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esp-idf/components/esp_http_server/include/esp_http_server.h
Angus Gratton 19fd436e88 Merge branch 'esp_http_server/lru_counter_for_timestamp' into 'master' 
esp_http_server/lru_counter_for_timestamp:Added LRU counter for timer

See merge request idf/esp-idf!4205
2019-02-28 07:04:21 +08:00

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// Copyright 2018 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef _ESP_HTTP_SERVER_H_
#define _ESP_HTTP_SERVER_H_
#include <stdio.h>
#include <string.h>
#include <freertos/FreeRTOS.h>
#include <freertos/task.h>
#include <http_parser.h>
#include <sdkconfig.h>
#include <esp_err.h>
#ifdef __cplusplus
extern "C" {
#endif
/*
note: esp_https_server.h includes a customized copy of this
initializer that should be kept in sync
*/
#define HTTPD_DEFAULT_CONFIG() { \
.task_priority = tskIDLE_PRIORITY+5, \
.stack_size = 4096, \
.server_port = 80, \
.ctrl_port = 32768, \
.max_open_sockets = 7, \
.max_uri_handlers = 8, \
.max_resp_headers = 8, \
.backlog_conn = 5, \
.lru_purge_enable = false, \
.recv_wait_timeout = 5, \
.send_wait_timeout = 5, \
.global_user_ctx = NULL, \
.global_user_ctx_free_fn = NULL, \
.global_transport_ctx = NULL, \
.global_transport_ctx_free_fn = NULL, \
.open_fn = NULL, \
.close_fn = NULL, \
.uri_match_fn = NULL \
}
#define ESP_ERR_HTTPD_BASE (0x8000) /*!< Starting number of HTTPD error codes */
#define ESP_ERR_HTTPD_HANDLERS_FULL (ESP_ERR_HTTPD_BASE + 1) /*!< All slots for registering URI handlers have been consumed */
#define ESP_ERR_HTTPD_HANDLER_EXISTS (ESP_ERR_HTTPD_BASE + 2) /*!< URI handler with same method and target URI already registered */
#define ESP_ERR_HTTPD_INVALID_REQ (ESP_ERR_HTTPD_BASE + 3) /*!< Invalid request pointer */
#define ESP_ERR_HTTPD_RESULT_TRUNC (ESP_ERR_HTTPD_BASE + 4) /*!< Result string truncated */
#define ESP_ERR_HTTPD_RESP_HDR (ESP_ERR_HTTPD_BASE + 5) /*!< Response header field larger than supported */
#define ESP_ERR_HTTPD_RESP_SEND (ESP_ERR_HTTPD_BASE + 6) /*!< Error occured while sending response packet */
#define ESP_ERR_HTTPD_ALLOC_MEM (ESP_ERR_HTTPD_BASE + 7) /*!< Failed to dynamically allocate memory for resource */
#define ESP_ERR_HTTPD_TASK (ESP_ERR_HTTPD_BASE + 8) /*!< Failed to launch server task/thread */
/* Symbol to be used as length parameter in httpd_resp_send APIs
* for setting buffer length to string length */
#define HTTPD_RESP_USE_STRLEN -1
/* ************** Group: Initialization ************** */
/** @name Initialization
* APIs related to the Initialization of the web server
* @{
*/
/**
* @brief HTTP Server Instance Handle
*
* Every instance of the server will have a unique handle.
*/
typedef void* httpd_handle_t;
/**
* @brief HTTP Method Type wrapper over "enum http_method"
* available in "http_parser" library
*/
typedef enum http_method httpd_method_t;
/**
* @brief Prototype for freeing context data (if any)
* @param[in] ctx object to free
*/
typedef void (*httpd_free_ctx_fn_t)(void *ctx);
/**
* @brief Function prototype for opening a session.
*
* Called immediately after the socket was opened to set up the send/recv functions and
* other parameters of the socket.
*
* @param[in] hd server instance
* @param[in] sockfd session socket file descriptor
* @return status
*/
typedef esp_err_t (*httpd_open_func_t)(httpd_handle_t hd, int sockfd);
/**
* @brief Function prototype for closing a session.
*
* @note It's possible that the socket descriptor is invalid at this point, the function
* is called for all terminated sessions. Ensure proper handling of return codes.
*
* @param[in] hd server instance
* @param[in] sockfd session socket file descriptor
*/
typedef void (*httpd_close_func_t)(httpd_handle_t hd, int sockfd);
/**
* @brief Function prototype for URI matching.
*
* @param[in] reference_uri URI/template with respect to which the other URI is matched
* @param[in] uri_to_match URI/template being matched to the reference URI/template
* @param[in] match_upto For specifying the actual length of `uri_to_match` up to
* which the matching algorithm is to be applied (The maximum
* value is `strlen(uri_to_match)`, independent of the length
* of `reference_uri`)
* @return true on match
*/
typedef bool (*httpd_uri_match_func_t)(const char *reference_uri,
const char *uri_to_match,
size_t match_upto);
/**
* @brief HTTP Server Configuration Structure
*
* @note Use HTTPD_DEFAULT_CONFIG() to initialize the configuration
* to a default value and then modify only those fields that are
* specifically determined by the use case.
*/
typedef struct httpd_config {
unsigned task_priority; /*!< Priority of FreeRTOS task which runs the server */
size_t stack_size; /*!< The maximum stack size allowed for the server task */
/**
* TCP Port number for receiving and transmitting HTTP traffic
*/
uint16_t server_port;
/**
* UDP Port number for asynchronously exchanging control signals
* between various components of the server
*/
uint16_t ctrl_port;
uint16_t max_open_sockets; /*!< Max number of sockets/clients connected at any time*/
uint16_t max_uri_handlers; /*!< Maximum allowed uri handlers */
uint16_t max_resp_headers; /*!< Maximum allowed additional headers in HTTP response */
uint16_t backlog_conn; /*!< Number of backlog connections */
bool lru_purge_enable; /*!< Purge "Least Recently Used" connection */
uint16_t recv_wait_timeout; /*!< Timeout for recv function (in seconds)*/
uint16_t send_wait_timeout; /*!< Timeout for send function (in seconds)*/
/**
* Global user context.
*
* This field can be used to store arbitrary user data within the server context.
* The value can be retrieved using the server handle, available e.g. in the httpd_req_t struct.
*
* When shutting down, the server frees up the user context by
* calling free() on the global_user_ctx field. If you wish to use a custom
* function for freeing the global user context, please specify that here.
