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OVMS3-idf/components/http_server/include/http_server.h
Anurg Kar 656bef7bb7 Http Server : Add a simple light weight HTTP Server Component. 
Also add examples, docs and test apps for the HTTP Server.
2018-07-20 15:49:17 +05:30

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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 _HTTP_SERVER_H_
#define _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
#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, \
};
#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 */
/* ************** 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 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)*/
} 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
* @{
*/
/**
* @brief Function type for freeing context data (if any)
*/
typedef void (*httpd_free_sess_ctx_fn_t)(void *sess_ctx);
/* 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_sess_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: TX/RX ************** */
/** @name TX / RX
* Prototype for HTTPDs low-level send/recv functions
* @{
*/
/**
* @brief Prototype for HTTPDs low-level send function
* @return
* - Bytes : The number of bytes sent successfully
* - -VE : In case of error
*/
typedef int (*httpd_send_func_t)(int sockfd, const char *buf, size_t buf_len, int flags);
/**
* @brief Prototype for HTTPDs low-level recv function
* @return
* - Bytes : The number of bytes received successfully
* - -VE : In case of error
*/
typedef int (*httpd_recv_func_t)(int sockfd, char *buf, size_t buf_len, int flags);
/** 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
*
* This function overrides the web server's receive function. This same function is
* used to read and parse HTTP headers as well as body.
*
* @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
* @param[in] recv_func The receive function to be set for this request
*
* @return
* - ESP_OK : On successfully registering override
* - ESP_ERR_INVALID_ARG : Null arguments
* - ESP_ERR_HTTPD_INVALID_REQ : Invalid request pointer
*/
esp_err_t httpd_set_recv_override(httpd_req_t *r, httpd_recv_func_t recv_func);
/**
* @brief Override web server's send function
*
* 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 only from the context of
* a URI handler where httpd_req_t* request pointer is valid.
*
* @param[in] r The request being responded to
* @param[in] send_func The send function to be set for this request
*
* @return
* - ESP_OK : On successfully registering override
* - ESP_ERR_INVALID_ARG : Null arguments
* - ESP_ERR_HTTPD_INVALID_REQ : Invalid request pointer
*/
esp_err_t httpd_set_send_override(httpd_req_t *r, httpd_send_func_t send_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_trigger_sess_close(),
* httpd_sess_update_timestamp().
*
* @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
* - Zero : When no more data is left for read
* - -1 : On raw recv error / Null arguments / Request pointer is invalid
*/
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 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
*
* @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, size_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 data from the buffer that should be sent out
*
* @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, size_t buf_len);
/* 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_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 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
*/
esp_err_t httpd_resp_send_404(httpd_req_t *r);
/**
* @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
* - -1 : Error in raw send / Invalid request / Null arguments
*/
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 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_trigger_sess_close(httpd_handle_t handle, int sockfd);
/**
* @brief Update timestamp for a given socket
*
* Timestamps 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
* timestamp is closed automatically.
*
* Updating the timestamp 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 timestamp
* is to be updated
*
* @return
* - ESP_OK : Socket found and timestamp updated
* - ESP_ERR_NOT_FOUND : Socket not found
* - ESP_ERR_INVALID_ARG : Null arguments
*/
esp_err_t httpd_sess_update_timestamp(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 /* ! _HTTP_SERVER_H_ */
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