Envoyer des e-mails

Il existe deux façons d'envoyer des e-mails à l'aide de l'API Gmail:

  • Vous pouvez l'envoyer directement à l'aide de la méthode messages.send.
  • Vous pouvez l'envoyer à partir d'un brouillon à l'aide de la méthode drafts.send.

Les e-mails sont envoyés sous forme de chaînes encodées en base64url dans la propriété raw d'une ressource de message. Pour envoyer un e-mail, procédez comme suit:

  1. Créez le contenu de l'e-mail de manière pratique et encodez-le en tant que chaîne base64url.
  2. Créez une ressource de message et définissez sa propriété raw sur la chaîne base64url que vous venez de créer.
  3. Appelez messages.send ou, si vous envoyez un brouillon, drafts.send pour envoyer le message.

Les détails de ce workflow peuvent varier en fonction de la bibliothèque cliente et du langage de programmation choisis.

Créer des messages

L'API Gmail nécessite des e-mails MIME conformes à la norme RFC 2822 et encodés sous forme de chaînes base64url. De nombreux langages de programmation disposent de bibliothèques ou d'utilitaires qui simplifient le processus de création et d'encodage des messages MIME. Les exemples de code suivants montrent comment créer un message MIME à l'aide des bibliothèques clientes des API Google pour différents langages.

Java

La création d'un e-mail peut être considérablement simplifiée avec la classe MimeMessage du package javax.mail.internet. L'exemple suivant montre comment créer l'e-mail, y compris les en-têtes:

gmail/snippets/src/main/java/CreateEmail.java
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;
  }
}

L'étape suivante consiste à encoder le MimeMessage, à instancier un objet Message et à définir la chaîne de message encodée en base64url comme valeur de la propriété raw.

gmail/snippets/src/main/java/CreateMessage.java
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

L'exemple de code suivant montre comment créer un message MIME, l'encoder dans une chaîne base64url et l'attribuer au champ raw de la ressource Message:

gmail/snippet/send mail/create_draft.py
from __future__ import print_function

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()

Créer des messages avec des pièces jointes

La création d'un message avec une pièce jointe est semblable à celle de n'importe quel autre message, mais le processus d'importation du fichier en tant que message MIME en plusieurs parties dépend du langage de programmation. Les exemples de code suivants illustrent différentes manières de créer un message MIME en plusieurs parties avec une pièce jointe.

Java

L'exemple suivant montre comment créer un message MIME en plusieurs parties. Les étapes d'encodage et d'attribution sont les mêmes que ci-dessus.

gmail/snippets/src/main/java/CreateDraftWithAttachment.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.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

Comme dans l'exemple précédent, cet exemple gère également l'encodage du message en base64url et son attribution au champ raw de la ressource Message.

gmail/snippet/send mail/create_draft_with_attachment.py
from __future__ import print_function

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()

Envoyer des messages

Une fois que vous avez créé un message, vous pouvez l'envoyer en le fournissant dans le corps de la requête d'un appel à messages.send, comme illustré dans les exemples suivants.

Java

gmail/snippets/src/main/java/SendMessage.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

gmail/snippet/send mail/send_message.py
from __future__ import print_function

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()

Si vous essayez d'envoyer une réponse et souhaitez que l'e-mail soit placé dans le fil de discussion, vérifiez les points suivants:

  1. Les en-têtes Subject correspondent
  2. Les en-têtes References et In-Reply-To sont conformes à la norme RFC 2822.

Pour plus d'informations sur l'envoi d'un message à partir d'un brouillon, consultez la section Créer des brouillons.