進行Chunked編碼傳輸的HTTP Response會在訊息頭部設定:
Transfer-Encoding: chunked
表示Content Body將用Chunked編碼傳輸內容。
Chunked編碼使用若干個Chunk串聯而成,由一個標明長度為0的chunk標示結束。每個Chunk分為頭部和本文兩部分,頭部內容指定下一段本文的字元總數(十六進位的數字)和數量單位(一般不寫),本文部分就是指定長度的實際內容,兩部分之間用斷行符號換行(CRLF)隔開。在最後一個長度為0的Chunk中的內容是稱為footer的內容,是一些附加的Header資訊(通常可以直接忽略)。具體的Chunk編碼格式如下:
複製代碼 代碼如下: Chunked-Body = *chunk
"0" CRLF
footer
CRLF
chunk = chunk-size [ chunk-ext ] CRLF
chunk-data CRLF
hex-no-zero = <HEX excluding "0">
chunk-size = hex-no-zero *HEX
chunk-ext = *( ";" chunk-ext-name [ "=" chunk-ext-value ] )
chunk-ext-name = token
chunk-ext-val = token | quoted-string
chunk-data = chunk-size(OCTET)
footer = *entity-header
RFC文檔中的Chunked解碼過程如下: 複製代碼 代碼如下: length := 0
read chunk-size, chunk-ext (if any) and CRLF
while (chunk-size > 0) {
read chunk-data and CRLF
append chunk-data to entity-body
length := length + chunk-size
read chunk-size and CRLF
}
read entity-header
while (entity-header not empty) {
append entity-header to existing header fields
read entity-header
}
Content-Length := length
Remove "chunked" from Transfer-Encoding
最後提供一段PHP版本的chunked解碼代碼: 複製代碼 代碼如下:$chunk_size = (integer)hexdec(fgets( $socket_fd, 4096 ) );
while(!feof($socket_fd) && $chunk_size > 0) {
$bodyContent .= fread( $socket_fd, $chunk_size );
fread( $socket_fd, 2 ); // skip \r\n
$chunk_size = (integer)hexdec(fgets( $socket_fd, 4096 ) );
}