ephemeris

• Ephemeris
• Installation
• Blog Generation
  • Blog Format
• Demo Blog
• Hacking
• Feedback

Ephemeris

ephemeris is a golang CLI-application which will generate a blog from a collection of static text-files, complete with:

• An archive-view.
  • Showing posts by year, and month.
• Comment support.
  • See COMMENTS.md for more details on the setup required.
• A tag-cloud.
  • Containing all tags, and a list of posts using a specified tag.
• An RSS feed.
  • Containing the most recent ten posts.
  • Full text is included in the feed.

The project was primarily written to generate my own blog, which was previously generated with the perl-based chronicle blog compiler - if you've used chronicle you may consult the brief notes on migration.

Installation

You can install from source, by cloning the repository and running:

$ cd ephemeris/cmd/ephemeris
$ go build .
$ go install .

Or if you just wish to install the binary:

$ go install github.com/skx/ephemeris/cmd/ephemeris@latest

Alternatively you may find precompiled binaries available for many systems upon the release page.

Blog Generation

A blog is generated from two things:

• A series of blog-posts, stored beneath a given directory.
• An optional set of comments, which are plaintext files associated with a given blog-post.

To build/generate/create your blog you need to create a configuration file that contains the appropriate directories. The configuration file is assumed to be named ephemeris.json in the current-directory, and a sample configuration file would look like this:

    {
      "CommentsPath":  "./comments/",
      "OutputPath":    "./output/",
      "PostsPath":     "./posts/",
      "Prefix":        "http://blog.steve.fi/"
    }

Once you have a configuration file simply run the command to compile and generate your blog:

$ ephemeris

As expected the generated output will be placed beneath the output/ directory. The possible configuration-keys in the JSON file are:

• PostsPath - Mandatory
  • This is the path to the directory containing your blog-posts.
  • This directory will be searched recursively for content.
• CommentAPI
  • The URL of the CGI script to receive comments, this is used in the add-comment form.
    • See COMMENTS.md for a discussion of comments.
• CommentsPath
  • This is the path to the directory containing your comments.
  • If this is empty then no comments will be read/inserted into your output
  • See COMMENTS.md for a discussion of comments.
• OutputPath
  • The path beneath which all output content should be written.
  • This defaults to output/ if not specified.
• Prefix - Mandatory
  • This is the URL-prefix used to generate all links.
• ThemePath
  • This is the path to a local theme you're using, if you don't wish to use the default theme embedded within the binary.
  • See the theming section in this document for more details.

There is a command-line flag which lets you specify an alternative configuration-file, if you do not wish to use the default. Run ephemeris -help to see details.

Blog Format

The input to this program is a directory tree containing a series of blog-posts. Each post will be stored in a single file, with the entry being prefixed by a simple header containing meta-data.

A sample post would look like this:

Tags: compilers, assembly, golang, brainfuck
Date: 14/06/2020 19:00
Subject: Writing a brainfuck compiler.
Format: markdown

So last night I had the idea..

There are a few things to note here:

• The header and the content are separated by a single blank line.
• The date MUST be in the specified format.
• If there is no format: markdown header then the body will be assumed to be HTML.
  • All my early posts were written in HTML.
  • Later I switched to markdown.

As noted the input directory will be processed recursively, which allows you to group posts by topic, year, or in any other way you might prefer. I personally file my entries by year, like so:

data/
  ├── 2005
  | ├── 1.txt
  | └── 2.txt
  ├── 2006
  | ├── 3.txt
  | └── 4.txt
  ..
  ├── 2018
  | ├── 5.txt
  | └── 6.txt
  ├── 2019
  | ├── 7.txt
  | └── 8.txt
  └── 2020
    ├── 9.txt
    ├── 10.txt
    └── 11.txt

Demo Blog

There is a demo-blog contained within this repository, along with a lightly-modified theme. To compile the blog into a set of HTML output-pages simple change into the appropriate directory and run the command:

$ cd _demo
$ ephemeris

This will generate ./output/. As you can see from the configuration file the blog will have an URL-prefix of http://localhost:8000 so you can try serving it with a local webserver on that port to view it in your browser:

cd output/
python -m SimpleHTTPServer 8000

Once the simple HTTP-server is running open http://localhost:8000/ with your browser to see the compiled/generated result.

Theming

The main binary contains an embedded set of text/template resources which are used to generate the output blog. If you wished to update those static-resources you'd need to edit the application-source and rebuild it which is a bit cumbersome, and future releases would almost certainly overwrite your changes.

Instead of having to rebuild the application to change the generated output you can use a local directory of templates instead of the embedded resources.

To get started you should export the default templates to a local directory:

ephemeris -export-theme=./blog-theme/

This will give you the following contents:

blog-theme/
├── archive_page.tmpl
├── archive.tmpl
├── entry.tmpl
├── inc
│   ├── add_comment_form.tmpl
│   ├── blog_post.tmpl
│   ├── comments_on_blog_post.tmpl
│   ├── css.tmpl
│   ├── recent_posts.tmpl
│   └── rss.tmpl
├── index.rss
├── index.tmpl
├── tag_page.tmpl
└── tags.tmpl

1 directory, 13 files

Now that you have the local templates available you can edit them, changing the text and layout as you wish, and specify that local directory as the ThemePath in your ephemeris.json configuration file.

• NOTE: The templates are processed using the standard golang text/template package.

Feedback

This project is not documented to my usual and preferred standard, no doubt it will improve over time.

However there are many blog packages out there, so I expect this project will only be of interest to those wishing to switch from chronicle.

Steve