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/*! \file ELClientRest.h
\brief Definitions for ELClientRes
\author B. Runnels
\author T. von Eicken
\date 2016
*/
// Copyright (c) 2016 by B. Runnels and T. von Eicken
#ifndef _EL_CLIENT_REST_H_
#define _EL_CLIENT_REST_H_
#include <Arduino.h>
#include "FP.h"
#include "ELClient.h"
// Default timeout for REST requests when waiting for a response
#define DEFAULT_REST_TIMEOUT 5000 /**< Default timeout for REST requests when waiting for a response */
typedef enum {
HTTP_STATUS_OK = 200 /**< HTTP status OK response. */
} HTTP_STATUS;
// The ELClientRest class makes simple REST requests to a remote server. Each instance
// is used to communicate with one server and multiple instances can be created to make
// requests to multiple servers.
// The ELClientRest class does not support concurrent requests to the same server because
// only a single response can be recevied at a time and the responses of the two requests
// may arrive out of order.
// A major limitation of the REST class is that it does not store the response body. The
// response status is saved in the class instance, so after a request completes and before
// the next request is made a call to getResponse will return the status. However, only a pointer
// to the response body is saved, which means that if any other message arrives and is
// processed then the response body is overwritten by it. What this means is that if you
// need the response body you best use waitResponse or ensure that any call to ELClient::process
// is followed by a call to getResponse. Ideally someone improves this class to take a callback
// into the user's sketch?
// Another limitation is that the response body is 100 chars long at most, this is due to the
// limitation of the SLIP protocol buffer available.
class ELClientRest {
public:
ELClientRest(ELClient *e);
// Initialize communication to a remote server, this communicates with esp-link but does not
// open a connection to the remote server. Host may be a hostname or an IP address,
// security causes HTTPS to be used (not yet supported). Returns 0 if the set-up is
// successful, returns a negative error code if it failed.
int begin(const char* host, uint16_t port=80, boolean security=false);
// Make a request to the remote server. The data must be null-terminated
void request(const char* path, const char* method, const char* data=NULL);
// Make a request to the remote server.
void request(const char* path, const char* method, const char* data, int len);
// Make a GET request to the remote server with NULL-terminated data
void get(const char* path, const char* data=NULL);
// Make a POST request to the remote server with NULL-terminated data
void post(const char* path, const char* data);
// Make a PUT request to the remote server with NULL-terminated data
void put(const char* path, const char* data);
// Make a DELETE request to the remote server
void del(const char* path);
// Retrieve the response from the remote server, returns the HTTP status code, 0 if no
// response (may need to wait longer)
uint16_t getResponse(char* data, uint16_t maxLen);
// Wait for the response from the remote server, returns the HTTP status code, 0 if no
// response (timeout occurred). This is not recommended except for quick demos, use
// getResponse periodically instead.
uint16_t waitResponse(char* data, uint16_t maxLen, uint32_t timeout=DEFAULT_REST_TIMEOUT);
// Set the user-agent for all subsequent requests
void setUserAgent(const char* value);
// Set the Content-Type Header for all subsequent requests
void setContentType(const char* value);
// Set a custom header for all subsequent requests
void setHeader(const char* value);
private:
int32_t remote_instance; /**< Connection number, value can be 0 to 3 */
ELClient *_elc; /**< ELClient instance */
void restCallback(void* resp);
FP<void, void*> restCb; /**< Pointer to external callback function */
int16_t _status; /**< Connection status */
uint16_t _len; /**< Number of sent/received bytes */
void *_data; /**< Buffer for received data */
};
#endif // _EL_CLIENT_REST_H_