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, indexes are created for files in the archive, and changed files are uploaded to the remote server.
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 a beta release for version two of followme. In the past the code constructed 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 variable 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 second 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 third change is that the configuration file format has changed to use a subset of yaml. The new configuration file format is decribed below.
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 convert 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, after the run_efore line:
run_before: - App::Followme::EditSections - App::Followme::FormatPage - App::Followme::ConvertPage
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 in a subset of yaml format. The format is described in App::Followme::NestedText. Briefy, the top level is a hash, with name-value pairs in the format
There should be no space between the name and the colon and one space between the colon and value. The value may also be an array. The array elements are listed one per line preceded by a dash:
name: - first value - second value
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. These parameters should be arrays, and thus are listed one per line indented from the field name and preceded by a dash:
run_before: - App::Followme::FormatPage - 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.
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. A complete listing of the variables is given in the variables section.
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 @files --> <!-- endfor -->
indicate the section of the template that is repeated for each file contained in the index.
Create a photo gallery for images in a directory. Each image must have a thumbnail image whose name has the suffix "-thumb". The suffix name is a configuration parameter. The code is very similar to App::Followme::CreateIndex, but the template is more complex, so it is a separate module.
This module creates an rss file from the metadata of the most recently updated files in a directory. It is a companion to App::Followme::CreateIndex and should be used if you also want an rss file.
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 of 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. Array variable names (variable names starting with a
@) may have a suffix that indicates how the array is sorted. You can add a suffix to a scalar variable (variable names strting with a
$) but it will have no effect. The format for the name is:
the brackets are not part of the variable name. They are there to indicate that these sections are optional. Two examples of variables with sort suffixes are
The second suffix, _reversed, indicates that the variable is sorted from largest to smallest instead of the usual format, from smallest to largest. When used with date fields _reversed indicates the variable is sorted from most recent to oldest.
The following commands are supported in templates:
The remainder of the line is interpreted as Perl code.
Expand the text between the "for" and "endfor" commands several times. The argument to the "for" command should be an expression evaluating to a list. The code will expand the text in the for block once for each element in the list.
<ul> <!-- for @files --> <li><a href="$url">$title</a></li> <!-- endfor --> </ul>
The text until the matching
endifis 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 before the "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. For more information about the use of templates, see App::Followme::Template.
Templates contain if commands, for loops and variables. The following variables are arrays that can be used as arguments to for loops:
An array of files in a directory. The files in the list are controlled by the configuration variables extension, exclude, and exclude_index.
An array of all files in a directory and its subdirectories. The files are controlled by the same configuration variables as @files.
An array of the most recently modified files in a directory and its subdirectories. The number of files in the array is controlled by configuration variable list_length. The files in the list are controlled by the same configuration variables as used by @files.
An array of subdirectories in a directory. The subdirectories in the list are controlled by the configuration parameter exclude_dirs.
An array of index file urls of the directories above the directory containing the current file.
A list of files with the same file root name as a specified file. This list is not filtered by the configuration variables extension and exclude.
An array with one element, the most recently modified file in a directory or its subdirectories. It is an array so that other variables can be used inside its for loop.
The following variables can only be used inside of loops:
A copy of the array in the enclosing for loop. This is used to build double for loops over the same array.
An array with only one element, the name of the thumbnail file for an image file. It is an array so that other variables that are functions of the name can be used inside its for loop.
True for the first pass through the for loop, false for all following passes. Used in if statements.
True for the last pass through the for loop, false for all previous passes. Used in if statements.
The count of the pass through the loop. Starts at one and goes up to the number of elements in the array.
The count prefixed by a string, which is set by the configuration variable target_prefix. It is used to construct tatgets for links within a web page.
The count of the previous pass through the for loop, prefixed by the configuration variable target_prefix. It is a zero length string for the first pass through the loop.
The count of the next pass through the for loop, prefixed by the configuration variable target_prefix. It is a zero length string for the last pass through the loop.
The relative url of the previous file processed by the for loop. It is a zero length string for the first pass through the for loop.
The relative url of the next file to be processed by the for loop. It is a zero length string for the last pass through the for loop.
The following variables can be used inside or outside of for loop. If used inside, the refer to the filename of the current iteration of the loop. If outside, they refer to the current file being processed.
The absolute url of the top folder on the site on the remote system. Set by the configuration variable of the same name.
The absolute url of the top folder on the site on the local system. Set by the configuration variable of the same name. If the configuration variable is not set, it is constructed from the name of the top folder of the site.
The url of a file, relative to the url of the top folder.
The relative url of the index file in the same folder
The relative url of a file prefixed by the site url.
The relative url of a file without any file extension. Used to create the urls of any related files.
The name of a file.
The extension of a filename.
True if a file is an index file, that is, its name minus the extension is "index". Used in if statements.
The creation date of a file, if available, the date of last modification, if not. The format of this variable is set by the configuration variable date_format.
The date of last modification of a file. The format of this variable is set by the configuration variable date_format.
The size of the file in bytes.
The title of a file. Constructed from the filename if it is not otherwise available.
The body text of a file.
A summary of the file, constructed from the first paragraph of the body.
A description of the contents of the file, constructed from the first sentence of the body if it is not otherwise available.
A comma separated list of keywords describing a file. Constructed from the name of the folder containing the file if it is not otherwise available.
The name of the author of a file. Taken from the configuration variable of the same name if it is not otherwise available.
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::CreateSitemap 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>