Facebook Messenger: How to send multiple messages with nodejs - node.js

Question

I just want to send a messages to all the subscribers with nodejs.
This is my code ( I have hidden the PSID below ):
app.get('/helloguys', function (req, res) {
var messageData = {
batch: [
{recipient: {id: "..."}},{recipient: {id: "..."}}
],
message: {
text: "Hi guys :)",
metadata: "DEVELOPER_DEFINED_METADATA"
}
};
request({
uri: 'https://graph.facebook.com/v2.6/me/messages',
qs: { access_token: token },
method: 'POST',
json: messageData
}, function (error, response, body) {
if (!error && response.statusCode == 200) {
console.log("Ok", response.statusCode);
} else {
console.error("Failed calling Send API", response.statusCode, response.statusMessage, body.error);
}
});
res.send('Hi :)')
})
I get this in the nodejs console:
Ok 200
but users don't receive the message.
Why ?
EDIT for Lix:
body:
2017-10-18T13:38:43.538998+00:00 app[web.1]: [ { code: 400,
2017-10-18T13:38:43.538999+00:00 app[web.1]: headers: [Object],
2017-10-18T13:38:43.538999+00:00 app[web.1]: body: '{"error":{"message":"Unsupported get request. Please read the Graph API documentation at https:\\/\\/developers.facebook.com\\/docs\\/graph-api","type":"GraphMethodException","code":100,"error_subcode":33,"fbtrace_id":"Dd6+kHN7Tl+"}}' },
EDIT for CBroe:
var messageData = {
batch: [
{method:"POST", message: "Hello", recipient: {id: "1552389158161227"}},{method:"POST", message: "Hello", recipient: {id: "1419003191530571"}}
]
};
It doesn't work
EDIT for CBroe 2:
app.get('/helloguys', function (req, res) {
var batch = [
{method:"POST", body: "message=Test status update&recipient=..."},
{method:"POST", body: "message=Test status update&recipient=..."}
];
request({
uri: 'https://graph.facebook.com/v2.6/me/messages',
qs: { access_token: token },
method: 'POST',
json: batch
}, function (error, response, body) {
if (!error && response.statusCode == 200) {
console.log("ok", response.statusCode, response.statusMessage, response);
res.send('hi')
} else {
console.error("Failed calling Send API", response.statusCode, response.statusMessage, body.error);
}
});
})
And now I get:
2017-10-18T15:36:05.981999+00:00 app[web.1]: Failed calling Send API 400 Bad Request { message: '(#100) The parameter recipient is required',
2017-10-18T15:36:05.982009+00:00 app[web.1]: type: 'OAuthException',
2017-10-18T15:36:05.982010+00:00 app[web.1]: code: 100,
2017-10-18T15:36:05.982011+00:00 app[web.1]: fbtrace_id: 'EJLQgP9UoMT' }

Answer 1

As per FB dev docs (they stated somewhere within the docs, and not very obvious)
Note the URLEncoding for the body param
Also, multiple POST requests (batched requests):
While GET and DELETE operations must only have a relative_url and a method field, POST and PUT operations may contain an optional body field.
And >>
This should be formatted as a raw HTTP POST body string, similar to a URL query string.
Also, this type of request should be made as multipart/form-data.
Then, batch request requirements are:
(1) to be multipart/form-data;
(2) consist of URLEncoding strings in 'body' parameter;
(3) batch request should be raw HTTP POST body string.
Node.js request module could send form-data (through form-data module). See docs
So, your code should be like this >>
app.get('/helloguys', function (req, res) {
var batchUrl = 'https://graph.facebook.com';
var r = request.post(batchUrl, function(error, response, body) {
if (error) {return console.log("error\n", error)};
console.log("successfull\n", body) //but fb sends error in body message, so check body.error for any errors
});
var form = r.form();
var multipleMessages = [];
var message = "message=" + encodeURIComponent(JSON.stringify(
{
"text": "​Hi guys :)"
}
));
//loop throught user IDs (PSIDs)
for (var i=0; i<users; i++) {
var recipient = "recipient=" + encodeURIComponent(JSON.stringify({"id": users[i].id}));
var batchMessage = {
"method": "POST",
"relative_url":"v2.6/me/messages",
"body": recipient + "&" + message
};
multipleMessages.push(batchMessage);
}
form.append("access_token", token)
form.append("batch", JSON.stringify(multipleMessages));
res.send('Hi :)')
})

Answer 2

Try to move res.send('Hi') inside your request callback:
function (error, response, body) {
if (!error && response.statusCode == 200) {
console.log("Ok", response.statusCode);
res.send('Hi');
} else {
console.error("Failed calling Send API", response.statusCode, response.statusMessage, body.error);
}
});