Reference

classytags.arguments

This module contains standard argument types.

class classytags.arguments.Argument(name[, default=None][, required=True], [resolve=True])

A basic single value argument with name as it’s name.

default is used if required is False and this argument is not given.

If resolve is False, the argument will not try to resolve it’s contents against the context. This is especially useful for ‘as varname’ arguments. Note that quotation marks around the argument will be removed if there are any.

value_class

The class to be used to wrap the value in. Defaults to classytags.values.StringValue.

get_default()

Returns the default value for this argument

parse(parser, token, tagname, kwargs)

Parses a single token into kwargs. Should return True if it consumed this token or False if it didn’t.

parse_token(parser, token)

Parses a single token using parser into an object which is can be resolved against a context. Usually this is a template variable, a filter expression or a classytags.utils.TemplateConstant.

class classytags.arguments.Argument(name[, default=None][, required=True], [resolve=True])

Same as classytags.arguments.Argument but with classytags.values.StrictStringValue as value_class.

class classytags.arguments.KeywordArgument(name[, default=None][, required=True] [, resolve=True][, defaultkey=None][, splitter='='])

An argument that allows key=value notation.

defaultkey is used as key if no key is given or the default value should be used.

splitter is used to split the key value pair.

wrapper_class

Class to use to wrap the key value pair in. Defaults to classytags.values.DictValue.

class classytags.arguments.IntegerArgument

Same as classytags.arguments.Argument but with classytags.values.IntegerValue as value_class.

class classytags.arguments.ChoiceArgument(name, choices[, default=None][, required=True] [, resolve=True])

An argument which validates it’s input against predefined choices.

class classytags.arguments.MultiValueArgument(name[, default=NULL][, required=True] [, max_values=None][, resolve=True])

An argument which accepts a variable amount of values. The maximum amount of accepted values can be controlled with the max_values argument which defaults to None, meaning there is no maximum amount of values.

default is an empty list if required is False.

resolve has the same effects as in classytags.arguments.Argument however applies to all values of this argument.

The default value for value_class is$ classytags.values.ListValue.

sequence_class

Class to be used to build the sequence. Defaults to classytags.utils.ResolvableList.

class classytags.arguments.MultiKeywordArgument(name[, default=None][, required=True] [, resolve=True][, max_values=None] [, splitter='='])

Similar to classytags.arguments.KeywordArgument but allows multiple key value pairs to be given. The will be merged into one dictionary.

Arguments are the same as for classytags.arguments.KeywordArgument and classytags.arguments.MultiValueArgument, except that default_key is not accepted and default should be a dictionary or None.

class classytags.arguments.Flag(name[, default=NULL][, true_values=None][, false_values=None] [, case_sensitive=False])

A boolean flag. Either true_values or false_values must be provided.

If default is not given, this argument is required.

true_values and false_values must be either a list or a tuple of strings. If both true_values and false_values are given, any value not in those sequences will raise a classytag.exceptions.InvalidFlag exception.

case_sensitive defaults to False and controls whether the values are matched case sensitive or not.

classytags.blocks

This module contains classes for Advanced Block Definition.

class classytags.blocks.BlockDefintion(alias, *names)

A block definition with the given alias and a sequence of names. The members of the names sequence must either be strings, classytags.blocks.VariableBlockName instances or other objects implementing at least a collect() method compatible with the one of classytags.blocks.VariableBlockName.

alias

The alias for this definition to be used in the tag’s kwargs.

names

Sequence of strings or block name definitions.

validate(options)

Validates this definition against an instance of classytags.core.Options by calling the validate() on all it’s names if such a method is available.

collect(parser)

Returns a sequence of strings to be used in the parse_until statement. This is a sequence of strings that this block accepts to be handled. The parser argument is an instance of classytags.parser.Parser.

class classytags.blocks.VariableBlockName(template, argname)

A block name definition to be used in classytags.blocks.BlockDefinition to implement block names that depend on the (unresolved) value of an argument. The template argument to this class should be a string with the value string substitution placeholder. For example: 'end_my_block %(value)s'. The argname argument is the name of the argument from which the value should be extracted.

validate(options)