*/
void * global_user_ctx;
/**
* Free function for global user context
*/
httpd_free_ctx_fn_t global_user_ctx_free_fn;
/**
* Global transport context.
*
* Similar to global_user_ctx, but used for session encoding or encryption (e.g. to hold the SSL context).
* It will be freed using free(), unless global_transport_ctx_free_fn is specified.
*/
void * global_transport_ctx;
/**
* Free function for global transport context
*/
httpd_free_ctx_fn_t global_transport_ctx_free_fn;
/**
* Custom session opening callback.
*
* Called on a new session socket just after accept(), but before reading any data.
*
* This is an opportunity to set up e.g. SSL encryption using global_transport_ctx
* and the send/recv/pending session overrides.
*
* If a context needs to be maintained between these functions, store it in the session using
* httpd_sess_set_transport_ctx() and retrieve it later with httpd_sess_get_transport_ctx()
*/
httpd_open_func_t open_fn;
/**
* Custom session closing callback.
*
* Called when a session is deleted, before freeing user and transport contexts and before
* closing the socket. This is a place for custom de-init code common to all sockets.
*
* Set the user or transport context to NULL if it was freed here, so the server does not
* try to free it again.
*
* This function is run for all terminated sessions, including sessions where the socket
* was closed by the network stack - that is, the file descriptor may not be valid anymore.
*/
httpd_close_func_t close_fn;
/**
* URI matcher function.
*
* Called when searching for a matching URI:
* 1) whose request handler is to be executed right
* after an HTTP request is successfully parsed
* 2) in order to prevent duplication while registering
* a new URI handler using `httpd_register_uri_handler()`
*
* Available options are:
* 1) NULL : Internally do basic matching using `strncmp()`
* 2) `httpd_uri_match_wildcard()` : URI wildcard matcher
*
* Users can implement their own matching functions (See description
* of the `httpd_uri_match_func_t` function prototype)
*/
httpd_uri_match_func_t uri_match_fn;
} httpd_config_t;
/**
* @brief Starts the web server
*
* Create an instance of HTTP server and allocate memory/resources for it
* depending upon the specified configuration.
*
* Example usage:
* @code{c}
*
* //Function for starting the webserver
* httpd_handle_t start_webserver(void)
* {
* // Generate default configuration
* httpd_config_t config = HTTPD_DEFAULT_CONFIG();
*
* // Empty handle to http_server
* httpd_handle_t server = NULL;
*
* // Start the httpd server
* if (httpd_start(&server, &config) == ESP_OK) {
* // Register URI handlers
* httpd_register_uri_handler(server, &uri_get);
* httpd_register_uri_handler(server, &uri_post);
* }
* // If server failed to start, handle will be NULL
* return server;
* }
*
* @endcode
*
* @param[in] config Configuration for new instance of the server
* @param[out] handle Handle to newly created instance of the server. NULL on error
* @return
* - ESP_OK : Instance created successfully
* - ESP_ERR_INVALID_ARG : Null argument(s)
* - ESP_ERR_HTTPD_ALLOC_MEM : Failed to allocate memory for instance
* - ESP_ERR_HTTPD_TASK : Failed to launch server task
*/
esp_err_t httpd_start(httpd_handle_t *handle, const httpd_config_t *config);
/**
* @brief Stops the web server
*
* Deallocates memory/resources used by an HTTP server instance and
* deletes it. Once deleted the handle can no longer be used for accessing
* the instance.
*
* Example usage:
* @code{c}
*
* // Function for stopping the webserver
* void stop_webserver(httpd_handle_t server)
* {
* // Ensure handle is non NULL
* if (server != NULL) {
* // Stop the httpd server
* httpd_stop(server);
* }
* }
*
* @endcode
*
* @param[in] handle Handle to server returned by httpd_start
* @return
* - ESP_OK : Server stopped successfully
* - ESP_ERR_INVALID_ARG : Handle argument is Null
*/
esp_err_t httpd_stop(httpd_handle_t handle);
/** End of Group Initialization
* @}
*/
/* ************** Group: URI Handlers ************** */
/** @name URI Handlers
* APIs related to the URI handlers
* @{
*/
/* Max supported HTTP request header length */
#define HTTPD_MAX_REQ_HDR_LEN CONFIG_HTTPD_MAX_REQ_HDR_LEN
/* Max supported HTTP request URI length */
#define HTTPD_MAX_URI_LEN CONFIG_HTTPD_MAX_URI_LEN
/**
* @brief HTTP Request Data Structure
*/
typedef struct httpd_req {
httpd_handle_t handle; /*!< Handle to server instance */
int method; /*!< The type of HTTP request, -1 if unsupported method */
const char uri[HTTPD_MAX_URI_LEN + 1]; /*!< The URI of this request (1 byte extra for null termination) */
size_t content_len; /*!< Length of the request body */
void *aux; /*!< Internally used members */
/**
* User context pointer passed during URI registration.
*/
void *user_ctx;
/**
* Session Context Pointer
*
* A session context. Contexts are maintained across 'sessions' for a
* given open TCP connection. One session could have multiple request
* responses. The web server will ensure that the context persists
* across all these request and responses.
*
* By default, this is NULL. URI Handlers can set this to any meaningful
* value.
*
* If the underlying socket gets closed, and this pointer is non-NULL,
* the web server will free up the context by calling free(), unless
* free_ctx function is set.
*/
void *sess_ctx;
/**
* Pointer to free context hook
*
* Function to free session context
*
* If the web server's socket closes, it frees up the session context by
* calling free() on the sess_ctx member. If you wish to use a custom
* function for freeing the session context, please specify that here.
*/
httpd_free_ctx_fn_t free_ctx;
} httpd_req_t;
/**
* @brief Structure for URI handler
*/
typedef struct httpd_uri {
const char *uri; /*!< The URI to handle */
httpd_method_t method; /*!< Method supported by the URI */
/**
* Handler to call for supported request method. This must
* return ESP_OK, or else the underlying socket will be closed.
*/
esp_err_t (*handler)(httpd_req_t *r);
/**
* Pointer to user context data which will be available to handler
*/
void *user_ctx;
} httpd_uri_t;
/**
* @brief Registers a URI handler
*
* @note URI handlers can be registered in real time as long as the
* server handle is valid.
