Added the user form, and revised the text in the user list and user detail in the Mia core application.

mia_core/forms.py

@@ -0,0 +1,161 @@
+# The core application of the Mia project.
+#   by imacat <imacat@mail.imacat.idv.tw>, 2020/8/9
+
+#  Copyright (c) 2020 imacat.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+"""The forms of the Mia core application.
+
+"""
+from django import forms
+from django.core.validators import RegexValidator
+from django.db.models import Q
+from django.utils.translation import gettext as _
+
+from mia_core.models import User
+
+
+class UserForm(forms.Form):
+    """A user account form."""
+    login_id = forms.CharField(
+        max_length=32,
+        error_messages={
+            "required": _("Please fill in the log in ID."),
+            "max_length": _("This log in ID is too long (max 32 characters)."),
+        },
+        validators=[
+            RegexValidator(
+                regex="^[^/]+$",
+                message=_("You cannot use slash (/) in the log in ID.")),
+        ])
+    password = forms.CharField(required=False)
+    password2 = forms.CharField(required=False)
+    name = forms.CharField(
+        max_length=32,
+        error_messages={
+            "required": _("Please fill in the name."),
+            "max_length": _("This name is too long (max 32 characters)."),
+        })
+    is_disabled = forms.BooleanField()
+
+    def __init__(self, *args, **kwargs):
+        super(UserForm, self).__init__(*args, **kwargs)
+        self.user = None
+        self.current_user = None
+
+    def clean(self):
+        """Validates the form globally.
+
+        Raises:
+            ValidationError: When the validation fails.
+        """
+        errors = []
+        validators = [self._validate_login_id_unique,
+                      self._validate_password_required,
+                      self._validate_password2_required,
+                      self._validate_passwords_equal,
+                      self._validate_is_disabled_not_oneself]
+        for validator in validators:
+            try:
+                validator()
+            except forms.ValidationError as e:
+                errors.append(e)
+        if errors:
+            raise forms.ValidationError(errors)
+
+    def _validate_login_id_unique(self):
+        """Validates whether the log in ID is unique.
+
+        Raises:
+            forms.ValidationError: When the validation fails.
+        """
+        if "login_id" not in self.data:
+            return
+        condition = Q(login_id=self.data["login_id"])
+        if self.user is not None:
+            condition = condition & ~Q(pk=self.user.pk)
+        if User.objects.filter(condition).first() is None:
+            return
+        error = forms.ValidationError(_("This log in ID is already in use."),
+                                      code="login_id_unique")
+        self.add_error("login_id", error)
+        raise error
+
+    def _validate_password_required(self):
+        """Validates whether the password is entered for newly-created users.
+
+        Raises:
+            forms.ValidationError: When the validation fails.
+        """
+        if self.user is not None:
+            return
+        if "password" in self.data:
+            return
+        error = forms.ValidationError(_("Please fill in the password."),
+                                      code="password_required")
+        self.add_error("password", error)
+        raise error
+
+    def _validate_password2_required(self):
+        """Validates whether the second password is entered.
+
+        Raises:
+            forms.ValidationError: When the validation fails.
+        """
+        if "password" not in self.data:
+            return
+        if "password2" in self.data:
+            return
+        error = forms.ValidationError(
+            _("Please enter the password again to verify it."),
+            code="password2_required")
+        self.add_error("password2", error)
+        raise error
+
+    def _validate_passwords_equal(self):
+        """Validates whether the two passwords are equa.
+
+        Raises:
+            forms.ValidationError: When the validation fails.
+        """
+        if "password" not in self.data:
+            return
+        if "password2" not in self.data:
+            return
+        if self.data["password"] == self.data["password2"]:
+            return
+        error = forms.ValidationError(_("The two passwords do not match."),
+                                      code="passwords_equal")
+        self.add_error("password2", error)
+        raise error
+
+    def _validate_is_disabled_not_oneself(self):
+        """Validates whether the user tries to disable herself
+
+        Raises:
+            forms.ValidationError: When the validation fails.
+        """
+        if "is_disabled" not in self.data:
+            return
+        if self.user is None:
+            return
+        if self.current_user is None:
+            return
+        if self.user.pk != self.current_user.pk:
+            return
+        error = forms.ValidationError(
+            _("You cannot disable your own account."),
+            code="not_oneself")
+        self.add_error("is_disabled", error)
+        raise error

