[wip] static file cache data structure works

2025-10-22 13:17:39 -07:00
parent 80945de92d
commit 8b938fdd42
4 changed files with 174 additions and 55 deletions
@@ -1,2 +1,99 @@
 % @doc non-servery functions for static file caching
-module(fd_sfc_entry)
+%
+% this spams the filesystem, so it's not "pure" code
+-module(fd_sfc_entry).
+
+-export_type([
+    encoding/0,
+    entry/0
+]).
+
+-export([
+    %% constructor
+    new/1,
+    %% accessors
+    fs_path/1, last_modified/1, mime_type/1, encoding/1, contents/1
+]).
+
+-include("$zx_include/zx_logger.hrl").
+
+%% types
+
+% id = not compressed
+-type encoding() :: none | gzip.
+
+-record(e, {fs_path       :: file:filename(),
+            last_modified :: file:date_time(),
+            mime_type     :: string(),
+            encoding      :: encoding(),
+            contents      :: binary()}).
+
+-opaque entry() :: #e{}.
+
+%% accessors
+
+fs_path(#e{fs_path = X}) -> X.
+last_modified(#e{last_modified = X}) -> X.
+mime_type(#e{mime_type = X}) -> X.
+encoding(#e{encoding = X}) -> X.
+contents(#e{contents = X}) -> X.
+
+%% API
+
+-spec new(Path) -> Result
+    when Path     :: file:filename(),
+         Result   :: {found, entry()}
+                   | not_found.
+% @doc
+% absolute file path stored in resulting record
+%
+% returns not_found if ANY I/O error occurs during the process. will be logged
+
+new(Path) ->
+    tell("~tp:new(~tp)", [?MODULE, Path]),
+    case file:read_file(Path) of
+        {ok, Binary} ->
+            {found, new2(Path, Binary)};
+        Error ->
+            tell("~tp:new(~tp): file read error: ~tp", [?MODULE, Path, Error]),
+            not_found
+    end.
+
+%% can assume file exists
+new2(FsPath, FileBytes) ->
+    LastModified         = filelib:last_modified(FsPath),
+    {Encoding, MimeType} = mimetype_compress(FsPath),
+    Contents =
+        case Encoding of
+            none -> FileBytes;
+            gzip -> zlib:gzip(FileBytes)
+        end,
+    #e{fs_path       = FsPath,
+       last_modified = LastModified,
+       mime_type     = MimeType,
+       encoding      = Encoding,
+       contents      = Contents}.
+
+mimetype_compress(FsPath) ->
+    case string:casefold(filename:extension(FsPath)) of
+        %% only including the ones i anticipate encountering
+        %% plaintext formats
+        ".css"  -> {gzip, "text/css"};
+        ".htm"  -> {gzip, "text/html"};
+        ".html" -> {gzip, "text/html"};
+        ".js"   -> {gzip, "text/javascript"};
+        ".json" -> {gzip, "application/json"};
+        ".map"  -> {gzip, "application/json"};
+        ".md"   -> {gzip, "text/markdown"};
+        ".ts"   -> {gzip, "text/x-typescript"};
+        ".txt"  -> {gzip, "text/plain"};
+        %% binary formats
+        ".gif"  -> {none, "image/gif"};
+        ".jpg"  -> {none, "image/jpeg"};
+        ".jpeg" -> {none, "image/jpeg"};
+        ".mp4"  -> {none, "video/mp4"};
+        ".png"  -> {none, "image/png"};
+        ".webm" -> {none, "video/webm"};
+        ".webp" -> {none, "image/webp"};
+        _       -> {none, "application/octet-stream"}
+    end.