path: root/docs/manual.txt

The Nikola Handbook
===================

:Version: 5.4.2
:Author: Roberto Alsina <ralsina@netmanagers.com.ar>

.. class:: alert alert-info pull-right

.. contents::


All You Need to Know
--------------------

After you have Nikola installed:

Create a empty site:
    ``nikola init mysite``

You can create a site with demo files in it with ``nikola init mysite --demo``

The rest of these commands have to be executed inside the new ``mysite`` folder.

Create a post:
    ``nikola new_post``

Edit the post:
    The filename should be in the output of the previous command.

Build the site:
     ``nikola build``

Start the test server:
     ``nikola serve``

See the site:
     http://127.0.0.1:8000

That should get you going. If you want to know more, this manual will always be here
for you.

DON'T READ THIS MANUAL. IF YOU NEED TO READ IT I FAILED, JUST USE THE THING.

On the other hand, if anything about Nikola is not as obvious as it should be, by all
means tell me about it :-)

What's Nikola and what can you do with it?
------------------------------------------

Nikola is a static website and blog generator. The very short explanation is
that it takes some texts you wrote, and uses them to create a folder full
of HTML files. If you upload that folder to a server, you will have a
rather full-featured website, done with little effort.

It's original goal is to create blogs, but it supports most kind of sites, and
can be used as a CMS, as long as what you present to the user is your own content
instead of something the user generates.

Nikola can do:

* A blog (`example <http://lateral.netmanagers.com.ar>`__)
* Your company's site
* Your personal site
* A software project's site (`example <http://nikola.ralsina.com.ar>`__)
* A book's site

Since Nikola-based sites don't run any code on the server, there is no way to process
user input in forms.

Nikola can't do:

* Twitter
* Facebook
* An Issue tracker
* Anything with forms, really (except for comments_!)

Keep in mind that "static" doesn't mean **boring**. You can have animations, slides
or whatever fancy CSS/HTML5 thingie you like. It only means all that HTML is
generated already before being uploaded. On the other hand, Nikola sites will
tend to be content-heavy. What Nikola is good at is at putting what you write
out there.

Getting Help
------------

* Feel free to contact me at ralsina@netmanagers.com.ar for questions about Nikola.
* You can file bugs at `the issue tracker <http://code.google.com/p/nikola-generator/issues/list>`__
* You can discuss Nikola at the `nikola-discuss google group <http://groups.google.com/group/nikola-discuss>`_
* You can subscribe to `the Nikola Blog <http://nikola.ralsina.com.ar/blog>`_
* You can follow `Nikola on Twitter <https://twitter.com/#!/nikolagenerator>`_

Why Static?
-----------

Most "modern" websites are *dynamic* in the sense that the contents of the site
live in a database, and are converted into presentation-ready HTML only when a
user wants to see the page. That's great. However, it presents some minor issues
that static site generators try to solve.

In a static site, the whole site, every page, *everything*, is created before
the first user even sees it and uploaded to the server as a simple folder full
of HTML files (and images, CSS, etc).

So, let's see some reasons for using static sites:

Security
    Dynamic sites are prone to experience security issues. The solution for that
    is constant vigilance, keeping the software behind the site updated, and
    plain old good luck. The stack of software used to provide a static site,
    like those Nikola generates, is much smaller (Just a webserver).

    A smaller software stack implies less security risk.

Obsolescense
    If you create a site using (for example) Wordpress, what happens when Wordpress
    releases a new version? You have to update your Wordpress. That is not optional,
    because of security and support issues. If I release a new version of Nikola, and
    you don't update, *nothing* happens. You can continue to use the version you
    have now forever, no problems.

    Also, in the longer term, the very foundations of dynamic sites shift. Can you
    still deploy a blog software based on Django 0.96? What happens when your
    host stops supporting the php version you rely on? And so on.

    You may say those are long term issues, or that they won't matter for years. Well,
    I believe things should work forever, or as close to it as we can make them.
    Nikola's static output and its input files will work as long as you can install
    a Python > 2.6 in a Linux, Windows, or Mac and can find a server
    that sends files over HTTP. That's probably 10 or 15 years at least.

    Also, static sites are easily handled by the Internet Archive.

