1 files changed, 299 insertions, 0 deletions

diff --git a/src/blog/2022-11-23-git-host/git-host.md b/src/blog/2022-11-23-git-host/git-host.md
new file mode 100644
index 0000000..cc9fc27
--- /dev/null
+++ b/src/blog/2022-11-23-git-host/git-host.md
@@ -0,0 +1,299 @@
+# Self-hosted git pages with stagit (featuring ed, the standard editor)
+
+This is a follow-up to my earlier blog entry
+[How I update my website](../2022-08-14-website).
+
+If you work on one or more personal software projects as a hobby,
+chances are you are using `git`. To publish your project online
+you may be using a website like GitHub, or perhaps a more
+open source friendly alternative such as
+[GitLab](https://about.gitlab.com/) or [sourcehut](https://sourcehut.org/).
+
+But have you considered hosting your repositories, and serving them
+via web pages, on your personal server? In this post I am going to show
+you how I do it, in the usual minimalist and
+not-using-what-I-do-not-understand style.
+
+You can see the final result on my [git pages](https://git.tronto.net).
+The scripts and other files I use to set this up are accessible
+[here](https://git.tronto.net/git-hooks).
+
+## Hosting git repositories on your own server
+
+This step is quite simple, and you can just follow
+[Roman Zolotarev's tutorial](https://rgz.ee/git.html) like I did - adapting
+the first few steps to your OS if you are not running OpenBSD.
+
+To sum it up, you need to:
+
+1. Create a dedicate `git` account on your server (optional, if you know
+   what you are doing).
+
+2. Add your public SSH key to the `~/.ssh/authorized_keys` file of your newly
+   created remote account.
+
+3. Initialize a git repository on your server with `git init REPOSITORY`.
+
+4. Clone it via SSH with `git clone git@SERVER:REPOSITORY`.
+
+And you are done! If you want to use multiple remotes, for example your private
+server and GitHub, you can do so by adding a push-only URL with
+`git remote set-url --add --push origin URL`. But don't trust me on this
+exact command, I always have to look it up
+- you should do the same before running it.
+
+Now your repositories are online, but how can you make them browsable via web?
+
+## stagit
+
+The tool I use to serve my git repositories as static web pages is
+[stagit](https://codemadness.org/stagit.html). It is very easy to describe what
+stagit does: running it on a git reporitory produces some directories with
+a bunch of html files that you can simply move to your www hosting directory.
+
+After generating the pages you can personalize them by copying your logo,
+[favicon](https://en.wikipedia.org/wiki/Favicon) or CSS style sheet. You can
+use `stagit-index` to generate
+[an index page for your repositories](https://git.tronto.net/). Since everything
+consists of html files, you can simply edit them to personalize your git pages
+even further - and below you'll see some examples.
+
+But you definitely do not want to do this by hand every time you push a commit.
+Since the pages stagit generates are *static*, they do not update
+automatically: you'll have to run stagit again every time. You can automate
+this for example by running stagit periodically with cron, but there is an
+easier way:
+[git hooks](https://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks).
+
+## Git hooks
+
+By saving suitably named executable files inside your project's
+`.git/hooks` directory you can automate any process you want during
+certain stages of your git workflow. For example you can use a `pre-commit`
+script to run commands before you commit changes, or a `pre-push` script
+to do something before pushing a commit.
+
+The hooks are divided in client-side and server-side. We are interested in
+the server-side `post-receive` hook, which is executed on the remote every
+time a commit is received. This is the last ingredient we need for our setup:
+a simple `post-receive` hook that runs stagit and copies the files it
+generates to the appropriate folder will do the trick.
+
+## My setup
+
+Throughout the rest of the post I will use the following variables, to be
+set at the beginning of the script:
+
+```
+yourname="Sebastiano Tronto" # Author's name
+repo="$PWD" # The full path of the repository
+name="$(basename $repo .git)" # The name of the repository
+baseurl="https://git.tronto.net" # The base URL for the repository
+basedir="/var/www/htdocs/git.tronto.net" # The base directory for www files
+htdir="$basedir/$name" # The www directory for the repository
+```
+
+### Basic stagit usage
+
+The first thing we want to do is to set up some basic information in the
+`owner` and `url` files that stagit is going to use. The hook is run in the
+repository's directory, so it is not necessary to specify a full path:
+
+```
+echo "$yourname" > owner
+echo "$baseurl/$name" > url
+```
+
+Next we prepare the target directory by removing old files and creating
+it if necessary:
+
+```
+rm -rf "$htdir"
+mkdir -p "$basedir"
+```
+
+To make the repository clonable by anyone from the same URL used to
+view it, we need to copy the whole directory to the
+www directory we have just created:
+
+```
+cp -r "$repo" "$htdir"
+```
+
+And finally we can run stagit:
+
+```
+cd "$htdir"
+stagit -l 100 "$repo"
+```
+
+The `-l` option is used to specify how many commits should be visibile
+in the log page.
+
+For some basic personalization we can choose a different default page (index
+file). I like to have the file list:
+
+```
+cp "$htdir/files.html" "$htdir/index.html"
+```
+
+And we can use our css style sheet, logo and icon:
+
+```
+cp $filesdir/favicon.png ./
+cp $filesdir/logo.png ./
+cp $filesdir/style.css ./
+```
+
+### Bells and whistles
+
+I like stagit's simplicity, but there are a couple of things that I want to
+add or change:
+
+* I would like every page to show a simple footer at the bottom of
+  each page.
