fix(multipart): fix error when parsing file name in utf8 format (#5428)

std/mime/multipart.ts

@@ -206,7 +206,7 @@ class PartReader implements Reader, Closer {
     const cd = this.headers.get("content-disposition");
     const params: { [key: string]: string } = {};
     assert(cd != null, "content-disposition must be set");
-    const comps = cd.split(";");
+    const comps = decodeURI(cd).split(";");
     this.contentDisposition = comps[0];
     comps
       .slice(1)

std/mime/multipart_test.ts

@@ -188,6 +188,10 @@ test({
     const file = form.file("file");
     assert(isFormFile(file));
     assert(file.content !== void 0);
+    const file2 = form.file("file2");
+    assert(isFormFile(file2));
+    assert(file2.filename === "中文.json");
+    assert(file2.content !== void 0);
     o.close();
   },
 });

std/mime/testdata/sample.txt

@@ -12,16 +12,24 @@ bar
 content-disposition: form-data; name="file"; filename="tsconfig.json"
 content-type: application/octet-stream
 
-{
-  "compilerOptions": {
-    "target": "es2018",
-    "baseUrl": ".",
-    "paths": {
-      "deno": ["./deno.d.ts"],
-      "https://*": ["../../.deno/deps/https/*"],
-      "http://*": ["../../.deno/deps/http/*"]
-    }
-  }
-}
+{
+  "compilerOptions": {
+    "target": "es2018",
+    "baseUrl": ".",
+    "paths": {
+      "deno": ["./deno.d.ts"],
+      "https://*": ["../../.deno/deps/https/*"],
+      "http://*": ["../../.deno/deps/http/*"]
+    }
+  }
+}
+
+----------------------------434049563556637648550474
+content-disposition: form-data; name="file2"; filename="中文.json"
+content-type: application/octet-stream
+
+{
+  "test": "filename"
+}
 
 ----------------------------434049563556637648550474--

std/textproto/mod.ts

@@ -8,6 +8,9 @@ import { charCode } from "../io/util.ts";
 import { concat } from "../bytes/mod.ts";
 import { decode } from "../encoding/utf8.ts";
 
+// FROM https://github.com/denoland/deno/blob/b34628a26ab0187a827aa4ebe256e23178e25d39/cli/js/web/headers.ts#L9
+const invalidHeaderCharRegex = /[^\t\x20-\x7e\x80-\xff]/g;
+
 function str(buf: Uint8Array | null | undefined): string {
   if (buf == null) {
     return "";
@@ -102,7 +105,10 @@ export class TextProtoReader {
       ) {
         i++;
       }
-      const value = str(kv.subarray(i));
+      const value = str(kv.subarray(i)).replace(
+        invalidHeaderCharRegex,
+        encodeURI
+      );
 
       // In case of invalid header we swallow the error
       // example: "Audio Mode" => invalid due to space in the key