Views katika Django ni nini?

Question

Accepted Answer

**View** ni tabaka la mantiki la Django — function au class inayopokea **request** ya HTTP, inafanya mantiki (kuhoji models, kuchakata input), na inarudisha **response** ya HTTP. Views ndipo unashughulikia kinachotokea wakati URL inapofikiwa.

## Function-based views (FBVs)

```python
from django.shortcuts import render, get_object_or_404
from django.http import JsonResponse, HttpResponse

def article_list(request):
    articles = Article.objects.all()                    # query models
    return render(request, "articles.html", {"articles": articles})  # render a template

def article_detail(request, pk):
    article = get_object_or_404(Article, pk=pk)         # 404 if not found
    return render(request, "detail.html", {"article": article})

def api_articles(request):
    data = list(Article.objects.values("title", "body"))
    return JsonResponse(data, safe=False)               # return JSON instead of HTML
```

Function-based view inapokea `request` (pamoja na parameters zozote za URL), inafanya kazi yake, na inarudisha response — `render()` kwa HTML, `JsonResponse` kwa JSON, `HttpResponse` kwa output ghafi.

## Kushughulikia HTTP methods tofauti na input

```python
def create_article(request):
    if request.method == "POST":
        form = ArticleForm(request.POST)
        if form.is_valid():
            form.save()
            return redirect("article_list")             # redirect after a successful POST
    else:
        form = ArticleForm()
    return render(request, "create.html", {"form": form})
```

Views zinakagua `request.method` (GET, POST, n.k.) na zinafikia input kupitia `request.POST`, `request.GET`, `request.user`, n.k.

## Class-based views (CBVs) — zinazoweza kutumika tena, boilerplate kidogo

```python
from django.views.generic import ListView, DetailView

# generic CBVs handle common patterns with minimal code
class ArticleListView(ListView):
    model = Article                                     # automatically lists all articles
    template_name = "articles.html"

class ArticleDetailView(DetailView):
    model = Article
```

Django pia inatoa **class-based views** — ikijumuisha generic views (`ListView`, `DetailView`, `CreateView`) zinazotekeleza mifumo ya kawaida (kuorodhesha, undani, CRUD) kwa code kidogo sana, zikipunguza boilerplate.

## Jukumu la view katika mtiririko wa request

```text
Request → URL routing → VIEW (logic) → queries models, renders template → Response
The view is the orchestrator: it connects the URL, the data (models), and the
presentation (template) to produce a response.
```

## Kwa nini ni muhimu

Views ni tabaka la mantiki la Django ("V" katika MVT, sawa na controller ya MVC) — ndipo unashughulikia kila request, kuzifanya kuwa za msingi kwa kujenga programu yoyote ya Django.

Kuelewa views ni muhimu kwa sababu ndizo waratibu wanaounganisha kila kitu pamoja: kupokea request, kutumia mantiki ya biashara, kuhoji models kwa data, kuchakata input ya mtumiaji (forms), na kurudisha response inayofaa (HTML kupitia templates, au JSON kwa API).

Kujua jinsi ya kuandika **function-based views** (wazi, zenye unyumbufu — nzuri kwa mantiki maalum), kushughulikia HTTP methods tofauti na kufikia data ya request, na kutumia **class-based/generic views** (zinazopunguza boilerplate kwa kiasi kikubwa kwa mifumo ya kawaida kama kuorodhesha na CRUD) kunashughulikia wigo wa kivitendo wa kujenga endpoints za Django.

Views ndipo mantiki nyingi ya kushughulikia request ya programu inapokaa, hivyo kuzimudu — mzunguko wa request/response, chaguo kati ya mbinu za function-based na class-based, na jinsi views zinavyounganisha URLs na models na templates — ni maarifa ya msingi ya kila siku kwa mwendelezaji yeyote wa Django na kitovu cha jinsi framework inavyochakata requests.