How to update a pull request by GitHub APP API? - node.js

Question

I developed GitHub APP to manage pull requests process, I'm using two APIs
1. statuses check API
2. update-a-pull-request API
I get this error message when a request to update an existing pull request that was created by one of the users.
How I can get installation token with the right permissions?
{
"message": "Validation Failed",
"errors": [
{
"message": "Only the pull request author may change the maintainer_can_modify value",
"resource": "PullRequest",
"field": "maintainer_can_modify",
"code": "invalid"
}
],
"documentation_url": "https://developer.github.com/v3/pulls/#update-a-pull-request"
}
To execute API call, I need token, I generated the token in this way:
Created app in GitHub Account
Created a private PEM key in the APP
In code, created JWT token using PEM key
Using the JWT token to create installation token as below
Header
function generateJwtToken() {
return jsonwebtoken.sign(
{
iat: Math.floor(new Date() / 1000),
exp: Math.floor(new Date() / 1000) + 60,
iss: ISSUER_ID,
},
PEM,
{algorithm: 'RS256'},
);
}
let githubHeadersToAccessToken = {
'User-Agent': 'nodejs',
'Content-Type': 'application/json',
'Authorization': 'Bearer ' + generateJwtToken(),
'Accept': 'application/vnd.github.machine-man-preview+json'
};
Get Installation token
payloadToken = {
"repository_ids": [
],
"permissions": {
"pull_requests": "write",
"statuses": "write",
"administration" : "write",
"organization_administration": "write",
"contents": "write",
"team_discussions": "write",
}
};
request.get({
url: 'https://api.github.com/app/installations',
headers: githubHeadersToAccessToken
}, function optionalCallback(err, httpResponse, body) {
if (err) {
return console.error('Connected App get token failed:', err);
}
console.log('APP Installation id');
console.log('Installation id: ' + JSON.parse(body)[0].id);
app_installed_id = JSON.parse(body)[0].id;
request.post({
url: 'https://api.github.com/app/installations/'+app_installed_id+'/access_tokens',
headers: githubHeadersToAccessToken,
json: payloadToken
}, function optionalCallback(err, httpResponse, body) {
if (err) {
return console.error('Failed to get access token to GitHub: ', err);
}
//console.log(body);
console.log('Access token to GitHub: ' + body.token);
});
});
Update existind pull request that was created by one of the users
request.post({
url: 'https://api.github.com/repos/'+owner+'/'+repo+'/statuses/'+sha,
headers: githubHeadersApiV3,
json: {
"state": status,
"context": "PR <> GUS Validation"
}
}, function optionalCallback(err, httpResponse, body) {
if (err) {
return console.error('Connected App get token failed:', err);
}
//console.log(body);
console.log('commit sha: ' + sha + ' updated with status: ' + status);
});

Answer 1

I want to update that the code is working, I can update pull request using Github APP.
The problem I mentioned happen when I try to change "maintainer_can_modify" in pull request, which is not allowed, only by owner, then I just removed it.
But in my case I wanted to add comment, change title, etc ..
I will leave this question as an example for building GitHub app to update pull request using NodeJS.