Merge branch 'main' of ssh://github.com/guettli/django-htmx-fun

README.md

@@ -31,7 +31,9 @@ are more colors than black and white.
 
 For more about htmx see the homepage: [htmx.org](//htmx.org)
 
-[HTMX: Frontend Revolution (Slides from DjangoCon EU 2021)](https://docs.google.com/presentation/d/1Gx1UGVAgD2ALLOucsIm9myF5mDflbP06-M6_d-RdZAY/edit?usp=sharing)
+[HTMX: Frontend Revolution (Slides from DjangoCon 2021)](https://docs.google.com/presentation/d/12dgaBnUgl4cmEkiOhUJL5hsbGQ6hB5sslDuozmBjVUA/edit?usp=sharing)
+
+Youtube video of the Talk [DjangoCon US 2021: HTMX, Frontend Revolution](https://www.youtube.com/watch?v=z0yPTv15Fjk)
 
 ## Install
 
@@ -41,7 +43,7 @@ If you want to install my small htmx demo application:
 python3 -m venv django-htmx-fun-env
 cd django-htmx-fun-env
 . bin/activate
-pip install -e git+ssh://git@github.com/guettli/django-htmx-fun.git#egg=django_htmx_fun
+pip install -e git+https://github.com/guettli/django-htmx-fun.git#egg=django-htmx-fun
 ```
 
 The source code is now in src/django-htmx-fun/
@@ -66,6 +68,32 @@ manage.py createsuperuser
 ```
 Admin: http://127.0.0.1:8000/admin
 
+## No need for the POST/Redirect/GET pattern
+
+If you are used to django's form handling, then you are used to the [POST/Redirect/GET Pattern](https://en.wikipedia.org/wiki/Post/Redirect/Get). This means after the client submitted a valid form, the server response has the http status 302 with a new location URL.
+
+This is not needed if you submit a form via htmx and you just want to update one part of the whole page.
+
+I use this pattern now:
+
+Case 1: The http POST was successful, and data was changed. The server returns the status code 201 "Created". I use this even if data was changed, and not "created". I use this and not the usual 200 to simplify testing. I never ever want to confuse the http status of a successful htmx POST with the http status of an invalid traditional django http POST. The response contains the new HTML. No need for a redirect.
+
+Case 2: The http POST was not successful, since the data in the form was not valid. Then my server code returns 422. 
+
+Related question: [Which http status codes to use when processing http post?](https://stackoverflow.com/q/69773241/633961)
+
+## Full Page (aka "client-side") Redirect
+
+If you use htmx, then most http responses will contains html fragments which will get swapped into the current page.
+
+But sometimes you want to do a traditional full page redirect. In the htmx docs it is called "client-side" redirect.
+
+Then you need return a http response which has the http header "HX-Redirect" set to the URL of the new location. Docs: [Response Headers](https://htmx.org/docs/#response-headers)
+
+A common mistake is the set the status code if this response to 302. But this will trigger a redirect inside htmx.
+
+Here is some code to do a full page redirect with Django: [hx-target: swap html vs full page reload](https://stackoverflow.com/a/65569741/633961)
+
 ## Naming Pattern
 
 Here is my personal naming pattern, which helps me to read the source more easily
@@ -80,6 +108,8 @@ Returns a HttpResponse with a full page.
 
 URL: `/foo`
 
+This servers only http GET. Updates (http POST) go to _hxpost URLs.
+
 ---
 
 **_hx():**
@@ -105,6 +135,8 @@ contains a HTML fragment.
 
 URL: `/foo_hxpost`
 
+It makes sense to use the [require_POST decorator](https://docs.djangoproject.com/en/dev/topics/http/decorators/#django.views.decorators.http.require_POST),if you have concerns that a GET request (where request.POST is empty) could accidently change data.
+
 ---
 
 **_json():**
@@ -139,13 +171,22 @@ If you need several pages for a model, then you will not use "/sunshine/foo" and
 
 ## Opinionated Best Practices
 
+I switched from Django class-based-views (CBV) to function-based-views (FBV). This simplifies things. 
+One URL corresponds to one Python method. If an action requires two HTTP verbs (GET and POST), then I use **two URLs**. Posts
+always go to hx-methods, not to URLs returning full pages.
+
 I like it conditionless. I try to avoid to have too many "if" and "else".
 
-I avoid to use `if request.method == 'POST'`.
+I avoid to use `if request.method == 'POST'`. This means I don't handle different http verbs in one function based view. A function based view handles either GET xor a POST. URLs are cheap I create two URLs if I need a a readonly view and a view which does something.
+
+I only use the http verbs GET and POST, although htmx can do http PUT, http PATCH, http DELETE, ...
 
 I don't use the special http headers which get added by htmx. I avoid this (pseudo code): "if request is a htmx request, then ...".
 Instead I create two endpoints: One which returns a full page, one which returns a fragment.
 
+Goodbye formsets. I use several `<form>` tags in one page. This means I hardly use formsets. Some for the "prefix" of forms: Since
+I don't put several Django form instances into one `<form>` tag, I don't need the prefix any more.
+
 
 ## Screenshot