Add RPC API

src/rpc.h

@@ -0,0 +1,22 @@
+#pragma once
+#include "json.h"
+
+// JSON-RPC request descriptor
+struct mg_rpc_req {
+  struct mg_str frame;  // Request, e.g. {"id":1,"method":"add","params":[1,2]}
+  mg_pfn_t pfn;         // Response printing function
+  void *pfn_data;       // Response printing function data
+  void *fn_data;        // Endpoint handler data
+};
+
+void mg_rpc_add(void **head, struct mg_str method_pattern,
+                void (*handler)(struct mg_rpc_req *), void *handler_data);
+void mg_rpc_free(void **head);
+void mg_rpc_process(void **head, struct mg_str json, mg_pfn_t pfn, void *pfnd);
+
+// Helper functions to print result or error frame
+void mg_rpc_ok(struct mg_rpc_req *, const char *fmt, ...);
+void mg_rpc_vok(struct mg_rpc_req *, const char *fmt, va_list *ap);
+void mg_rpc_err(struct mg_rpc_req *, int code, const char *fmt, ...);
+void mg_rpc_verr(struct mg_rpc_req *, int code, const char *fmt, va_list *);
+void mg_rpc_list(struct mg_rpc_req *r);