App::Followme::Guide - How to install, configure, and run followme
Updates a static website after changes. Constant portions of each page are updated to match, text files are converted to html, and indexes are created for files in the archive.
The followme script is run on the directory or file passed as its argument. If no argument is given, it is run on the current directory.
If a file is passed, the script is run on the directory the file is in. In addition, the script is run in quick mode, meaning that only the directory the file is in is checked for changes. Otherwise, not only that directory, but all directories below it are checked.
This version is the first beta release for version two of followme. The code changes have been made and pass test, but I need to update the documentation to match the code changes. The major changes are all internal. In the past the code qconstructed a hash and passed it to the template, which used the values in the hash to produce the web page. In version two the code passes an object to the template, which calls the build method for each vaiable in the template, passing the name of the variable and a filename to retrieve it from as arguments. The module then returns the value, which is used to fill in the template. The major user visible change is that the template syntax has changed, the new syntax is a subset of the previous syntax. Please see App::Followme::Template for a description of the template syntax. The other change is that the configuration parameters of some of the modules has changed. The new configuration parameters are described in each module. The motivation for the change is that placing the variable building in a separate class allows more than one type of file to be handled by modules placed in the configurarion file. Each class handles a type of file and the name of the class which builds the variables is a configuration parameter.
The beta release will be used to build a website documenting followme and the process of building the site will be used to debug any remaining problems. When this process is finished, the version will be bumped to 2.00.
First, install the App::Followme module from CPAN. It will copy the followme script to /usr/local/bin, so it will be on your search path.
sudo cpanm App::Followme
Then create a folder to contain the new website. Run followme with the init option in that directory
mkdir website cd website followme --init
When you run followme with the --init flag, it will install the initial templates and configuration files. The initial setup is configured to update pages to maintain a consistent look for the site and simplify the onboarding of new content.
The first page will serve as a prototype for the rest of your site. When you look at the html page, you will see that it contains comments looking like
<!-- section primary --> <!-- endsection primary -->
These comments mark the parts of the prototype that will change from page to page from the parts that are constant across the entire site. Everything outside the comments is the constant portion of the page. When you have more than one html page in the folder, you can edit any page, run followme, and the other pages will be updated to match it.
So you should edit your first page and add any other files you need to create the look of your site, such as the style sheets.
You can also use followme on an existing site. Run the command
in the top directory of your site. The init option will not overwrite any existing files in your site. Then look at the page template it has created:
Edit an existing page on your site to have all the section comments in this template. In the template shipped with this package there are three section names: meta, primary, and secondary. The meta section is in the html header and contains the page metadata, although it may also contain other content tht varies between pages. The primary section contains the page content that is maintained by you. None of this package's modules will change it. The secondary section contains content that is updated by the modules in this package and you will not normally change it.
After you edit a single page, you can place the App::Followme::EditSections module in the configuration file, as described in the next section. If you then run followme, it will modify the other pages on your website to match the page you have edited. Then remove the EditSections module from the configuration file.
The configuration file for followme is followme.cfg in the top directory of your site. Configuration file lines are organized as lines containing
NAME = VALUE
pairs. Configuration files may also contain blank lines or comment lines starting with a
#. Subdirectories of the top directory may also contain configuration files. Values in these configuration files are combined with those set in the configuration files in directories above it, If it has a parameter of the same name as a configuration file in a higher directory, it overrides it for that directory and its subdirectories.
Configuration files contain the names of the Perl modules to be run by followme in the parameters named run_before and run_after
run_before = App::Followme::FormatPage run_before = App::Followme::ConvertPage run_after = App::Followme::CreateSitemap
Perl modules are run in the order they appear in the configuration file. If they are named run_before then they are run before modules in any configuration files contained in subdirectories. If they are named run_after, they are run after modules which are named in the configuration files in subdirectories. Other parameters in the configuration files are written to a hash. This hash is passed to the new method of each module as it loaded, overriding the default values of the parameters when creating the new object.
Configuration files may also contain module names between square brackets, like this:
Values after a bracketed module name will only apply to that module. Values at the top of the file, before any bracketed module name, will apply to all modules. The run_before and run_after parameters should always be placed before any bracketed section names.
These modules are distributed with followme:
This module updates the web pages in a folder to match the most recently modified page. Each web page has sections that are different from other pages and other sections that are the same. The sections that differ are enclosed in html comments that look like
<!-- section name--> <!-- endsection name -->
and indicate where the section begins and ends. When a page is changed, this module checks the text outside of these comments. If that text has changed. the other pages on the site are also changed to match the page that has changed. Each page updated by substituting all its named blocks into corresponding block in the changed page. The effect is that all the text outside the named blocks are updated to be the same across all the web pages.
In addition to normal section blocks, there are per folder section blocks. The contents of these blocks is kept constant across all files in a folder and all subfolders of it. If the block is changed in one file in the folder, it will be updated in all the other files. Per folder section blocks look like
<!-- section name in folder_name --> <!-- endsection name -->
where folder_name is the the folder the content is kept constant across. The folder name is not a full path, it is the last folder in the path.
