From 7607b00952d942282b6ace11a1c181e59ebae8f4 Mon Sep 17 00:00:00 2001
From: Delyan Angelov <delian66@gmail.com>
Date: Wed, 7 Aug 2019 04:57:47 +0300
Subject: [PATCH] http: chunked decoding support

---
 vlib/http/chunked/dechunk.v | 63 +++++++++++++++++++++++++++++++++++++
 vlib/http/http.v            |  6 +++-
 vlib/http/openssl_backend.v |  3 ++
 3 files changed, 71 insertions(+), 1 deletion(-)
 create mode 100644 vlib/http/chunked/dechunk.v

diff --git a/vlib/http/chunked/dechunk.v b/vlib/http/chunked/dechunk.v
new file mode 100644
index 0000000000..461b2dca6d
--- /dev/null
+++ b/vlib/http/chunked/dechunk.v
@@ -0,0 +1,63 @@
+module chunked
+
+import strings
+
+// See: https://en.wikipedia.org/wiki/Chunked_transfer_encoding
+///////////////////////////////////////////////////////////////
+// The chunk size is transferred as a hexadecimal number 
+// followed by \r\n as a line separator, 
+// followed by a chunk of data of the given size.
+// The end is marked with a chunk with size 0.
+
+struct ChunkScanner {
+mut:
+	pos int
+	text string
+}
+
+fn (s mut ChunkScanner) read_chunk_size() int {
+	mut n := 0
+	for {
+		if s.pos >= s.text.len { break }
+		c := s.text[s.pos]
+		if !c.is_hex_digit() { break }
+		n = n << 4
+		n += int(unhex(c))
+		s.pos++
+	}
+	return n
+}
+
+fn unhex(c byte) byte {
+	if      `0` <= c && c <= `9` {   return c - `0`       } 
+	else if `a` <= c && c <= `f` {   return c - `a` + 10  } 
+	else if `A` <= c && c <= `F` {   return c - `A` + 10  }
+	return 0
+}
+
+fn (s mut ChunkScanner) skip_crlf() {
+	s.pos += 2
+}
+
+fn (s mut ChunkScanner) read_chunk(chunksize int) string {
+	startpos := s.pos
+	s.pos += chunksize
+	return s.text.substr(startpos, s.pos)
+}
+
+pub fn decode(text string) string {
+	mut sb := strings.new_builder(100)
+	mut cscanner := ChunkScanner {
+		pos: 0
+		text: text
+	}
+	for {
+		csize := cscanner.read_chunk_size()
+		if 0 == csize { break }
+		cscanner.skip_crlf()
+		sb.write( cscanner.read_chunk(csize) )
+		cscanner.skip_crlf()
+	}
+	cscanner.skip_crlf()
+	return sb.str()
+}
diff --git a/vlib/http/http.v b/vlib/http/http.v
index 27243af3d8..b1d81c5b58 100644
--- a/vlib/http/http.v
+++ b/vlib/http/http.v
@@ -5,6 +5,7 @@
 module http
 
 import net.urllib
+import http.chunked
 
 struct Request {
 pub:
@@ -141,7 +142,10 @@ pub fn (req &Request) do() Response {
 		key := h.left(pos)
 		val := h.right(pos + 2)
 		headers[key] = val.trim_space()
-	} 
+	}
+	if headers['Transfer-Encoding'] == 'chunked' {
+		text = chunked.decode( text )
+	}
 	return Response {
 		status_code: status_code 
 		headers: headers
diff --git a/vlib/http/openssl_backend.v b/vlib/http/openssl_backend.v
index 94ba48cbe8..2dc234857c 100644
--- a/vlib/http/openssl_backend.v
+++ b/vlib/http/openssl_backend.v
@@ -19,6 +19,9 @@ fn init_module() {
 	$if mac { 
 		C.SSL_library_init() 
 	} 
+	$if linux { 
+		C.SSL_library_init() 
+	} 
 	//C.SSL_load_error_strings() 
 	//C.OPENSSL_config(0) 
 }