Gmail API를 사용하여 이메일을 보내는 방법에는 두 가지가 있습니다.
messages.send
메서드를 사용하여 직접 전송할 수 있습니다.drafts.send
메서드를 사용하여 초안에서 전송할 수 있습니다.
이메일은 메시지 리소스의 raw
속성 내에 base64url로 인코딩된 문자열로 전송됩니다. 이메일을 보내는 상위 워크플로는 다음과 같습니다.
- 편리한 방법으로 이메일 콘텐츠를 만들고 base64url 문자열로 인코딩합니다.
- 새 메시지 리소스를 만들고
raw
속성을 방금 만든 base64url 문자열로 설정합니다. messages.send
를 호출하거나 초안을 보내는 경우drafts.send
를 호출하여 메시지를 보냅니다.
이 워크플로의 세부정보는 선택한 클라이언트 라이브러리와 프로그래밍 언어에 따라 다를 수 있습니다.
메시지 만들기
Gmail API를 사용하려면 RFC 2822를 준수하고 base64url 문자열로 인코딩된 MIME 이메일 메시지가 필요합니다. 많은 프로그래밍 언어에는 MIME 메시지를 만들고 인코딩하는 프로세스를 단순화하는 라이브러리 또는 유틸리티가 있습니다. 다음 코드 예는 다양한 언어에 대한 Google API 클라이언트 라이브러리를 사용하여 MIME 메시지를 만드는 방법을 보여줍니다.
Java
javax.mail.internet
패키지의 MimeMessage
클래스를 사용하면 이메일 메시지 작성을 크게 간소화할 수 있습니다. 다음 예에서는 헤더를 포함하여 이메일 메시지를 만드는 방법을 보여줍니다.
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; } }
다음 단계는 MimeMessage
를 인코딩하고, Message
객체를 인스턴스화하고, base64url로 인코딩된 메시지 문자열을 raw
속성 값으로 설정하는 것입니다.
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
다음 코드 샘플은 MIME 메시지를 만들고 base64url 문자열로 인코딩하여 Message
리소스의 raw
필드에 할당하는 방법을 보여줍니다.
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"] = "[email protected]" message["From"] = "[email protected]" 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()
첨부파일이 있는 메시지 만들기
첨부파일이 있는 메시지를 만드는 것은 다른 메시지를 만드는 것과 비슷하지만 여러 부분으로 구성된 MIME 메시지로 파일을 업로드하는 프로세스는 프로그래밍 언어에 따라 다릅니다. 다음 코드 예는 첨부파일이 있는 여러 부분으로 구성된 MIME 메시지를 만드는 방법을 보여줍니다.
Java
다음 예에서는 여러 부분으로 구성된 MIME 메시지를 만드는 방법을 보여줍니다. 인코딩 및 할당 단계는 위와 동일합니다.
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
이전 예와 마찬가지로 이 예시에서는 메시지를 base64url로 인코딩하고 Message
리소스의 raw
필드에 할당하는 작업도 처리합니다.
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"] = "[email protected]" mime_message["From"] = "[email protected]" 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()
메시지 전송
메시지를 만들었으면 다음 예와 같이 messages.send
호출의 요청 본문에 메시지를 제공하여 보낼 수 있습니다.
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"] = "[email protected]" message["From"] = "[email protected]" 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()
답장을 보내려는 경우 이메일을 대화목록으로 만들려면 다음 사항을 확인하세요.
Subject
헤더 일치References
및In-Reply-To
헤더는 RFC 2822 표준을 따릅니다.
초안에서 메시지를 보내는 방법에 대한 자세한 내용은 초안 만들기를 참조하세요.