*
* Example usage:
* @code{c}
*
* esp_err_t my_uri_handler(httpd_req_t* req)
* {
* // Recv , Process and Send
* ....
* ....
* ....
*
* // Fail condition
* if (....) {
* // Return fail to close session //
* return ESP_FAIL;
* }
*
* // On success
* return ESP_OK;
* }
*
* // URI handler structure
* httpd_uri_t my_uri {
* .uri = "/my_uri/path/xyz",
* .method = HTTPD_GET,
* .handler = my_uri_handler,
* .user_ctx = NULL
* };
*
* // Register handler
* if (httpd_register_uri_handler(server_handle, &my_uri) != ESP_OK) {
* // If failed to register handler
* ....
* }
*
* @endcode
*
* @param[in] handle handle to HTTPD server instance
* @param[in] uri_handler pointer to handler that needs to be registered
*
* @return
* - ESP_OK : On successfully registering the handler
* - ESP_ERR_INVALID_ARG : Null arguments
* - ESP_ERR_HTTPD_HANDLERS_FULL : If no slots left for new handler
* - ESP_ERR_HTTPD_HANDLER_EXISTS : If handler with same URI and
* method is already registered
*/
esp_err_t httpd_register_uri_handler(httpd_handle_t handle,
const httpd_uri_t *uri_handler);
/**
* @brief Unregister a URI handler
*
* @param[in] handle handle to HTTPD server instance
* @param[in] uri URI string
* @param[in] method HTTP method
*
* @return
* - ESP_OK : On successfully deregistering the handler
* - ESP_ERR_INVALID_ARG : Null arguments
* - ESP_ERR_NOT_FOUND : Handler with specified URI and method not found
*/
esp_err_t httpd_unregister_uri_handler(httpd_handle_t handle,
const char *uri, httpd_method_t method);
/**
* @brief Unregister all URI handlers with the specified uri string
*
* @param[in] handle handle to HTTPD server instance
* @param[in] uri uri string specifying all handlers that need
* to be deregisterd
*
* @return
* - ESP_OK : On successfully deregistering all such handlers
* - ESP_ERR_INVALID_ARG : Null arguments
* - ESP_ERR_NOT_FOUND : No handler registered with specified uri string
*/
esp_err_t httpd_unregister_uri(httpd_handle_t handle, const char* uri);
/** End of URI Handlers
* @}
*/
/* ************** Group: HTTP Error ************** */
/** @name HTTP Error
* Prototype for HTTP errors and error handling functions
* @{
*/
/**
* @brief Error codes sent as HTTP response in case of errors
* encountered during processing of an HTTP request
*/
typedef enum {
/* For any unexpected errors during parsing, like unexpected
* state transitions, or unhandled errors.
*/
HTTPD_500_INTERNAL_SERVER_ERROR = 0,
/* For methods not supported by http_parser. Presently
* http_parser halts parsing when such methods are
* encountered and so the server responds with 400 Bad
* Request error instead.
*/
HTTPD_501_METHOD_NOT_IMPLEMENTED,
/* When HTTP version is not 1.1 */
HTTPD_505_VERSION_NOT_SUPPORTED,
/* Returned when http_parser halts parsing due to incorrect
* syntax of request, unsupported method in request URI or
* due to chunked encoding / upgrade field present in headers
*/
HTTPD_400_BAD_REQUEST,
/* When requested URI is not found */
HTTPD_404_NOT_FOUND,
/* When URI found, but method has no handler registered */
HTTPD_405_METHOD_NOT_ALLOWED,
/* Intended for recv timeout. Presently it's being sent
* for other recv errors as well. Client should expect the
* server to immediately close the connection after
* responding with this.
*/
HTTPD_408_REQ_TIMEOUT,
/* Intended for responding to chunked encoding, which is
* not supported currently. Though unhandled http_parser
* callback for chunked request returns "400 Bad Request"
*/
HTTPD_411_LENGTH_REQUIRED,
/* URI length greater than CONFIG_HTTPD_MAX_URI_LEN */
HTTPD_414_URI_TOO_LONG,
/* Headers section larger than CONFIG_HTTPD_MAX_REQ_HDR_LEN */
HTTPD_431_REQ_HDR_FIELDS_TOO_LARGE,
/* Used internally for retrieving the total count of errors */
HTTPD_ERR_CODE_MAX
} httpd_err_code_t;
/**
* @brief Function prototype for HTTP error handling.
*
* This function is executed upon HTTP errors generated during
* internal processing of an HTTP request. This is used to override
* the default behavior on error, which is to send HTTP error response
* and close the underlying socket.
*
* @note
* - If implemented, the server will not automatically send out HTTP
* error response codes, therefore, httpd_resp_send_err() must be
* invoked inside this function if user wishes to generate HTTP
* error responses.
* - When invoked, the validity of `uri`, `method`, `content_len`
* and `user_ctx` fields of the httpd_req_t parameter is not
* guaranteed as the HTTP request may be partially received/parsed.
* - The function must return ESP_OK if underlying socket needs to
* be kept open. Any other value will ensure that the socket is
* closed. The return value is ignored when error is of type
* `HTTPD_500_INTERNAL_SERVER_ERROR` and the socket closed anyway.
*
* @param[in] req HTTP request for which the error needs to be handled
* @param[in] error Error type
*
* @return
* - ESP_OK : error handled successful
* - ESP_FAIL : failure indicates that the underlying socket needs to be closed
*/
typedef esp_err_t (*httpd_err_handler_func_t)(httpd_req_t *req,
httpd_err_code_t error);
/**
* @brief Function for registering HTTP error handlers
*
* This function maps a handler function to any supported error code
* given by `httpd_err_code_t`. See prototype `httpd_err_handler_func_t`
* above for details.