mia_core/locale/zh_Hant/LC_MESSAGES/django.po

@@ -7,8 +7,8 @@ msgid ""
 msgstr ""
 "Project-Id-Version: mia 1.0\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2020-08-09 20:48+0800\n"
+"POT-Creation-Date: 2020-08-09 22:03+0800\n"
-"PO-Revision-Date: 2020-08-09 20:48+0800\n"
+"PO-Revision-Date: 2020-08-09 22:05+0800\n"
 "Last-Translator: imacat <imacat@mail.imacat.idv.tw>\n"
 "Language-Team: Traditional Chinese <imacat@mail.imacat.idv.tw>\n"
 "Language: Traditional Chinese\n"
@@ -16,6 +16,46 @@ msgstr ""
 "Content-Type: text/plain; charset=UTF-8\n"
 "Content-Transfer-Encoding: 8bit\n"
 
+#: mia_core/forms.py:34
+msgid "Please fill in the log in ID."
+msgstr "請填寫登入帳號。"
+
+#: mia_core/forms.py:35
+msgid "This log in ID is too long (max 32 characters)."
+msgstr "登入帳號太長了（最長32個字）。"
+
+#: mia_core/forms.py:40
+msgid "You cannot use slash (/) in the log in ID."
+msgstr "登入帳號不可以包含斜線 (/) 。"
+
+#: mia_core/forms.py:47
+msgid "Please fill in the name."
+msgstr "請填寫姓名。"
+
+#: mia_core/forms.py:48
+msgid "This name is too long (max 32 characters)."
+msgstr "姓名太長了（最長32個字）。"
+
+#: mia_core/forms.py:90
+msgid "This log in ID is already in use."
+msgstr "登入帳號和其他人重複。"
+
+#: mia_core/forms.py:105
+msgid "Please fill in the password."
+msgstr "請填寫密碼。"
+
+#: mia_core/forms.py:121
+msgid "Please enter the password again to verify it."
+msgstr "請再次確認密碼。"
+
+#: mia_core/forms.py:138
+msgid "The two passwords do not match."
+msgstr "兩次密碼不符，請重新輸入。"
+
+#: mia_core/forms.py:158 mia_core/templates/mia_core/user_form.html:84
+msgid "You cannot disable your own account."
+msgstr "不能停用自己的帳號。"
+
 #: mia_core/period.py:447 mia_core/period.py:482 mia_core/period.py:500
 #: mia_core/period.py:513 mia_core/period.py:559
 #, python-format
@@ -133,6 +173,7 @@ msgid "Cancel"
 msgstr "取消"
 
 #: mia_core/templates/mia_core/user_detail.html:69
+#: mia_core/templates/mia_core/user_form.html:41
 msgid "Back"
 msgstr "回上頁"
 
@@ -161,13 +202,15 @@ msgstr "帳號已刪除。"
 
 #: mia_core/templates/mia_core/user_detail.html:99
 msgid "Log in ID.:"
-msgstr "帳號"
+msgstr "登入帳號："
 
 #: mia_core/templates/mia_core/user_detail.html:104
+#: mia_core/templates/mia_core/user_form.html:74
 msgid "Name:"
-msgstr "姓名"
+msgstr "姓名："
 
 #: mia_core/templates/mia_core/user_detail.html:110
+#: mia_core/templates/mia_core/user_form.html:88
 msgid "This account is disabled."
 msgstr "帳號停用。"
 
@@ -219,6 +262,26 @@ msgstr "更新時間："
 msgid "Updated by:"
 msgstr "更新人："
 
