Changes between Initial Version and Version 1 of AjaxDojoFormSub

Timestamp:

Jun 11, 2006, 11:45:38 PM (19 years ago)

Author:

anonymous

Comment:

--

AjaxDojoFormSub

@@ +1 @@
+
+
+{{{
+#!html
+<h1>Form submission </h1>
+}}}
+'''Inner links'''
+{{{
+#!html
+Part 1 <br/> <a href="#P1">Ajax basic form submission, Django server answers Ajax call.</a><br/>
+Part 2 <br/><a href="#P2">Handling the form when JavaScript is deactivated.</a><br/>
+Part 3 <br/><a href="#P3">Fixing the frozen fading when user resend the form without waiting for the first fading to end.</a>
+}}}
+
+
+{{{
+#!html
+<a name="P1"><h1>Ajax basic form submission, Django server answers Ajax call.</h1></a>
+}}}
+'''Ajax form submission using Dojo for the client side javaScript toolkit, and simpleJson for the client/server communication.'''
+
+This will take you through all the steps required to get started and to develop a handy form submission without reload.
+
+
+== What do you need  ==
+
+ - Django 
+ - Dojo (v0.3) [http://dojotoolkit.org/] an open source javascript toolkit. 
+ - Simple_Json (v1.3) [http://svn.red-bean.com/bob/simplejson/tags/simplejson-1.3/docs/index.html] used for javascript <-> python communication.
+
+
+== What do we want to achieve ==
+I will use the model of my current website, a recipe one.
+When a registered user sees the details of a recipe, the user can rate (mark) it or update their rating (mark) by selecting the mark with a small drop down list.
+But when the user clicks ok the whole page reloads. We will use some Ajax to make it transparent and fancy effect to show the change to the user.
+we can add a fading status message like "Your rating has been updated".
+The select box proposes a rating from 1 to 5, it is actually a form which is sent to the server via POST, which in django links to a method
+in the view.py : ''def details(request)'' which does the innerwork for the details page generation.
+
+
+== Installing Json ==
+get the SimpleJson from svn. 
+
+{{{
+svn co http://svn.red-bean.com/bob/simplejson/trunk/ json
+cd json
+sudo python setup.py install
+}}}
+
+== Django part ==
+'''view.py'''
+{{{
+#!python
+def details(request):
+        [more stuff]
+        if request.POST:
+                # Get all the mark for this recipe
+                # its not the best way i sould hava an oter entry or table, with total and nbr of marks for
+                # each recipe.
+                list_mark = Mark.objects.values('mark').filter(recipe__pk=r.id)
+                # loop to get the total
+                total = 0
+                for element in list_mark:
+                        total+= element['mark']
+                # round it
+                total = round((float(total) /  len(list_mark)),1)
+                # update the total
+                r.total_mark= total
+                # save the user mark
+                r.save()
+
+                # Now the intersting part for this tut
+                import simple_json
+                # it was a french string, if we dont't use unicode
+                # the result at the output of json in Dojo is wrong.
+                message = unicode( message, "utf-8" )
+                #
+                jsonList = simple_json.dumps((my_mark, total, form_message ,message))
+                return HttpResponse(jsonList)
+        [more stuff, if not POST return render_to_response('recettes/details.html' ...]
+}}}
+
+'''url.py'''
+
+Just normal url.py, remember the path which will point to the wanted method.
+{{{
+#!python
+from django.conf.urls.defaults import *
+
+urlpatterns = patterns('',
+        [...more...]
+        (r'^recettes/(?P<r_cat>[-\w]+)/(?P<r_slug>[-\w]+)/$', 'cefinban.recettes.views.details'),
+        [...more...]
+}}}
+
+
+== Html template with Dojo javascript ==
+'''Dojo use'''
+
+{{{
+{% load i18n %}
+{% extends "base.html" %}
+{% block script %}
+ <script type="text/javascript" src="/media/js/dojo/dojo.js"></script>
+ <script type="text/javascript">
+ 
+    dojo.require("dojo.widget.Tooltip");
+    dojo.require("dojo.fx.html");
+    dojo.require("dojo.event.*");
+    dojo.require("dojo.json");
+
+    // point to the same url details.html        
+    function sendForm()
+    {
+     dojo.io.bind({
+                    url: '.',
