- Implemented the user credentials import task

- Implemented the user report creation task

myprj/usermerge/forms.py

 import re
 from django import forms
-from .validators import ece_id_is_not_031YY000, platform_is_SLUB_or_exists_in_DB
+from .validators import (
+    ece_id_is_not_031YY000, last_login_is_selected_from_provided_list, platform_exists_in_DB, platform_is_SLUB_or_exists_in_DB
+)
 
 # Create your forms here.
 # https://docs.djangoproject.com/en/2.0/ref/forms/
@@ -43,3 +45,40 @@ class UserProfileRecoveryForm(UserProfileEditForm):
     first_name = None
     last_name = None
 
+class UserCredentialsImportForm(forms.Form):
+    platform = forms.CharField(error_messages = {'required': 'Το όνομα πλατφόρμας πρέπει απαραίτητα να επιλεχθεί και να είναι μη-κενό!'},
+                               validators = [platform_exists_in_DB])
+    credentials_file = forms.FileField(max_length = 50,
+                                       error_messages = {'required': 'Το αρχείο διαπιστευτηρίων πρέπει απαραίτητα να υποβληθεί και να '
+                                                                     'έχει μη-κενό όνομα!',
+                                                         'invalid': 'Η υποβολή του αρχείου διαπιστευτηρίων απέτυχε! Παρακαλούμε '
+                                                                    'ελέγξτε την ορθότητα του\n'
+                                                                    'τύπου κωδικοποίησης στη φόρμα προσθήκης διαπιστευτηρίων '
+                                                                    'και δοκιμάστε ξανά!',
+                                                         'missing': 'Η υποβολή του αρχείου διαπιστευτηρίων απέτυχε!',
+                                                         'max_length': 'Το όνομα του αρχείου διαπιστευτηρίων δεν πρέπει '
+                                                                       'να υπερβαίνει τους 50 χαρακτήρες!',
+                                                         'empty': 'Το περιεχόμενο του αρχείου διαπιστευτηρίων δεν πρέπει να είναι κενό!'})
+
+    def clean_credentials_file(self):
+        credentials_file = self.cleaned_data['credentials_file']
+        # Ensure that the credentials file is a plain text file whose size does not exceed 40KB.
+        # Otherwise, close it and raise a ValidationError exception with the appropriate error message and code.
+        if credentials_file.content_type != 'text/plain':
+            credentials_file.close()
+            raise forms.ValidationError('Το αρχείο διαπιστευτηρίων πρέπει να είναι ένα απλό αρχείο κειμένου!',
+                                        code = 'credentials_file_content_type_is_not_plain_text')
+        elif credentials_file.size > 1024 * 40:
+            credentials_file.close()
+            raise forms.ValidationError('Το μέγεθος του αρχείου διαπιστευτηρίων δεν πρέπει να υπερβαίνει τα 40KB!',
+                                        code = 'credentials_file_size_exceeds_40KB')
+        else:
+            return credentials_file
+
+class UserReportCreationForm(forms.Form):
+    platform = forms.CharField(error_messages = {'required': 'Το όνομα πλατφόρμας πρέπει απαραίτητα να επιλεχθεί και να είναι μη-κενό!'},
+                               validators = [platform_exists_in_DB])
+    last_login = forms.CharField(error_messages = {'required': 'Η περίοδος αναζήτησης τελευταίας εισόδου πρέπει απαραίτητα να επιλεχθεί '
+                                                               'και να είναι μη-κενή!'},
+                                 validators = [last_login_is_selected_from_provided_list])
+

myprj/usermerge/helper.py

@@ -32,6 +32,23 @@ def get_form_error_messages(form):
         raise TypeError('The form argument of get_form_error_messages() helper function '
                         'should be an instance of "django.forms.forms.Form" class!')
 
+def seq_to_aligned_str(seq, max_line_len):
+    """
+    Create an aligned string from the elements of the given sequence. This string separates every max_line_len elements (along with the
+    delimiting commas) by a newline character without changing their order (the last line may contain less than max_line_len elements).
+    If max_line_len is a non-positive number, raise a ValueError exception with the appropriate error message.
+    """
+    if max_line_len <= 0:
+        raise ValueError('The max_line_len argument of seq_to_aligned_str() helper function should be a positive integer!')
+    seq = list(seq) # Turn seq into a list to ensure that it has the appropriate sequence format.
+    aligned_str = ''
+    for idx in range(0, len(seq), max_line_len):
+        if idx + max_line_len < len(seq):
+            aligned_str += str(seq[idx:idx + max_line_len])[1:-1] + ',\n'
+        else:
+            aligned_str += str(seq[idx:len(seq)])[1:-1]
+    return aligned_str
+
 def _update_user_profile(request, changed_data, cleaned_data):
     """
     [Acts as inner function of the edit_user_profile() view] Check which fields of the user profile edit form have been changed, update