*
* @param[in] handle HTTP server handle
* @param[in] error Error type
* @param[in] handler_fn User implemented handler function
* (Pass NULL to unset any previously set handler)
*
* @return
* - ESP_OK : handler registered successfully
* - ESP_ERR_INVALID_ARG : invalid error code or server handle
*/
esp_err_t httpd_register_err_handler(httpd_handle_t handle,
httpd_err_code_t error,
httpd_err_handler_func_t handler_fn);
/** End of HTTP Error
* @}
*/
/* ************** Group: TX/RX ************** */
/** @name TX / RX
* Prototype for HTTPDs low-level send/recv functions
* @{
*/
#define HTTPD_SOCK_ERR_FAIL -1
#define HTTPD_SOCK_ERR_INVALID -2
#define HTTPD_SOCK_ERR_TIMEOUT -3
/**
* @brief Prototype for HTTPDs low-level send function
*
* @note User specified send function must handle errors internally,
* depending upon the set value of errno, and return specific
* HTTPD_SOCK_ERR_ codes, which will eventually be conveyed as
* return value of httpd_send() function
*
* @param[in] hd server instance
* @param[in] sockfd session socket file descriptor
* @param[in] buf buffer with bytes to send
* @param[in] buf_len data size
* @param[in] flags flags for the send() function
* @return
* - Bytes : The number of bytes sent successfully
* - HTTPD_SOCK_ERR_INVALID : Invalid arguments
* - HTTPD_SOCK_ERR_TIMEOUT : Timeout/interrupted while calling socket send()
* - HTTPD_SOCK_ERR_FAIL : Unrecoverable error while calling socket send()
*/
typedef int (*httpd_send_func_t)(httpd_handle_t hd, int sockfd, const char *buf, size_t buf_len, int flags);
/**
* @brief Prototype for HTTPDs low-level recv function
*
* @note User specified recv function must handle errors internally,
* depending upon the set value of errno, and return specific
* HTTPD_SOCK_ERR_ codes, which will eventually be conveyed as
* return value of httpd_req_recv() function
*
* @param[in] hd server instance
* @param[in] sockfd session socket file descriptor
* @param[in] buf buffer with bytes to send
* @param[in] buf_len data size
* @param[in] flags flags for the send() function
* @return
* - Bytes : The number of bytes received successfully
* - 0 : Buffer length parameter is zero / connection closed by peer
* - HTTPD_SOCK_ERR_INVALID : Invalid arguments
* - HTTPD_SOCK_ERR_TIMEOUT : Timeout/interrupted while calling socket recv()
* - HTTPD_SOCK_ERR_FAIL : Unrecoverable error while calling socket recv()
*/
typedef int (*httpd_recv_func_t)(httpd_handle_t hd, int sockfd, char *buf, size_t buf_len, int flags);
/**
* @brief Prototype for HTTPDs low-level "get pending bytes" function
*
* @note User specified pending function must handle errors internally,
* depending upon the set value of errno, and return specific
* HTTPD_SOCK_ERR_ codes, which will be handled accordingly in
* the server task.
*
* @param[in] hd server instance
* @param[in] sockfd session socket file descriptor
* @return
* - Bytes : The number of bytes waiting to be received
* - HTTPD_SOCK_ERR_INVALID : Invalid arguments
* - HTTPD_SOCK_ERR_TIMEOUT : Timeout/interrupted while calling socket pending()
* - HTTPD_SOCK_ERR_FAIL : Unrecoverable error while calling socket pending()
*/
typedef int (*httpd_pending_func_t)(httpd_handle_t hd, int sockfd);
/** End of TX / RX
* @}
*/
/* ************** Group: Request/Response ************** */
/** @name Request / Response
* APIs related to the data send/receive by URI handlers.
* These APIs are supposed to be called only from the context of
* a URI handler where httpd_req_t* request pointer is valid.
* @{
*/
/**
* @brief Override web server's receive function (by session FD)
*
* This function overrides the web server's receive function. This same function is
* used to read HTTP request packets.
*
* @note This API is supposed to be called either from the context of
* - an http session APIs where sockfd is a valid parameter
* - a URI handler where sockfd is obtained using httpd_req_to_sockfd()
*
* @param[in] hd HTTPD instance handle
* @param[in] sockfd Session socket FD
* @param[in] recv_func The receive function to be set for this session
*
* @return
* - ESP_OK : On successfully registering override
* - ESP_ERR_INVALID_ARG : Null arguments
*/
esp_err_t httpd_sess_set_recv_override(httpd_handle_t hd, int sockfd, httpd_recv_func_t recv_func);
/**
* @brief Override web server's send function (by session FD)
*
* This function overrides the web server's send function. This same function is
* used to send out any response to any HTTP request.
*
* @note This API is supposed to be called either from the context of
* - an http session APIs where sockfd is a valid parameter
* - a URI handler where sockfd is obtained using httpd_req_to_sockfd()
*
* @param[in] hd HTTPD instance handle
* @param[in] sockfd Session socket FD
* @param[in] send_func The send function to be set for this session
*
* @return
* - ESP_OK : On successfully registering override
* - ESP_ERR_INVALID_ARG : Null arguments
*/
esp_err_t httpd_sess_set_send_override(httpd_handle_t hd, int sockfd, httpd_send_func_t send_func);
/**
* @brief Override web server's pending function (by session FD)
*
* This function overrides the web server's pending function. This function is
* used to test for pending bytes in a socket.
*
* @note This API is supposed to be called either from the context of
* - an http session APIs where sockfd is a valid parameter
* - a URI handler where sockfd is obtained using httpd_req_to_sockfd()
*
* @param[in] hd HTTPD instance handle
* @param[in] sockfd Session socket FD
* @param[in] pending_func The receive function to be set for this session
*
* @return
* - ESP_OK : On successfully registering override
* - ESP_ERR_INVALID_ARG : Null arguments
*/
esp_err_t httpd_sess_set_pending_override(httpd_handle_t hd, int sockfd, httpd_pending_func_t pending_func);
/**
* @brief Get the Socket Descriptor from the HTTP request
*
* This API will return the socket descriptor of the session for
* which URI handler was executed on reception of HTTP request.
* This is useful when user wants to call functions that require
* session socket fd, from within a URI handler, ie. :
* httpd_sess_get_ctx(),
* httpd_sess_trigger_close(),
* httpd_sess_update_lru_counter().
*
* @note This API is supposed to be called only from the context of
* a URI handler where httpd_req_t* request pointer is valid.
*
* @param[in] r The request whose socket descriptor should be found
*
* @return
* - Socket descriptor : The socket descriptor for this request
* - -1 : Invalid/NULL request pointer
*/
int httpd_req_to_sockfd(httpd_req_t *r);
/**
* @brief API to read content data from the HTTP request
*
* This API will read HTTP content data from the HTTP request into
* provided buffer. Use content_len provided in httpd_req_t structure
* to know the length of data to be fetched. If content_len is too
* large for the buffer then user may have to make multiple calls to
* this function, each time fetching 'buf_len' number of bytes,
* while the pointer to content data is incremented internally by
* the same number.