Cost and Performance
    On dynamic sites, every time a reader wants a page, a whole lot of database
    queries are made. Then a whole pile of code chews that data, and HTML is
    produced, which is sent to the user. All that requires CPU and memory.

    On a static site, the highly optimized HTTP server reads the file from disk
    (or, if it's a popular file, from disk cache), and sends it to the user. You could
    probably serve a bazillion (technical term) pageviews from a phone using
    static sites.

Lockin
    On server-side blog platforms, sometimes you can't export your own data, or
    it's in strange formats you can't use in other services. I have switched
    blogging platforms from Advogato to PyCs to two homebrewed systems, to Nikola,
    and have never lost a file, a URL, or a comment. That's because I have *always*
    had my own data in a format of my choice.

    With Nikola, you own your files, and you can do anything with them.

Features
--------

Nikola has a very defined featureset: it has every feature I needed for my own sites.
Hopefully, it will be enough for others, and anyway, I am open to suggestions.

If you want to create a blog or a site, Nikola provides:

* Front page (and older posts pages)
* RSS Feeds
* Pages and feeds for each tag you used
* Custom search
* Full yearly archives
* Custom output paths for generated pages
* Easy page template customization
* Static pages (not part of the blog)
* Internationalization support (my own blog is English/Spanish)
* Google sitemap generation
* Custom deployment (if it's a command, you can use it)
* A (very) basic look and feel you can customize, and is even text-mode friendly
* The input format is light markup (`reStructuredText <quickstart.html>`_ or
  `Markdown <http://daringfireball.net/projects/markdown/>`_)
* Easy-to-create image galleries
* Support for displaying source code
* Image slideshows
* Client-side cloud tags

Also:

* A preview webserver
* "Live" re-rendering while you edit
* "Smart" builds: only what changed gets rebuilt (usually in seconds)
* Easy to extend with minimal Python knowledge.

Installing Nikola
-----------------

This is currently lacking on detail. Considering the niche Nikola is aimed at,
I suspect that's not a problem yet. So, when I say "get", the specific details
of how to "get" something for your specific operating system are left to you.

The short version is: ``pip install https://github.com/ralsina/nikola/archive/master.zip``

Longer version:

#. Get `Nikola <http://nikola.ralsina.com.ar/>`_
#. Install dependencies. To do that, either:

   #. ``pip install -r requirements.txt`` or...
   #. Install your distribution's packages for all the things
      mentioned below, if they exist, or...
   #. Get all of these manually (but why?, use requirements.txt):

      #. Get python, if you don't have it.
      #. Get `doit <http://pydoit.org>`_
      #. Get `docutils <http://docutils.sf.net>`_
      #. Get `Mako <http://makotemplates.org>`_
      #. Get `PIL <http://www.pythonware.com/products/pil/>`_ (or Pillow)
      #. Get `Pygments <http://pygments.org/>`_
      #. Get `unidecode <http://pypi.python.org/pypi/Unidecode/>`_
      #. Get `lxml <http://lxml.de/>`_
      #. Get `yapsy <http://yapsy.sourceforge.net>`_
      #. Get `configparser <http://pypi.python.org/pypi/configparser/3.2.0r3>`_

#. run ``python setup.py install``

After that, run ``nikola init --demo sitename`` and that will create a folder called
``sitename`` containing a functional demo site.

Nikola is packaged for some Linux distributions, you may get that instead.

*NOTE*: If you get a ``ERROR: /bin/sh: 1: xslt-config: not found`` or ``fatal error:
libxml/xmlversion.h: No such file or directory`` when running ``pip install -r requirements.txt``, install *libxml* and *libxslt* libraries, like so:

Debian systems:

    sudo apt-get install libxml2-dev
    sudo apt-get install libxslt1-dev

RHEL systems:

    yum install libxslt-devel libxml2-devel

Getting Started
---------------

To create posts and pages in Nikola, you write them in one of the supported input formats.
Those source files are later converted to HTML
The recommended formats are restructured text and Markdown, but there is also support
for textile and WikiCreole and even for just writing HTML.

.. note:: There is a great `quick tutorial to learn restructured text. <quickstart.html>`_

First, let's see how you "build" your site. Nikola comes with a minimal site to get you started.