+* I would like to have a download button so that people who don't use git
+  can still download my files. This makes sense especially for those
+  repos that are mostly documents, such as my
+  [lecture notes](https://git.tronto.net/mathsoftware) or my
+  [FMC tutorial](https://git.tronto.net/fmctutorial).
+* I would like to convert README.md files to html.
+
+If I were calling stagit by hand after each `git push`, I
+could simply make these changes with a text editor. But I want to automate
+this! How can we edit files in a shell script?
+
+Enter `ed`, [the standard editor](https://www.gnu.org/fun/jokes/ed-msg.html).
+`ed` is a [line text editor](https://en.wikipedia.org/wiki/Line_editor)
+initially released with UNIX Version 1. I am going to talk about it more
+extensively in the next episode of my
+[man page reading club](../2022-05-29-man/)
+series. Without going into detail, `ed` does not show you the text you
+are editing in a 2-dimensional windows: instead, it offers you a command
+line prompt that you can use to run editing commands, such as `a` to add
+text or `p` to print one or more lines of the file.
+
+This might seems like a totally cumbersome way of editing a file, but
+there is one nice side-effect: `ed` is completely scriptable.  This means
+that if you know exactly what the file you want to edit looks like,
+you can write the commands you want to run in advance and feed them to
+the editor via standard input, instead of typing them interactively.
+This is exactly what we want to do!
+
+Going back to my stagit setup, say we have a file `bottom.html` that
+looks like this:
+
+```
+<hr class="line">
+<footer> <table>
+<tr> <td class="contact">
+        Back to <a href="https://sebastiano.tronto.net"> sebastiano.tronto.net </a>
+</td>
+<td class="hosted">
+        Generated with <a href="https://codemadness.org/stagit.html">stagit</a>
+</td> </tr>
+</table> </footer>
+```
+
+and we want to insert its content in the file `file.html`, before
+the line that contains the closing tag `</body>`. We can use the
+following one-liner:
+
+```
+printf '%s\n' "/<\/body>" i "$(cat bottom.html)" . w | ed -s file.html
+```
+
+Here the `printf` command is used to feed the tokens `/<\/body>`, `i`,
+`$(cat bottom.html)`, `.` and `w` to `ed`. These are going to
+be interpreted as: "search for the closing tag `</body>`;
+insert the following text until you encounter a single dot on a line:
+[contents of the file `bottom.html`] single dot; save."
+If this seems obscure, I suggest you read
+[`ed`'s manual page](https://man.openbsd.org/OpenBSD-7.2/ed), or wait
+for my next blog post!
+
+The command for adding the download button is similar, after we
+generate a zip archive of the repository using `git archive`:
+
+```
+git archive HEAD -o "$basedir/$name.zip"
+printf '%s\n' \
+        "/log\.html\">Log<\/a>" i \
+        "<a href=\"$baseurl/$name.zip\">Download</a> |" . w \
+| ed -s file.html
+```
+
+Here I am using backlashes to ignore the newline character, so that
+I can use more lines for readability.
+
+The two code snippets above have to be run for every html file generated
+by stagit. To loop over all these files, you can use `find`:
+
+```
+for f in $(find "$htdir" -name "*.html"); do
+        [stuff...]
+done
+```
+
+The command to turn README.md files into a formatted html page is a bit
+more complicated, but I will try to keep the explanation short, since
+this post is already quite long. Feel free to send me an email if you
+have questions!
+
+To have an idea of what the README.md.html file generated by
+stagit looks like, you can check out the html of
+[this page](https://codemadness.org/git/stagit/file/README.html),
+for example (right click and "View page source" or something similar in
+most browsers, or `curl [URL]` if you are cool).
+
+First, since I am using bare git repositories, I need to actually "create"
+the original README.md file - instead of using its rendered-as-plain-text
+html version generated by stagit - using `git show`. Then we need to
+remove from README.md.html all the lines that
+are part of the code listing, i.e. all those that contain a `class="line"`
+string.  The `ed` command to do this is `g/class=\"line\"/d`. Then we
+need to remove a couple more lines and finally we can insert the result
+of the command `lowdown file/README.md`, which converts the markdown
+file to html, into the correct place. The final result is:
+
+```
+git show master:README.md > file/README.md
+printf '%s\n' \
+        g/class=\"line\"/d \
+        "/<pre id=\"blob\">" d d i "$(lowdown file/README.md)" . w \
+| ed -s file/README.md.html > /dev/null
+```
+
+### stagit-index
+
+Just a quick mention to how I use stagit-index, the command used to
+generate the index page.
+The only change I make from the default configuration is to change
+the links to each repository to point to the file list instead
+of the log page. stagit-index writes its result to standard output, so 
+I can simply use `sed`:
+
+```
+stagit-index /home/git/*.git | sed 's|/log\.html||g' > "$basedir/index.html"
+```
+
+And that's it. Well, I also copy the style files and add a bottom bar,
+and change the title from a `<span class="desc">` to an `<h1>` element,
+again using `ed`. If you want to see the details you can check them out
+[here](https://git.tronto.net/git-hooks/file/post-receive-stagit.html).
+
+## Conclusions
+
+stagit is the perfect minimalist tool to publish your git repository
+with a simple, static web interface. It requires nothing more than
+an http server capable of serving html files. Static files are also
+very simple to customize and tune to your needs.
+
+I have wanted to make this post for quite some time now, mainly
+as an excuse to clean up and document my scripts. I finally had some
+time to work on this - even if scattered around multiple days.
+
+As always, I have tried but failed to keep my post short - I am too
+eager to explain everything I know as clearly as possbile!
+I hope you enjoyed or found it useful. If you have questions or comments,
+feel free to send me an [email](mailto:sebastiano@tronto.net).