gzip.c File Reference

Gzip response compression middleware implementation. More...

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <zlib.h>
#include "csilk/csilk.h"
#include "csilk/core/internal.h"

Include dependency graph for gzip.c:

Data Structures
struct	gzip_async_state_t
	State for asynchronous gzip compression offloading. More...

Macros
#define	CSILK_GZIP_CHUNK   16384
#define	CSILK_GZIP_MIN_LENGTH   1024

Functions
static void	gzip_work_cb (uv_work_t *req)
	libuv work callback: perform gzip compression off the event loop.
static void	gzip_after_work_cb (uv_work_t *req, int status)
	libuv after-work callback: apply compressed body and send response.
void	csilk_gzip_middleware (csilk_ctx_t *c)
	Gzip response compression middleware (offloaded to thread pool).

Detailed Description

Gzip response compression middleware implementation.

Copyright

MIT License

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Data Structure Documentation

gzip_async_state_t

struct gzip_async_state_t

State for asynchronous gzip compression offloading.

Carries the compressed output buffer, capacity, actual compressed length, and the zlib return status between the work callback (running on the libuv thread pool) and the after-work callback (running on the event loop).

Data Fields
size_t	compressed_len	Actual compressed data length.
uint8_t *	dest	Compressed output buffer.
size_t	dest_cap	Capacity of the output buffer.
int	ret	zlib return status.

Macro Definition Documentation

CSILK_GZIP_CHUNK

#define CSILK_GZIP_CHUNK   16384

CSILK_GZIP_MIN_LENGTH

#define CSILK_GZIP_MIN_LENGTH   1024

Function Documentation

csilk_gzip_middleware()

void csilk_gzip_middleware

(

csilk_ctx_t *

c

)

Gzip response compression middleware (offloaded to thread pool).

Gzip response compression middleware.

Calls csilk_next() first, then inspects the response. Compression is skipped if:

• The response body is empty,
• Content-Encoding is already set,
• The Content-Type is binary / incompressible (image, video, audio, pdf, zip, gzip),
• The client does not advertise gzip in Accept-Encoding,
• The response body is smaller than CSILK_GZIP_MIN_LENGTH (1 KB).

When eligible, the response body is made managed (copied if necessary) and compression is offloaded to the libuv thread pool via a work request.

Parameters

c	The request context.

Note

This middleware must be registered AFTER handlers that produce the response body (since it calls csilk_next() first).

Warning

The response body is replaced in-place; subsequent middleware or cleanup code must not free the original pointer after compression.

gzip_after_work_cb()

static void gzip_after_work_cb ( uv_work_t *  req, int  status  )

static

libuv after-work callback: apply compressed body and send response.

Runs on the event loop after compression finishes. If compression succeeded (Z_STREAM_END), it replaces the original response body with the compressed data, sets Content-Encoding: gzip and Vary: Accept-Encoding headers, then sends the response. On failure the original uncompressed body is sent instead.

Parameters

req	libuv work request. req->data points to the csilk_ctx_t.
status	Work status — 0 on success, negative on cancellation.

Note

The original (uncompressed) response body is freed only if it was heap-managed (body_is_managed == 1).

gzip_work_cb()

static void gzip_work_cb ( uv_work_t *  req )

static

libuv work callback: perform gzip compression off the event loop.

Initializes a zlib deflate stream with gzip wrapper (windowBits = 15 + 16), compresses the response body into a dynamically allocated buffer, then stores the result in the gzip_async_state_t attached to the context.

Parameters

req	libuv work request. req->data points to the csilk_ctx_t.

Note

Runs on a libuv thread-pool thread. Must not touch non-thread-safe resources.