+                    handler: sendFormCallback,
+                    formNode: dojo.byId('myForm')
+                });
+    }
+
+  function sendFormCallback(type, data, evt)
+    {
+    if (type == 'error')
+        alert('Error when retrieving data from the server!');
+    else
+        // de code the simpleJson answer from django ''details'' method.
+        // it populates a Js array ! straigth so cool !
+        arrayData = dojo.json.evalJson(data);
+        // now we update the html using the css id as a pointer to the part 
+        // we want to update
+        dojo.byId("mark_total").innerHTML = arrayData[1];
+        dojo.byId("mark_message").innerHTML = arrayData[2];
+        dojo.byId("mark_status").innerHTML = arrayData[3];
+        // and the fancy fading effect
+        dojo.lfx.html.highlight("mark_status", [255, 151, 58], 700).play(300);
+    }
+    
+    function init()
+    {
+        var sendFormButton = dojo.byId('sendFormButton');
+        dojo.event.connect(sendFormButton, 'onclick', 'sendForm')
+    }
+ 
+    dojo.addOnLoad(init);
+        
+</script>
+}}}
+
+the following ''HTML code'' just comes after the upper code snipset.
+
+{{{
+[... total mark get updated, lets put css id="mark_total" ...]
+{% if r.total_mark  %}<li><b>Score</b>: <span id="mark_total">{{ r.total_mark }}</span>/5</li>{% endif %}
+[....]
+{% if not user.is_anonymous %}
+    {% ifnotequal user.id r.owner_id %}
+        <form enctype="multipart/form-data" id="myForm" method="post">
+            <span id="mark_message">{{mark_message}}</span>
+               <select name="select_mark">
+                    <option value ="1" {% ifequal my_mark 1 %} selected {% endifequal %}>1</option>
+                    <option value ="2" {% ifequal my_mark 2 %} selected {% endifequal %}>2</option>
+                    <option value ="3" {% ifequal my_mark 3 %} selected {% endifequal %}>3</option>
+                    <option value ="4" {% ifequal my_mark 4 %} selected {% endifequal %}>4</option>
+                    <option value ="5" {% ifequal my_mark 5 %} selected {% endifequal %}>5</option>
+               </select>
+       </form>
+      <button id="sendFormButton">Notez</button>
+      <br/>
+      <span id="mark_status">{{ mark_status }}</span>
+     {% endifnotequal %}
+{% endif %}
+}}}
+
+And, voila.
+
+To have a demo use guest as login, guest as password here [http://ozserver.no-ip.com:345] or if not working here [http://www.cefinban.net].
+Go to index and pick a recipe, update the rating.
+
+You can also have a look at the screenshot here :  [http://ozserver.no-ip.com/~greg/images/ajaxdjango.png]
+
+== Dreamhost and Simplejson ==
+
+If you are using dreamhost for hosting please be aware that simplejson is not installed.
+Instead you will have to install the source of simplejson in a folder in your home directory eg /proz/json/simple_json
+The simple_json directory contains the required __init__.py for it to be loaded as a python module.
+
+Then in your ~/.bash_profile add the directory to your python path like below.
+
+{{{
+export PYTHONPATH=$PYTHONPATH:$HOME/django/django_src:$HOME/django/django_projects:$HOME/progz/json
+}}}
+
+That will allow yout to use simpl_json in python shell.
+But '''dont forget''' to change django.fcgi !
+Add
+{{{
+sys.path +=['/home/coulix/progz/json']
+}}}
+log out/in and try import simple_json (or simplejson depends on what source you picked)
+
+{{{
+#!html
+<a name="P2"><h1>Handling the form when JavaScript is deactivated.</h1></a>
+}}}
+If a user has deactivated his browser's javascript support, or is using a text mode browser, we need a way of making the previous rating button submit the rating to the server which should this time return an html template instead of data to the Ajax call.
+
+== Updating the form HTML (details.html template) ==
+This time we put a submit type input inside the form instead of the button type in part 1.
+type="submit" as indicates its name, submits the form to the server, we will need a way of stopping this behavior using javaScript.
+
+{{{
+<form  enctype="multipart/form-data" id="myForm" method="post">
+        <span id="mark_message">{{mark_message}}</span>
+        <select name="select_mark">
+                [...]
+        </select>