myprj/usermerge/models.py

@@ -13,11 +13,11 @@ from django.utils.timezone import localtime
 
 # The id and last_login fields are populated/updated automatically (each model is implicitly given an id AutoField that acts as the corresponding primary key, each last_login field is initially empty and is updated whenever the corresponding user_logged_in signal is emitted - see the relative explanation on last_login fields below) and should NOT be declared during the creation/update of model instances. The REMAINING fields should satisfy specific requirements (see examples in populateDB.py):
 #   * The name field of a Platform instance should NEVER be empty. Its value can be changed validly/consistently but it should NEVER become empty. A Platform instance can be created/changed in usermergeDB ONLY in a NON-session context, e.g. fixture - see https://docs.djangoproject.com/en/2.0/howto/initial-data/, interactive shell - see https://docs.djangoproject.com/en/2.0/ref/django-admin/, file such as populateDB.py, etc.
-#   * ALL the fields of a Registry instance should be NON-empty. The user (user_id), username and password values can be changed validly/consistently (the platform - platform_id - value should NEVER be changed) but they should NEVER become empty. When a Registry instance is initially created, an empty User instance should also be created and associated with that Registry instance - see the below explanation about the User instance fields.
+#   * ALL the fields of a Registry instance should be NON-empty. The user (user_id), username and password values can be changed validly/consistently (the platform - platform_id - value should NEVER be changed) but they should NEVER become empty. When a Registry instance is initially created, an empty User instance should also be created and associated with that Registry instance - see the import_user_credentials() view.
 #   * ALL the fields of an Admin instance should be NON-empty. Their values can be changed validly/consistently but they should NEVER become empty. An Admin instance can be created/changed in usermergeDB ONLY in a NON-session context, e.g. fixture, interactive shell, file such as populateDB.py, etc. (see the relative references above).
-#   * The fields of a User instance should ALWAYS be in ONE of the following states: 1)ALL filled out, 2)ALL filled out EXCEPT FOR ece_id, 3)NONE filled out. The allowed transitions between field states are: 1-->1, 2-->1, 2-->2, 3-->1 and 3-->2 (empty field values can be changed to valid/consistent non-empty ones, non-empty field values can be changed validly/consistently but they should NEVER become empty). When a User instance is initially created, ALL its fields should be empty (state 3) and EXACTLY ONE Registry instance should be created to reference it - see the above explanation about the Registry instance fields. The fields can then be changed/filled out (state 1/2) ONLY by the corresponding user via the user profile edit form after he/she has logged in first - see the edit_user_profile() view (any other way of changing/filling out the fields is by NO means accepted).
+#   * The fields of a User instance should ALWAYS be in ONE of the following states: 1)ALL filled out, 2)ALL filled out EXCEPT FOR ece_id, 3)NONE filled out. The allowed transitions between field states are: 1-->1, 2-->1, 2-->2, 3-->1 and 3-->2 (empty field values can be changed to valid/consistent non-empty ones, non-empty field values can be changed validly/consistently but they should NEVER become empty). When a User instance is initially created, ALL its fields should be empty (state 3) and EXACTLY ONE Registry instance should be created to reference it - see the import_user_credentials() view. The fields can then be changed/filled out (state 1/2) ONLY by the corresponding user via the user profile edit form after he/she has logged in first - see the edit_user_profile() view (any other way of changing/filling out the fields is by NO means accepted).
 
-# A User instance retains ONE last_login value FOR EACH Platform instance that is associated with it via the corresponding Registry instance, while an Admin instance is associated ONLY with the SLUB "platform", i.e. it is NOT associated with any Platform instances, and thus retains EXACTLY ONE last_login value. Each time a user logs in, an appropriate user_logged_in signal is emitted - see the login() function in auth.py - causing the last_login field of the corresponding User/Admin instance for the login platform (SLUB in case of an Admin instance) to be updated INDEPENDENTLY of its other fields. A NON-empty User instance should ALWAYS retain a NON-empty last_login value FOR EACH of its associated Platform instances - see the edit_user_profile() and recover_user_profile() views. On the other hand, an empty User instance generally retains an empty last_login value for its ONLY associated Platform instance but can also retain a NON-empty one for it (the user logs in and, although his/her profile is empty, he/she opts to log out - or is logged out automatically due to session expiration - WITHOUT filling it out). An Admin instance generally retains a NON-empty last_login value for the SLUB "platform" as it should be logged in to access any Admin-targeted functionality/view, but can also retain an empty one for it (the user has NEVER logged in but his/her profile has ALREADY been filled out in a NON-session context, e.g. fixture, interactive shell, file such as populateDB.py, etc. - see the relative references above).
+# A User instance retains ONE last_login value FOR EACH Platform instance that is associated with it via the corresponding Registry instance, while an Admin instance is associated ONLY with the SLUB "platform", i.e. it is NOT associated with any Platform instances, and thus retains EXACTLY ONE last_login value. Each time a user logs in, an appropriate user_logged_in signal is emitted - see the login() function in auth.py - causing the last_login field of the corresponding User/Admin instance for the login platform (SLUB in case of an Admin instance) to be updated INDEPENDENTLY of its other fields. A NON-empty User instance should ALWAYS retain a NON-empty last_login value FOR EACH of its associated Platform instances - see the edit_user_profile() and recover_user_profile() views. On the other hand, an empty User instance generally retains an empty last_login value for its ONLY associated Platform instance - see the import_user_credentials() view - but can also retain a NON-empty one for it (the user logs in and, although his/her profile is empty, he/she opts to log out - or is logged out automatically due to session expiration - WITHOUT filling it out). An Admin instance generally retains a NON-empty last_login value for the SLUB "platform" as it should be logged in to access any Admin-targeted functionality/view, but can also retain an empty one for it (the user has NEVER logged in but his/her profile has ALREADY been filled out in a NON-session context, e.g. fixture, interactive shell, file such as populateDB.py, etc. - see the relative references above).
 # Given that support for time zones is enabled (USE_TZ setting is True), DateTimeField values (datetime objects) are stored in UTC format in usermergeDB and are generally displayed in the current time zone, that is 'Europe/Athens' by default (specified by the TIME_ZONE setting), in templates. It is possible to manually convert these values to a different time zone or/and change their display format if needed, e.g. convert them to local time (default time zone, i.e. 'Europe/Athens') or/and display them in 'DD/MM/YYYY HH:MM:SS' format. For more information on time zone support and datetime objects, see https://docs.djangoproject.com/en/2.0/topics/i18n/timezones/ and the "Internationalization" part of settings.py .
 # The get_session_auth_hash() methods and is_authenticated attributes are needed for user authentication, e.g. in the login() and get_user() functions defined in auth.py and login_required() decorator used in views.py and decorators.py . Original source code for these methods/attributes can be found in https://github.com/django/django/blob/master/django/contrib/auth/base_user.py (for more information, see https://docs.djangoproject.com/en/2.0/topics/auth/customizing/).
 

