View¶
The view’s responsibility is solely the visual presentation of data provided by the controller. In FLOW3 views are cleanly decoupled from the rest of the MVC framework. This allows you to either take advantage of Fluid (FLOW3’s template engine), write your own custom PHP view class or use almost any other template engine by writing a thin wrapper building a bridge between FLOW3’s interfaces and the template engine’s functions. In this tutorial we focus on Fluid-based templates as this is what you usually want to use.
Resources¶
Before we design our first Fluid template we need to spend a thought on the resources our template is going to use (I’m talking about all the images, style sheets and javascript files which are referred to by your HTML code). You remember that only the Web directory is accessible from the web, right? And the resources are part of the package and thus hidden from the public. That’s why FLOW3 comes with a powerful resource manager whose main task is to manage access to your package’s resources.
The deal is this: All files which are located in the public resources directory of your package will automatically be mirrored to the public resources directory below the Web folder. Let’s take a look at the directory layout of the Blog package:
| Directory | Description |
|---|---|
| Classes/ | All the .php class files of your package |
| Documentation/ | The package’s manual and other documentation |
| Meta/ | Package.xml and other package meta information |
| Resources/ | Top folder for resources |
| Resources/Public/ | Public resources - will be mirrored to the Web directory |
| Resources/Private/ | Private resources - won’t be mirrored to the Web directory |
No matter what files and directories you create below Resources/Public/ - all of them will be symlinked to Web/_Resources/Static/Packages/TYPO3.Blog/ on the next hit.
Tip
There are more possible directories in a package and we do have some conventions for naming certain sub directories. All that is explained in fine detail in the FLOW3 reference manual.
Important
For the blog example in this tutorial we created some style sheets and icons. If you’d like to brush up the following examples a little, then it’s now time to copy Resources/Public/ in the CheatSheet to your blog’s public resources folder (Packages/Application/TYPO3.Blog/Resources/Public/).
Layouts¶
Fluid knows the concepts of layouts, templates and partials. Usually all of them are just plain HTML files which contain special tags known by the Fluid template view. The following figure illustrates the use of layout, template and partials in our blog example:
Layout, Template and Partial
A Fluid layout provides the basic layout of the output which is supposed to be shared by multiple templates. You will use the same layout throughout this tutorial - only the templates will change depending on the current controller and action. Elements shared by multiple templates can be extracted as a partial to assure consistency and avoid duplication.
Let’s build a simple layout for your blog. You only need to adjust the file called Default.html inside the TYPO3.Blog/Resources/Private/Layouts directory to contain the following code:
Resources/Private/Layouts/Default.html:
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html lang="en" xml:lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<f:base />
<title>{blog.title}</title>
<link rel="stylesheet" href="{f:uri.resource(path: 'Blog.css')}" type="text/css" media="all" />
</head>
<body>
<div id="header">
<f:if condition="{blog}">
<f:link.action action="index" controller="Post">
<h1 class="title">{blog.title}</h1></f:link.action>
<p class="description">{blog.description}</p>
</f:if>
</div>
<div id="maincontainer">
<div id="mainbox"><f:render section="mainbox" /></div>
<div class="clear"></div>
</div>
<div id="footer">
<a href="http://flow3.typo3.org">Powered by FLOW3
<img src="{f:uri.resource(path: 'FLOW3-Logo-11px.png')}" width="11" height="11" />
</a>
</div>
</body>
</html>
On first sight this looks like plain HTML code, but you’ll surely notice the various <f: ... > tags. Fluid provides a range of view helpers which are addressed by these tags. By default they live in the f namespace resulting in tags like <f:base> or <f:if>. You can define your own namespaces and even develop your own view helpers, but for now let’s look at what you used in your layout:
The first Fluid tag used is the <f:base> tag. This tag instructs Fluid to render an HTML <base> tag containing the correct absolute base URI for your site – in your case resulting in:
Resources/Private/Layouts/Default.html:
<base href="http://dev.tutorial.local/"></base>
The second occurrence of Fluid markup is actually no tag but a variable accessor:
Resources/Private/Layouts/Default.html:
<title>{blog.title}</title>
As you will see in a minute, Fluid allows your controller to define variables for the template view. In order to display the blog’s name, you’ll need to make sure that your controller assigns the current Blog object to the template variable blog. The value of such a variable can be inserted anywhere in your layout, template or partial by inserting the variable name wrapped by curly braces. However, in the above case blog is not a value you can output right away – it’s an object. Fortunately Fluid can display properties of an object which are accessible through a getter function: to display the blog title, you just need to note down {blog.title}.