*
* @note
* - This API is supposed to be called only from the context of
* a URI handler where httpd_req_t* request pointer is valid.
* - If an error is returned, the URI handler must further return an error.
* This will ensure that the erroneous socket is closed and cleaned up by
* the web server.
* - Presently Chunked Encoding is not supported
*
* @param[in] r The request being responded to
* @param[in] buf Pointer to a buffer that the data will be read into
* @param[in] buf_len Length of the buffer
*
* @return
* - Bytes : Number of bytes read into the buffer successfully
* - 0 : Buffer length parameter is zero / connection closed by peer
* - HTTPD_SOCK_ERR_INVALID : Invalid arguments
* - HTTPD_SOCK_ERR_TIMEOUT : Timeout/interrupted while calling socket recv()
* - HTTPD_SOCK_ERR_FAIL : Unrecoverable error while calling socket recv()
*/
int httpd_req_recv(httpd_req_t *r, char *buf, size_t buf_len);
/**
* @brief Search for a field in request headers and
* return the string length of it's value
*
* @note
* - This API is supposed to be called only from the context of
* a URI handler where httpd_req_t* request pointer is valid.
* - Once httpd_resp_send() API is called all request headers
* are purged, so request headers need be copied into separate
* buffers if they are required later.
*
* @param[in] r The request being responded to
* @param[in] field The header field to be searched in the request
*
* @return
* - Length : If field is found in the request URL
* - Zero : Field not found / Invalid request / Null arguments
*/
size_t httpd_req_get_hdr_value_len(httpd_req_t *r, const char *field);
/**
* @brief Get the value string of a field from the request headers
*
* @note
* - This API is supposed to be called only from the context of
* a URI handler where httpd_req_t* request pointer is valid.
* - Once httpd_resp_send() API is called all request headers
* are purged, so request headers need be copied into separate
* buffers if they are required later.
* - If output size is greater than input, then the value is truncated,
* accompanied by truncation error as return value.
* - Use httpd_req_get_hdr_value_len() to know the right buffer length
*
* @param[in] r The request being responded to
* @param[in] field The field to be searched in the header
* @param[out] val Pointer to the buffer into which the value will be copied if the field is found
* @param[in] val_size Size of the user buffer "val"
*
* @return
* - ESP_OK : Field found in the request header and value string copied
* - ESP_ERR_NOT_FOUND : Key not found
* - ESP_ERR_INVALID_ARG : Null arguments
* - ESP_ERR_HTTPD_INVALID_REQ : Invalid HTTP request pointer
* - ESP_ERR_HTTPD_RESULT_TRUNC : Value string truncated
*/
esp_err_t httpd_req_get_hdr_value_str(httpd_req_t *r, const char *field, char *val, size_t val_size);
/**
* @brief Get Query string length from the request URL
*
* @note This API is supposed to be called only from the context of
* a URI handler where httpd_req_t* request pointer is valid
*
* @param[in] r The request being responded to
*
* @return
* - Length : Query is found in the request URL
* - Zero : Query not found / Null arguments / Invalid request
*/
size_t httpd_req_get_url_query_len(httpd_req_t *r);
/**
* @brief Get Query string from the request URL
*
* @note
* - Presently, the user can fetch the full URL query string, but decoding
* will have to be performed by the user. Request headers can be read using
* httpd_req_get_hdr_value_str() to know the 'Content-Type' (eg. Content-Type:
* application/x-www-form-urlencoded) and then the appropriate decoding
* algorithm needs to be applied.
* - This API is supposed to be called only from the context of
* a URI handler where httpd_req_t* request pointer is valid
* - If output size is greater than input, then the value is truncated,
* accompanied by truncation error as return value
* - Use httpd_req_get_url_query_len() to know the right buffer length
*
* @param[in] r The request being responded to
* @param[out] buf Pointer to the buffer into which the query string will be copied (if found)
* @param[in] buf_len Length of output buffer
*
* @return
* - ESP_OK : Query is found in the request URL and copied to buffer
* - ESP_ERR_NOT_FOUND : Query not found
* - ESP_ERR_INVALID_ARG : Null arguments
* - ESP_ERR_HTTPD_INVALID_REQ : Invalid HTTP request pointer
* - ESP_ERR_HTTPD_RESULT_TRUNC : Query string truncated
*/
esp_err_t httpd_req_get_url_query_str(httpd_req_t *r, char *buf, size_t buf_len);
/**
* @brief Helper function to get a URL query tag from a query
* string of the type param1=val1&param2=val2
*
* @note
* - The components of URL query string (keys and values) are not URLdecoded.
* The user must check for 'Content-Type' field in the request headers and
* then depending upon the specified encoding (URLencoded or otherwise) apply
* the appropriate decoding algorithm.
* - If actual value size is greater than val_size, then the value is truncated,
* accompanied by truncation error as return value.
*
* @param[in] qry Pointer to query string
* @param[in] key The key to be searched in the query string
* @param[out] val Pointer to the buffer into which the value will be copied if the key is found
* @param[in] val_size Size of the user buffer "val"
*
* @return
* - ESP_OK : Key is found in the URL query string and copied to buffer
* - ESP_ERR_NOT_FOUND : Key not found
* - ESP_ERR_INVALID_ARG : Null arguments
* - ESP_ERR_HTTPD_RESULT_TRUNC : Value string truncated
*/
esp_err_t httpd_query_key_value(const char *qry, const char *key, char *val, size_t val_size);
/**
* @brief Test if a URI matches the given wildcard template.
*
* Template may end with "?" to make the previous character optional (typically a slash),
* "*" for a wildcard match, and "?*" to make the previous character optional, and if present,
* allow anything to follow.
*
* Example:
* - * matches everything
* - /foo/? matches /foo and /foo/
* - /foo/\* (sans the backslash) matches /foo/ and /foo/bar, but not /foo or /fo
* - /foo/?* or /foo/\*? (sans the backslash) matches /foo/, /foo/bar, and also /foo, but not /foox or /fo
*
* The special characters "?" and "*" anywhere else in the template will be taken literally.
*
* @param[in] uri_template URI template (pattern)
* @param[in] uri_to_match URI to be matched
* @param[in] match_upto how many characters of the URI buffer to test
* (there may be trailing query string etc.)
*
* @return true if a match was found
*/
bool httpd_uri_match_wildcard(const char *uri_template, const char *uri_to_match, size_t match_upto);
/**
* @brief API to send a complete HTTP response.