myprj/usermerge/templates/admin_home.html

@@ -12,5 +12,10 @@
     </nav>
 
     <h4>Αρχική Σελίδα Διαχειριστή</h4>
-    <p><a href="{% url 'logout' %}">Έξοδος</a></p>
+
+    <nav id="home_nav">
+        <p><a href="{% url 'default_user_credentials_import' %}">Προσθήκη Διαπιστευτηρίων Χρηστών</a></p>
+        <p><a href="{% url 'default_user_report_creation' %}">Δημιουργία Αναφοράς Χρηστών</a></p>
+        <p><a href="{% url 'logout' %}">Έξοδος</a></p>
+    </nav>
 {% endblock %}

myprj/usermerge/templates/user_credentials_import.html

+{% extends 'base.html' %}
+
+{% block title %}
+    SLUB - Προσθήκη Διαπιστευτηρίων Χρηστών
+{% endblock %}
+
+{% block content %}
+    <nav id="session_nav">
+        Έχετε εισέλθει ως <strong>{{ user.first_name }} {{ user.last_name }}</strong>!
+        | <a href="{% url 'admin_home' %}">Αρχική Σελίδα</a>
+        | <a href="{% url 'logout' %}">Έξοδος</a>
+    </nav>
+
+    <h4>Προσθήκη Διαπιστευτηρίων Χρηστών</h4>
+
+    <form id="user_credentials_import_form" accept-charset="utf-8" enctype="multipart/form-data"
+          action="{% url 'import_user_credentials' %}" method="post">
+        {% csrf_token %}
+
+        <table>
+            <tbody>
+                <tr>
+                    <td style="text-align:right;"><label for="platform">Πλατφόρμα διαπίστευσης:</label></td>
+                    <td style="text-align:left;">
+                        <select name="platform" id="platform" required="required">
+                            <option value=""></option>
+                            {% for name in platform_names %}
+                                <option value="{{ name }}">{{ name }}</option>
+                            {% endfor %}
+                        </select>
+                    </td>
+                </tr>
+                <tr>
+                    <td style="text-align:right;">
+                        <label for="credentials_file">Αρχείο διαπιστευτηρίων<span style="color:darkorange;">*</span>:</label>
+                    </td>
+                    <td style="text-align:left;">
+                        <input type="file" accept="text/plain" name="credentials_file" id="credentials_file" required="required" />
+                    </td>
+                </tr>
+            </tbody>
+        </table>
+
+        <p style="color:darkorange;">
+            <strong>
+                * Το αρχείο διαπιστευτηρίων πρέπει να είναι ένα μη-κενό απλό αρχείο κειμένου, να έχει μέγεθος έως 40KB και να <br />
+                  περιλαμβάνει μόνο γραμμές της μορφής &lt;Login: X Password: Y&gt; (χωρίς τις γωνιακές αγκύλες) όπου X είναι <br />
+                  ένα μη-κενό όνομα χρήστη, Y είναι ένας μη-κενός κωδικός πρόσβασης και κανένα από τα δύο δεν περιέχει τη <br />
+                  συμβολοσειρά &lt; Password: &gt; (χωρίς τις γωνιακές αγκύλες) ή/και χαρακτήρες μη-αποκωδικοποιήσιμους σε UTF-8!
+            </strong>
+        </p>
+
+        <input type="submit" value="Προσθήκη" />
+    </form>
+
+    {% if success_message %}
+        <p style="color:green;">
+            <img src="images/tick.png" alt="Επιβεβαίωση:" />
+            <strong>{{ success_message | linebreaksbr }}</strong>
+        </p>
+    {% endif %}
+
+    {% if error_messages %}
+        {% for message in error_messages %}
+            <p style="color:red;">
+                <img src="images/warning.svg" alt="Σφάλμα:" />
+                <strong>{{ message | linebreaksbr }}</strong>
+            </p>
+        {% endfor %}
+    {% endif %}
+
+    <p><a href="{% url 'admin_home' %}">&#x21B5; Επιστροφή στην Αρχική Σελίδα</a></p>
+{% endblock %}
+