+        <input id="sendFormButton" type="submit" value="Notez" />
+</form>
+}}}
+
+Now, how can we tell our details method in view.py to know if it comes from a normal submit request or an Ajax request ?
+Two solutions,
+
+The '''first''' uses a hidden variable in form.html and an added content element in the JS part.
+
+{{{
+    function sendForm()
+    {
+     dojo.byId("mark_status").innerHTML = "Loading ...";
+     dojo.io.bind({
+                    url: '.',
+                    handler: sendFormCallback,
+                    content: {"js", "true"},
+                    formNode: dojo.byId('myForm')
+                });
+    }
+
+
+[...]
+<form  enctype="multipart/form-data" id="myForm" method="post">
+[...]
+<input type="hidden" name="js" value="false">
+</form>
+}}}
+
+With this, in our django method in view.py we can test for request["js"]=="true" it would means that Js is activatd and we return the appropriate answer to the Ajax request.
+
+The '''second''' uses the url to pass a new variable ajax_or_not to the detail method.
+
+{{{
+#!python
+def details(request, r_slug, r_cat, ajax_or_not=None):
+[...]
+}}}
+
+We modify the url.py to accept this new parameter.
+{{{
+#!python
+(r'^recettes/(?P<r_cat>[-\w]+)/(?P<r_slug>[-\w]+)/(?P<ajax_or_not>.*)$', 'cefinban.recettes.views.details'),
+}}}
+
+The dojo binding needs to append a variable to the original document url, to make ajax_or_not not None.
+
+{{{
+    function sendForm()
+    {
+     dojo.byId("mark_status").innerHTML = "Loading ...";
+     dojo.io.bind({
+                    url: './ajax/',
+                    handler: sendFormCallback,
+                    formNode: dojo.byId('myForm')
+                });
+    }
+}}}
+
+== New details method in view.py ==
+
+We just need to test for the existence of ajax_or_not
+
+{{{
+#!python
+def details(request, r_slug, r_cat, ajax_or_not=None):
+[...]
+        if request.POST:
+                [...] same as part 1 
+                # except here we check ajax_or_not
+                if  ajax_or_not:
+                        # use json for python js exchange
+                        # it was a french string, if we dont't use unicode
+                        # the result at the output of json in Dojo is wrong.
+                        message = unicode( message, "utf-8" )
+                        jsonList = simple_json.dumps((my_mark, total, form_message ,message))
+                        return HttpResponse(jsonList)
+
+        return render_to_response('recettes/details.html', {'r': r, 'section':'index',
+                 'mark_status':message , 'mark_message':form_message, 'my_mark': my_mark},
+                  context_instance=RequestContext(request),)
+}}}
+
+{{{
+#!html
+<a name="P3"><h1>Fixing the frozen fading when user resend the form without waiting for the first fading to end.</h1></a>
+}}}
+If you haven't realised yet, if two or more calls are sent to the javascript function sendForm in a short time, the fading effect of the current sendForm Callback method might get stuck / froze / bugged. 
+We need a way of avoiding this by desactivating the connection between the submit button and the sendForm method while the fading '''animation''' is active.
+Thanks Dojo there is such things ! in two lines of code its done.
+
+
+{{{
+function sendFormCallback(type, data, evt)
+    {
+       [...as before ...]
+        // and the fancy fading effect
+        
+        // first disconnect the listener !
+        dojo.event.disconnect(sendFormButton, 'onclick', 'sendForm');
+        // assign our fading effect to an anim variable.
+        var anim = dojo.lfx.html.highlight("mark_status", [255, 151, 58], 700).play(300);
+        // When this anim is finish, reconnect
+        dojo.event.connect(anim, "onEnd", function() {  dojo.event.connect(sendFormButton, 'onclick', 'sendForm'); });
+    }
+}}}
+
+how nice is this !
+Careful, while talking about how to fix the problem using onEnd in Dojo IRC chanel, they realised play() method didnt behave properly and updated it to react to onEnd and such.
+su you need at least revision '''4286'''.
+Update your dojo source
+
+{{{
+svn co http://svn.dojotoolkit.org/dojo/trunk dojo
+}}}
+
+
+
+
+'''Note'''  It might be completely wrong.
+More questions / complaints: coulix@gmail.com 
+