Error 400: redirect_uri_mismatch using google OAuth

[DeadSo0ul]

Hi, I am trying to connect google's oauth to my app but I face a mismatch between the redirect_uri
Here is my code:

#pragma once

#include <QMainWindow>
#include <QOAuth2AuthorizationCodeFlow>
#include "googlegateway.hpp"
QT_BEGIN_NAMESPACE
namespace Ui {
class MainWindow;
}
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private slots:
    void on_pushButton_clicked();

private:
    Ui::MainWindow *ui;
    GoogleGateway* google;
};

#include "googlegateway.hpp"
#include <QObject>
#include <QJsonDocument>
#include <QJsonObject>
#include <QJsonArray>
#include <QString>
#include <QFile>
#include <QDir>
#include <QUrl>
#include <QOAuthHttpServerReplyHandler>
#include <QDesktopServices>


GoogleGateway::GoogleGateway(QObject *parent) : QObject(parent)
{
    this->google = new QOAuth2AuthorizationCodeFlow(this);
    this->google->setScope("email");

    connect(this->google, &QOAuth2AuthorizationCodeFlow::authorizeWithBrowser, &QDesktopServices::openUrl);

    QByteArray val;
    QFile file;
    file.setFileName(QDir::toNativeSeparators("/Users/boyankiovtorov/Downloads/auth.json"));
    if(file.open(QIODevice::ReadOnly | QIODevice::Text))
    {
        val = file.readAll();
        file.close();
    }


    QJsonDocument document = QJsonDocument::fromJson(val);
    QJsonObject object = document.object();
    const auto settingsObject = object["web"].toObject();
    const QUrl authUri(settingsObject["auth_uri"].toString());
    const auto clientId = settingsObject["client_id"].toString();   
    const QUrl tokenUri(settingsObject["token_uri"].toString());
    const auto clientSecret(settingsObject["client_secret"].toString());

    const auto redirectUris = settingsObject["redirect_uris"].toArray();
    const QUrl redirectUri(redirectUris[0].toString());
    const auto port = static_cast<quint16>(redirectUri.port());

    this->google->setAuthorizationUrl(authUri);
    this->google->setClientIdentifier(clientId);
    this->google->setAccessTokenUrl(tokenUri);
    this->google->setClientIdentifierSharedKey(clientSecret);

    auto replyHandler = new QOAuthHttpServerReplyHandler(port, this);
    this->google->setReplyHandler(replyHandler);
    this->google->grant();

    connect(this->google, &QOAuth2AuthorizationCodeFlow::granted, [=](){
        qDebug() << __FUNCTION__ << __LINE__ << "Access Granted!";
        auto reply = this->google->get(QUrl("https://www.googleapis.com/plus/v1/people/me"));
        connect(reply, &QNetworkReply::finished, [reply](){
            qDebug() << "REQUEST FINISHED. Error? " << (reply->error() != QNetworkReply::NoError);
            qDebug() << reply->readAll();
        });
    });
}

The Authorized redirect URI in the google cloud console is
http://localhost:8080/cb

I downloaded the json from google and so the redirect uri is the same
"redirect_uris":["http://localhost:8080/cb"]

But I still get error when trying to connect to google

Error 400: redirect_uri_mismatch

You cannot log in to this app because it does not comply with Google's OAuth 2.0 rules.

If you are the programmer of the application, register the Google Cloud Console URI for redirect.
Application details: redirect_uri = http://127.0.0.1:8080/

[SGaist]

Hi,

Might be a silly question but did you check the the QUrl object containing the redirect URI contains the correct value ?

[DeadSo0ul]

Hi,
I did, with

    const QUrl redirectUri(redirectUris[0].toString());
    qDebug() << redirectUri;

It appears to be coorect

QUrl("http://localhost:8080/cb")

[SGaist]

@DeadSo0ul looks like something funky is going on the Google side. What happens if you remove cb when doing the request ? (I know, it's not intuitive but might lead to a new message more helpful).

[ChrisW67]

This:

"redirect_uris":["http://localhost:8080/cb"]

may be considered by Google to not match this:

Application details: redirect_uri = http://127.0.0.1:8080/

Have you tried using 127.0.0.1 in place of localhost?

[DeadSo0ul]

@ChrisW67
I did

"redirect_uris":["http://127.0.0.1:8080/cb"],"javascript_origins":["http://127.0.0.1:8080"]

Same error on the google side

Application details: redirect_uri = http://127.0.0.1:8080/

I also tried to change

,"redirect_uris":["http://127.0.0.1:8080/"],"javascript_origins":["http://127.0.0.1:8080"]}}

(removed the cb)

but the error stays the same

[SGaist]

@DeadSo0ul Might be a silly question but did you also change the Google settings to use 127.0.0.1 in place of localhost ?

[DeadSo0ul]

Hi, Sorry for the late reply. I did change the google side to 127.0.0.1 today and the error changed a bit

Application details: redirect_uri = http://127.0.0.1:0/

[SGaist]

That's pretty strange... it's the first time I see port 0 being added... what if you set the port to 80 explicitly ?

[DeadSo0ul]

I set the port to 80 in the cloud console. Now it looks like

http://127.0.0.1:80/cb

the qDebug() says

QUrl("http://127.0.0.1:80/cb")

but the error on google side stays the same

Error 400: redirect_uri_mismatch

You cannot log in to this app because it does not comply with Google's OAuth 2.0 rules.

If you are the programmer of the application, register the Google Cloud Console URI for redirect.
Application details: redirect_uri = http://127.0.0.1:0/