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libwebsockets
Lightweight C library for HTML5 websockets
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libwebsockets
Lightweight C library for HTML5 websockets
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Data Structures | |
| struct | lws_ext_options |
| struct | lws_ext_option_arg |
| struct | lws_extension |
Typedefs | |
| typedef int | lws_extension_callback_function(struct lws_context *context, const struct lws_extension *ext, struct lws *wsi, enum lws_extension_callback_reasons reason, void *user, void *in, size_t len) |
Enumerations | |
| enum | lws_extension_callback_reasons { LWS_EXT_CB_CONSTRUCT = 4 , LWS_EXT_CB_CLIENT_CONSTRUCT = 5 , LWS_EXT_CB_DESTROY = 8 , LWS_EXT_CB_PACKET_TX_PRESEND = 12 , LWS_EXT_CB_PAYLOAD_TX = 21 , LWS_EXT_CB_PAYLOAD_RX = 22 , LWS_EXT_CB_OPTION_DEFAULT = 23 , LWS_EXT_CB_OPTION_SET = 24 , LWS_EXT_CB_OPTION_CONFIRM = 25 , LWS_EXT_CB_NAMED_OPTION_SET = 26 } |
| enum | lws_ext_options_types { EXTARG_NONE , EXTARG_DEC , EXTARG_OPT_DEC } |
Functions | |
| LWS_VISIBLE LWS_EXTERN int | lws_set_extension_option (struct lws *wsi, const char *ext_name, const char *opt_name, const char *opt_val) |
| LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT | lws_ext_parse_options (const struct lws_extension *ext, struct lws *wsi, void *ext_user, const struct lws_ext_options *opts, const char *o, int len) |
| LWS_VISIBLE LWS_EXTERN int | lws_extension_callback_pm_deflate (struct lws_context *context, const struct lws_extension *ext, struct lws *wsi, enum lws_extension_callback_reasons reason, void *user, void *in, size_t len) |
Ws defines optional extensions, lws provides the ability to implement these in user code if so desired.
We provide one extensions permessage-deflate.
| struct lws_ext_options |
struct lws_ext_options - Option arguments to the extension. These are used in the negotiation at ws upgrade time. The helper function lws_ext_parse_options() uses these to generate callbacks
Definition at line 68 of file lws-ws-ext.h.
Collaboration diagram for lws_ext_options:| Data Fields | ||
|---|---|---|
| const char * | name |
Option name, eg, "server_no_context_takeover" |
| enum lws_ext_options_types | type |
What kind of args the option can take |
| struct lws_ext_option_arg |
struct lws_ext_option_arg
Definition at line 77 of file lws-ws-ext.h.
Collaboration diagram for lws_ext_option_arg:| Data Fields | ||
|---|---|---|
| const char * | option_name |
may be NULL, option_index used then |
| int | option_index |
argument ordinal to use if option_name missing |
| const char * | start |
value |
| int | len |
length of value |
| struct lws_extension |
struct lws_extension - An extension we support
Definition at line 139 of file lws-ws-ext.h.
Collaboration diagram for lws_extension:| Data Fields | ||
|---|---|---|
| const char * | name |
Formal extension name, eg, "permessage-deflate" |
| lws_extension_callback_function * | callback |
Service callback |
| const char * | client_offer |
String containing exts and options client offers |
| typedef int lws_extension_callback_function(struct lws_context *context, const struct lws_extension *ext, struct lws *wsi, enum lws_extension_callback_reasons reason, void *user, void *in, size_t len) |
#include <include/libwebsockets/lws-ws-ext.h>
typedef lws_extension_callback_function() - Hooks to allow extensions to operate
| context | Websockets context |
| ext | This extension |
| wsi | Opaque websocket instance pointer |
| reason | The reason for the call |
| user | Pointer to ptr to per-session user data allocated by library |
| in | Pointer used for some callback reasons |
| len | Length set for some callback reasons Each extension that is active on a particular connection receives
callbacks during the connection lifetime to allow the extension to
operate on websocket data and manage itself.
