add: basic relay structure

add: improved sql calls

helpers/create_sql_filtered_query.cc

@@ -0,0 +1,49 @@
+#include <helpers.h>
+#include <drogon/drogon.h>
+#include <globals.h>
+
+sqlite3_stmt*
+helpers::create_sql_filtered_query(const char *sql, sql_filter_builder **filters)
+{
+    char *old_query = (char*)sql;
+    char *new_query;
+
+    sql_filter_builder *filter;
+    int filter_count = 0;
+
+    do
+    {
+        filter = filters[filter_count];
+
+        filter_count++;
+        asprintf(&new_query, " %s %s=?%d %s", old_query, filter->col_name, filter_count, filter->logic);
+
+        if(old_query != sql)
+        {
+            free(old_query);
+        }
+        old_query = new_query;
+    } while(filter->logic[0] != ';');
+
+    sqlite3_stmt *stmt;
+
+    sqlite3_prepare_v2(globals::db, new_query, -1, &stmt, nullptr);
+
+    free(new_query);
+
+    for(int i = 0; i < filter_count; i++)
+    {
+        filter = filters[i];
+
+        if(filter->bind_func == (intptr_t)&sqlite3_bind_int)
+        {
+            sqlite3_bind_int(stmt, i + 1, (int)(intptr_t)filter->value);
+        }
+        if(filter->bind_func == (intptr_t)&sqlite3_bind_text)
+        {
+            sqlite3_bind_text(stmt, i + 1, (char*)filter->value, -1, SQLITE_STATIC);
+        }
+    }
+
+    return stmt;
+}