myprj/usermerge/templates/user_report_creation.html

+{% extends 'base.html' %}
+
+{% block title %}
+    SLUB - Δημιουργία Αναφοράς Χρηστών
+{% endblock %}
+
+{% block content %}
+    <nav id="session_nav">
+        Έχετε εισέλθει ως <strong>{{ user.first_name }} {{ user.last_name }}</strong>!
+        | <a href="{% url 'admin_home' %}">Αρχική Σελίδα</a>
+        | <a href="{% url 'logout' %}">Έξοδος</a>
+    </nav>
+
+    <h4>Δημιουργία Αναφοράς Χρηστών</h4>
+
+    <form id="user_report_creation_form" accept-charset="utf-8" action="{% url 'create_user_report' %}" method="post">
+        {% csrf_token %}
+
+        <table>
+            <tbody>
+                <tr>
+                    <td style="text-align:right;"><label for="platform">Πλατφόρμα αναφοράς:</label></td>
+                    <td style="text-align:left;">
+                        <select name="platform" id="platform" required="required">
+                            <option value=""></option>
+                            {% for name in platform_names %}
+                                <option value="{{ name }}">{{ name }}</option>
+                            {% endfor %}
+                        </select>
+                    </td>
+                </tr>
+                <tr>
+                    <td style="text-align:right;">
+                        <label for="last_login">
+                            Tελευταία είσοδος με διαπιστευτήρια <br />
+                            της πλατφόρμας αναφοράς:
+                        </label>
+                    </td>
+                    <td style="text-align:left;">
+                        <select name="last_login" id="last_login" required="required">
+                            <option value=""></option>
+                            <option value="last_six_months">εντός του τελευταίου εξαμήνου</option>
+                            <option value="last_year">εντός του τελευταίου έτους</option>
+                            <option value="all_time">από την αρχή του χρόνου</option>
+                        </select>
+                    </td>
+                </tr>
+            </tbody>
+        </table>
+
+        <br />
+        <input type="submit" value="Δημιουργία" />
+    </form>
+
+    {% if error_messages %}
+        {% for message in error_messages %}
+            <p style="color:red;">
+                <img src="images/warning.svg" alt="Σφάλμα:" />
+                <strong>{{ message | linebreaksbr }}</strong>
+            </p>
+        {% endfor %}
+    {% endif %}
+
+    <p><a href="{% url 'admin_home' %}">&#x21B5; Επιστροφή στην Αρχική Σελίδα</a></p>
+{% endblock %}
+

myprj/usermerge/urls.py

@@ -24,10 +24,17 @@ urlpatterns = [
     re_path(r'^user/home$', views.display_user_home_page, name = 'user_home'),
     re_path(r'^user/profile/edit/default$', views.display_default_user_profile_edit_page, name = 'default_user_profile_edit'),
     re_path(r'^user/profile/edit/submit$', views.edit_user_profile, name = 'edit_user_profile'),
-    re_path(r'^user/profile/recovery/default$', views.display_default_user_profile_recovery_page, name = 'default_user_profile_recovery'),
+    re_path(r'^user/profile/recovery/default$', views.display_default_user_profile_recovery_page,
+                                                name = 'default_user_profile_recovery'),
     re_path(r'^user/profile/recovery/search$', views.search_for_recovery_user_profile, name = 'search_for_recovery_user_profile'),
     re_path(r'^user/profile/recovery/submit$', views.recover_user_profile, name = 'recover_user_profile'),
     re_path(r'^admin/home$', views.display_admin_home_page, name = 'admin_home'),
+    re_path(r'^admin/user-credentials-import/default$', views.display_default_user_credentials_import_page,
+                                                        name = 'default_user_credentials_import'),
+    re_path(r'^admin/user-credentials-import/submit$', views.import_user_credentials, name = 'import_user_credentials'),
+    re_path(r'^admin/user-report-creation/default$', views.display_default_user_report_creation_page,
+                                                     name = 'default_user_report_creation'),
+    re_path(r'^admin/user-report-creation/submit$', views.create_user_report, name = 'create_user_report'),
     re_path(r'^logout$', views.log_out, name = 'logout'),
 ]
 

myprj/usermerge/validators.py

@@ -18,6 +18,16 @@ def platform_is_SLUB_or_exists_in_DB(platform):
         raise ValidationError('Το όνομα πλατφόρμας πρέπει να επιλέγεται μεταξύ εκείνων\n'
                               'που παρέχονται στην αντίστοιχη αναπτυσσόμενη λίστα!', code = 'platform_is_not_SLUB_and_does_not_exist_in_DB')
 
