HTTP headers: create

Functions
LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT	lws_add_http_header_status (struct lws *wsi, unsigned int code, unsigned char **p, unsigned char *end)
LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT	lws_add_http_header_by_name (struct lws *wsi, const unsigned char *name, const unsigned char *value, int length, unsigned char **p, unsigned char *end)
LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT	lws_add_http_header_by_token (struct lws *wsi, enum lws_token_indexes token, const unsigned char *value, int length, unsigned char **p, unsigned char *end)
LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT	lws_add_http_header_content_length (struct lws *wsi, unsigned long content_length, unsigned char **p, unsigned char *end)
LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT	lws_finalize_http_header (struct lws *wsi, unsigned char **p, unsigned char *end)

Detailed Description

HTTP headers: Create

These apis allow you to create HTTP response headers in a way compatible with both HTTP/1.x and HTTP/2.

They each append to a buffer taking care about the buffer end, which is passed in as a pointer. When data is written to the buffer, the current position p is updated accordingly.

All of these apis are LWS_WARN_UNUSED_RESULT as they can run out of space and fail with nonzero return.

Function Documentation

LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT lws_add_http_header_by_name	(	struct lws *	wsi,
		const unsigned char *	name,
		const unsigned char *	value,
		int	length,
		unsigned char **	p,
		unsigned char *	end
	)

#include <lib/libwebsockets.h>

lws_add_http_header_by_name() - append named header and value

Parameters

wsi	the connection to check
name	the hdr name, like "my-header"
value	the value after the = for this header
length	the length of the value
p	pointer to current position in buffer pointer
end	pointer to end of buffer

Appends name: value to the headers

LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT lws_add_http_header_by_token	(	struct lws *	wsi,
		enum lws_token_indexes	token,
		const unsigned char *	value,
		int	length,
		unsigned char **	p,
		unsigned char *	end
	)

#include <lib/libwebsockets.h>

lws_add_http_header_by_token() - append given header and value

Parameters

wsi	the connection to check
token	the token index for the hdr
value	the value after the = for this header
length	the length of the value
p	pointer to current position in buffer pointer
end	pointer to end of buffer

Appends name=value to the headers, but is able to take advantage of better HTTP/2 coding mechanisms where possible.

LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT lws_add_http_header_content_length	(	struct lws *	wsi,
		unsigned long	content_length,
		unsigned char **	p,
		unsigned char *	end
	)

#include <lib/libwebsockets.h>

lws_add_http_header_by_name() - append content-length helper

Parameters

wsi	the connection to check
content_length	the content length to use
p	pointer to current position in buffer pointer
end	pointer to end of buffer

Appends content-length: content_length to the headers

LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT lws_add_http_header_status	(	struct lws *	wsi,
		unsigned int	code,
		unsigned char **	p,
		unsigned char *	end
	)

#include <lib/libwebsockets.h>

lws_add_http_header_status() - add the HTTP response status code

Parameters

wsi	the connection to check
code	an HTTP code like 200, 404 etc (see enum http_status)
p	pointer to current position in buffer pointer
end	pointer to end of buffer

Adds the initial response code, so should be called first

LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT lws_finalize_http_header	(	struct lws *	wsi,
		unsigned char **	p,
		unsigned char *	end
	)

#include <lib/libwebsockets.h>

lws_finalize_http_header() - terminate header block

Parameters

wsi	the connection to check
p	pointer to current position in buffer pointer
end	pointer to end of buffer

Indicates no more headers will be added