The tool used to do builds is called `doit <http://pydoit.org>`_, and it rebuilds the
files that are not up to date, so your site always reflects your latest content. To do our
first build, just run "nikola build"::

    $ nikola build
    Scanning posts  . . done!
    .  render_posts:stories/manual.html
    .  render_posts:posts/1.html
    .  render_posts:stories/1.html
    .  render_archive:output/2012/index.html
    .  render_archive:output/archive.html
    .  render_indexes:output/index.html
    .  render_pages:output/posts/welcome-to-nikola.html
    .  render_pages:output/stories/about-nikola.html
    .  render_pages:output/stories/handbook.html
    .  render_rss:output/rss.xml
    .  render_sources:output/stories/about-nikola.txt
    :
    :
    :

Nikola will print a line for every output file it generates. If we do it again, that
will be much much shorter::

    $ nikola build
    Scanning posts  . . done!

That is because `doit <http://pydoit.org>`_ is smart enough not to generate
all the pages again, unless you changed something that the page requires. So, if you change
the text of a post, or its title, that post page, and all index pages where it is mentioned,
will be recreated. If you change the post page template, then all the post pages will be rebuilt.

Nikola is mostly a series of doit *tasks*, and you can see them by doing ``nikola build list``::

    $ nikola build list
    Scanning posts  . . done!
    build_bundles
    copy_assets
    copy_files
    deploy
    redirect
    render_archive
    render_galleries
    render_indexes
    render_listings
    render_pages
    render_posts
    render_rss
    render_site
    render_sources
    render_tags
    sitemap

You can make Nikola redo everything by calling ``nikola build forget``, you can make it do just a specific
part of the site using task names, for example ``nikola build render_pages``, and even individual files like
``nikola build render_indexes:output/index.html``

Nikola also has other commands besides ``build``::

    $ nikola help
    Nikola
    Available commands:
      nikola auto            automatically execute tasks when a dependency changes
      nikola bootswatch_theme                Given a swatch name and a parent theme, creates a custom theme.
      nikola build           run tasks
      nikola check           Check links and files in the generated site.
      nikola clean           clean action / remove targets
      nikola console                 A short explanation.
      nikola deploy                  Deploy the site.
      nikola dumpdb                  dump dependency DB
      nikola forget                  clear successful run status from internal DB
      nikola help            show help
      nikola ignore                  ignore task (skip) on subsequent runs
      nikola import_blogger                  Import a blogger dump.
      nikola import_wordpress                Import a wordpress dump.
      nikola init            Create a Nikola site in the specified folder.
      nikola install_theme           Install theme into current site.
      nikola list            list tasks from dodo file
      nikola new_post                Create a new blog post or site page.
      nikola run             run tasks
      nikola serve           Start the test webserver.
      nikola strace                  use strace to list file_deps and targets

      nikola help              show help / reference
      nikola help <command>    show command usage
      nikola help <task-name>  show task usage

The ``serve`` command starts a web server so you can see the site you are creating::

    $ nikola serve
    Serving HTTP on 127.0.0.1 port 8000 ...


After you do this, you can point your web browser to http://localhost:8000 and you should see
the sample site. This is useful as a "preview" of your work.

By default, the ``serve`` command runs the web server on port 8000 on the IP address 127.0.0.1.
You can pass in an IP address and port number explicity using ``-a IP_ADDRESS``
(short version of ``--address``) or ``-p PORT_NUMBER`` (short version of ``--port``)
Example usage::

    $ nikola serve --address 0.0.0.0 --port 8080
    Serving HTTP on 0.0.0.0 port 8080 ...

Creating a Blog Post
--------------------

To create a new post, the easiest way is to run ``nikola new_post``. You  will
be asked for a title for your post, and it will tell you where the post's file
is located.

By default, that file will contain also some extra information about your post ("the metadata").
It can be placed in a separate file by using the ``-2`` option, but it's generally
easier to keep it in a single location.

The contents of your post have to be written (by default) in `restructured text <http://docutils.sf.net>`_
but you can use a lot of different markups using the ``-f`` option. Currently
Nikola supports bbcode, wiki, markdown, html, txt2tags and textile in addition
to restructured text.

