Remove exposure of libcoap internals

Since the virtualization layer of EDDIE shouldn't know the actual implementation of the communication layer, exposing libcoap internals in the signature of the communication APIs was a mistake.

communication/include/CoapNode.h

@@ -12,6 +12,26 @@
 
 std::string get_local_node_ip();
 
+typedef enum {GET, POST, PUT, DELETE} coap_method;
+
+coap_method coap_method_from_s(const std::string& input);
+
+static std::string pdu_type_to_string(coap_pdu_type_t type);
+
+static std::string pdu_code_to_string(coap_pdu_code_t code);
+
+static const char *msg_option_string(uint8_t code, uint16_t option_type);
+
+static unsigned int
+print_content_format(unsigned int format_type, unsigned char *result, unsigned int buf_len);
+
+int is_binary(int content_format);
+
+static size_t print_readable(const uint8_t *data, size_t len, unsigned char *result,
+                             size_t buf_len, int encode_always);
+
+std::string pdu_to_string(coap_pdu_t *pdu);
+
 class CoapNode {
 private:
     CoapClient *client = nullptr;
@@ -32,10 +52,10 @@ public:
 
     std::string discover();
 
-    int send_message(coap_pdu_code_t method, const char *dst_ip, const char *dst_port,
+    int send_message(coap_method method, const char *dst_ip, const char *dst_port,
                      const char *dst_res, const char *query, const char *data);
 
-    coap_pdu_t *receive_message(int token, int max_timeout);
+    std::string receive_message(int token, int max_timeout);
 };
 
 #endif //EDDIE_COAPNODE_H