UID file configuration for Meilix

Meilix has by default one user which is hotelos. Each user has a UID known as Unique Identification Display. Each UID is assigned some unique number. The range for uid is from 1000 to 65000. The login manager doesn’t create user which doesn’t have a uid in this range.

Problem:

We found out that hotelos has a uid = 999 through this autologin file meilix-default-settings/usr/share/initramfs-tools/scripts/casper-bottom/15autologin. Therefore sddm would not accept this as the username.

Solution:

Way 1: Increase the uid of the hotelos

Way 2: Decrease the default sddm uid through configuration file

We here tried with the second approach to decrease the uid of the sddm to 500, so that it will take hotelos as the default user.

 

[Users]
HideShells=/sbin/nologin,/bin/false
# Hidden users, this is if any system users fall within your range, see /etc/passwd on your system.
HideUsers=git,sddm,systemd-journal-remote,systemd-journal-upload

# Maximum user id for displayed users
MaximumUid=65000

# Minimum user id for displayed users
MinimumUid=500 #My UID is 999

 

This is one of the way through which we have decreased the UID to 500.

We can use id -u in the terminal to check the uid of the user.

Root has uid = 0.

We can see different operations uid in the file /etc/passwd .

It looks like this:

We have a file /etc/login.defs where we can manage the max and min uid for the user.

#
# Min/max values for automatic uid selection in useradd
#
UID_MIN                     	1000
UID_MAX                    	60000
# System accounts
#SYS_UID_MIN              	100
#SYS_UID_MAX              	999

We can modify it to accept hotelos as the user.

\sed -i '/UID_MIN/ c\UID_MIN 998' /etc/login.defs

 

This will change the UID_MIN value to 998.

References

  1. User ID definition: http://www.linfo.org/uid.html
  2. SDDM User Issue: https://wiki.archlinux.org/index.php/SDDM#One_or_more_users_don.27t_show_up_on_the_greeter
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Metadata Updation in Badgeyay

Badgeyay is a simple badge generator service to develop badges for technical events and conferences developed by FOSSASIA. Badgeyay is a SPA (Single Page Application) developed in ember, whose backend is in Flask. Now when user logins, he can see an option for user profile, in which all the metadata of its profile can be seen (extracted from Firebase). Now user should be able to change its metadata like profile image and username etc. So we will look how the profile image is being changed and updated in badgeyay.

Procedure

  1. Create function in frontend to listen for onclick events and initiate a file upload dialog box for selecting an image. We will use document property to initiate a dummy click event, else there will be a button with the text to upload a file and that won’t look consistent as we only need an image and nothing else on the UI.

class=“ui small circular image profile-image”>
    “{{user.photoURL}}”>
    “display: none;” id=“profileImageSelector” type=“file” onchange={{action “profileImageSelected”}}>
    

“profile-change” onclick={{action “updateProfileImage”}}>Change


</div>

 

  1. Function to upload file and initiate a dummy click event
updateProfileImage() {
    // Initate a dummy click event
    document.getElementById(‘profileImageSelector’).click();
  },

  profileImageSelected(event) {
    const reader = new FileReader();
    const { target } = event;
    const { files } = target;
    const [file] = files;
    const _this = this;

    reader.onload = () => {
      _this.get(‘sendProfileImage’)(reader.result, file.type.split(‘/’)[1]);
    };

    reader.readAsDataURL(file);
  }

 

  1. Profile update function in the main controller to call the API endpoint to upload the data to backend. This will send the payload to backend which will later upload the image to cloud storage and save in the link in the database.
updateProfileImage(profileImageData, extension) {
    const _this = this;
    const user = this.get(‘store’).peekAll(‘user’);
    user.forEach(user_ => {
      _this.set(‘uid’, user_.get(‘id’));
    });
    let profileImage = _this.get(‘store’).createRecord(‘profile-image’, {
      image   : profileImageData,
      uid   : _this.uid,
      extension : ‘.’ + extension
    });
    profileImage.save()
      .then(record => {
        user.forEach(user_ => {
          user_.set(‘photoURL’, record.photoURL);
        });
      })
      .catch(err => {
        let userErrors = profileImage.get(‘errors.user’);
        if (userErrors !== undefined) {
          _this.set(‘userError’, userErrors);
        }
      });
  }
  1. Route to update profile image from backend
@router.route(‘/profileImage’, methods=[‘POST’])
def update_profile_image():
  try:
      data = request.get_json()[‘data’][‘attributes’]
  except Exception:
      return ErrorResponse(PayloadNotFound().message, 422, {‘Content-Type’: ‘application/json’}).respond()

  if not data[‘image’]:
      return ErrorResponse(ImageNotFound().message, 422, {‘Content-Type’: ‘application/json’}).respond()

  if not data[‘extension’]:
      return ErrorResponse(ExtensionNotFound().message, 422, {‘Content-Type’: ‘application/json’}).respond()

  uid = data[‘uid’]
  image = data[‘image’]
  extension = data[‘extension’]

  try:
      imageName = saveToImage(imageFile=image, extension=extension)
  except Exception:
      return ErrorResponse(ImageNotFound().message, 422, {‘Content-Type’: ‘application/json’}).respond()

  fetch_user, imageLink = update_database(uid, imageName)
  return jsonify(UpdateUserSchema().dump(fetch_user).data)

 

This will first create a temp file with the data URI and them upload that file to cloud storage and generate the link and then update the user in the database.

def update_database(uid, imageName):
  fetch_user = User.getUser(user_id=uid)
  if fetch_user is None:
      return ErrorResponse(UserNotFound(uid).message, 422, {‘Content-Type’: ‘application/json’}).respond()
  imagePath = os.path.join(app.config.get(‘BASE_DIR’), ‘static’, ‘uploads’, ‘image’) + ‘/’ + imageName
  imageLink = fileUploader(imagePath, ‘profile/images/’ + imageName)
  fetch_user.photoURL = imageLink
  fetch_user.save_to_db()

  try:
      os.unlink(imagePath)
  except Exception:
      print(‘Unable to delete the temporary file’)

  return fetch_user, imageLink

 

Link to PR – Link

Topics Involved

  • Google Cloud Admin Storage SDK
  • Ember data

Resources

  • Firebase admin sdk documentation – Link
  • Google Cloud Storage SDK Python – Link
  • Blob Management – Link
  • Documents API – Link
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