message id Returns: Message object, including message id Load pre-authorized user credentials from the environment. TODO(developer) - See https://developers.google.com/identity for guides on implementing OAuth2 for the application. """ creds, _ = google.auth.default() try: service = build("gmail", "v1", credentials=creds) message = EmailMessage() message.set_content("This is automated draft mail") message["To"] = "gduser1@workspacesamples.dev" message["From"] = "gduser2@workspacesamples.dev" message["Subject"] = "Automated draft" # encoded message encoded_message = base64.urlsafe_b64encode(message.as_bytes()).decode() create_message = {"raw": encoded_message} # pylint: disable=E1101 send_message = ( service.users() .messages() .send(userId="me", body=create_message) .execute() ) print(f'Message Id: {send_message["id"]}') except HttpError as error: print(f"An error occurred: {error}") send_message = None return send_message if __name__ == "__main__": gmail_send_message()
返信するときは、次のことを確認してください。
Subject
ヘッダーが一致しています。References
ヘッダーとIn-Reply-To
ヘッダーは、 RFC 2822 標準。
メールの下書きの送信について詳しくは、以下をご覧ください。 下書きの作成。