You can control what markup compiler is used for each file extension with the ``post_compilers``
option. The default configuration expects them to be placed in ``posts`` but that can be
changed (see below, the post_pages option)

This is how it works::

    $ nikola new_post
    Creating New Post
    -----------------

    Enter title: How to make money
    Your post's text is at:  posts/how-to-make-money.txt

The content of that file is as follows::

    .. title: How to make money
    .. slug: how-to-make-money
    .. date: 2012/09/15 19:52:05
    .. tags:
    .. link:
    .. description:

    Write your post here.

The ``slug`` is the pagename. Since often titles will have
characters that look bad on URLs, it's generated as a "clean" version of the title.
The third line is the post's date, and is set to "now".

The other lines are optional. Tags are comma-separated. The ``link`` is an original
source for the content, and ``description`` is mostly useful for SEO.

You can add your own metadata fields in the same manner, if you use a theme that
supports them (for example: ``.. author: John Doe``)


.. note:: The Two-File Format

   Nikola originally used a separate ``.meta`` file. That will still work!
   The format of the meta files is the same as shown above, but without the
   explanations::

        How to make money
        how-to-make-money
        2012/09/15 19:52:05

If you are writing a multilingual site, you can also create a per-language
post file (for example: ``how-to-make-money.txt.es``). This one can have two
lines of metadata:

1) The translated title for the post or page
2) A translated version of the pagename

You can edit these files with your favourite text editor, and once you are happy
with the contents, generate the pages as explained in `Getting Started`_

Currently supported languages are

* Catalan
* English
* French
* German
* Greek
* Italian
* Polish
* Russian
* Simplified Chinese.
* Spanish

If you wish to add support for more languages, check out the instructions
at the `theming guide <http://nikola.ralsina.com.ar/theming.html>`_.

The post page is generated using the ``post.tmpl`` template, which you can use
to customize the output.

The place where the post will be placed by ``new_post`` is based on the ``post_pages``
configuration option::

    # post_pages contains (wildcard, destination, template, use_in_feed) tuples.
    #
    # The wildcard is used to generate a list of reSt source files (whatever/thing.txt)
    # That fragment must have an associated metadata file (whatever/thing.meta),
    # and opcionally translated files (example for spanish, with code "es"):
    #     whatever/thing.txt.es and whatever/thing.meta.es
    #
    # From those files, a set of HTML fragment files will be generated:
    # cache/whatever/thing.html (and maybe cache/whatever/thing.html.es)
    #
    # These files are combinated with the template to produce rendered
    # pages, which will be placed at
    # output / TRANSLATIONS[lang] / destination / pagename.html
    #
    # where "pagename" is specified in the metadata file.
    #
    # if use_in_feed is True, then those posts will be added to the site's
    # rss feeds.
    #
    post_pages = (
        ("posts/*.txt", "posts", "post.tmpl", True),
        ("stories/*.txt", "stories", "story.tmpl", False),
    )

It will use the first location that has the last parameter set to True, or the last
one in the list if all of them have it set to False.

The ``new_post`` command supports some options::

    $ nikola help new_post 
    Purpose: Create a new blog post or site page.
    Usage:   nikola new_post [options] [path]
    
    Options:
      -p, --page                Create a page instead of a blog post.
      -t ARG, --title=ARG       Title for the page/post.
      --tags=ARG                Comma-separated tags for the page/post.
      -1                        Create post with embedded metadata (single file format)
      -2                        Create post with separate metadata (two file format)
      -f ARG, --format=ARG      Markup format for post, one of rest, markdown, wiki, bbcode, html, textile, txt2tags

The optional ``path`` parameter tells nikola exactly where to put it instead of guessing from your config.
So, if you do ``nikola new_post posts/random/foo.txt`` you will have a post in that path, with
"foo" as its slug.

Teasers
~~~~~~~

You may not want to show the complete content of your posts either on your
index page or in RSS feeds, but to display instead only the beginning of them.

If it's the case, you only need to add a "magical comment" in your post.

In restructuredtext::

   .. TEASER_END

In Markdown::

   <!-- TEASER_END -->

By default all your RSS feeds will be shortened (they'll contain only teasers)
whereas your index page will still show complete posts. You can change
this behaviour with your ``conf.py``: ``INDEX_TEASERS`` defines whether index
page should display the whole contents or only teasers. ``RSS_TEASERS``
works the same way for your RSS feeds.

By default, teasers will include a "read more" link at the end. If you want to
change that text, you can use a custom teaser::

    .. TEASER_END: click to read the rest of the article

Drafts
~~~~~~

If you add a "draft" tag to a post, then it will not be shown in indexes and feeds.
It *will* be compiled, and if you deploy it it *will* be made available, so use
with care.


