Unable to send mail using gmail api node js - node.js

Question

I have followed gmail api for sending email. I am getting error as:
"message": "400 - \"{\n \\"error\\": {\n \\"errors\\": [\n {\n \\"domain\\": \\"global\\",\n \\"reason\\": \\"invalidArgument\\",\n \\"message\\": \\"'raw' RFC822 payload message string or uploading message via /upload/* URL required\\"\n }\n ],\n \\"code\\": 400,\n \\"message\\": \\"'raw' RFC822 payload message string or uploading message via /upload/* URL required\\"\n }\n}\n\""
Here is the piece of code I have written for sending mail using gmail api with node.js. Help me out to resolve the issue.
router.post('/composeMail', async (req, res, next) => {
function makeBody(to, from, subject, message) {
let str = ["Content-Type: text/plain; charset=\"UTF-8\"\n",
"Content-length: 5000\n",
"Content-Transfer-Encoding: message/rfc822\n",
"to: ", to,"\n",
"from: ", from,"\n",
"subject: ", subject,"\n\n",
message
].join('');
console.log("String: ", str);
// let encodedMail = new Buffer(str).toString("base64").replace(/\+/g, '-').replace(/\//g, '_');
let encodedMail = btoa(str).replace(/\+/g, '-').replace(/\//g, '_');
return encodedMail;
}
let raw = makeBody("dinesh.kumar#gmail.com", "dinesh.kumar#gmail.com", "Test mail", "Everything is fine");
let obj = {};
obj.raw = raw;
let body = JSON.stringify(obj);
let option = {
url: "https://www.googleapis.com/gmail/v1/users/userId/messages/send",
method: 'POST',
headers: {
'Authorization': `Bearer ${req.query.access_token}`
},
qs: {
userId: 'me'
},
body: body
};
await request(option).then(body => {
return res.apiOk(body);
}).catch(err => {
return res.apiError(err);
})
});

Answer 1

You want to send an email using Gmail API by the request module.
If my understanding is correct, how about this modification? I think that there are several answers. So please think of this as one of them.
Modification points:
Please use https://www.googleapis.com/upload/gmail/v1/users/userId/messages/send as the endpoint.
Use the value as a string.
Add 'Content-Type': 'message/rfc822' to the headers.
Modified script:
Please modify makeBody() as follows.
function makeBody(to, from, subject, message) {
let str = [
"to: ", to, "\n",
"from: ", from, "\n",
"subject: ", subject, "\n\n",
message,
].join('');
return str;
}
Please modify option as follows.
let raw = makeBody("dinesh.kumar#gmail.com", "dinesh.kumar#gmail.com", "Test mail", "Everything is fine");
const userId = 'me'; // Please modify this for your situation.
let option = {
url: "https://www.googleapis.com/upload/gmail/v1/users/" + userId + "/messages/send",
method: 'POST',
headers: {
'Authorization': `Bearer ${req.query.access_token}`,
'Content-Type': 'message/rfc822',
},
body: raw,
};
Note:
This modified script supposes that Gmail API is enabled at API console and the required scope for sending emails is included in the scopes of access token.
Reference:
Users.messages: send
In my environment, I could confirm that this modified script worked fine. But if this was not what you want, I'm sorry.