Grantlee  5.2.0
Public Types | Public Member Functions | List of all members
Grantlee::Context Class Reference

The Context class holds the context to render a Template with. More...

#include <grantlee/context.h>

Public Types

enum  UrlType { AbsoluteUrls, RelativeUrls }

Public Member Functions

 Context ()
 Context (const QVariantHash &hash)
 Context (const Context &other)
 ~Context ()
QList< QPair< QString, QString > > externalMedia () const
void insert (const QString &name, QObject *object)
void insert (const QString &name, const QVariant &variant)
QSharedPointer< AbstractLocalizerlocalizer () const
QVariant lookup (const QString &str) const
Contextoperator= (const Context &other)
void pop ()
void push ()
QString relativeMediaPath () const
RenderContextrenderContext () const
void setLocalizer (QSharedPointer< AbstractLocalizer > localizer)
void setRelativeMediaPath (const QString &relativePath)
void setUrlType (UrlType type)
UrlType urlType () const

Detailed Description

For application developers, using the Context class is a matter of inserting keys and values as appropriate for rendering a Template using the insert method.

auto t = engine->newTemplate(
"Name is {% name %} and age is {% age %}.", "some_template" );
c1.insert( "name", "Tom" );
c1.insert( "age", 34 );
c2.insert( "name", "Harry" );
c2.insert( "age", 43 );
t->render(c1); // Returns "Name is Tom and age is 43."
t->render(c2); // Returns "Name is Harry and age is 34."

Note that one Template may be rendered multiple times with different contexts. Note also that any QVariant may be inserted into a Context object. Most commonly, QObjects will be used here.

See also
Custom objects

Context Stack.

For template tag developers, some other Context API is relevant.

It is possible to push and pop layers of context while a template is being rendered. This is useful if your template tag makes additional variables temporarily available in a part of a template. Template tags should only modify layers of context that they push themselves, and should pop any layers created before finishing its rendering step.

See for example the {% with %} tag. In a template such as

Some content
{% with|toUpper as lowerName %}
Name is {% lowerName %}
{% endwith %}

In this case, lowerName is available in the context only between the {% with %} and {% endwith %} tags. The implementation of the {% with %} tag render method is:

void WithNode::render( OutputStream *stream, Context *c ) const
// {% with m_filterExpression as m_name %}
c->insert( m_name, m_filterExpression.resolve( c ) );
m_list.render( stream, c );
c->pop(); // The section of context defining m_name is removed.

Note that a Context may temporarily override a variable in a parent context. This is why it is important to push a new context when adding items to context and pop it when finished.

Some content
{% with "foo" as var %}
Var is {% var %} // Var is "foo"
{% with "bar" as var %}
Var is {% var %} // Var is "bar"
{% endwith %}
Var is {% var %} // Var is "foo"
{% endwith %}
Stephen Kelly

Definition at line 117 of file context.h.

Member Enumeration Documentation

◆ UrlType

The type of urls to external media that should be put in the template.


Absolute URLs should be put in the template.


Relative URLs should be put in the template.

Definition at line 241 of file context.h.

Constructor & Destructor Documentation

◆ Context() [1/3]

Grantlee::Context::Context ( )

Creates an empty context

◆ Context() [2/3]

Grantlee::Context::Context ( const QVariantHash &  hash)

Sets every key in the hash as a property name with the variant as the value.

◆ Context() [3/3]

Grantlee::Context::Context ( const Context other)

Copy Constructor

◆ ~Context()

Grantlee::Context::~Context ( )


Member Function Documentation

◆ externalMedia()

QList<QPair<QString, QString> > Grantlee::Context::externalMedia ( ) const

Returns the external media encountered in the Template while rendering.

◆ insert() [1/2]

void Grantlee::Context::insert ( const QString name,
QObject object 

Insert the context object object identified by name into the Context.

◆ insert() [2/2]

void Grantlee::Context::insert ( const QString name,
const QVariant variant 

Insert the context object variant identified by name into the Context.

◆ localizer()

QSharedPointer<AbstractLocalizer> Grantlee::Context::localizer ( ) const

Returns the localizer currently in use.

◆ lookup()

QVariant Grantlee::Context::lookup ( const QString str) const

Returns the context object identified by the key str

◆ operator=()

Context& Grantlee::Context::operator= ( const Context other)

Assignmant operator

◆ pop()

void Grantlee::Context::pop ( )

Pops the context.

See also
Context Stack.

◆ push()

void Grantlee::Context::push ( )

Pushes a new context.

See also
Context Stack.

◆ relativeMediaPath()

QString Grantlee::Context::relativeMediaPath ( ) const

The relative path to external media to be used in templates.

◆ renderContext()

RenderContext* Grantlee::Context::renderContext ( ) const

Returns a modifiable RenderContext. This may be used to make Template rendering threadsafe so that render state does not need to be stored in the Node implementation itself.

◆ setLocalizer()

void Grantlee::Context::setLocalizer ( QSharedPointer< AbstractLocalizer localizer)

Sets the localizer to be used.

The Context takes ownerwhip of the localizer.

◆ setRelativeMediaPath()

void Grantlee::Context::setRelativeMediaPath ( const QString relativePath)

Sets the relative path to external media to be used in templates to relativePath

See also

◆ setUrlType()

void Grantlee::Context::setUrlType ( UrlType  type)

Sets the type of external media URL to be used in the template to type.

See also

◆ urlType()

UrlType Grantlee::Context::urlType ( ) const

The type of URL used in the template.