Creating a Page
---------------

Pages are the same as posts, except that:

* They are not added to the front page
* They don't appear on the RSS feed
* They use the ``story.tmpl`` template instead of ``post.tmpl`` by default

The default configuration expects the page's metadata and text files to be on the
``stories`` folder, but that can be changed (see post_pages option above).

You can create the page's files manually or use the ``new_post`` command
with the ``-p`` option, qhich will place the files in the folder that
has ``use_in_feed`` set to False.

Redirections
------------

If you need a page to be available in more than one place, you can define redirections
in your ``conf.py``::

    # A list of redirection tuples, [("foo/from.html", "/bar/to.html")].
    #
    # A HTML file will be created in output/foo/from.html that redirects
    # to the "/bar/to.html" URL. notice that the "from" side MUST be a
    # relative URL.
    #
    # If you don't need any of these, just set to []

    REDIRECTIONS = [("index.html", "/weblog/index.html")]

It's better if you can do these using your web server's configuration, but if
you can't, this will work.

Configuration
-------------

The configuration file is called ``conf.py`` and can be used to customize a lot of
what Nikola does. Its syntax is python, but if you don't know the language, it
still should not be terribly hard to grasp.

The default ``conf.py`` you get with Nikola should be fairly complete, and is quite
commented, but just in case, here is a full,
`customized example configuration <sampleconfig.html>`_ (the one I use for
`my site <http://lateral.netmanagers.com.ar>`_)

You surely want to edit these options::

    # Data about this site
    BLOG_TITLE = "Demo Site"
    BLOG_URL = "http://nikola.ralsina.com.ar"
    BLOG_EMAIL = "joe@demo.site"
    BLOG_DESCRIPTION = "This is a demo site for Nikola."


Customizing Your Site
---------------------

There are lots of things you can do to personalize your website, but let's see
the easy ones!

CSS tweaking
    The default configuration includes a file, ``themes/default/assets/css/custom.css``
    which is empty. Put your CSS there, for minimal disruption of the provided CSS files.

    If you feel tempted to touch other files in assets, you probably will be better off
    with a `custom theme <theming.html>`_.

Template tweaking
    If you really want to change the pages radically, you will want to do a
    `custom theme <theming.html>`_.


Sidebar
    ``LICENSE`` is a HTML snippet for things like a CC badge, or whatever you prefer.

    The 'sidebar_links' option lets you define what links go in the right-hand
    sidebar, so you can link to important pages, or to other sites.

    The ``SEARCH_FORM`` option contains the HTML code for a search form based on
    duckduckgo.com which should always work, but feel free to change it to
    something else.

Footer
    ``CONTENT_FOOTER`` is displayed, small at the bottom of all pages, I use it for
    the copyright notice.

Analytics
    This is probably a misleading name, but the ``ANALYTICS`` option lets you define
    a HTML snippet that will be added at the bottom of body. The main usage is
    a Google analytics snippet or something similar, but you can really put anything
    there.


Adding Files
------------

Any files you want to be in ``output/`` but are not generated by Nikola (for example,
``favicon.ico``, just put it in ``files/``. Everything there is copied into
``output`` by the ``copy_files`` task. Remember that you can't have files that collide
with files Nikola generates (it will give an error).

.. admonition:: Important

   Don't put any files manually in ``output/``. Ever. Really. Maybe someday Nikola
   will just wipe ``output/`` and then you will be sorry. So, please don't do that.

If you want to copy more than one folder of static files into ``output`` you can
change the FILES_FOLDERS option::

    # One or more folders containing files to be copied as-is into the output.
    # The format is a dictionary of "source" "relative destination".
    # Default is:
    # FILES_FOLDERS = {'files': '' }
    # Which means copy 'files' into 'output'

Getting More Themes
-------------------

There are not so many themes for Nikola. On occasion, I port something I like, and make
it available for download. Nikola has a builtin theme download/install mechanism, its
``install_theme`` command::

    $ nikola install_theme -l
    Themes:
    -------
    blogtxt
    readable

    $ nikola install_theme -n blogtxt
    Downloading: http://nikola.ralsina.com.ar/themes/blogtxt.zip
    Extracting: blogtxt into themes

And there you are, you now have themes/blogtxt installed. It's very rudimentary, but it
should work in most cases.

