1 files changed, 134 insertions, 0 deletions
diff --git a/web/bubblegum/examples/blog.nix b/web/bubblegum/examples/blog.nix
new file mode 100644
index 000000000000..9359d38fa28e
--- /dev/null
+++ b/web/bubblegum/examples/blog.nix
@@ -0,0 +1,134 @@
+{ depot, ... }:
+
+let
+  inherit (depot.third_party.nixpkgs)
+    lib
+    ;
+
+  inherit (depot.users.sterni.nix)
+    url
+    fun
+    string
+    ;
+
+  inherit (depot.web.bubblegum)
+    pathInfo
+    scriptName
+    respond
+    absolutePath
+    ;
+
+  # substituted using substituteAll in default.nix
+  blogdir = "@blogdir@";
+  # blogdir = toString ./posts; # for local testing
+
+  parseDate = post:
+    let
+      matched = builtins.match "/?([0-9]+)-([0-9]+)-([0-9]+)-.+" post;
+    in
+      if matched == null
+      then [ 0 0 0 ]
+      else builtins.map builtins.fromJSON matched;
+
+  parseTitle = post:
+    let
+      matched = builtins.match "/?[0-9]+-[0-9]+-[0-9]+-(.+).html" post;
+    in
+      if matched == null
+      then "no title"
+      else builtins.head matched;
+
+  dateAtLeast = a: b:
+    builtins.all fun.id
+      (lib.zipListsWith (partA: partB: partA >= partB) a b);
+
+  byPostDate = a: b:
+    dateAtLeast (parseDate a) (parseDate b);
+
+  posts = builtins.sort byPostDate
+    (builtins.attrNames
+      (lib.filterAttrs (_: v: v == "regular")
+        (builtins.readDir blogdir)));
+
+  generic = { title, inner, ... }: ''
+    <!doctype html>
+    <html>
+      <head>
+        <meta charset="utf-8">
+        <title>${title}</title>
+        <style>a:link, a:visited { color: blue; }</style>
+      </head>
+      <body>
+      ${inner}
+      </body>
+    </html>
+  '';
+
+  index = posts: ''
+    <main>
+      <h1>blog posts</h1>
+      <ul>
+  '' + lib.concatMapStrings (post: ''
+      <li>
+        <a href="${absolutePath (url.encode {} post)}">${parseTitle post}</a>
+      </li>
+  '') posts + ''
+      </ul>
+    </main>
+  '';
+
+  formatDate =
+    let
+      # Assume we never deal with years < 1000
+      formatDigit = d: string.fit {
+        char = "0"; width = 2;
+      } (toString d);
+    in lib.concatMapStringsSep "-" formatDigit;
+
+  post = title: post: ''
+    <main>
+      <h1>${title}</h1>
+      <div id="content">
+        ${builtins.readFile (blogdir + "/" + post)}
+      </div>
+    </main>
+    <footer>
+      <p>Posted on ${formatDate (parseDate post)}</p>
+      <nav><a href="${scriptName}">index</a></nav>
+    </footer>
+  '';
+
+  validatePathInfo = pathInfo:
+    let
+      chars = string.toChars pathInfo;
+    in builtins.length chars > 1
+      && !(builtins.elem "/" (builtins.tail chars));
+
+  response =
+    if pathInfo == "/"
+    then {
+      title = "blog";
+      status = 200;
+      inner = index posts;
+    }
+    else if !(validatePathInfo pathInfo)
+    then {
+      title = "Bad Request";
+      status = 400;
+      inner = "No slashes in post names 😡";
+    }
+    # CGI should already url.decode for us
+    else if builtins.pathExists (blogdir + "/" + pathInfo)
+    then rec {
+      title = parseTitle pathInfo;
+      status = 200;
+      inner = post title pathInfo;
+    } else {
+      title = "Not Found";
+      status = 404;
+      inner = "<h1>404 — not found</h1>";
+    };
+in
+  respond response.status {
+    "Content-type" = "text/html";
+  } (generic response)