Send large attachments (> 5 MB) with the Gmail API Node.js client

问题

When I use the Gmail API Node.js client to send an email with an attachment larger than 5 MB I get an error "413 Request Entity Too Large".

I first create a string mimeMessage which contains a MIME message of type multipart/mixed. One part of this message is a base64 encoded attachment with a size > 5 MB. Then I try to send it:

gmail = google.gmail({ version: 'v1', auth: authentication });

encodedMimeMessage = Buffer.from(mimeMessage)
  .toString('base64')
  .replace(/\+/g, '-')
  .replace(/\//g, '_')
  .replace(/=+$/, '');

gmail.users.messages.send({
  userId: 'me',
  resource: { raw: encodedMimeMessage }
}, (err, res) => {
  ...
});

This results in an error response "413 Request Entity Too Large".

According to the api documentation a resumable upload should be used (https://developers.google.com/gmail/api/guides/uploads#resumable). But the documentation only gives examples for HTTP requests and does not describe how it can be done using the Node.js client. I would like to avoid mixing calls to the google-api-nodejs-client with HTTP requests. If this cannot be avoided I would highly appreciate a good example how to do this in Node.js.

I tried to set uploadType to resumable:

gmailApi.users.messages.send({
  userId: 'me',
  uploadType: 'resumable',
  resource: { raw: encodedMimeMessage }
}, (err, res) => {
  ...
});

I see from the server response that it ended up in the query string, but it did not solve the problem.

I found examples in PHP (Send large attachment with Gmail API, How to send big attachments with gmail API), Java (https://developers.google.com/api-client-library/java/google-api-java-client/media-upload) and Python (Error 10053 When Sending Large Attachments using Gmail API). But they are using a 'Google_Http_MediaFileUpload', 'MediaHttpUploader' and 'MediaIoBaseUpload' respectively and I do not know how to apply this to the nodejs-client.

I found an example in Python (Using Gmail API to Send Attachments Larger than 10mb) which uses uploadType = 'multipart' and a message that is not base64 encoded. But I always get an error response when I do not base64 encode the message.

回答1:

In case someone else comes across this problem: Do not use the resource.raw property of the first method argument when sending an email. Instead use the media property:

const request = {
  userId: 'me',
  resource: {},
  media: {mimeType: 'message/rfc822', body: mimeMessage}
};

gmailApi.users.messages.send(request, (err, res) => {
  ...
});

The mimeMessage must not be encoded with base64 in this case. In the resource you can optionally specify the property threadId.

const request = {
  userId: 'me',
  resource: {threadId: '...'},
  media: {mimeType: 'message/rfc822', body: mimeMessage}
};

gmailApi.users.messages.send(request, (err, res) => {
  ...
});

来源：https://stackoverflow.com/questions/55639575/send-large-attachments-5-mb-with-the-gmail-api-node-js-client

标签

node.js

gmail-api

google-api-nodejs-client