+def platform_exists_in_DB(platform):
+    """
+    Ensure that the platform (name) is selected among the ones provided in the corresponding form drop-down list (this list includes the
+    platforms that exist in usermergeDB). If it is not (e.g. it is misedited via JavaScript), raise a ValidationError exception with the
+    appropriate error message and code.
+    """
+    if not platform in get_all_platform_names_from_DB():
+        raise ValidationError('Το όνομα πλατφόρμας πρέπει να επιλέγεται μεταξύ εκείνων\n'
+                              'που παρέχονται στην αντίστοιχη αναπτυσσόμενη λίστα!', code = 'platform_does_not_exist_in_DB')
+
 def ece_id_is_not_031YY000(ece_id):
     """
     Ensure that the ece_id (format) is not 031YY000.
@@ -25,3 +35,14 @@ def ece_id_is_not_031YY000(ece_id):
     """
     if ece_id[5:] == '000':
         raise ValidationError('Ο αριθμός μητρώου απαγορεύεται να είναι της μορφής 031YY000 (YY: έτος)!', code = 'ece_id_is_031YY000')
+
+def last_login_is_selected_from_provided_list(last_login):
+    """
+    Ensure that the last login (search period) is selected among the ones provided in the corresponding form drop-down list.
+    If it is not (e.g. it is misedited via JavaScript), raise a ValidationError exception with the appropriate error message and code.
+    """
+    if not last_login in ['last_six_months', 'last_year', 'all_time']:
+        raise ValidationError('Η περίοδος αναζήτησης τελευταίας εισόδου πρέπει να επιλέγεται μεταξύ\n'
+                              'εκείνων που παρέχονται στην αντίστοιχη αναπτυσσόμενη λίστα!',
+                              code = 'last_login_is_not_selected_from_provided_list')
+

myprj/usermerge/views.py

-import logging
+import csv, datetime, io, logging, re
 from django.contrib.auth import authenticate, logout
 from django.contrib.auth.decorators import login_required
+from django.contrib.auth.hashers import make_password
 from django.contrib.auth.models import AnonymousUser
 from django.core.exceptions import PermissionDenied
-# from django.db.models import Q
+from django.db.models import Q
+from django.http import HttpResponse
 from django.shortcuts import redirect
 from django.template.response import TemplateResponse
+from django.utils import timezone
 from .auth import login, PLATFORM_SESSION_KEY
 from .decorators import Admin_login_required, User_login_required
-from .forms import LoginForm, UserProfileEditForm, UserProfileRecoveryForm
+from .forms import LoginForm, UserCredentialsImportForm, UserProfileEditForm, UserProfileRecoveryForm, UserReportCreationForm
 from .helper import (
-    get_all_platform_names_from_DB, get_form_error_messages, _display_user_profile_edit_error_messages,
+    get_all_platform_names_from_DB, get_form_error_messages, seq_to_aligned_str, _display_user_profile_edit_error_messages,
     _display_user_profile_recovery_error_messages, _display_user_profile_recovery_success_message, _update_user_profile
 )
-from .models import Registry, User
+from .models import Platform, Registry, User
 
 # Create your views here.
 # https://docs.djangoproject.com/en/2.0/topics/http/views/
@@ -22,6 +25,9 @@ from .models import Registry, User
 # For more information on default/customizing user authentication and password management, see https://docs.djangoproject.com/en/2.0/topics/auth/, auth.py, backends.py and AuthenticationMiddleware of middleware.py .
 # For more information on making database queries, i.e. creating, retrieving, updating and deleting model instances, see https://docs.djangoproject.com/en/2.0/topics/db/queries/ .
 # For more information on working with forms, see https://docs.djangoproject.com/en/2.0/topics/forms/ .
+# For more information on handling file uploads, see https://docs.djangoproject.com/en/2.0/topics/http/file-uploads/ .
+# For more information on outputting CSV files, see https://docs.djangoproject.com/en/2.0/howto/outputting-csv/ .
+# For more information on time zone support and datetime objects, see https://docs.djangoproject.com/en/2.0/topics/i18n/timezones/ and the "Internationalization" part of settings.py .
 # For more information on using TemplateResponse objects - instead of standard HttpResponse objects and calls to the render() shortcut function - to display application pages/templates, see https://docs.djangoproject.com/en/2.0/ref/template-response/ .
 