+#: mia_core/templates/mia_core/user_form.html:31
+msgid "Add a New Account"
+msgstr "建立帳號"
+
+#: mia_core/templates/mia_core/user_form.html:50
+msgid "Log in ID:"
+msgstr "登入帳號："
+
+#: mia_core/templates/mia_core/user_form.html:58
+msgid "Password:"
+msgstr "密碼："
+
+#: mia_core/templates/mia_core/user_form.html:66
+msgid "Confirm password:"
+msgstr "確認密碼："
+
+#: mia_core/templates/mia_core/user_form.html:97
+msgid "Submit"
+msgstr "傳送"
+
 #: mia_core/templates/mia_core/user_list.html:27
 msgid "Account Management"
 msgstr "帳號管理"
@@ -229,7 +292,7 @@ msgstr "新增"
 
 #: mia_core/templates/mia_core/user_list.html:43
 msgid "Log in ID"
-msgstr "帳號"
+msgstr "登入帳號"
 
 #: mia_core/templates/mia_core/user_list.html:44
 msgid "Name"

mia_core/locale/zh_Hant/LC_MESSAGES/djangojs.po

@@ -0,0 +1,46 @@
+# Traditional Chinese PO file for the JavaScript on the Mia Website
+# Copyright (C) 2020 imacat
+# This file is distributed under the same license as the Mia package.
+# imacat <imacat@mail.imacat.idv.tw>, 2020.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: core 1.0\n"
+"Report-Msgid-Bugs-To: \n"
+"POT-Creation-Date: 2020-08-09 21:54+0800\n"
+"PO-Revision-Date: 2020-08-09 22:05+0800\n"
+"Last-Translator: imacat <imacat@mail.imacat.idv.tw>\n"
+"Language-Team: Traditional Chinese <imacat@mail.imacat.idv.tw>\n"
+"Language: Traditional Chinese\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=1; plural=0;\n"
+
+#: mia_core/static/mia_core/js/user-form.js:129
+msgid "Please fill in the log in ID."
+msgstr "請填寫登入帳號。"
+
+#: mia_core/static/mia_core/js/user-form.js:134
+msgid "You cannot use slash (/) in the log in ID."
+msgstr "登入帳號不可以包含斜線 (/) 。"
+
+#: mia_core/static/mia_core/js/user-form.js:154
+msgid "This log in ID is already in use."
+msgstr "登入帳號和其他人重複。"
+
+#: mia_core/static/mia_core/js/user-form.js:177
+msgid "Please fill in the password."
+msgstr "請填寫密碼。"
+
+#: mia_core/static/mia_core/js/user-form.js:201
+msgid "Please enter the password again to verify it."
+msgstr "請再次確認密碼。"
+
+#: mia_core/static/mia_core/js/user-form.js:207
+msgid "The two passwords do not match."
+msgstr "兩次密碼不符，請重新輸入。"
+
+#: mia_core/static/mia_core/js/user-form.js:228
+msgid "Please fill in the name."
+msgstr "請填寫姓名。"