The third appearance of Fluid syntax is an alternative way to address view helpers, the view helper shorthand syntax:
Resources/Private/Layouts/Default.html:
<link rel="stylesheet" href="{f:uri.resource(path: 'Blog.css')}" type="text/css" />
This instructs the URI view helper to create a relative resource URL pointing to your style sheet. The generated HTML code will look like this:
Resources/Private/Layouts/Default.html:
<link rel="stylesheet" href="Resources/Packages/TYPO3.Blog/Blog.css" type="text/css" />
If you look at the remaining markup of the layout you’ll find more uses of view helpers, including conditions and link generation. There’s only one more view helper you need to know about before proceeding with our first template, the render view helper:
Resources/Private/Layouts/Default.html:
<f:render section="mainbox" />
This tag tells Fluid to insert the section mainbox defined in the current template at this place. For this to work there must be a section with the specified name in the template referring to the layout – because that’s the way it works: A template declares on which layout it is based on, defines sections which in return are included by the layout. Confusing? Let’s look at a concrete example.
Templates¶
Templates are, as already mentioned, tailored to a specific action. The action controller chooses the right template automatically according to the current package, controller and action - if you follow the naming conventions. Let’s replace the automatically generated template for the Post controller’s index action in TYPO3.Blog/Resources/Private/Templates/Post/Index.html by some more meaningful HTML:
Resources/Private/Templates/Post/Index.html:
<f:layout name="Default" />
<f:section name="mainbox">
<f:flashMessages class="flashmessages" />
<f:if condition="{posts}">
<f:then>
<div id="navigation">
<span class="buttons"><f:link.action action="new" controller="Post"><img src="{f:uri.resource(path: 'Icons/FamFamFam/page_add.png')}" title="Create a new post"/></f:link.action></span>
<div class="clear"></div>
</div>
<ol class="posts">
<f:for each="{posts}" as="post">
<li class="post">
<h2>
<f:link.action action="show" controller="Post" arguments="{post: post}">{post.title}</f:link.action>
</h2>
<f:render partial="PostMetaData" arguments="{post: post}"/>
<p class="content"><f:format.crop maxCharacters="500">{post.content}</f:format.crop> <f:link.action action='show' arguments='{post: post,}'>More</f:link.action></p>
</li>
</f:for>
</ol>
</f:then>
<f:else>
<p>This blog currently doesn't contain any posts. <f:link.action action="new" controller="Post">Create the first post</f:link.action></p>
</f:else>
</f:if>
</f:section>
There you have it: In the first line of your template there’s a reference to the master layout. All HTML code is wrapped in a <f:section> tag. Even though this is the way you usually want to design templates, you should know that using layouts is not mandatory – you could equally put all your code into one template and omit the <f:layout> and <f:section> tags.
Take a quick look at the template. You’ll note that we’re using a new view helper right at the top – flashMessages generates an unordered list with all flash messages. Well, maybe you remember this line in the createAction of our PostController:
$this->addFlashMessage('Created a new post.');
Flash messages are a great way to display success or error messages to the user. And because they are so useful, the action controller provides the FlashMessageContainer and Fluid offers the flashMessages view helper. Therefore, if you create a new post, you’ll see the message Your new post was created at the top of your blog index on the next hit.
The main job of this template is to display a list of the most recent posts. An <f:if> condition makes sure that the list of posts is only rendered if posts actually contains posts. But currently the view doesn’t know anything about posts - you need to adapt the indexAction of the PostController to assign blogs to the view:
*Classes/Controller/PostController.php*:
/**
* List action for this controller. Displays latest posts
*
* @return void
*/
public function indexAction() {
$blog = $this->blogRepository->findActive();
$this->view->assign('blog', $blog);
$this->view->assign('posts', $blog->getPosts());
}
To fully understand the above code you need to know two facts:
- $this->view is automatically set by the action controller and points to a Fluid template view.
- if an action method returns NULL, the controller will automatically call $this->view->render() after executing the action.