 # The below defined views refer to the application site; therefore, they are not targeted at the default user model but at the application user models (see the _get_user_model_label() function of auth.py), i.e. the views can be accessed only by usermerge.{User/Admin} instances (the "usermerge." prefix is usually omitted in the application context) and not by auth.User ones - see the User_login_required() and Admin_login_required() decorators. Furthermore, the user instances (including the session one) that are created, retrieved, updated or deleted in the context of each view are usermerge.{User/Admin} instances. On the other hand, the admin site (see https://docs.djangoproject.com/en/2.0/ref/contrib/admin/) is not targeted at the application user models but at the default user model as only auth.User instances can be active staff members - each one has the is_active and is_staff attributes and the latter are set to True - and also have permissions - each one has the is_superuser, groups and user_permissions attributes as well as the relative methods, e.g. get_group_permissions(), get_all_permissions(), etc. - to access the site and utilize some or all of its capabilities. The admin site should generally be used for retrieving/reviewing model instances and not for creating, updating or deleting them - the latter actions should better be performed by appropriately defined views. When trying to create, update or delete instances via the admin site, extra care should be given to retain consistency in usermergeDB, e.g. a Platform instance could be created without any problem, while the updated password of an Admin instance would wrongly be stored in raw format (without being hashed first), etc. (for more information, see models.py).
@@ -453,6 +459,205 @@ def display_admin_home_page(request):
     """
     return TemplateResponse(request, 'admin_home.html', {})
 
