Implementation method of Chunked encoding in HTTP Response under PHP

Implementation method of Chunked encoding in HTTP Response under PHP_PHP tutorial

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Release： 2016-07-21 15:48:17

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The HTTP Response for Chunked encoding transmission will be set in the message header:
Transfer-Encoding: chunked
means that the Content Body will use Chunked encoding to transmit the content.
Chunked encoding is formed by concatenating several Chunks and ends with a chunk indicating a length of 0. Each Chunk is divided into two parts: the header and the text. The header content specifies the total number of characters (hexadecimal numbers) and the quantity unit (generally not written) of the next paragraph of text. The text part is the actual content of the specified length. The two parts Separate them with carriage return and line feed (CRLF). The content in the last Chunk of length 0 is called footer, which is some additional Header information (usually can be ignored directly). The specific Chunk encoding format is as follows:

Copy code The code is as follows:

 Chunked-Body = *chunk 
　　　 "0 " CRLF 
　footer 
　CRLF 
 chunk = chunk-size [ chunk-ext ] CRLF 
 chunk-data CRLF 
 hex-no-zero =  
 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 document The Chunked decoding process is as follows:

Copy code The code is as follows:

 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 

Finally, a PHP version of the chunked decoding code is provided:

Copy code The code is as follows:

$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 rn 
$chunk_size = (integer)hexdec(fgets( $socket_fd, 4096 ) ); 
} 