This module changes Markdown files to html files. Markdown format is described at:
It builds several variables and substitutes them into the page template. The most significant variable is body, which is the contents of the text file after it has been converted by Markdown. The title is built from the title of the Markdown file if one is put at the top of the file. If the file has no title, it is built from the file name, replacing dashes with blanks and capitalizing each word, The url and absolute_url are built from the html file name. To change the look of the html page, edit the page template. Only blocks inside the section comments will be in the resulting page, editing the text outside it will have no effect on the resulting page.
This module builds an index for a directory containing links to all the files with the specified extension contained in it. The same variables mentioned above are calculated for each file, with the exception of body. Comments that look like
<!-- for @filenames --> <!-- endfor -->
indicate the section of the template that is repeated for each file contained in the index.
This module generates an html file from the most recently updated files in the news directory. It also creates index files in each directory and subdirectory in the news directory. The same variables mentioned under App::Followme::ConvertPages are calculated for each file included in the indexes.
This module creates a sitemap file, which is a text file containing the url of every page on the site, one per line. It is also intended as a simple example of how to write a module that can be run by followme.
This module uploads changed files to a remote site. The default method to do the uploads is local copy, but that can be changed by changing the parameter upload_pkg. This package computes a checksum for every file in the site. If the checksum has changed since the last time it was run, the file is uploaded to the remote site. If there is a checksum, but no local file, the file is deleted from the remote site. If followme is run in quick mode, only files whose modification date is later then the last time it was run are checked.
The followme script is run on the directory or file passed as its argument. If no argument is given, it is run on the current directory. If a file is passed, the script is run on the directory the file is in and followme is run in quick mode. Quick mode is an implicit promise that only the named file has been changed since last time. Each module can make up this assumption what it will, but it is supposed to shorten the list of files examined.
Followme looks for its configuration files in all the directories above the directory it is run from and runs all the modules it finds in them. But they are are only run on the folder it is run from and subfolders of it. Followme only looks at the folder it is run from to determine if other files in the folder need to be updated. So after changing a file, followme should be run from the directory containing the file. Templates support the basic control structures in Perl: "for" loops and "if-else" blocks. Creating output is a two step process. First you generate a subroutine from one or more templates, then you call the subroutine with your data to generate the output.
The template format is line oriented. Commands are enclosed in html comments (<!-- -->). A command may be preceded by white space. If a command is a block command, it is terminated by the word "end" followed by the command name. For example, the "for" command is terminated by an "endfor" command and the "if" command by an "endif" command.
All lines may contain variables. As in Perl, variables are a sigil character ('$' or '@') followed by one or more word characters. For example,
@names. To indicate a literal character instead of a variable, precede the sigil with a backslash. When you run the subroutine that this module generates, you pass it a metadata object. The subroutine replaces variables in the template with the value in the field built by the metadata object.
If the first non-white characters on a line are the command start string, the line is interpreted as a command. The command name continues up to the first white space character. The text following the initial span of white space is the command argument. The argument continues up to the command end string.
Variables in the template have the same format as ordinary Perl variables, a string of word characters starting with a sigil character. for example,
are examples of variables. The following commands are supported in templates:
The remainder of the line is interpreted as Perl code.
Expand the text between the "for" and "endfor" commands several times. The argument to the "for" command should be an expression evaluating to a list. The code will expand the text in the for block once for each element in the list.
<ul> <!-- for @files --> <li><a href="$url">$title</a></li> <!-- endfor --> </ul>
The text until the matching
endif is included only if the expression in the "if" command is true. If false, the text is skipped.
<div class="column"> <!-- for @files --> <!-- if $count % 20 == 0 --> </div> <div class="column"> <!-- endif --> $title<br /> <!-- endfor --> </div>
The "if" and "for" commands can contain an
else. The text beforethe "else" is included if the expression in the enclosing command is true and the text after the "else" is included if the "if" command is false or the "for" command does not execute. You can also place an "elsif" command inside a block, which includes the following text if its expression is true.
Templates are read either from the same directory as the configuration file containing the name of the module being run or from the _templates subdirectory of the top directory of the site.
New modules can be written and then invoked via the configuration file, exactly like the modules that have been distributed with App::Followme. Each module to be run must have new and run methods. An object of the module's class is created by calling the new method with the a reference to a hash containing the configuration parameters. The run method is then called with the directory as its argument.
The signature of the new method is
$obj = $module_name->new($configuration);
where $configuration is a reference to a hash containing the configuration parameters. $module name is the same as the name in the configuration file.
All the modules distributed with App::Followme subclass App::Followme::Module to access its methods, which provide consistent behavior, such as looping over files and template handling. It also supplies a new method, so if you subclass it, you will not need to supply a new method in your class.
The signature of the run method is
where $obj is the object created by the new method and $directory is the name of the directory the module is being run on. All modules included in App::Followme use App::Followme::Module as a base class, so they can use its methods, such as visiting all files in a directory and compiling a template. If you wish to write your own module, you can use App::Followme::Sitemap as a guide. If you use App::Followme::Module as a base class, you should not supply your own new method, but rely on the new method in App::Followme::ConfiguredObject, which you will inherit.
Copyright (C) Bernie Simon.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
Bernie Simon <firstname.lastname@example.org>