Validates that the given argname is actually available on the tag.

collect(parser)

Returns the template substitued with the value extracted from the tag.

classytags.core

This module contains the core objects to create tags.

class classytags.core.Options(*options, **kwargs)

Holds the options of a tag. options should be a sequence of classytags.arguments.Argument subclasses or strings (for breakpoints). You can give they keyword argument blocks to define a list of blocks to parse until. You can specify a custom argument parser by providing the keyword argument parser_class.

all_argument_names

A list of all argument names in this tag options. Used by classytags.blocks.VariableBlockName to validate it’s definition.

get_parser_class()

Returns classytags.parser.Parser or a subclass of it.

bootstrap()

An internal method to bootstrap the arguments. Returns an instance of classytags.utils.StructuredOptions.

parse(parser, token):

An internal method to parse the template tag. Returns a tuple (arguments, blocks).

class classytags.core.TagMeta

The metaclass of classytags.core.Tag which ensures the tag has a name attribute by setting one based on the classes name if none is provided.

class classytags.core.Tag(parser, token)

The Tag class is nothing other than a subclass of django.template.Node which handles argument parsing in it’s __init__() method rather than an external function. In a normal use case you should only override name, options and render_tag().

Note

When registering your template tag, register the class object, not an instance of it.

name

The name of this tag (for use in templates). This attribute is optional and if not provided, the un-camelcase class name will be used instead. So MyTag becomes my_tag.

options

An instance of classytags.core.Options which holds the options of this tag.

__init__(parser, token):

Warning

This is an internal method. It is only documented here for those who would like to extend django-classy-tags.

This is where the arguments to this tag get parsed. It’s the equivalent to a compile function in Django’s standard templating system. This method does nothing else but assing the kwargs and blocks attributes to the output of options.parse() with the given parser and token.

render(context)

Warning

This is an internal method. It is only documented here for those who would like to extend django-classy-tags.

This method resolves the arguments to this tag against the context and then calls render_tag() with the context and those arguments and returns the return value of that method.

render_tag(context[, **kwargs])

The method used to render this tag for a given context. kwargs is a dictionary of the (already resolved) options of this tag as well as the blocks (as nodelists) this tag parses until if any are given. This method should return a string.

classytags.exceptions

This module contains the custom exceptions used by django-classy-tags.

exception classytags.exceptions.BaseError

The base class for all custom excpetions, should never be raised directly.

exception classytags.exceptions.ArgumentRequiredError(argument, tagname)

Gets raised if an option of a tag is required but not provided.

exception classytags.exceptions.InvalidFlag(argname, actual_value, allowed_values, tagname)

Gets raised if a given value for a flag option is neither in true_values nor false_values.

exception classytags.exceptions.BreakpointExpected(tagname, breakpoints, got)

Gets raised if a breakpoint was expected, but another argument was found.

exception classytags.exceptions.TooManyArguments(tagname, extra)

Gets raised if too many arguments are provided for a tag.

classytags.helpers

This modules contains helper classes to make building template tags even easier.

class classytags.helpers.AsTag

A helper tag base class to build ‘as varname’ tags. Note that the option class still has to contain the ‘as varname’ information. This tag will use the last argument in the options class to set the value into the context.

This class implements the method classytags.helpers.AsTag.get_value() which gets the context and all arguments except for the varname argument as arguments. It should always return the value this tag comes up with, the class then takes care of either putting the value into the context or returns it if the varname argument is not provided.

Note

You should not override the render_tag() method of this class.

get_value_for_context(context, **kwargs):

New in version 0.5.

Should return the value of this tag if used in the ‘as varname’ form. By default this method just calls get_value and returns that.

You may want to use this method if you want to suppress exceptions in the ‘as varname’ case.

get_value(context, **kwargs)

Should return the value of this tag. The context setting is done in the classytags.core.Tag.render_tag() method of this class.

class classytags.helpers.InclusionTag

A helper class for writing inclusion tags (template tags which render a template).

Note

You should not override the render_tag() method of this class.

template

The template to use if get_template() is not overridden.

push_context

New in version 0.5.2.