If you create a nice theme, please share it! You can post about it on
`the nikola forum <http://groups.google.com/group/nikola-discuss>`_ and I will
make it available for download.

One other option is to tweak an existing theme using a different color scheme,
typography and CSS in general. Nikola provides a ``bootswatch_theme`` option
to create a custom theme by downloading free CSS files from http://bootswatch.com::

    $ nikola bootswatch_theme -n custom_theme -s spruce -p site
    Creating 'custom_theme' theme from 'spruce' and 'site'
    Downloading:  http://bootswatch.com/spruce/bootstrap.min.css
    Downloading:  http://bootswatch.com/spruce/bootstrap.css
    Theme created. Change the THEME setting to "custom_theme" to use it.

You can even try what different swatches do on an existing site using
their handy `bootswatchlet <http://news.bootswatch.com/post/29555952123/a-bookmarklet-for-bootswatch>`_

Play with it, there's cool stuff there. This feature was suggested by
`clodo <http://elgalpondebanquito.com.ar>`_.

Deployment
----------

Nikola doesn't really have a concept of deployment. However, if you can specify your
deployment procedure as a series of commands, you can put them in the ``DEPLOY_COMMANDS``
option, and run them with ``nikola deploy``.

One caveat is that if any command has a % in it, you should double them.

Here is an example, from my own site's deployment script::

    DEPLOY_COMMANDS = [
        'rsync -rav --delete output/* ralsina@lateral.netmanagers.com.ar:/srv/www/lateral',
        'rdiff-backup output ~/bartleblog-backup',
        "links -dump 'http://www.twingly.com/ping2?url=lateral.netmanagers.com.ar'",
        'rsync -rav ~/bartleblog-backup/* ralsina@netmanagers.com.ar:bartleblog-backup',
    ]

Other interesting ideas are using
`git as a deployment mechanism <http://toroid.org/ams/git-website-howto>`_ (or any other VCS
for that matter), using `lftp mirror <http://lftp.yar.ru/>`_ or unison, or dropbox, or
Ubuntu One. Any way you can think of to copy files from one place to another is good enough.

Comments
--------

While Nikola creates static sites, there is a minimum level of user interaction you
are probably expecting: comments.

The default templates contain support for `Disqus <http://disqus.com>`_. All you have
to do is register a forum, put its short name in the ``DISQUS_FORUM`` option.

Disqus is a good option because:

1) It doesn't require any server-side software on your site
2) They offer you a way to export your comments, so you can take
   them with you if you need to.
3) It's free.
4) It's damn nice.

.. admonition:: Important

   In some cases, when you run the test site, you won't see the comments.
   That can be fixed by adding the disqus_developer flag to the templates
   but it's probably more trouble than it's worth.


Image Galleries
---------------

To create an image gallery, all you have to do is add a folder inside ``galleries``,
and put images there. Nikola will take care of creating thumbnails, index page, etc.

If you click on images on a gallery, you should see a bigger image, thanks to
the excellent `colorbox <http://www.jacklmoore.com/colorbox>`_

The gallery pages are generated using the ``gallery.tmpl`` template, and you can
customize it there (you could switch to another lightbox instead of colorbox, change
its settings, change the layout, etc.).

The ``conf.py`` options affecting gallery pages are these::

    # Galleries are folders in galleries/
    # Final location of galleries will be output / GALLERY_PATH / gallery_name
    GALLERY_PATH = "galleries"
    THUMBNAIL_SIZE = 180
    MAX_IMAGE_SIZE = 1280
    USE_FILENAME_AS_TITLE = True

If you add a file in ``galleries/gallery_name/index.txt`` its contents will be
converted to HTML and inserted above the images in the gallery page.

If you add some image filenames in ``galleries/gallery_name/exclude.meta``, they
will be excluded in the gallery page.

If ``USE_FILENAME_AS_TITLE`` is True the filename (parsed as a readable string)
is used as the photo caption. If the filename starts with a number, it will
be stripped. For example ``03_an_amazing_sunrise.jpg`` will be render as *An amazing sunrise*.