mia_core/static/mia_core/js/user-form.js

@@ -0,0 +1,234 @@
+/* The Mia Website
+ * edit.js: The JavaScript to edit the user data
+ */
+
+/*  Copyright (c) 2019-2020 imacat.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+/* Author: imacat@mail.imacat.idv.tw (imacat)
+ * First written: 2020/3/26
+ */
+
+// Initializes the page JavaScript.
+$(function () {
+    $("#user-login-id").on("blur", function () {
+        validateLoginId();
+    });
+    $("#user-password").on("blur", function () {
+        validatePassword();
+    });
+    $("#user-password2").on("blur", function () {
+        validatePassword2();
+    });
+    $("#user-name").on("blur", function () {
+        validateName();
+    });
+    $("#user-form").on("submit", function () {
+        return validateForm();
+    });
+});
+
+
+/*******************
+ * Form Validation *
+ *******************/
+
+/**
+ * The validation result
+ * @type {object}
+ * @private
+ */
+let isValidated;
+
+/**
+ * Validates the form.
+ *
+ * @returns {boolean} true if the validation succeed, or false
+ *                    otherwise
+ * @private
+ */
+function validateForm() {
+    isValidated = {
+        "id": null,
+        "_sync": true,
+    };
+    validateLoginIdAsync().then();
+    validateSyncColumns();
+    return false;
+}
+
+/**
+ * Validates the form on synchronous validations.
+ *
+ * @private
+ */
+function validateSyncColumns() {
+    let isSyncValidated = true;
+    isSyncValidated = isSyncValidated && validatePassword();
+    isSyncValidated = isSyncValidated && validatePassword2();
+    isSyncValidated = isSyncValidated && validateName();
+    isValidated["_sync"] = isSyncValidated;
+    validateFormAsync();
+}
+
+/**
+ * Validates the form for the asynchronous validation.
+ *
+ * @private
+ */
+function validateFormAsync() {
+    let isFormValidated = true;
+    const keys = Object.keys(isValidated);
+    for (let i = 0; i < keys.length; i++) {
+        if (isValidated[keys[i]] === null) {
+            return;
+        }
+        isFormValidated = isFormValidated && isValidated[keys[i]];
+    }
+    if (isFormValidated) {
+        $("#user-form")[0].submit();
+    }
+}
+
+/**
+ * Validates the log in ID for asynchronous form validation.
+ *
+ * @returns {Promise<void>}
+ * @private
+ */
+async function validateLoginIdAsync() {
+    isValidated["id"] = await validateLoginId();
+    validateFormAsync();
+}
+
+/**
+ * Validates the log in ID.
+ *
+ * @returns {boolean} true if the validation succeed, or false
+ *                    otherwise
+ * @private
+ */
+async function validateLoginId() {
+    const id = $("#user-login-id")[0];
+    const errorMessage = $("#user-login-id-error");
+    id.value = id.value.trim();
+    if (id.value === "") {
+        id.classList.add("is-invalid");
+        errorMessage.text(gettext("Please fill in the log in ID."));
+        return false;
+    }
+    if (id.value.match(/\//)) {
+        id.classList.add("is-invalid");
+        errorMessage.text(gettext("You cannot use slash (/) in the log in ID."));
+        return false;
+    }
+    const originalId = $("#user-login-id-original").val();
+    if (originalId === "" || id.value !== originalId) {
+        let exists = null;
+        const request = new XMLHttpRequest();
+        request.onreadystatechange = function() {
+            if (this.readyState === 4 && this.status === 200) {
+                exists = JSON.parse(this.responseText);
+            }
+        };
+        const url = $("#exists-url").val().replace("ID", id.value);
+        request.open("GET", url, true);
+        request.send();
+        while (exists === null) {
+            await new Promise(r => setTimeout(r, 200));
+        }
+        if (exists) {
+            id.classList.add("is-invalid");
+            errorMessage.text(gettext("This log in ID is already in use."));
+            return false;
+        }
+    }
+    id.classList.remove("is-invalid");
+    errorMessage.text("");
+    return true;
+}
+
+/**
+ * Validates the password.
+ *
+ * @returns {boolean} true if the validation succeed, or false
+ *                    otherwise
+ * @private
+ */
+async function validatePassword() {
+    const password = $("#user-password")[0];
+    const errorMessage = $("#user-password-error");
+    password.value = password.value.trim();
+    if (password.required) {
+        if (password.value === "") {
+            password.classList.add("is-invalid");
+            errorMessage.text(gettext("Please fill in the password."));
+            return false;
+        }
+    }
+    password.classList.remove("is-invalid");
+    errorMessage.text("");
+    return true;
+}
+
+/**
+ * Validates the password verification.
+ *
+ * @returns {boolean} true if the validation succeed, or false
+ *                    otherwise
+ * @private
+ */
+function validatePassword2() {
+    const password2 = $("#user-password2")[0];
+    const errorMessage = $("#user-password2-error");
+    password2.value = password2.value.trim();
+    const password = $("#user-password").val();
+    if (password !== "") {
+        if (password2.value === "") {
+            password2.classList.add("is-invalid");
+            errorMessage.text(gettext("Please enter the password again to verify it."));
+            return false;
+        }
+    }
+    if (password2.value !== password) {
+        password2.classList.add("is-invalid");
+        errorMessage.text(gettext("The two passwords do not match."));
+        return false;
+    }
+    password2.classList.remove("is-invalid");
+    errorMessage.text("");
+    return true;
+}
+
+/**
+ * Validates the name.
+ *
+ * @returns {boolean} true if the validation succeed, or false
+ *                    otherwise
+ * @private
+ */
+function validateName() {
+    const name = $("#user-name")[0];
+    const errorMessage = $("#user-name-error");
+    name.value = name.value.trim();
+    if (name.value === "") {
+        name.classList.add("is-invalid");
+        errorMessage.text(gettext("Please fill in the name."));
+        return false;
+    }
+    name.classList.remove("is-invalid");
+    errorMessage.text("");
+    return true;
+}