By default, this is False. If it’s set to True the context will be pushed before rendering the included template, preventing context pollution.

get_template(context, **kwargs)

This method should return a template (path) for this context and arguments. By default returns the value of template.

get_context(context, **kwargs)

Should return the context (as a dictionary or an instance of django.template.Context or a subclass of it) to use to render the template. By default returns an empty dictionary.

classytags.parser

The default argument parser lies here.

class classytags.parser.Parser(options)

The default argument parser class. It get’s initialized with an instance of classytags.utils.StructuredOptions.

options

The classytags.utils.StructuredOptions instance given when the parser was instantiated.

parser

The (template) parser used to parse this tag.

bits

The split tokens.

tagname

Name of this tag.

kwargs

The data extracted from the bits.

blocks

A dictionary holding the block nodelists.

arguments

The arguments in the current breakpoint scope.

current_argument

The current argument if any.

todo

Remaining bits. Used for more helpful exception messages.

parse(parser, token)

Parses a token stream. This is called when your template tag is parsed.

handle_bit(bit)

Handle the current bit (token).

handle_next_breakpoint(bit)

The current bit is the next breakpoint. Make sure the current scope can be finished successfully and shift to the next one.

handle_breakpoints(bit)

The current bit is a future breakpoint, try to close all breakpoint scopes before that breakpoint and shift to it.

handle_argument(bit)

The current bit is an argument. Handle it and contribute to kwargs.

parse_blocks()

Parses the blocks this tag wants to parse until if any are provided.

finish()

After all bits have been parsed, finish all remaining breakpoint scopes.

check_required()

A helper method to check if there’s any required arguments left in the current breakpoint scope. Raises a classytags.exceptions.ArgumentRequiredError if one is found and contributes all optional arguments to kwargs.

classytags.utils

Utility classes and methods for django-classy-tags.

class classytags.utils.NULL

A pseudo type.

class classytags.utils.TemplateConstant(value)

A constant pseudo template variable which always returns it’s initial value when resolved.

literal

Used by the classytags.blocks.VariableBlockName to generate it’s final name.

class classytags.utils.StructuredOptions(options, breakpoints)

A helper class to organize options.

options

The arguments in this options.

breakpoints

A copy of the breakpoints in this options

blocks

A copy of the list of tuples (blockname, alias) of blocks of this tag.

current_breakpoint

The current breakpoint.

next_breakpoint

The next breakpoint (if there is any).

shift_breakpoint()

Shift to the next breakpoint and update current_breakpoint and next_breakpoint.

get_arguments()

Returns a copy of the arguments in the current breakpoint scope.

class classytags.utils.ResolvableList(item)

A subclass of list which resolves all it’s items against a context when it’s resolve method gets called.

classytags.utils.get_default_name(name)

Turns ‘CamelCase’ into ‘camel_case’.

classytags.values

class classytags.values.StringValue(var)
errors

A dictionary holding error messages which can be caused by this value class. Defaults to an empty dictionary.

value_on_error

The value to use when the validation of a input value fails in non-debug mode. Defaults to an empty string.

var

The variable wrapped by this value instance.

resolve(context)

Resolve var against context and validate it by calling the clean() method with the resolved value.

clean(value)

Validates and/or cleans a resolved value. This method should always return something. If validation fails, the error() helper method should be used to properly handle debug modes.

error(value, category)

Handles an error in category caused by value. In debug mode this will cause a django.template.TemplateSyntaxError to be raised, otherwise a TemplateSyntaxWarning is called and value_on_error is returned. The message to be used for both the exception and the warning will be constructed by the message in errors if category is in it. The value can be used as a named string formatting parameter.

class classytags.values.StrictStringValue(var)

Same as StringValue but enforces that the value passed to it is a string (instance of basestring).

class classytags.values.IntegerValue(var)

Subclass of StringValue.

clean(value)

Tries to convert the value to an integer.

class classytags.values.ListValue(value)

Subclass of StringValue and list.

Appends the initial value to itself in initialization.

resolve(context)

Resolves all items in itself against context and calls clean() with the list of resolved values.

class classytags.values.DictValue(dict)

Subclass of StringValue and dict.

resolve(context)

Resolves all values against context and calls clean() with the resolved dictionary.