After creating the folder Resources/Private/Partials/ add the following to a file named PostMetaData.html:
Resources/Private/Partials/PostMetaData.html:
<p class="metadata">
Published on <f:format.date format='d.m.Y'>{post.date}</f:format.date> by {post.author}
<f:link.action action="show" controller="Post" arguments="{post: post}" section="comments"><img src="../../Public/Icons/FamFamFam/comments.png" title="Comments"/>
<f:if condition="{post.numberOfComments} > 0">
<f:then>
<f:if condition="{post.numberOfComments} == 1">
<f:then>{post.numberOfComments} comment</f:then>
<f:else>{post.numberOfComments} comments</f:else>
</f:if>
</f:then>
<f:else>No comments</f:else>
</f:if>
</f:link.action>
<br />
<f:if condition="{post.category}">Filed under: <f:link.action action="index" controller="Post" arguments="{category: post.category.name}" format="html">{post.category}</f:link.action></f:if>
<f:if condition="{post.tags}">
| Tags: <f:for each="{post.tags}" as="tag"><f:link.action action="index" controller="Post" arguments="{tag: tag.name}" >{tag.name}</f:link.action> </f:for>
</f:if>
</p>
Now you should now see the list of recent posts by accessing http://dev.tutorial.local/typo3.blog/post:
Creating a new post won’t work yet because, you even though there exists a newAction already, the template for it doesn’t contain a mainbox section yet:
Forms¶
Create a New Post¶
Time to create a form which allows you to enter details for a new post. The first component you need is the newAction whose sole purpose is displaying the form:
Classes/Controller/PostController.php:
/**
* Shows a form for creating a new post object
*
* @return void
*/
public function newAction() {
$blog = $this->blogRepository->findActive();
$this->view->assign('blog', $blog);
}
No code? Almost no code. What will happen is this: the action controller selects the New.html template and assigns it to $this->view which will automatically be rendered after newAction has been called. That’s enough for displaying the form. The only thing we need to assign here is the blog, otherwise the title and description in our header (defined in Master.html) would be empty.
The second component is the actual form. Adjust the template New.html in the Resources/Public/Templates/Post/ folder:
Resources/Public/Templates/Post/New.html:
<f:layout name="Default" />
<f:section name="mainbox">
<h2 class="flow3-firstHeader">Create a new post</h2>
<f:flashMessages class="flashmessages"/>
<f:form method="post" action="create" object="{newPost}" name="newPost" enctype="multipart/form-data">
<f:form.hidden name="blog" value="{blog}" />
<label for="author">Author</label><br />
<f:form.textbox property="author" id="author" /><br />
<label for="title">Title</label><br />
<f:form.textbox property="title" id="title" /><br />
<label for="linkTitle">Link Title (optional)</label><br />
<f:form.textbox property="linkTitle" id="linkTitle" /><br />
<label for="content">Content</label><br />
<f:form.textarea property="content" rows="5" cols="40" id="content" /><br />
<f:form.submit value="Submit post"/>
</f:form>
</f:section>
Here is how it works: The <f:form> view helper renders a form tag. Its attributes are similar to the action link view helper you might have seen in previous examples: action specifies the action to be called on submission of the form, controller would specify the controller and package the package respectively. If controller or package are not set, the URI builder will assume the current controller or package respectively. name finally declares the name of the form and at the same time specifies the name of the action method argument which will receive the form values.
It is important to know that the whole form is (usually) bound to one object and that the values of the form’s elements become property values of this object. In this example the form contains (property) values for a post object. The form’s elements are named after the class properties of the Post domain model: blog, author, title, content and relatedPosts. Let’s look at the createAction again:
Classes/Controller/PostController.php:
/**
* Creates a new post
*
* @param \TYPO3\Blog\Domain\Model\Post $post
* @return void
*/
public function createAction(\TYPO3\Blog\Domain\Model\Post $newPost) {
$blog = $this->blogRepository->findActive();
$blog->addPost($newPost);
$this->postRepository->add($newPost);
$this->flashMessageContainer->add('Created a new post.');
$this->redirect('index');
}
It’s important that the createAction uses the type hint \TYPO3\Blog\Domain\Model\Post and comes with a proper @param annotation because this is how FLOW3 determines the type to which the submitted form values must be converted. Because this action requires a Post it gets a post (object) - as long as the property names of the object and the form match.
Time to test your new newAction and its template – click on the little plus sign above the first post lets the newAction render this form:
Enter some data and click the submit button:
You should now find your new post in the list of posts.
Edit a Post¶
While you’re dealing with forms you should also create form for editing an existing post. The editAction will display this form.
This is pretty straight forward: we add a link to each post in the Index.html template which passes an argument $post to the edit action and the action on its part assigns the blog to the template.
First you need to add the “edit” link to the post index template:
Resources/Public/Templates/Post/Index.html:
...