*
* This API will send the data as an HTTP response to the request.
* This assumes that you have the entire response ready in a single
* buffer. If you wish to send response in incremental chunks use
* httpd_resp_send_chunk() instead.
*
* If no status code and content-type were set, by default this
* will send 200 OK status code and content type as text/html.
* You may call the following functions before this API to configure
* the response headers :
* httpd_resp_set_status() - for setting the HTTP status string,
* httpd_resp_set_type() - for setting the Content Type,
* httpd_resp_set_hdr() - for appending any additional field
* value entries in the response header
*
* @note
* - This API is supposed to be called only from the context of
* a URI handler where httpd_req_t* request pointer is valid.
* - Once this API is called, the request has been responded to.
* - No additional data can then be sent for the request.
* - Once this API is called, all request headers are purged, so
* request headers need be copied into separate buffers if
* they are required later.
*
* @param[in] r The request being responded to
* @param[in] buf Buffer from where the content is to be fetched
* @param[in] buf_len Length of the buffer, HTTPD_RESP_USE_STRLEN to use strlen()
*
* @return
* - ESP_OK : On successfully sending the response packet
* - ESP_ERR_INVALID_ARG : Null request pointer
* - ESP_ERR_HTTPD_RESP_HDR : Essential headers are too large for internal buffer
* - ESP_ERR_HTTPD_RESP_SEND : Error in raw send
* - ESP_ERR_HTTPD_INVALID_REQ : Invalid request
*/
esp_err_t httpd_resp_send(httpd_req_t *r, const char *buf, ssize_t buf_len);
/**
* @brief API to send one HTTP chunk
*
* This API will send the data as an HTTP response to the
* request. This API will use chunked-encoding and send the response
* in the form of chunks. If you have the entire response contained in
* a single buffer, please use httpd_resp_send() instead.
*
* If no status code and content-type were set, by default this will
* send 200 OK status code and content type as text/html. You may
* call the following functions before this API to configure the
* response headers
* httpd_resp_set_status() - for setting the HTTP status string,
* httpd_resp_set_type() - for setting the Content Type,
* httpd_resp_set_hdr() - for appending any additional field
* value entries in the response header
*
* @note
* - This API is supposed to be called only from the context of
* a URI handler where httpd_req_t* request pointer is valid.
* - When you are finished sending all your chunks, you must call
* this function with buf_len as 0.
* - Once this API is called, all request headers are purged, so
* request headers need be copied into separate buffers if they
* are required later.
*
* @param[in] r The request being responded to
* @param[in] buf Pointer to a buffer that stores the data
* @param[in] buf_len Length of the buffer, HTTPD_RESP_USE_STRLEN to use strlen()
*
* @return
* - ESP_OK : On successfully sending the response packet chunk
* - ESP_ERR_INVALID_ARG : Null request pointer
* - ESP_ERR_HTTPD_RESP_HDR : Essential headers are too large for internal buffer
* - ESP_ERR_HTTPD_RESP_SEND : Error in raw send
* - ESP_ERR_HTTPD_INVALID_REQ : Invalid request pointer
*/
esp_err_t httpd_resp_send_chunk(httpd_req_t *r, const char *buf, ssize_t buf_len);
/**
* @brief API to send a complete string as HTTP response.
*
* This API simply calls http_resp_send with buffer length
* set to string length assuming the buffer contains a null
* terminated string
*
* @param[in] r The request being responded to
* @param[in] str String to be sent as response body
*
* @return
* - ESP_OK : On successfully sending the response packet
* - ESP_ERR_INVALID_ARG : Null request pointer
* - ESP_ERR_HTTPD_RESP_HDR : Essential headers are too large for internal buffer
* - ESP_ERR_HTTPD_RESP_SEND : Error in raw send
* - ESP_ERR_HTTPD_INVALID_REQ : Invalid request
*/
static inline esp_err_t httpd_resp_sendstr(httpd_req_t *r, const char *str) {
return httpd_resp_send(r, str, (str == NULL) ? 0 : strlen(str));
}
/**
* @brief API to send a string as an HTTP response chunk.
*
* This API simply calls http_resp_send_chunk with buffer length
* set to string length assuming the buffer contains a null
* terminated string
*
* @param[in] r The request being responded to
* @param[in] str String to be sent as response body (NULL to finish response packet)
*
* @return
* - ESP_OK : On successfully sending the response packet
* - ESP_ERR_INVALID_ARG : Null request pointer
* - ESP_ERR_HTTPD_RESP_HDR : Essential headers are too large for internal buffer
* - ESP_ERR_HTTPD_RESP_SEND : Error in raw send
* - ESP_ERR_HTTPD_INVALID_REQ : Invalid request
*/
static inline esp_err_t httpd_resp_sendstr_chunk(httpd_req_t *r, const char *str) {
return httpd_resp_send_chunk(r, str, (str == NULL) ? 0 : strlen(str));
}
/* Some commonly used status codes */
#define HTTPD_200 "200 OK" /*!< HTTP Response 200 */
#define HTTPD_204 "204 No Content" /*!< HTTP Response 204 */
#define HTTPD_207 "207 Multi-Status" /*!< HTTP Response 207 */
#define HTTPD_400 "400 Bad Request" /*!< HTTP Response 400 */
#define HTTPD_404 "404 Not Found" /*!< HTTP Response 404 */
#define HTTPD_408 "408 Request Timeout" /*!< HTTP Response 408 */
#define HTTPD_500 "500 Internal Server Error" /*!< HTTP Response 500 */
/**
* @brief API to set the HTTP status code
*
* This API sets the status of the HTTP response to the value specified.
* By default, the '200 OK' response is sent as the response.
*
* @note
* - This API is supposed to be called only from the context of
* a URI handler where httpd_req_t* request pointer is valid.
* - This API only sets the status to this value. The status isn't
* sent out until any of the send APIs is executed.
* - Make sure that the lifetime of the status string is valid till
* send function is called.
*
* @param[in] r The request being responded to
* @param[in] status The HTTP status code of this response
*
* @return
* - ESP_OK : On success
* - ESP_ERR_INVALID_ARG : Null arguments
* - ESP_ERR_HTTPD_INVALID_REQ : Invalid request pointer
*/
esp_err_t httpd_resp_set_status(httpd_req_t *r, const char *status);
/* Some commonly used content types */
#define HTTPD_TYPE_JSON "application/json" /*!< HTTP Content type JSON */
#define HTTPD_TYPE_TEXT "text/html" /*!< HTTP Content type text/HTML */
#define HTTPD_TYPE_OCTET "application/octet-stream" /*!< HTTP Content type octext-stream */
/**
* @brief API to set the HTTP content type
*
* This API sets the 'Content Type' field of the response.