mia_core/templates/mia_core/user_form.html

@@ -0,0 +1,103 @@
+{% extends "base.html" %}
+{% comment %}
+The Mia Core Application
+user_form.html: The template for the form of a user
+
+ Copyright (c) 2020 imacat.
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+
+Author: imacat@mail.imacat.idv.tw (imacat)
+First written: 2020/8/9
+{% endcomment %}
+{% load static %}
+{% load i18n %}
+{% load mia_core %}
+
+{% block settings %}
+  {% if form.user %}
+    {% setvar "title" user.name %}
+  {% else %}
+    {% setvar "title" _("Add a New Account") %}
+  {% endif %}
+  {% static "mia_core/js/user-form.js" as file %}{% add_js file %}
+{% endblock %}
+
+{% block content %}
+
+<div class="btn-group btn-actions">
+  <a class="btn btn-primary" role="button" href="{% if form.user %}{% url "mia_core:users.detail" user %}{% else %}{% url "mia_core:users" %}{% endif %}">
+    <i class="fas fa-chevron-circle-left"></i>
+    {{ _("Back")|force_escape }}
+  </a>
+</div>
+
+<form id="user-form" action="{% if form.user %}{% url "mia_core:users.update" user %}{% else %}{% url "mia_core:users.store" %}{% endif %}" method="POST">
+  {% csrf_token %}
+  <input id="exists-url" type="hidden" value="{% url "mia_core:api.users.exists" "ID" %}" />
+  <input id="user-login-id-original" type="hidden" value="{{ form.user.login_id }}" />
+  <div class="row form-group">
+    <label class="col-sm-2 col-form-label" for="user-login-id">{{ _("Log in ID:")|force_escape }}</label>
+    <div class="col-sm-10">
+      <input id="user-login-id" class="form-control {% if form.login_id.errors %} is-invalid {% endif %}" type="text" name="login-id" value="{{ form.login_id.value|default:"" }}" maxlength="32" required="required" />
+      <div id="user-login-id-error" class="invalid-feedback">{{ form.login_id.errors.0 }}</div>
+    </div>
+  </div>
+
+  <div class="row form-group">
+    <label class="col-sm-2 col-form-label" for="user-password">{{ _("Password:")|force_escape }}</label>
+    <div class="col-sm-10">
+      <input id="user-password" class="form-control {% if form.password.errors %} is-invalid {% endif %}" type="password" name="password" value="" {% if not form.user %} required="required" {% endif %} />
+      <div id="user-password-error" class="invalid-feedback">{{ form.password.errors.0 }}</div>
+    </div>
+  </div>
+
+  <div class="row form-group">
+    <label class="col-sm-2 col-form-label" for="user-password2">{{ _("Confirm password:")|force_escape }}</label>
+    <div class="col-sm-10">
+      <input id="user-password2" class="form-control {% if form.password2.errors %} is-invalid {% endif %}" type="password" name="password2" value="" {% if not form.user %} required="required" {% endif %} />
+      <div id="user-password2-error" class="invalid-feedback">{{ form.password2.errors.0 }}</div>
+    </div>
+  </div>
+
+  <div class="row form-group">
+    <label class="col-sm-2 col-form-label" for="user-name">{{ _("Name:")|force_escape }}</label>
+    <div class="col-sm-10">
+      <input id="user-name" class="form-control {% if form.name.errors %} is-invalid {% endif %}" type="text" name="name" value="{{ form.name.value|default:"" }}" maxlength="32" required="required" />
+      <div id="user-name-error" class="invalid-feedback">{{ form.name.errors.0 }}</div>
+    </div>
+  </div>
+
+  <div class="row form-group form-check">
+    <div class="col-sm-12">
+      {% if form.user and form.user.pk == request.user.pk %}
+        {{ _("You cannot disable your own account.")|force_escape }}
+      {% else %}
+        <input id="user-is-disabled" class="form-check-input" type="checkbox" name="is_disabled" value="1" {% if form.is_disabled.value %} checked="checked" {% endif %} />
+        <label class="form-check-label" for="user-is-disabled">
+          {{ _("This account is disabled.")|force_escape }}
+        </label>
+      {% endif %}
+    </div>
+  </div>
+
+  <div class="row form-group">
+    <div class="col-sm-12">
+      <button class="btn btn-primary" type="submit">
+        {{ _("Submit")|force_escape }}
+      </button>
+    </div>
+  </div>
+</form>
+
+{% endblock %}