Here is a `demo gallery </galleries/demo>`_ of historic, public domain Nikola
Tesla pictures taken from `this site <http://kerryr.net/pioneers/gallery/tesla.htm>`_.

Post Processing Filters
-----------------------

You can apply post processing to the files in your site, in order to optimize them
or change them in arbitrary ways. For example, you may want to compress all CSS
and JS files using yui-compressor.

To do that, you can use the provided helper adding this in your ``config.py``::

  from nikola import filters

  FILTERS = {
    ".css": [filters.yui_compressor],
    ".js": [filters.yui_compressor],
  }

Where ``filters.yui_compressor`` is a helper function provided by Nikola. You can
replace that with strings describing command lines, or arbitrary python functions.

If there's any specific thing you expect to be generally useful as a filter, contact
me and I will add it to the filters library so that more people use it.

Optimizing Your Website
-----------------------

One of the main goals of Nikola is to make your site fast and light. So here are a few
tips we have found when setting up Nikola with Apache. If you have more, or
different ones, or about other webservers, please share!

#. Use a speed testing tool. I used Yahoo's YSlow but you can use any of them, and
   it's probably a good idea to use more than one.

#. Enable compression in Apache::

      AddOutputFilterByType DEFLATE text/html text/plain text/xml text/css

#. If even after you did the previous step the CSS files are not sent compressed::

      AddType text/css .css

#. Optionally you can greate static compressed copies and save some CPU on your server
   with the GZIP_FILES option in Nikola. 

#. The webassets Nikola plugin can drastically decrease the number of CSS and JS files your site fetches.

#. Through the filters feature, you can run your files through arbitrary commands, so that images
   are recompressed, Javascript is minimized, etc.

#. The USE_CDN option offloads standard Javascript and CSS files to a CDN so they are not
   downloaded from your server.

Restructured Text Extensions
----------------------------

Nikola includes support for a few directives that are not part of docutils, but which
we think are handy for website development.

Youtube
~~~~~~~

To link to a youtube video, you need the id of the video. For example, if the
URL of the video is http://www.youtube.com/watch?v=8N_tupPBtWQ what you need is
**8N_tupPBtWQ**

Once you have that, all you need to do is::

    .. youtube:: 8N_tupPBtWQ

Vimeo
~~~~~

To link to a vimeo video, you need the id of the video. For example, if the
URL of the video is http://www.vimeo.com/20241459 then the id is **20241459**

Once you have that, all you need to do is::

    .. vimeo:: 20241459

If you are running python 2.6 or later, or have the json module installed and
have internet connectivity when generating your site, the height and width of
the embedded player will be set to the native height and width of the video.
You can override this if you wish::

    .. vimeo:: 20241459
        height=240
        width=320

Soundcloud
~~~~~~~~~~

This directive lets you share music from http://soundcloud.com You first need to get the
ID for the piece, which you can find in the "share" link. For example, if the
Wordpress code starts like this::

    [soundcloud url="http://api.soundcloud.com/tracks/78131362"

The ID is 78131362 and you can embed the audio with this::

    .. soundcloud:: 78131362

code-block
~~~~~~~~~~

This is a somewhat complicated directive to display code nicely. You can just
embed code like this::

    .. code-block:: python

        print "Hello World!"

Or you can include the code from a file::

    .. code-block:: python
       :include: /foo/bar/baz.py

listing
~~~~~~~

To use this, you have to put your source code files inside ``listings`` or whatever your
``LISTINGS_FOLDER`` variable is set to. Assuming you have a ``foo.py`` inside that folder::

    .. listing:: foo.py python

Will include the source code from ``foo.py``, highlight its syntax in python mode,
and also create a ``listings/foo.py.html`` page and the listing will have a title linking to it.

Advanced Code Options
~~~~~~~~~~~~~~~~~~~~~

Both code-block and listing support a number of options, including these:

start-at
    A string, the diplayed code will start when it finds this
end-at
    A string, the diplayed code will end when it finds this
start-after
    A string, the diplayed code will start in the line after this
end-before
    A string, the diplayed code will end in the line before this
linenos
    Display line numbers
linenos_offset
    Use the original file's line numbers (warning: broken)
tab-width
    Size of the tabs (default 4)

gist
~~~~

You can easily embed GitHub gists with this directive, like this::

    .. gist:: 2395294

Producing this:

.. gist:: 2395294

This degrades gracefully if the browser doesn't support javascript.

Slideshows
~~~~~~~~~~