* The default content type is 'text/html'.
*
* @note
* - This API is supposed to be called only from the context of
* a URI handler where httpd_req_t* request pointer is valid.
* - This API only sets the content type to this value. The type
* isn't sent out until any of the send APIs is executed.
* - Make sure that the lifetime of the type string is valid till
* send function is called.
*
* @param[in] r The request being responded to
* @param[in] type The Content Type of the response
*
* @return
* - ESP_OK : On success
* - ESP_ERR_INVALID_ARG : Null arguments
* - ESP_ERR_HTTPD_INVALID_REQ : Invalid request pointer
*/
esp_err_t httpd_resp_set_type(httpd_req_t *r, const char *type);
/**
* @brief API to append any additional headers
*
* This API sets any additional header fields that need to be sent in the response.
*
* @note
* - This API is supposed to be called only from the context of
* a URI handler where httpd_req_t* request pointer is valid.
* - The header isn't sent out until any of the send APIs is executed.
* - The maximum allowed number of additional headers is limited to
* value of max_resp_headers in config structure.
* - Make sure that the lifetime of the field value strings are valid till
* send function is called.
*
* @param[in] r The request being responded to
* @param[in] field The field name of the HTTP header
* @param[in] value The value of this HTTP header
*
* @return
* - ESP_OK : On successfully appending new header
* - ESP_ERR_INVALID_ARG : Null arguments
* - ESP_ERR_HTTPD_RESP_HDR : Total additional headers exceed max allowed
* - ESP_ERR_HTTPD_INVALID_REQ : Invalid request pointer
*/
esp_err_t httpd_resp_set_hdr(httpd_req_t *r, const char *field, const char *value);
/**
* @brief For sending out error code in response to HTTP request.
*
* @note
* - This API is supposed to be called only from the context of
* a URI handler where httpd_req_t* request pointer is valid.
* - Once this API is called, all request headers are purged, so
* request headers need be copied into separate buffers if
* they are required later.
* - If you wish to send additional data in the body of the
* response, please use the lower-level functions directly.
*
* @param[in] req Pointer to the HTTP request for which the response needs to be sent
* @param[in] error Error type to send
* @param[in] msg Error message string (pass NULL for default message)
*
* @return
* - ESP_OK : On successfully sending the response packet
* - ESP_ERR_INVALID_ARG : Null arguments
* - ESP_ERR_HTTPD_RESP_SEND : Error in raw send
* - ESP_ERR_HTTPD_INVALID_REQ : Invalid request pointer
*/
esp_err_t httpd_resp_send_err(httpd_req_t *req, httpd_err_code_t error, const char *msg);
/**
* @brief Helper function for HTTP 404
*
* Send HTTP 404 message. If you wish to send additional data in the body of the
* response, please use the lower-level functions directly.
*
* @note
* - This API is supposed to be called only from the context of
* a URI handler where httpd_req_t* request pointer is valid.
* - Once this API is called, all request headers are purged, so
* request headers need be copied into separate buffers if
* they are required later.
*
* @param[in] r The request being responded to
*
* @return
* - ESP_OK : On successfully sending the response packet
* - ESP_ERR_INVALID_ARG : Null arguments
* - ESP_ERR_HTTPD_RESP_SEND : Error in raw send
* - ESP_ERR_HTTPD_INVALID_REQ : Invalid request pointer
*/
static inline esp_err_t httpd_resp_send_404(httpd_req_t *r) {
return httpd_resp_send_err(r, HTTPD_404_NOT_FOUND, NULL);
}
/**
* @brief Helper function for HTTP 408
*
* Send HTTP 408 message. If you wish to send additional data in the body of the
* response, please use the lower-level functions directly.
*
* @note
* - This API is supposed to be called only from the context of
* a URI handler where httpd_req_t* request pointer is valid.
* - Once this API is called, all request headers are purged, so
* request headers need be copied into separate buffers if
* they are required later.
*
* @param[in] r The request being responded to
*
* @return
* - ESP_OK : On successfully sending the response packet
* - ESP_ERR_INVALID_ARG : Null arguments
* - ESP_ERR_HTTPD_RESP_SEND : Error in raw send
* - ESP_ERR_HTTPD_INVALID_REQ : Invalid request pointer
*/
static inline esp_err_t httpd_resp_send_408(httpd_req_t *r) {
return httpd_resp_send_err(r, HTTPD_408_REQ_TIMEOUT, NULL);
}
/**
* @brief Helper function for HTTP 500
*
* Send HTTP 500 message. If you wish to send additional data in the body of the
* response, please use the lower-level functions directly.
*
* @note
* - This API is supposed to be called only from the context of
* a URI handler where httpd_req_t* request pointer is valid.
* - Once this API is called, all request headers are purged, so
* request headers need be copied into separate buffers if
* they are required later.
*
* @param[in] r The request being responded to
*
* @return
* - ESP_OK : On successfully sending the response packet
* - ESP_ERR_INVALID_ARG : Null arguments
* - ESP_ERR_HTTPD_RESP_SEND : Error in raw send
* - ESP_ERR_HTTPD_INVALID_REQ : Invalid request pointer
*/
static inline esp_err_t httpd_resp_send_500(httpd_req_t *r) {
return httpd_resp_send_err(r, HTTPD_500_INTERNAL_SERVER_ERROR, NULL);
}
/**
* @brief Raw HTTP send
*
* Call this API if you wish to construct your custom response packet.
* When using this, all essential header, eg. HTTP version, Status Code,
* Content Type and Length, Encoding, etc. will have to be constructed
* manually, and HTTP delimeters (CRLF) will need to be placed correctly
* for separating sub-sections of the HTTP response packet.
*
* If the send override function is set, this API will end up
* calling that function eventually to send data out.
*
* @note
* - This API is supposed to be called only from the context of
* a URI handler where httpd_req_t* request pointer is valid.