mia_core/urls.py

@@ -27,19 +27,17 @@ register_converter(converters.UserConverter, "user")
 app_name = "mia_core"
 urlpatterns = [
     path("users", views.UserListView.as_view(), name="users"),
-    # TODO: To be done.
+    path("users/create", views.user_form, name="users.create"),
-    path("users/create", views.todo, name="users.create"),
     # TODO: To be done.
     path("users/store", views.todo, name="users.store"),
     path("users/<user:user>", views.UserView.as_view(), name="users.detail"),
-    # TODO: To be done.
+    path("users/<user:user>/edit", views.user_form, name="users.edit"),
-    path("users/<user:user>/edit", views.todo, name="users.edit"),
     # TODO: To be done.
     path("users/<user:user>/update", views.todo, name="users.update"),
     # TODO: To be done.
     path("users/<user:user>/delete", views.todo, name="users.delete"),
     # TODO: To be done.
-    path("api/users/<str:login_id>/exists", views.todo,
+    path("api/users/<str:login_id>/exists", views.api_users_exists,
          name="api.users.exists"),
     # TODO: To be done.
     path("my-account", views.todo, name="my-account"),

mia_core/views.py

@@ -21,13 +21,16 @@
 from django.contrib import messages
 from django.contrib.auth import logout as logout_user
 from django.contrib.messages.views import SuccessMessageMixin
-from django.http import HttpResponse
+from django.http import HttpResponse, JsonResponse
-from django.shortcuts import redirect
+from django.shortcuts import redirect, render
-from django.views.decorators.http import require_POST
+from django.views.decorators.http import require_POST, require_GET
 from django.views.generic import DeleteView as CoreDeleteView, ListView, \
     DetailView
 
-from mia_core.models import User
+from . import stored_post
+from .digest_auth import login_required
+from .forms import UserForm
+from .models import User
 
 
 class DeleteView(SuccessMessageMixin, CoreDeleteView):
@@ -67,6 +70,54 @@ class UserView(DetailView):
         return self.request.resolver_match.kwargs["user"]
 
 
+@require_GET
+@login_required
+def user_form(request, user=None):
+    """The view to edit an accounting transaction.
+
+    Args:
+        request (HttpRequest): The request.
+        user (User): The account.
+
+    Returns:
+        HttpResponse: The response.
+    """
+    previous_post = stored_post.get_previous_post(request)
+    if previous_post is not None:
+        form = UserForm(previous_post)
+    elif user is not None:
+        form = UserForm({
+            "login_id": user.login_id,
+            "name": user.name,
+            "is_disabled": user.is_disabled,
+        })
+    else:
+        form = UserForm()
+    form.user = user
+    form.current_user = request.user
+    return render(request, "mia_core/user_form.html", {
+        "form": form,
+    })
+
+
+def api_users_exists(request, login_id):
+    """The view to check whether a user with a log in ID exists.
+
+    Args:
+        request (HttpRequest): The request.
+        login_id (str): The log in ID.
+
+    Returns:
+        JsonResponse: The response.
+    """
+    try:
+        User.objects.get(login_id=login_id)
+    except User.DoesNotExist:
+        return JsonResponse(False, safe=False)
+    return JsonResponse(True, safe=False)
+
+
+
 # TODO: To be removed.
 def todo(request, **kwargs):
     """A dummy placeholder view for the URL settings that are not