+@Admin_login_required
+def display_default_user_credentials_import_page(request):
+    """
+    Display the user credentials import page in default mode, i.e. without any form-submission-related messages.
+    """
+    return TemplateResponse(request, 'user_credentials_import.html', {'platform_names': get_all_platform_names_from_DB()})
+
+@Admin_login_required
+def import_user_credentials(request):
+    """
+    Collect the data, i.e. platform and credentials file, POSTed via the user credentials import form and validate them. If they are not
+    valid, display the appropriate validation error messages in the user credentials import page. Otherwise, examine each line of the
+    credentials file by checking the line format first, the length of the credentials second and the uniqueness of the platform-username
+    key in usermergeDB last. If any of the checks fails, skip the remaining checks of the examined line, mark it as incorrect in the
+    specific check and then continue to the next line. If none of the checks fails, mark the examined line as correct, create a new empty
+    User instance in usermergeDB, hash the line password, create a new Registry instance in usermergeDB that associates the created User
+    instance with the selected platform, the line username and the hashed password and then continue to the next line. After examining
+    all the lines, display the appropriate success and error messages in the user credentials import page and include all the line numbers
+    in its context grouped by import result.
+    """
+    form = UserCredentialsImportForm(request.POST, request.FILES)
+    if form.is_valid():
+        platform = form.cleaned_data['platform']
+        credentials_file = form.cleaned_data['credentials_file']
+        platform_instance = Platform.objects.get(name = platform)
+        credentials_import_success_line_nos = []
+        wrong_line_format_error_line_nos = []
+        prohibited_credentials_length_error_line_nos = []
+        duplicate_platform_username_error_line_nos = []
+        # The utf8_decoded_credentials_file is an in-memory text stream based on the UTF-8 decoding of the credentials_file in-memory
+        # binary stream. In the text stream, UTF-8 non-decodable characters are replaced by the Unicode replacement character \ufffd,
+        # while alternative newline characters \r and \r\n are replaced by the Unix newline character \n.
+        with credentials_file, io.StringIO(credentials_file.read().decode(errors = 'replace'), None) as utf8_decoded_credentials_file:
+            for line_no, line in enumerate(utf8_decoded_credentials_file, 1):
+                # The format of each line should be <Login: X Password: Y> (without the angle brackets) where X is a non-empty username,
+                # Y is a non-empty password and neither contains the string < Password: > (without the angle brackets) or/and UTF-8
+                # non-decodable characters.
+                if not re.fullmatch('Login: [^\n\ufffd]+ Password: [^\n\ufffd]+\n?', line):
+                    wrong_line_format_error_line_nos.append(line_no)
+                else:
+                    try:
+                        username, password = line[7:].split(' Password: ')
+                    except ValueError:
+                        wrong_line_format_error_line_nos.append(line_no)
+                    else:
+                        # The credentials of the examined line are first stripped of any leading and trailing whitespace characters
+                        # before their length is checked. The minimum and maximum lengths for each credential are 8 and 50 respectively.
+                        username = username.strip()
+                        password = password.strip()
+                        if not (8 <= len(username) <= 50 and 8 <= len(password) <= 50):
+                            prohibited_credentials_length_error_line_nos.append(line_no)
+                        else:
+                            try:
+                                Registry.objects.get(platform = platform_instance, username = username)
+                            except Registry.DoesNotExist:
+                                Registry.objects.create(user = User.objects.create(), platform = platform_instance,
+                                                        username = username, password = make_password(password))
+                                credentials_import_success_line_nos.append(line_no)
+                            else:
+                                duplicate_platform_username_error_line_nos.append(line_no)
+        filename = credentials_file.name
+        str_align_factor = 10
+        success_message = ''
+        error_messages = []
+        line_nos_grouped_by_import_result = {}
+        if credentials_import_success_line_nos:
+            success_message = ('Η προσθήκη διαπιστευτηρίων της δηλωθείσας πλατφόρμας <%s> στη βάση από\n'
+                               'το υποβληθέν αρχείο <%s> ήταν επιτυχής για τις εξής %d γραμμές:\n'
+                               '%s'
+                              ) % (platform, filename, len(credentials_import_success_line_nos),
+                                   seq_to_aligned_str(credentials_import_success_line_nos, str_align_factor))
+            line_nos_grouped_by_import_result.update({'credentials_import_success_line_nos': credentials_import_success_line_nos})
+        if wrong_line_format_error_line_nos:
+            error_messages.append('Η προσθήκη διαπιστευτηρίων της δηλωθείσας πλατφόρμας <' + platform + '> στη βάση από το υποβληθέν\n'
+                                  'αρχείο <' + filename + '> απέτυχε για τις εξής ' + str(len(wrong_line_format_error_line_nos)) + ' '
+                                  'γραμμές των οποίων η μορφή δεν συνάδει\n'
+                                  'με όσα περιγράφονται στην αντίστοιχη επεξήγηση της φόρμας προσθήκης διαπιστευτηρίων:\n' +
+                                  seq_to_aligned_str(wrong_line_format_error_line_nos, str_align_factor))
+            line_nos_grouped_by_import_result.update({'wrong_line_format_error_line_nos': wrong_line_format_error_line_nos})
+        if prohibited_credentials_length_error_line_nos:
+            error_messages.append('Η προσθήκη διαπιστευτηρίων της δηλωθείσας πλατφόρμας <' + platform + '> στη βάση από το υποβληθέν\n'
+                                  'αρχείο <' + filename + '> απέτυχε για τις εξής ' +
+                                  str(len(prohibited_credentials_length_error_line_nos)) + ' γραμμές όπου το όνομα χρήστη ή/και\n'
+                                  'ο κωδικός πρόσβασης έχουν μήκος μικρότερο των 8 ή μεγαλύτερο των 50 χαρακτήρων\n'
+                                  'μετά την αφαίρεση των αρχικών και τελικών μη-εκτυπώσιμων χαρακτήρων τους:\n' +
+                                  seq_to_aligned_str(prohibited_credentials_length_error_line_nos, str_align_factor))
+            line_nos_grouped_by_import_result.update({'prohibited_credentials_length_error_line_nos':
+                                                       prohibited_credentials_length_error_line_nos})
+        if duplicate_platform_username_error_line_nos:
+            error_messages.append('Η προσθήκη διαπιστευτηρίων της δηλωθείσας πλατφόρμας <' + platform + '> στη βάση από το υποβληθέν\n'
+                                  'αρχείο <' + filename + '> απέτυχε για τις εξής ' +
+                                  str(len(duplicate_platform_username_error_line_nos)) + ' γραμμές όπου το όνομα χρήστη είναι ήδη\n'
+                                  'καταχωρημένο στη βάση και συσχετισμένο με τη συγκεκριμένη πλατφόρμα:\n' +
+                                  seq_to_aligned_str(duplicate_platform_username_error_line_nos, str_align_factor))
+            line_nos_grouped_by_import_result.update({'duplicate_platform_username_error_line_nos':
+                                                       duplicate_platform_username_error_line_nos})