* - Unless the response has the correct HTTP structure (which the
* user must now ensure) it is not guaranteed that it will be
* recognized by the client. For most cases, you wouldn't have
* to call this API, but you would rather use either of :
* httpd_resp_send(),
* httpd_resp_send_chunk()
*
* @param[in] r The request being responded to
* @param[in] buf Buffer from where the fully constructed packet is to be read
* @param[in] buf_len Length of the buffer
*
* @return
* - Bytes : Number of bytes that were sent successfully
* - HTTPD_SOCK_ERR_INVALID : Invalid arguments
* - HTTPD_SOCK_ERR_TIMEOUT : Timeout/interrupted while calling socket send()
* - HTTPD_SOCK_ERR_FAIL : Unrecoverable error while calling socket send()
*/
int httpd_send(httpd_req_t *r, const char *buf, size_t buf_len);
/** End of Request / Response
* @}
*/
/* ************** Group: Session ************** */
/** @name Session
* Functions for controlling sessions and accessing context data
* @{
*/
/**
* @brief Get session context from socket descriptor
*
* Typically if a session context is created, it is available to URI handlers
* through the httpd_req_t structure. But, there are cases where the web
* server's send/receive functions may require the context (for example, for
* accessing keying information etc). Since the send/receive function only have
* the socket descriptor at their disposal, this API provides them with a way to
* retrieve the session context.
*
* @param[in] handle Handle to server returned by httpd_start
* @param[in] sockfd The socket descriptor for which the context should be extracted.
*
* @return
* - void* : Pointer to the context associated with this session
* - NULL : Empty context / Invalid handle / Invalid socket fd
*/
void *httpd_sess_get_ctx(httpd_handle_t handle, int sockfd);
/**
* @brief Set session context by socket descriptor
*
* @param[in] handle Handle to server returned by httpd_start
* @param[in] sockfd The socket descriptor for which the context should be extracted.
* @param[in] ctx Context object to assign to the session
* @param[in] free_fn Function that should be called to free the context
*/
void httpd_sess_set_ctx(httpd_handle_t handle, int sockfd, void *ctx, httpd_free_ctx_fn_t free_fn);
/**
* @brief Get session 'transport' context by socket descriptor
* @see httpd_sess_get_ctx()
*
* This context is used by the send/receive functions, for example to manage SSL context.
*
* @param[in] handle Handle to server returned by httpd_start
* @param[in] sockfd The socket descriptor for which the context should be extracted.
* @return
* - void* : Pointer to the transport context associated with this session
* - NULL : Empty context / Invalid handle / Invalid socket fd
*/
void *httpd_sess_get_transport_ctx(httpd_handle_t handle, int sockfd);
/**
* @brief Set session 'transport' context by socket descriptor
* @see httpd_sess_set_ctx()
*
* @param[in] handle Handle to server returned by httpd_start
* @param[in] sockfd The socket descriptor for which the context should be extracted.
* @param[in] ctx Transport context object to assign to the session
* @param[in] free_fn Function that should be called to free the transport context
*/
void httpd_sess_set_transport_ctx(httpd_handle_t handle, int sockfd, void *ctx, httpd_free_ctx_fn_t free_fn);
/**
* @brief Get HTTPD global user context (it was set in the server config struct)
*
* @param[in] handle Handle to server returned by httpd_start
* @return global user context
*/
void *httpd_get_global_user_ctx(httpd_handle_t handle);
/**
* @brief Get HTTPD global transport context (it was set in the server config struct)
*
* @param[in] handle Handle to server returned by httpd_start
* @return global transport context
*/
void *httpd_get_global_transport_ctx(httpd_handle_t handle);
/**
* @brief Trigger an httpd session close externally
*
* @note Calling this API is only required in special circumstances wherein
* some application requires to close an httpd client session asynchronously.
*
* @param[in] handle Handle to server returned by httpd_start
* @param[in] sockfd The socket descriptor of the session to be closed
*
* @return
* - ESP_OK : On successfully initiating closure
* - ESP_FAIL : Failure to queue work
* - ESP_ERR_NOT_FOUND : Socket fd not found
* - ESP_ERR_INVALID_ARG : Null arguments
*/
esp_err_t httpd_sess_trigger_close(httpd_handle_t handle, int sockfd);
/**
* @brief Update LRU counter for a given socket
*
* LRU Counters are internally associated with each session to monitor
* how recently a session exchanged traffic. When LRU purge is enabled,
* if a client is requesting for connection but maximum number of
* sockets/sessions is reached, then the session having the earliest
* LRU counter is closed automatically.
*
* Updating the LRU counter manually prevents the socket from being purged
* due to the Least Recently Used (LRU) logic, even though it might not
* have received traffic for some time. This is useful when all open
* sockets/session are frequently exchanging traffic but the user specifically
* wants one of the sessions to be kept open, irrespective of when it last
* exchanged a packet.
*
* @note Calling this API is only necessary if the LRU Purge Enable option
* is enabled.
*
* @param[in] handle Handle to server returned by httpd_start
* @param[in] sockfd The socket descriptor of the session for which LRU counter
* is to be updated
*
* @return
* - ESP_OK : Socket found and LRU counter updated
* - ESP_ERR_NOT_FOUND : Socket not found
* - ESP_ERR_INVALID_ARG : Null arguments
*/
esp_err_t httpd_sess_update_lru_counter(httpd_handle_t handle, int sockfd);
/** End of Session
* @}
*/
/* ************** Group: Work Queue ************** */
/** @name Work Queue
* APIs related to the HTTPD Work Queue
* @{
*/
/**
* @brief Prototype of the HTTPD work function
* Please refer to httpd_queue_work() for more details.
* @param[in] arg The arguments for this work function
*/
typedef void (*httpd_work_fn_t)(void *arg);
/**
* @brief Queue execution of a function in HTTPD's context
*
* This API queues a work function for asynchronous execution
*
* @note Some protocols require that the web server generate some asynchronous data
* and send it to the persistently opened connection. This facility is for use
* by such protocols.
*
* @param[in] handle Handle to server returned by httpd_start
* @param[in] work Pointer to the function to be executed in the HTTPD's context
* @param[in] arg Pointer to the arguments that should be passed to this function
*
* @return
* - ESP_OK : On successfully queueing the work
* - ESP_FAIL : Failure in ctrl socket
* - ESP_ERR_INVALID_ARG : Null arguments
*/
esp_err_t httpd_queue_work(httpd_handle_t handle, httpd_work_fn_t work, void *arg);
/** End of Group Work Queue
* @}
*/
#ifdef __cplusplus
}
#endif
#endif /* ! _ESP_HTTP_SERVER_H_ */
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