From 2b80be0fcf73e77376d4bced412485a14a3122d1 Mon Sep 17 00:00:00 2001
From: Emery Hemingway <ehmry@posteo.net>
Date: Mon, 1 Apr 2024 19:24:18 +0100
Subject: [PATCH] Add base64 decoder

---
 base64.prs                        |  4 +++
 config.prs                        |  4 +++
 src/schema/base64.nim             | 19 ++++++++++++
 src/schema/config.nim             |  8 +++++
 src/syndesizer.nim                |  2 ++
 src/syndesizer/base64_decoder.nim | 51 +++++++++++++++++++++++++++++++
 6 files changed, 88 insertions(+)
 create mode 100644 base64.prs
 create mode 100644 src/schema/base64.nim
 create mode 100644 src/syndesizer/base64_decoder.nim

diff --git a/base64.prs b/base64.prs
new file mode 100644
index 0000000..cd84369
--- /dev/null
+++ b/base64.prs
@@ -0,0 +1,4 @@
+version 1.
+
+Base64Text = <base64 @txt string @bin bytes> .
+Base64File = <base64-file @txt string @path string @size int> .
diff --git a/config.prs b/config.prs
index 8a3bdb8..738f24d 100644
--- a/config.prs
+++ b/config.prs
@@ -1,6 +1,10 @@
 version 1 .
 embeddedType EntityRef.Cap .
 
+Base64DecoderArguments = <base64-decoder {
+  dataspace: #:any
+}>.
+
 CacheArguments = <cache {
   dataspace: #:any
   lifetime: float
diff --git a/src/schema/base64.nim b/src/schema/base64.nim
new file mode 100644
index 0000000..0e88fa2
--- /dev/null
+++ b/src/schema/base64.nim
@@ -0,0 +1,19 @@
+
+import
+  preserves
+
+type
+  Base64File* {.preservesRecord: "base64-file".} = object
+    `txt`*: string
+    `path`*: string
+    `size`*: BiggestInt
+
+  Base64Text* {.preservesRecord: "base64".} = object
+    `txt`*: string
+    `bin`*: seq[byte]
+
+proc `$`*(x: Base64File | Base64Text): string =
+  `$`(toPreserves(x))
+
+proc encode*(x: Base64File | Base64Text): seq[byte] =
+  encode(toPreserves(x))
diff --git a/src/schema/config.nim b/src/schema/config.nim
index ca4650a..e491ae4 100644
--- a/src/schema/config.nim
+++ b/src/schema/config.nim
@@ -17,6 +17,12 @@ type
   JsonTranslatorArguments* {.preservesRecord: "json-stdio-translator".} = object
     `field0`*: JsonTranslatorArgumentsField0
 
+  Base64DecoderArgumentsField0* {.preservesDictionary.} = object
+    `dataspace`* {.preservesEmbedded.}: EmbeddedRef
+
+  Base64DecoderArguments* {.preservesRecord: "base64-decoder".} = object
+    `field0`*: Base64DecoderArgumentsField0
+
   JsonTranslatorConnected* {.preservesRecord: "connected".} = object
     `path`*: string
 
@@ -88,6 +94,7 @@ type
     `port`*: BiggestInt
 
 proc `$`*(x: WebsocketArguments | JsonTranslatorArguments |
+    Base64DecoderArguments |
     JsonTranslatorConnected |
     JsonSocketTranslatorArguments |
     XsltArguments |
@@ -103,6 +110,7 @@ proc `$`*(x: WebsocketArguments | JsonTranslatorArguments |
   `$`(toPreserves(x))
 
 proc encode*(x: WebsocketArguments | JsonTranslatorArguments |
+    Base64DecoderArguments |
     JsonTranslatorConnected |
     JsonSocketTranslatorArguments |
     XsltArguments |
diff --git a/src/syndesizer.nim b/src/syndesizer.nim
index dabc665..68470ef 100644
--- a/src/syndesizer.nim
+++ b/src/syndesizer.nim
@@ -10,6 +10,7 @@ const
   withSqlite* {.booldefine.}: bool = true
 
 import ./syndesizer/[
+  base64_decoder,
   cache_actor,
   file_system_usage,
   json_socket_translator,
@@ -27,6 +28,7 @@ when withSqlite:
 runActor("syndesizer") do (turn: var Turn):
   resolveEnvironment(turn) do (turn: var Turn; ds: Cap):
     discard spawnTimerDriver(turn, ds)
+    discard spawnBase64Decoder(turn, ds)
     discard spawnCacheActor(turn, ds)
     discard spawnFileSystemUsageActor(turn, ds)
     discard spawnJsonSocketTranslator(turn, ds)
diff --git a/src/syndesizer/base64_decoder.nim b/src/syndesizer/base64_decoder.nim
new file mode 100644
index 0000000..b230f27
--- /dev/null
+++ b/src/syndesizer/base64_decoder.nim
@@ -0,0 +1,51 @@
+# SPDX-FileCopyrightText: ☭ Emery Hemingway
+# SPDX-License-Identifier: Unlicense
+
+import std/[base64, os]
+import pkg/hashlib/misc/blake2
+import preserves, syndicate
+import ../schema/config
+import ../schema/base64 as schema
+
+export Base64DecoderArguments
+export schema
+
+proc spawnBase64Decoder*(turn: var Turn; root: Cap): Actor {.discardable.} =
+  spawnActor(turn, "base64-decoder") do (turn: var Turn):
+    let tmpDir = getTempDir()
+    during(turn, root, ?:Base64DecoderArguments) do (ds: Cap):
+
+      let decTextPat = ?Observe(pattern: !Base64Text) ?? { 0: grabLit() }
+      during(turn, ds, decTextPat) do (txt: string):
+        discard publish(turn, ds, Base64Text(
+            txt: txt,
+            bin: cast[seq[byte]](decode(txt)),
+          ))
+
+      let encTextPat = ?Observe(pattern: !Base64Text) ?? { 1: grabLit() }
+      during(turn, ds, encTextPat) do (bin: seq[byte]):
+        discard publish(turn, ds, Base64Text(
+            txt: encode(bin),
+            bin: bin,
+          ))
+
+      let decFilePat = ?Observe(pattern: !Base64File) ?? { 0: grabLit() }
+      during(turn, ds, decFilePat) do (txt: string):
+        var bin = decode(txt)
+        var ctx = init[BLAKE2B_512]()
+        ctx.update(bin)
+        let
+          digest = $ctx.final()
+          path = tmpDir / digest
+        writeFile(path, bin)
+        discard publish(turn, ds, Base64File(
+            txt: txt,
+            path: path,
+            size: bin.len,
+          ))
+
+when isMainModule:
+  import syndicate/relays
+  runActor("main") do (turn: var Turn):
+    resolveEnvironment(turn) do (turn: var Turn; ds: Cap):
+      spawnBase64Decoder(turn, ds)