<h2>
<f:link.action action="show" controller="Post" arguments="{post: post}">{post.title}</f:link.action>
<f:link.action action="edit" arguments="{post: post}" controller="Post">
<img src="{f:uri.resource(path: 'Icons/FamFamFam/page_edit.png')}" title="Edit this post"/>
</f:link.action>
</h2>
...
The modified template will now render a little pencil next to each post:
Adjust the template Templates/Post/Edit.html and insert the following HTML code:
Resources/Public/Templates/Post/Edit.html:
<f:layout name="Default" />
<f:section name="mainbox">
<h2 class="flow3-firstHeader">Edit post "{post.title}"</h2>
<f:form method="post" action="update" object="{post}" name="post" enctype="multipart/form-data">
<label for="author">Author</label><br />
<f:form.textbox property="author" id="author" /><br />
<label for="title">Title</label><br />
<f:form.textbox property="title" id="title" /><br />
<label for="linkTitle">Link Title (optional)</label><br />
<f:form.textbox property="linkTitle" id="linkTitle" /><br />
<label for="content">Content</label><br />
<f:form.textarea property="content" rows="5" cols="40" id="content" /><br />
<f:form.submit value="Update"/>
</f:form>
</f:section>
Most of this should already look familiar. However, there is a tiny difference to the new form you created earlier: in this edit form you added object="{post}" to the <f:form> tag. This attribute binds the variable {post} to the form and it simplifies the further definition of the form’s elements. Each element – in our case the text box and the text area – comes with a property attribute declaring the name of the property which is supposed to be displayed and edited by the respective element.
Because you specified property="title" for the text box, Fluid will fetch the value of the post’s title property and display it as the default value for the rendered text box. The resulting input tag will also contain the name "title" due to the property attribute you defined. The id attribute only serves as a target for the label tag and is not required by Fluid.
What’s missing now is a small adjustment to the PHP code displaying the edit form:
*Classes/Controller/PostController.php*:
/**
* Shows a form for editing an existing post object
*
* @param \TYPO3\Blog\Domain\Model\Post $post The post to edit
* @return void
*/
public function editAction(\TYPO3\Blog\Domain\Model\Post $post) {
$blog = $this->blogRepository->findActive();
$this->view->assign('blog', $blog);
$this->view->assign('post', $post);
}
Enough theory, let’s try out the edit form in practice. A click on the edit link of your list of posts should result in a screen similar to this:
When you submit the form you call the updateAction:
*Classes/Controller/PostController.php*:
/**
* Updates the given post object
*
* @param \TYPO3\Blog\Domain\Model\Post $post The post to update
*/
public function updateAction(\TYPO3\Blog\Domain\Model\Post $post) {
$this->postRepository->update($post);
$this->addFlashMessage('Updated the post.');
$this->redirect('index');
}
Quite easy as well, isn’t it? The updateAction expects the edited post as its argument and passes it to the repository’s update method (note that we used the PostRepository!). Before we disclose the secret how this magic actually works behind the scenes try out if updating the post really works:
A Closer Look on Updates¶
Although updating objects is very simple on the user’s side (that’s where you live), it is a bit complex on behalf of the framework. You may skip this section if you like - but if you dare to take a quick look behind the scenes to get a better understanding of the mechanism behind the updateAction read on ...
The updateAction expects one argument, namely the edited post. “Edited post” means that this is a Post object which already contains the values submitted by the edit form.
These modifications will not be persisted automatically. To persist the changes to the post object, call the PostRepository’s update method. It schedules an object for the dirty check at the end of the request.
If all these details didn’t scare you, you might now ask yourself how FLOW3 could know that the updateAction expects a modified object and not the original? Great question. And the answer is – literally – hidden in the form generated by Fluid’s form view helper:
HTML Code:
<form method="post" name="post" action="post/update">
<input type="hidden" name="post[__identity]"
value="2d064493-ce45-4bc9-9d0c-38e40f2c4afe" />
...
</form>
Fluid automatically renders a hidden field containing information about the technical identity of the form’s object, if the object is an original, previously retrieved from a repository.
On receiving a request, the MVC framework checks if a special identity field (such as the above hidden field) is present and if further properties have been submitted. This results in three different cases:
| Situation | Case | Consequence |
|---|---|---|
| identity missing, properties present | New / Create | Create a completely new object and set the given properties |
| identity present, properties missing | Show / Delete / ... | Retrieve original object with given identifier |
| identity present, properties present | Edit / Update | Retrieve original object, and set the given properties |
Because the edit form contained both identity and properties, FLOW3 prepared an instance with the given properties for our updateAction.
