More StreamField Examples – Top news stories block by tag

We thought it would be useful to be able to display say the top 5 news stories tagged with a certain word anywhere within a page using StreamField, so for example the latest sport related news stories could be added into a column next to something else on a page in Wagtail. You could adapt this example to use any page type in your Models.py, doesn’t have to be news. Also I really like the way you can set a default template for a latest news block, but then override that and set another one if you need it rendered within a thinner column. Anyway here’s what I did :

Firstly make a new block class bases on StructBlock,

The filter below on the query for news assumes your news model is hooked up using taggit so each news story can be tagged.



class NewsStoriesBlock(blocks.StructBlock):
    tagged_by_keyword = blocks.CharBlock(required=True)
    stories_limit = blocks.CharBlock(required=True,max_length=2)
    
    def render(self, value): 
        news = NewsPage.objects.filter(live=True).filter(tags__name=value['tagged_by_keyword']).order_by('-date')
        news = news[:value['stories_limit']]
        
        return render_to_string(self.meta.template, { 
            'self': value, 
            'news_stories': news, 
            
        })
        
    class Meta:
        template = 'yourapp/blocks/news_stories.html'
        icon = 'cogs'
        label = 'News Stories Widget'

tagged_by_keyword is the field used to hold the tag name ‘sport’ etc

for stories_limit I’ve set max_length to 2, meaning 99 is the most a user could request, but you could more practically change this to a choiceBlock of restricted values, or even add some code into the render method, so it checks the value is no more than say 30, and if it is just sets it 30 as a cap.

Then add the new block to your StreamField in your page model, like in the example one below. For how to do a two column block see ‘Some Wagtail v1 StreamField Examples‘ post


class ArticlePage(Page):
    ...
    page_content = StreamField([
            ('heading', blocks.CharBlock(classname="full title",icon="title")),
            ('paragraph', blocks.RichTextBlock()),
            ('image', ImageChooserBlock(icon="image")),
            ('two_columns', TwoColumnBlock()),
            ('news_stories', NewsStoriesBlock()),
        ],null=True,blank=True)
     ...

When you add the news block to a two column StreamField, set another block template if you need it rendered in a different format better suited to a thinner half column, like


...
left_column = blocks.StreamBlock([
            ('heading', blocks.CharBlock(classname="full title")),
            ('paragraph', blocks.RichTextBlock()),
            ('image', ImageChooserBlock()),
            ('news_stories', NewsStoriesBlock(icon="cogs",template='yourapp/blocks/news_stories_cols.html')),
        ], icon='arrow-left', label='Left column content')            
...

And a block template for rendering news into three bootstrap columns (note you need to use a filter from a template tag to make news page URL workable, code below. You can’t use {% pageurl news %} there is no request object at this level, if someone knows how to do that, or if I’m missing something let me know)

Also this assumes your news model has a title, date and news_image field, change to reflect your page setup.


{% load wagtailimages_tags static yourapp_tags %}

{% if news_stories %}
		
<div class="container-newsbytag">

  <div class="row">
		
              <div class="col-md-12">
                 <h2>News tagged with {{ self.tagged_by_keyword }}</h2>
              </div>
			
	      {% for news in news_stories %}
	      
              {% if forloop.first %}<div class='row'>{% endif %}	

              <div class="col-md-4">

                   <a href="{{ news.url_path|clean_root_url }}" class="news_itembytag">
      
                      {% image news.news_image fill-300x200 class="img-responsive" %}
		
                      <h4>{{ news.title }}</h4>
                      <p class="date">{{ news.date|date:"j F Y" }}</p>

                   </a>


              </div>
	      
              {% if forloop.counter|divisibleby:3 %}</div><div class='row'>{% endif %}
			
              {% if forloop.last %}</div>{% endif %}	
		  	
	      {% empty %} No News Stories found
							
              {% endfor %}

 </div>

</div>
	

{% endif %}


in your yourapp_tags.py (what ever ‘templatetags’ code you have setup. This is used to remove the root /home/ part from the url_path of the news page.


@register.filter
def clean_root_url(url):
    url = url.split('/')
    new_url = ""
    for item in url[2:]:
        new_url = new_url + "/" + item
          
    return new_url
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