vweb: read the entire request body from buffered reader (#9644)

vlib/vweb/request.v

@@ -36,7 +36,10 @@ fn parse_request(mut reader io.BufferedReader) ?http.Request {
 		n := length.int()
 		if n > 0 {
 			body = []byte{len: n}
-			reader.read(mut body) or {}
+			mut count := 0
+			for count < body.len {
+				count += reader.read(mut body[count..]) or { break }
+			}
 		}
 	}
 	h.free()

vlib/vweb/request_test.v

@@ -12,7 +12,9 @@ fn (mut s StringReader) read(mut buf []byte) ?int {
 	if s.place >= s.text.len {
 		return none
 	}
-	n := copy(buf, s.text[s.place..].bytes())
+	max_bytes := 100
+	end := if s.place + max_bytes >= s.text.len { s.text.len } else { s.place + max_bytes }
+	n := copy(buf, s.text[s.place..end].bytes())
 	s.place += n
 	return n
 }
@@ -135,3 +137,11 @@ ${contents[1]}
 		names[1]: contents[1] + '\n'
 	}
 }
+
+fn test_parse_large_body() ? {
+	body := 'A'.repeat(101) // greater than max_bytes
+	req := 'GET / HTTP/1.1\r\nContent-Length: $body.len\r\n\r\n$body'
+	result := parse_request(mut reader(req)) ?
+	assert result.data.len == body.len
+	assert result.data == body
+}