To create an image slideshow, you can use the ``slides`` directive. For example::

    .. slides::
       :preload:
       :play: 350

       /galleries/demo/tesla_conducts_lg.jpg
       /galleries/demo/tesla_lightning2_lg.jpg
       /galleries/demo/tesla4_lg.jpg
       /galleries/demo/tesla_lightning1_lg.jpg
       /galleries/demo/tesla_tower1_lg.jpg

This is based on `slidejs <http://slidesjs.com/>`_ and it supports
`the options described there <http://slidesjs.com/#options>`_ with one minor tweak to make them
fit in docutils convention: If the option takes a boolean value, you just have to add it or not. For example,
to enable preloading, just use the ``:preload:`` option.

If the option takes any other kind of argument, just use it after the option, like ``play`` in the
above example.

Importing Your Wordpress Site Into Nikola
-----------------------------------------

If you like Nikola, and want to start using it, but you have a Wordpress blog, Nikola
supports importing it. Here's the steps to do it:

1) Get a XML dump of your site [#]_
2) nikola import_wordpress -f mysite.wordpress.2012-12-20.xml

After some time, this will crate a ``new_site`` folder with all your data. It currently supports
the following:

* All your posts and pages
* Keeps "draft" status
* Your tags and categories
* Imports your attachments and fixes links to point to the right places
* Will try to add redirects that send the old post URLs to the new ones
* Will give you a url_map so you know where each old post was

  This is also useful for Disqus thread migration!

* Will try to convert the content of your posts. This is *not* error free, because
  wordpress uses some unholy  mix of HTML and strange things. Currently we are treating it
  as markdown, which does a reasonabe job of it.

  You will find your old posts in ``new_site/posts/post-title.wp`` in case you need to fix
  any of them.

This feature is a work in progress, and the only way to improve it is to have it used for
as many sites as possible and make it work better each time, so I am happy to get requests
about it.

.. [#] The dump needs to be in 1.2 format. You can check by reading it, it should say
       ``xmlns:excerpt="http://wordpress.org/export/1.2/excerpt/"`` near the top of the
       file. If it says ``1.1`` instead of ``1.2`` you will have to update your
       wordpress before dumping.

       Other versions may or may not work.

Importing To A Custom Location Or Into An Existing Site
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

It is possible to either import into a location you desire or into an already existing Nikola site.
To do so you can specify a location after the dump.::

    $ nikola import_wordpress -f mysite.wordpress.2012-12-20.xml -o import_location

With this command Nikola will import into the folder ``import_location``.

If the folder already exists Nikola will not overwrite an existing ``conf.py``.
Instead a new file with a timestamp at the end of the filename will be created.

Using Twitter Cards
-------------------

Twitter Cards enable you to show additional information in Tweets that link
to you content.
Nikola supports `Twitter Cards <https://dev.twitter.com/docs/cards>`_.
They are implemented to use *Open Graph* tags whenever possible.

.. admonition:: Important

    To use Twitter Cards you need to opt-in on Twitter.
    To do so please use the form that can be found at https://dev.twitter.com/form/participate-twitter-cards

To enable and configure your use of Twitter Cards please modify the
corresponding lines in your ``conf.py``.
An example configuration that uses the Twitter nickname of the website
and the authors Twitter user ID is found below.

.. code-block:: Python

    TWITTER_CARD = {
        'use_twitter_cards': True,  # enable Twitter Cards / Open Graph
        'site': '@website',  # twitter nick for the website
        # 'site:id': 123456,  # Same as site, but the website's Twitter user ID instead.
        # 'creator': '@username',  # Username for the content creator / author.
        'creator:id': 654321,  # Same as creator, but the Twitter user's ID.
    }

License
-------

Nikola is released under a `MIT license <https://github.com/ralsina/nikola/blob/master/LICENSE.txt>`_ which
is a free software license. Some components shipped along with Nikola, or required by it are
released under other licenses.

If you are not familiar with free software licensing: In general, you should be able to
do pretty much anything you want, unless you modify Nikola. If you modify it, and share
it with someone else, that someone else should get all your modifications under the same
license you got it.