+        template_context = {'platform_names': get_all_platform_names_from_DB()}
+        if success_message:
+            template_context.update({'success_message': success_message})
+        if error_messages:
+            template_context.update({'error_messages': error_messages})
+        template_context.update({'line_nos_grouped_by_import_result': line_nos_grouped_by_import_result})
+        return TemplateResponse(request, 'user_credentials_import.html', template_context)
+    else:
+        return TemplateResponse(request, 'user_credentials_import.html', {'platform_names': get_all_platform_names_from_DB(),
+                                                                          'error_messages': get_form_error_messages(form)})
+
+@Admin_login_required
+def display_default_user_report_creation_page(request):
+    """
+    Display the user report creation page in default mode, i.e. without any form-submission-related messages.
+    """
+    return TemplateResponse(request, 'user_report_creation.html', {'platform_names': get_all_platform_names_from_DB()})
+
+@Admin_login_required
+def create_user_report(request):
+    """
+    Collect the data, i.e. platform and last login, POSTed via the user report creation form and validate them. If they are not valid,
+    display the appropriate validation error messages in the user report creation page. Otherwise, use them to query usermergeDB for
+    registries (Registry instances) of interest and demand that the latter reference users (User instances) with essential information,
+    i.e. non-empty profile, to report (empty user profiles contain no information at all and are thus omitted from the report along
+    with their corresponding registries). If no such registries are retrieved from usermergeDB, display the appropriate post-validation
+    error message in the user report creation page and include the corresponding error code in the page context. Otherwise, create the
+    CSV report with the appropriate name and content, i.e. creation details as well as field values and metrics extracted from the
+    retrieved registries and referenced users, and output it as a file attachment.
+    """
+    session_user = request.user
+    form = UserReportCreationForm(request.POST)
+    if form.is_valid():
+        platform = form.cleaned_data['platform']
+        last_login = form.cleaned_data['last_login']
+        current_UTC_datetime = timezone.now()
+        current_local_datetime = timezone.localtime(current_UTC_datetime)
+        platform_Q = Q(platform__name = platform)
+        last_login_Q = None
+        last_login_text = 'από την αρχή του χρόνου'
+        if last_login == 'last_six_months':
+            # Use 183 days (half leap year) as six-month interval to ensure that all the registries of interest are retrieved from
+            # usermergeDB. Some additional registries of no interest are also retrieved most of the time, albeit with insignificant cost.
+            last_login_Q = Q(last_login__gte = current_UTC_datetime - datetime.timedelta(183))
+            last_login_text = 'εντός του τελευταίου εξαμήνου'
+        elif last_login == 'last_year':
+            # Use 366 days (leap year) as year interval to ensure that all the registries of interest are retrieved from usermergeDB.
+            # Some additional registries of no interest are also retrieved most of the time, albeit with insignificant cost.
+            last_login_Q = Q(last_login__gte = current_UTC_datetime - datetime.timedelta(366))
+            last_login_text = 'εντός του τελευταίου έτους'
+        non_empty_profile_Q = ~Q(user__email = None)
+        retrieved_registries = Registry.objects.none()
+        if last_login_Q is None: # last_login == 'all_time'
+            retrieved_registries = Registry.objects.filter(platform_Q, non_empty_profile_Q).select_related('user')
+        else:
+            retrieved_registries = Registry.objects.filter(platform_Q, non_empty_profile_Q, last_login_Q).select_related('user')
+        if not retrieved_registries:
+            return TemplateResponse(request, 'user_report_creation.html',
+                                    {'platform_names': get_all_platform_names_from_DB(),
+                                     'error_messages': ['Το σύστημα δεν μπορεί να δημιουργήσει τη ζητούμενη αναφορά χρηστών '
+                                                        'καθώς δεν εντοπίστηκε\n'
+                                                        'κανένας χρήστης με συμπληρωμένο προφίλ στη βάση που να πληροί '
+                                                        'τα δηλωθέντα κριτήρια\n'
+                                                        '[Πλατφόρμα <' + platform + '>, Τελευταία είσοδος <' + last_login_text + '>]!'],
+                                     'post_validation_error_codes': ['unsatisfied_report_creation_criteria']})
+        else:
+            response = HttpResponse(content_type = 'text/csv') # Create the HttpResponse object with the appropriate CSV header.
+            response['Content-Disposition'] = ('attachment; filename="%s.csv"') % ('SLUB_user_report_' + platform + '_' + last_login +
+                                                                                   '_' + current_local_datetime.strftime('%d%m%Y_%H%M%S'))
+            writer = csv.writer(response)
+            # Insert the report creation details into the report.
+            writer.writerow(['SoftLab UserBase:', 'Αναφορά Χρηστών'])
+            writer.writerow([])
+            writer.writerow(['Δημιουργία από:', session_user.first_name + ' ' + session_user.last_name + ' <' + session_user.email + '>'])
+            writer.writerow(['Ημερομηνία δημιουργίας:', current_local_datetime.strftime('%d/%m/%Y %H:%M:%S')])
+            writer.writerow([])
+            writer.writerow(['Πλατφόρμα αναφοράς:', platform + ' (αναγνωριστικό: ' + str(retrieved_registries[0].platform_id) + ')'])
+            writer.writerow(['Tελευταία είσοδος με διαπιστευτήρια\n'
+                             'της πλατφόρμας αναφοράς:', last_login_text])
+            writer.writerow([])
+            writer.writerow([])
+            # Insert the significant field values of the retrieved registries and referenced users into the report.
+            writer.writerow(['Αναγνωριστικό χρήστη', 'Όνομα', 'Επώνυμο', 'Αριθμός μητρώου',
+                             'Ηλεκτρονικό ταχυδρομείο', 'Τελευταία είσοδος', 'Όνομα χρήστη'])
+            unregistered_ece_id_count = 0
+            for registry in retrieved_registries:
+                reg_user = registry.user
+                writer.writerow([reg_user.id, reg_user.first_name, reg_user.last_name,
+                                 '[Δεν έχει καταχωρηθεί]' if reg_user.ece_id is None else reg_user.ece_id, reg_user.email,
+                                 timezone.localtime(registry.last_login).strftime('%d/%m/%Y %H:%M:%S'), registry.username])
+                if reg_user.ece_id is None:
+                    unregistered_ece_id_count += 1
+            writer.writerow([])
+            writer.writerow([])
+            # Insert the field metrics extracted from the retrieved registries and referenced users into the report.
+            writer.writerow(['Συνολικός αριθμός αναφερθέντων χρηστών:', len(retrieved_registries)])
+            writer.writerow(['Αριθμός αναφερθέντων χρηστών με\n'
+                             'ακαταχώρητο αριθμό μητρώου:', unregistered_ece_id_count])
+            return response
+    else:
+        return TemplateResponse(request, 'user_report_creation.html', {'platform_names': get_all_platform_names_from_DB(),
+                                                                       'error_messages': get_form_error_messages(form)})
+
 # The session user's model can be either auth.User or usermerge.{User/Admin} .
 @login_required(redirect_field_name = None, login_url = 'default_login')
 def log_out(request):