Form validation

project/jinja2env.py

@@ -1,10 +1,20 @@
+from typing import Any
+
 from jinja2 import Environment
 
 
+def conditional_cls(conditions: dict[str, Any]) -> str:
+    result = []
+    for cls, condition in conditions.items():
+        if condition:
+            result.append(cls)
+    return " ".join(result)
+
+
 def environment(**options):
     env = Environment(**options)
 
     env.globals.update({
-        # "url": reverse_url,
+        "conditional_cls": conditional_cls,
     })
     return env

project/main/templates/main/form_validation.html

@@ -2,7 +2,18 @@
 
 
 {% block content %}
-    <p>
+	<form
-        This is some form validation content bellow.
+		hx-post="{{ url("form-validation") }}"
-    </p>
+		hx-target="#validation-form-content"
+		hx-swap="outerHTML"
+	>
+		<div class="card p-4">
+			{% include "main/form_validation_content.html" %}
+			<div class="d-flex">
+				<button type="submit" class="btn btn-success ms-auto">
+					Submit
+				</button>
+			</div>
+		</div>
+	</form>
 {% endblock %}

project/main/templates/main/form_validation_content.html

@@ -0,0 +1,59 @@
+<div id="validation-form-content">
+    <div class="row">
+        <div class="col">
+            <div class="mb-3">
+                <label for="validation-form-number" class="form-label">Enter name, length 3..10</label>
+                <input
+                    type="text"
+                    class="form-control {{ conditional_cls({
+                        "is-invalid": validation.name_error,
+                        "is-valid": validation.validated and not validation.name_error,
+                    }) }}"
+                    name="name"
+                    id="validation-form-number"
+                    value="{{ validation.name | default_if_none("") }}"
+                />
+                {% if validation.name_error %}
+                    <div class="invalid-feedback">{{ validation.name_error }}</div>
+                {% endif %}
+            </div>
+        </div>
+        <div class="col">
+            <div class="mb-3">
+                <label for="validation-form-number" class="form-label">Enter age, 1..100</label>
+                <input
+                    type="text"
+                    class="form-control {{ conditional_cls({
+                        "is-invalid": validation.age_error,
+                        "is-valid": validation.validated and not validation.age_error,
+                    }) }}"
+                    name="age"
+                    id="validation-form-number"
+                    value="{{ validation.age | default_if_none("") }}"
+                />
+                {% if validation.age_error %}
+                    <div class="invalid-feedback">{{ validation.age_error }}</div>
+                {% endif %}
+            </div>
+        </div>
+    </div>
+
+    <div class="form-check">
+        <input
+            class="form-check-input {{ conditional_cls({
+                "is-invalid": validation.consent_error,
+                "is-valid": validation.validated and not validation.consent_error,
+            }) }}"
+            type="checkbox"
+            name="consent"
+            id="consent-checkbox"
+            {% if validation.consent %}checked{% endif %}
+        >
+        <label class="form-check-label" for="consent-checkbox">
+            I consent to use this data for what ever you want
+        </label>
+        {% if validation.consent_error %}
+            <div class="invalid-feedback">{{ validation.consent_error }}</div>
+        {% endif %}
+    </div>
+</div>

project/main/views/form_validation.py

@@ -1,7 +1,66 @@
+from dataclasses import dataclass
+from typing import Any, Optional
+
+from django.core.handlers.wsgi import WSGIRequest
+from django.http import HttpResponse
+from django.shortcuts import render
+
 from project.main.views.demo_view_base import DemoViewBase
 
 
+@dataclass
+class Validation:
+    validated: bool = False
+
+    name: Optional[str] = None
+    consent: Optional[bool] = None
+    age: Optional[int] = None
+
+    name_error: Optional[str] = None
+    age_error: Optional[str] = None
+    consent_error: Optional[str] = None
+
+
 class FormValidationView(DemoViewBase):
     template_name = "main/form_validation.html"
     active_section = "form-validation"
     title = "Form Validation"
+
+    def get_context_data(self, **kwargs) -> dict[str, Any]:
+        context = super().get_context_data(**kwargs)
+        context.update(
+            {
+                "validation": Validation(),
+            }
+        )
+        return context
+
+    def post(self, request: WSGIRequest, *args, **kwargs) -> HttpResponse:
+        validation = Validation(
+            validated=True,
+            name=request.POST.get("name", ""),
+            age=request.POST.get("age", ""),
+            consent=request.POST.get("consent") == "on",
+        )
+
+        if len(validation.name) < 3 or len(validation.name) > 10:
+            validation.name_error = "Name must be between 3 and 10 chars long"
+
+        try:
+            age = int(validation.age)
+        except ValueError:
+            validation.age_error = "Invalid integer"
+        else:
+            if age < 1 or age > 100:
+                validation.age_error = "Age should be between 1 and 100"
+
+        if not validation.consent:
+            validation.consent_error = "You should consent"
+
+        return render(
+            context={
+                "validation": validation,
+            },
+            template_name="main/form_validation_content.html",
+            request=request,
+        )