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\n \n
\n\n

This chapter lists some preferred solutions to common tasks and\npitfalls you may encounter while developing with templates.<\/p>\n

\n

Variable Naming<\/h2>\n

Name your variables for what they represent. If you are searching for\narticles, name the search result variable article<\/span><\/code> to make things clear.<\/p>\n

In particular, if you are iterating over a list or other iterable\nvariable called images, then your item variable should be named image<\/span><\/code>.\nThis makes generative templates easier to follow.<\/p>\n<\/div>\n

\n

Use id<\/span><\/code> instead of m.rsc<\/span><\/code><\/h2>\n

For the most frequently used model m_rsc<\/span><\/a>, use a shortcut syntax:\nwrite {{<\/span> id.title<\/span> }}<\/span><\/code> instead of {{<\/span> m.rsc[id].title<\/span> }}<\/span><\/code>. So this:<\/p>\n

<\/span><li><\/span>\n  <h3><\/span>{{<\/span> m.rsc<\/span>[<\/span>id<\/span>]<\/span>.title<\/span> }}<\/span><\/h3><\/span>\n  <\/span>{%<\/span> for<\/span> image_id<\/span> in<\/span> m.rsc<\/span>[<\/span>id<\/span>]<\/span>.o.depiction<\/span> %}<\/span><\/span>\n  <figure><\/span>\n      <\/span>{%<\/span> media<\/span> image_id<\/span> width<\/span>=<\/span>100<\/span> link<\/span>=<\/span>id<\/span> %}<\/span><\/span>\n      <\/span>{%<\/span> if<\/span> m.rsc<\/span>[<\/span>image_id<\/span>]<\/span>.summary<\/span> %}<\/span><\/span>\n          <p class="image-caption"><\/span>{{<\/span> m.rsc<\/span>[<\/span>image_id<\/span>]<\/span>.summary<\/span> }}<\/span><\/p><\/span>\n      <\/span>{%<\/span> endif<\/span> %}<\/span><\/span>\n  <\/figure><\/span>\n  <\/span>{%<\/span> endfor<\/span> %}<\/span><\/span>\n<\/li><\/span>\n<\/pre><\/div>\n<\/div>\n
becomes:<\/p>\n
<\/span><li><\/span>\n    <h3><\/span>{{<\/span> id.title<\/span> }}<\/span><\/h3><\/span>\n    <\/span>{%<\/span> for<\/span> image_id<\/span> in<\/span> id.o.depiction<\/span> %}<\/span><\/span>\n    <figure><\/span>\n      <\/span>{%<\/span> media<\/span> image_id<\/span> width<\/span>=<\/span>100<\/span> link<\/span>=<\/span>id<\/span> %}<\/span><\/span>\n      <\/span>{%<\/span> if<\/span> image_id.summary<\/span> %}<\/span><\/span>\n          <p class="image-caption"><\/span>{{<\/span> image_id.summary<\/span> }}<\/span><\/p><\/span>\n      <\/span>{%<\/span> endif<\/span> %}<\/span><\/span>\n    <\/figure><\/span>\n    <\/span>{%<\/span> endfor<\/span> %}<\/span><\/span>\n<\/li><\/span>\n<\/pre><\/div>\n<\/div>\n<\/div>\n
\n
Pitfalls<\/h2>\n
\n
Using ‘m’ as a template variable blocks model access<\/h3>\n
Avoid using the name m<\/span><\/code> for a variable.  It has a special meaning\nin templates for accessing models like m_site<\/span><\/a> and\nm_rsc<\/span><\/a> as m.site<\/cite> and m.rsc<\/cite>.  Effectively. all Erlang\nmodules with names starting with m_<\/cite> are made available in templates\nthrough the m<\/span><\/code> variable.<\/p>\n
It is particularly important since using m as a variable name will\ndisable model module access for the entire scope within which that\nvariable is defined.  This can lead to very confusing template errors.<\/p>\n<\/div>\n
\n
Using ‘id’ as a template variable blocks access to the current page<\/h3>\n
When rendering a page through controller_page<\/span><\/a>, Zotonic sets the\nid<\/cite> variable based on the resource<\/span><\/a> (page) being rendered.  It\nis also conventionally used by dispatch rules to supply the id of the\npage to render.<\/p>\n
Note, however, that there are legitmate cases for using id as a\ntemplate variable. It is a good idea to reuse another template to\nrender a section for one page and treating related content as the\n“current page” for that template by assigning id in a for loop or with\ncontext.  Using id otherwise will likely confuse other developers\ntrying to read your templates.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n           <\/div>","category_id":{"id":317,"is_a":["meta","category"],"name":"developerguide","title":"Developer guide","uri":"https:\/\/zotonic.com\/id\/developerguide"},"content_group_id":{"id":339,"is_a":["meta","content_group"],"name":"default_content_group","title":{"_type":"trans","tr":{"en":"Default Content Group"}},"uri":"https:\/\/zotonic.com\/id\/default_content_group"},"created":"2020-05-30T05:47:41Z","creator_id":{"id":336,"is_a":["person","robot"],"name":"gitbot","title":"Git","uri":"https:\/\/zotonic.com\/id\/336"},"github_url":"https:\/\/github.com\/zotonic\/zotonic\/tree\/master\/doc\/best-practices\/templates.rst","is_authoritative":true,"is_dependent":false,"is_featured":false,"is_protected":false,"is_published":true,"is_unfindable":false,"language":["en"],"modified":"2022-02-15T10:01:27Z","modifier_id":{"id":336,"is_a":["person","robot"],"name":"gitbot","title":"Git","uri":"https:\/\/zotonic.com\/id\/336"},"name":"doc_bestpractices_templates","pivot_geocode":null,"pivot_location_lat":null,"pivot_location_lng":null,"privacy":0,"publication_end":"9999-06-01T00:00:00Z","publication_start":"2022-02-15T10:01:27Z","slug":"template-best-practices-and-pitfalls","title":"Template Best Practices and Pitfalls","title_slug":"template-best-practices-and-pitfalls","tz":"UTC","uri":null,"version":18,"visible_for":0},"uri":"https:\/\/zotonic.com\/id\/1860","uri_template":"https:\/\/zotonic.com\/id\/:id","websub":{"hub":"https:\/\/zotonic.com\/.zotonic\/websub","topic":"https:\/\/zotonic.com\/.zotonic\/websub\/topic\/1860"}},"status":"ok"}