Libwebsockets takes care of allocating and freeing "user" memory for
each active extension on each connection. That is what is pointed to
by the user parameter.
LWS_EXT_CB_CONSTRUCT: called when the server has decided to
select this extension from the list provided by the client,
just before the server will send back the handshake accepting
the connection with this extension active. This gives the
extension a chance to initialize its connection context found
in user.
LWS_EXT_CB_CLIENT_CONSTRUCT: same as LWS_EXT_CB_CONSTRUCT
but called when client is instantiating this extension. Some
extensions will work the same on client and server side and then
you can just merge handlers for both CONSTRUCTS.
LWS_EXT_CB_DESTROY: called when the connection the extension was
being used on is about to be closed and deallocated. It's the
last chance for the extension to deallocate anything it has
allocated in the user data (pointed to by user) before the
user data is deleted. This same callback is used whether you
are in client or server instantiation context.
LWS_EXT_CB_PACKET_TX_PRESEND: this works the same way as
LWS_EXT_CB_PACKET_RX_PREPARSE above, except it gives the
extension a chance to change websocket data just before it will
be sent out. Using the same lws_token pointer scheme in in,
the extension can change the buffer and the length to be
transmitted how it likes. Again if it wants to grow the
buffer safely, it should copy the data into its own buffer and
set the lws_tokens token pointer to it.
LWS_EXT_CB_ARGS_VALIDATE:
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Definition at line 133 of file lws-ws-ext.h.
#include <include/libwebsockets/lws-ws-ext.h>
Definition at line 39 of file lws-ws-ext.h.
#include <include/libwebsockets/lws-ws-ext.h>
enum lws_ext_options_types
| Enumerator | |
|---|---|
| EXTARG_NONE | does not take an argument |
| EXTARG_DEC | requires a decimal argument |
| EXTARG_OPT_DEC | may have an optional decimal argument |
Definition at line 55 of file lws-ws-ext.h.
| LWS_VISIBLE LWS_EXTERN int lws_set_extension_option | ( | struct lws * | wsi, |
| const char * | ext_name, | ||
| const char * | opt_name, | ||
| const char * | opt_val | ||
| ) |
#include <include/libwebsockets/lws-ws-ext.h>
lws_set_extension_option(): set extension option if possible
| wsi | websocket connection |
| ext_name | name of ext, like "permessage-deflate" |
| opt_name | name of option, like "rx_buf_size" |
| opt_val | value to set option to |
| LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT lws_ext_parse_options | ( | const struct lws_extension * | ext, |
| struct lws * | wsi, | ||
| void * | ext_user, | ||
| const struct lws_ext_options * | opts, | ||
| const char * | o, | ||
| int | len | ||
| ) |
#include <include/libwebsockets/lws-ws-ext.h>
lws_ext_parse_options() - deal with parsing negotiated extension options
| ext | related extension struct |
| wsi | websocket connection |
| ext_user | per-connection extension private data |
| opts | list of supported options |
| o | option string to parse |
| len | length |
| LWS_VISIBLE LWS_EXTERN int lws_extension_callback_pm_deflate | ( | struct lws_context * | context, |
| const struct lws_extension * | ext, | ||
| struct lws * | wsi, | ||
| enum lws_extension_callback_reasons | reason, | ||
| void * | user, | ||
| void * | in, | ||
| size_t | len | ||
| ) |
#include <include/libwebsockets/lws-ws-ext.h>
lws_extension_callback_pm_deflate() - extension for RFC7692
| context | lws context |
| ext | related lws_extension struct |
| wsi | websocket connection |
| reason | incoming callback reason |
| user | per-connection extension private data |
| in | pointer parameter |
| len | length parameter |
Built-in callback implementing RFC7692 permessage-deflate
1.9.1 
