E-Mails senden

Es gibt zwei Möglichkeiten, E-Mails über die Gmail API zu senden:

• Sie können sie direkt über die messages.send-Methode.
• Sie können sie als Entwurf senden, indem Sie die drafts.send-Methode.

E-Mails werden als base64url-codierte Strings in der raw-Eigenschaft einer Nachrichtenressource. Die allgemeine wie folgt vorgehen, um eine E-Mail zu senden:

1. Erstellen Sie den Inhalt der E-Mail auf bequeme Weise und codieren Sie ihn als base64url-String.
2. Neue Nachrichtenressource erstellen und ihr Attribut raw auf base64url festlegen die Sie gerade erstellt haben.
3. Rufen Sie messages.send auf. Wenn Sie einen Entwurf senden, drafts.send um die Nachricht zu senden.

Die Details dieses Workflows können je nach Kunde variieren. Bibliothek und Programmiersprache.

Mitteilungen erstellen

Für die Gmail API sind MIME-E-Mail-Nachrichten erforderlich, die mit RFC 2822 und codiert als base64url-Strings. Viele Programmiersprachen haben Bibliotheken oder Dienstprogramme, die die Erstellung und Codierung von MIME vereinfachen. Nachrichten. Die folgenden Codebeispiele zeigen, wie eine MIME-Nachricht erstellt wird mit den Google API-Clientbibliotheken für verschiedene Sprachen.

Java

Das Erstellen von E-Mail-Nachrichten lässt sich mit der MimeMessage erheblich vereinfachen. Klasse im javax.mail.internet-Paket. Das folgende Beispiel zeigt, , um die E-Mail zu erstellen, einschließlich der Header:

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

Auf GitHub ansehen

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;
  }
}

Der nächste Schritt besteht darin, MimeMessage zu codieren, eine Message zu instanziieren und legen Sie den base64url-codierten Nachrichtenstring als Wert des raw-Property.

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

Auf GitHub ansehen

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

Im folgenden Codebeispiel wird das Erstellen einer MIME-Nachricht, die Codierung für einen base64url-String und weisen ihn dem Feld raw von Message zu Ressource:

gmail/snippet/send mail/create_draft.py

Auf GitHub ansehen

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"] = "[e-mail]"
    message["From"] = "[e-mail]"
    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()

Nachrichten mit Anhängen erstellen

Eine Nachricht mit einem Anhang wird wie jede andere Nachricht erstellt: Das Hochladen der Datei als mehrteiliges MIME- Nachricht hängt von der Programmiersprache ab. Der folgende Code Beispiele zeigen mögliche Möglichkeiten zum Erstellen einer mehrteiligen MIME-Nachricht mit Anhang hinzufügen.

Java

Das folgende Beispiel zeigt, wie Sie eine mehrteilige MIME-Nachricht erstellen, sind dieselben Schritte wie oben.

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

Auf GitHub ansehen

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

Ähnlich wie im vorherigen Beispiel wird in diesem Beispiel auch die Codierung des an base64url und weist sie dem Feld raw der Message zu .

gmail/snippet/send mail/create_draft_with_attachment.py

Auf GitHub ansehen

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"] = "[e-mail]"
    mime_message["From"] = "[e-mail]"
    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()

Nachrichten senden

Nachdem Sie eine Nachricht erstellt haben, können Sie sie senden, indem Sie sie im Anforderungstext eines Aufrufs an messages.send, wie gezeigt in den folgenden Beispielen.

Java

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

Auf GitHub ansehen

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

Auf GitHub ansehen

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"] = "[e-mail]"
    message["From"] = "[e-mail]"
    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()

Wenn Sie eine Antwort senden möchten und die E-Mail in einer Konversation zusammengefasst werden soll, achten Sie auf Folgendes:

1. Die Subject-Header stimmen überein
2. Die Header References und In-Reply-To folgen den RFC 2822-Standard.

Informationen zum Senden einer Nachricht aus einem Entwurf finden Sie unter Entwürfe erstellen: