pyzim.header.Header

class documentation

class Header(ModifiableMixIn):

Constructor: Header(magic_number, major_version, minor_version, uuid, ...)

The header of a ZIM file.

The header contains various metadata informations about the ZIM file as well as the offsets of some other datastructures in the ZIM file.

Class Method	`from_bytes`	Construct a header from a bytestring.
Class Method	`from_file`	Read the header from a file.
Class Method	`placeholder`	Generate a placeholder header and return it.
Method	`__init__`	The default constructor.
Method	`__str__`	Return a string displaying the content of the header.
Method	`check_compatible`	Check if this header is compatible, raising an exception if not.
Method	`checksum_position.setter`	The offset to the checksum.
Method	`cluster_count.setter`	The number of clusters in this archive.
Method	`cluster_pointer_position.setter`	The offset to the cluster pointer list.
Method	`entry_count.setter`	The number of entries in this archive.
Method	`get_disk_size`	Calculate the size of this object when written to a file.
Method	`layout_page.setter`	The index of the layout page in the url pointer list, `None` if not present.
Method	`magic_number.setter`	The magic number of this ZIM file.
Method	`main_page.setter`	The index of the main page in the url pointer list, `None` if not present.
Method	`major_version.setter`	The major version of this ZIM file.
Method	`mime_list_position.setter`	The offset to the mime type list.
Method	`minor_version.setter`	The minor version of this ZIM file.
Method	`title_pointer_position.setter`	The offset to the directory pointer list ordered by title.
Method	`to_bytes`	Dump this header into a bytestring.
Method	`to_dict`	Dump this header into a dictionary and return it.
Method	`url_pointer_position.setter`	The offset to the directory pointer list ordered by URL.
Method	`uuid.setter`	The UUID of this ZIM file.
Constant	`FORMAT`	the format of a ZIM header
Constant	`LENGTH`	length of the ZIM header
Constant	`MAGIC_NUMBER`	the magic number used to identify ZIM files.
Property	`checksum_position`	The offset to the checksum.
Property	`cluster_count`	The number of clusters in this archive.
Property	`cluster_pointer_position`	The offset to the cluster pointer list.
Property	`entry_count`	The number of entries in this archive.
Property	`has_layout_page`	A boolean indicating whether this header knows the position of the layout page or not.
Property	`has_main_page`	A boolean indicating whether this header knows the position of the main page or not.
Property	`layout_page`	The index of the layout page in the url pointer list, `None` if not present.
Property	`magic_number`	The magic number of this ZIM file.
Property	`main_page`	The index of the main page in the url pointer list, `None` if not present.
Property	`major_version`	The major version of this ZIM file.
Property	`mime_list_position`	The offset to the mime type list.
Property	`minor_version`	The minor version of this ZIM file.
Property	`title_pointer_position`	The offset to the directory pointer list ordered by title.
Property	`url_pointer_position`	The offset to the directory pointer list ordered by URL.
Property	`uuid`	The UUID of this ZIM file.
Instance Variable	`_checksum_position`	offset to the checksum
Instance Variable	`_cluster_count`	number of clusters in the archive
Instance Variable	`_cluster_pointer_position`	offset to the cluster pointer list
Instance Variable	`_entry_count`	number of entries in the archive
Instance Variable	`_layout_page`	index of the layout page in the url pointer list, 0xffffffff if not present
Instance Variable	`_magic_number`	magic number of this ZIM file.
Instance Variable	`_main_page`	index of the main page in the url pointer list, 0xffffffff if not present
Instance Variable	`_major_version`	the major version of this ZIM file
Instance Variable	`_mime_list_position`	offset to the mime type list
Instance Variable	`_minor_version`	the minor version of this ZIM file
Instance Variable	`_title_pointer_position`	offset tot he directory pointer list ordered by title
Instance Variable	`_url_pointer_position`	offset to the directory pointer list ordered by URL
Instance Variable	`_uuid`	uuid of the ZIM file

Inherited from ModifiableMixIn:

Method	`add_submodifiable`	Add another modifiable object as a child of this one.
Method	`after_flush_or_read`	This method should be called after this object has been read and/or flushed to disk. In other words, it should be called at least once whenever this object matches the state of the object on the disk.
Method	`dirty.setter`	Setter for `ModifiableMixIn.dirty`
Method	`ensure_mutable`	If this object is non-mutable, raise an Exception.
Method	`get_initial_disk_size`	Return the size of this object on disk as it has been read.
Method	`get_unmodified_disk_size`	Return the size of this object when written to a file before any modifications has been made since the last read/flush.
Method	`mark_dirty`	Convenience function to mark this object as dirty.
Method	`remove_submodifiable`	Remove a submodifiable from this object.
Instance Variable	`dirty`	True if this object or a sub-modifiable has been modified.
Instance Variable	`mutable`	if not nonzero, prevent modifications of this object.
Instance Variable	`_dirty`	a boolean flag that's nonzero if this object has been modified
Instance Variable	`_old_disk_size`	the size of this object on disk before any modifications since the last flush/read
Instance Variable	`_submodifiables`	a list of child objects, whose dirty state will affect this objects dirty state.

@classmethod

def from_bytes(cls, s): ¶

Construct a header from a bytestring.

Parameters
s:`bytes`	string to parse

Returns
`pyzim.header.Header`	the header parsed from the bytes

@classmethod

def from_file(cls, f, seek=None): ¶

Read the header from a file.

Parameters
f:file-like	file-like object to read from
seek:`int` or `None`	if specified, seek this position of the file before reading

Returns
`pyzim.header.Header`	the header read from the file

@classmethod

def placeholder(cls): ¶

Generate a placeholder header and return it.

A placeholder header is a header populated with some reasonable defaults as well as placeholder values. It is not usable for an actual ZIM file, but has the correct length. This makes it useful as part of the ZIM creation process.

Returns
`Header`	a placeholder header

def __init__(self, magic_number, major_version, minor_version, uuid, entry_count, cluster_count, url_pointer_position, title_pointer_position, cluster_pointer_position, mime_list_position, main_page, layout_page, checksum_position): ¶

overrides pyzim.modifiable.ModifiableMixIn.__init__

The default constructor.

The arguments are arranged in the same order as they appear in the ZIM header. This allows directly unpacking the header string into this constructor.

Parameters
magic_number:`int`	magic number of this ZIM file. If set to None (recommended), use default.
major_version:`int`	the major version of this ZIM file
minor_version:`int`	the minor version of this ZIM file
uuid:`int` or `bytes` or `uuid.UUID`	uuid of the ZIM file
entry_count:`int`	number of entries in the archive
cluster_count:`int`	number of clusters in the archive
url_pointer_position:`int`	offset to the directory pointer list ordered by URL
title_pointer_position:`int`	offset tot he directory pointer list ordered by title
cluster_pointer_position:`int`	offset to the cluster pointer list
mime_list_position:`int`	offset to the mime type list
main_page:`int`	index of the main page in the url pointer list, 0xffffffff if not present
layout_page:`int`	index of the layout page in the url pointer list, 0xffffffff if not present
checksum_position:`int`	offset to the checksum

def __str__(self): ¶

Return a string displaying the content of the header.

Returns
`str`	a string describing the header

def check_compatible(self): ¶

Check if this header is compatible, raising an exception if not.

Raises
`pyzim.exceptions.NotAZimFile`	when the provided file is not a ZIM file.
`pyzim.exceptions.IncompatibleZimFile`	when the ZIM file is not compatible

@checksum_position.setter

def checksum_position(self, value): ¶

The offset to the checksum.

Parameters
value:`int`	value to set

Raises
`TypeError`	if value is not an integer
`pyzim.exceptions.NonMutable`	if this header is set to be inmutable.
`ValueError`	if the value is invalid (e.g. negative)

@cluster_count.setter

def cluster_count(self, value): ¶

The number of clusters in this archive.

Parameters
value:`int`	value to set

Raises
`TypeError`	if value is not an integer
`pyzim.exceptions.NonMutable`	if this header is set to be inmutable.
`ValueError`	if the value is invalid (e.g. negative)

@cluster_pointer_position.setter

def cluster_pointer_position(self, value): ¶

The offset to the cluster pointer list.

Parameters
value:`int`	value to set

Raises
`TypeError`	if value is not an integer
`pyzim.exceptions.NonMutable`	if this header is set to be inmutable.
`ValueError`	if the value is invalid (e.g. negative)

@entry_count.setter

def entry_count(self, value): ¶

The number of entries in this archive.

Parameters
value:`int`	value to set

Raises
`TypeError`	if value is not an integer
`pyzim.exceptions.NonMutable`	if this header is set to be inmutable.
`ValueError`	if the value is invalid (e.g. negative)

def get_disk_size(self): ¶

overrides pyzim.modifiable.ModifiableMixIn.get_disk_size

Calculate the size of this object when written to a file.

NOTE: in this context, size refers to the direct size of the object. If this object contains references to other objects, their sizes will not be included. For example, a pyzim.entry.ContentEntry also links to a blob, but this function will only return the size of the entry itself, excluding the referenced blob.

Returns
`int`	the size, in bytes

@layout_page.setter

def layout_page(self, value): ¶

The index of the layout page in the url pointer list, None if not present.

Parameters
value:`int` or `None`	value to set

Raises
`TypeError`	if value is not an integer nor `None`
`pyzim.exceptions.NonMutable`	if this header is set to be inmutable.
`ValueError`	if the value is invalid (e.g. negative)

@magic_number.setter

def magic_number(self, value): ¶

The magic number of this ZIM file.

Parameters
value:`int`	value to set

Raises
`TypeError`	if value is not an integer
`pyzim.exceptions.NonMutable`	if this header is set to be inmutable.

@main_page.setter

def main_page(self, value): ¶

The index of the main page in the url pointer list, None if not present.

Parameters
value:`int` or `None`	value to set

Raises
`TypeError`	if value is not an integer nor `None`
`pyzim.exceptions.NonMutable`	if this header is set to be inmutable.
`ValueError`	if the value is invalid (e.g. negative)

@major_version.setter

def major_version(self, value): ¶

The major version of this ZIM file.

Parameters
value:`int`	value to set

Raises
`TypeError`	if value is not an integer
`pyzim.exceptions.NonMutable`	if this header is set to be inmutable.
`ValueError`	if the value is invalid (e.g. negative).

@mime_list_position.setter

def mime_list_position(self, value): ¶

The offset to the mime type list.

Parameters
value:`int`	value to set

Raises
`TypeError`	if value is not an integer
`pyzim.exceptions.NonMutable`	if this header is set to be inmutable.
`ValueError`	if the value is invalid (e.g. negative)

@minor_version.setter

def minor_version(self, value): ¶

The minor version of this ZIM file.

Parameters
value:`int`	value to set

Raises
`TypeError`	if value is not an integer
`pyzim.exceptions.NonMutable`	if this header is set to be inmutable.
`ValueError`	if the value is invalid (e.g. negative).

@title_pointer_position.setter

def title_pointer_position(self, value): ¶

The offset to the directory pointer list ordered by title.

Parameters
value:`int`	value to set

Raises
`TypeError`	if value is not an integer
`pyzim.exceptions.NonMutable`	if this header is set to be inmutable.
`ValueError`	if the value is invalid (e.g. negative)

def to_bytes(self): ¶

Dump this header into a bytestring.

Returns
`bytes`	a bytestring representation of this header.

def to_dict(self): ¶

Dump this header into a dictionary and return it.

Some values may be converted.

Returns
`dict`	a dictionary containing the information in this header

@url_pointer_position.setter

def url_pointer_position(self, value): ¶

The offset to the directory pointer list ordered by URL.

Parameters
value:`int`	value to set

Raises
`TypeError`	if value is not an integer
`pyzim.exceptions.NonMutable`	if this header is set to be inmutable.
`ValueError`	if the value is invalid (e.g. negative)